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394  DISSECTION    OF    THE    PERINiEUM. 

The  anterior  branch  (')  passes  under  the  transverse  muscle,  and  accom- 
panies the  other  to  the  scrotum..  Muscular  otlsets  are  furnished  by  it  to 
the  levator  ani  and  the  other  superficial  muscles. 

The  superficial  perinatal  branches  communicate  with  one  another,  and 
the  posterior  is  joined  by  the  inferior  pudendal  nerve.  At  the  scrotum 
they  are  distributed  by  long  slender  filaments,  which  reach  as  far  as  the 
under  surface  of  the  penis.  In  the  female  these  nerves  supply  the  labia 
pudendi. 

Other  muscular  branches  of  the  pudic  will  be  afterwards  examined  (p. 
399). 

The  inferior  pudendal  nerve  (*)  is  a  branch  of  the  small  sciatic.  It 
pierces  the  ftiscia  lata  about  one  inch  in  front  of  the  ischial  tuberosity,  and 
enters  beneath  the  superficial  fascia  of  the  perinaeum,  to  end  in  the  outer 
and  fore  parts  of  the  scrotum.  Communications  take  place  between  this 
nerve,  the  inferior  liaRmorrhoidal,  and  the  posterior  of  the  two  superficial 
perinaeal  branches.  In  the  female  the  inferior  pudendal  nerve  is  distri- 
buted to  the  labium. 

Dissection.  For  the  display  of  the  muscles,  the  fatty  layer,  as  well  as 
the  vessels  and  nerves  of  the  left  side,  must  be  taken  aw^ay  from  the  ante- 
rior half  of  the  perinaeal  space.  Afterwards  a  thin  subjacent  aponeurotic 
layer  is  to  be  removed  from  the  muscles.  Along  the  middle  line  lies  the 
ejaculator  urinae ;  and  in  cleaning  it  the  student  is  to  follow  two  fasciculi 
of  fibres  from  it  on  the  same  side — one  in  front,  the  other  behind.  On  the 
outer  part  of  the  space  is  the  erector  penis.  And  behind,  passing  obliquely 
between  the  other  two,  is  the  transverse  muscle. 

The  student  should  seek,  on  the  right  side,  the  branches  of  the  two 
superficial  perinaeal  nerves  to  the  underlying  muscles  ;  and  beneath  the 
transversalis,  an  offset  of  the  perinaeal  branch  which  supplies  the  deep 
muscles  and  the  urethra. 

Muscles  (fig.  130).  Superficial  to  the  triangular  ligament  in  the  ante- 
rior half  of  the  perinaeal  space,  are  three  muscles,  viz.,  the  erector  penis, 
the  ejaculator  urinae,  and  the  transversalis  perinaei.  Other  muscles  of  the 
urethra  are  contained  between  the  layers  of  the  triangular  ligament,  and 
will  be  subsequently  seen. 

Central  point  of  the  perinceum.  Between  the  urethra  and  the  rectum  is 
a  white  fibrous  spot,  to  which  this  term  has  been  applied.  It  occupies  the 
middle  line,  half  an  inch  in  front  of  the  anus.  In  it  the  muscles  acting  on 
the  rectum  and  the  urethra  are  united ;  and  it  serves  as  a  common  point 
of  support  to  the  space. 

The  ERECTOR  PENIS  (fig.  130,  ^)  is  the  most  external  of  the  three  mus- 
cles, and  is  narrower  at  each  end  than  in  the  middle.  It  covers  the  crus 
penis;  and  its  fibres  arise  horn,  the  ischial  tuberosity  farther  back  than  the 
attachment  of  the  penis,  and  from  the  bone  on  each  side  of  the  crus.  Su- 
periorly the  muscle  is  inserted  into  the  inner  and  outer  surfaces  of  the  crus 
penis.     It  rests  on  the  root  of  the  penis  and  the  bone. 

Action.  The  muscle  compresses  the  crus  penis  against  the  subjacent 
bone,  and  retards  the  escape  of  the  blood  from  that  organ  by  the  veins :  in 
that  way  it  will  contribute  to  the  continuance  of  distension. 

The  EJACULATOR  URiN^  muscle  (fig.  130,  ^)  lies  on  the  urethra.  The 
muscles  of  opposite  sides  unite  by  a  median  tendon  along  the  middle  line 
and  in  the  central  point  of  the  perinaeum  (origin).  The  fibres  are  directed 
outwards,  curving  around  the  convexity  of  the  urethra,  and  give  rise  to  a 
thin  muscle,  which  has  the  following  insertion: — The  most  posterior  fibres 


SUPERFICIAL    MUSCLES    OF    URETHRA.  395 

are  lost  on  the  front  of  the  triangular  ligament.  The  anterior  fibres,  which 
are  the  longest  and  best  marked,  are  inserted  into  the  penis  on  its  outer 
aspect  before  the  erector ;  and,  according  to  Kobelt,^  they  send  a  tendinous 
expansion  over  the  dorsal  vessels  of  the  penis.  Whilst  the  middle  or  in- 
tervening fibres  turn  round  the  urethra,  surrounding  it  for  two  inches,  and 
join  its  fellow  by  a  tendon. 

The  ejaculator  muscle  covers  the  bulb  and  the  urethra  for  three  inches 
in  front  of  the  triangular  ligament.^  If  the  muscle  be  cut  through  on  the 
right  side,  and  turned  off  the  urethra,  the  junction  with  its  fellow  above 
that  tube  will  be  apparent. 

Action.  The  two  halves,  actino;  as  one  muscle,  can  diminish  the  urethra, 
and  eject  forcibly  its  contents.  During  the  flow  of  fluid  in  micturition  the 
fibres  are  relaxed,  but  they  come  into  use  at  the  end  of  the  process,  when 
the  passage  has  to  be  cleared.  The  action  is  involuntary  in  the  emission 
of  the  semen. 

The  TRANSVERSALS  PERiN^T  (fig.  130,  ^)  is  a  small  thin  muscle,  which 
lies  across  the  perinjeum  opposite  the  base  of  the  triangular  ligament. 
Arising  fvov[\  the  inner  surface  of  the  pubic  arch  near  the  ischial  tuberosity, 
it  is  inserted  into  the  central  point  of  the  periniieum  with  the  muscle  of  the 
opposite  side,  and  with  the  sphincter  ani  and  the  ejaculator  urinas.  Be- 
hind this  muscle  the  superficial  fascia  bends  down  to  join  the  triangular 
ligament. 

Sometimes  there  is  a  second  small  fleshy  slip,  anterior  to  the  transver- 
salis,  which  has  been  named  transversalis  alter  ;  this  throws  itself  into  the 
ejaculator  muscle. 

Action.  From  the  direction  of  the  fibres  the  muscle  will  draw  back- 
wards the  central  point  of  the  perinjeum,  and  help  to  fix  it,  preparatory  to 
the  contraction  of  the  ejaculator. 

The  three  muscles  above  described,  when  separated  from  each  other  by 
the  dissection,  limit  a  triangular  space,  of  which  the  ejaculator  urinre 
forms  the  inner  boundary,  the  erector  penis  the  outer  side,  and  the  trans- 
versalis perinaei  muscle  the  base.  In  the  area  of  this  interval  is  the  trian- 
gular ligament  of  the  urethra,  with  the  superficial  perineeal  vessels  and 
nerves.  Should  the  knife  enter  the  posterior  part  of  this  space  during  the 
deeper  incisions  in  the  lateral  operation  of  lithotomy,  it  will  divide  the 
transverse  muscle  and  artery,  and  probably  the  superficial  perinaeal  vessels 
and  nerves. 

Dissection  (fig.  131).  For  the  display  of  the  triangular  ligament,  the 
muscles  and  the  crus  penis,  which  are  superficial  to  it,  are  to  be  detached 
in  the  following  way: — On  the  left  side  the  ejaculator  urinas  is  to  be  re- 
moved completely  from  the  front  of  the  ligament,  and  the  erector  muscle 
from  the  crus  of  the  penis.  Next,  the  crus  penis  is  to  be  detached  from 
the  bone ;  but  this  must  be  done  with  care  so  as  not  to  cut  the  triangular 
■  ligament,  nor  to  injure,  near  the  pubes,  the  terminal  branches  of  the  pudic 
artery  and  nerve  to  the  penis. 

On  the  right  side  the  dissector  should  trace  out  beneath  the  transversalis 

*  Die  Mannlichen  und  Weiblichen  Wollust-Organe,  von  G.  L.  Kobelt,  1844. 

2  Some  of  the  deeper  fibres  which  immediately  surround  the  bulb,  have  been 
described  as  a  separate  stratum  by  Kobelt.  These  are  separated  from  the  super- 
ficial layer  by  thin  areolar  tissue,  and  join  the  corresponding  part  of  the  other 
muscle  by  a  small  tendon  above  the  urethra.  The  name  compressor  hemisphcerium 
hulhi  has  been  proposed  for  it  by  that  anatomist. 


€ 


DEMONSTRATIONS 


ANATOMY; 


GUIDE  TO  THE  KNOWLEDGE  OP  THE  HUMAN  BODY 


DISSECTION. 


BY 


GEOEGE  YINER /ELLIS, 

EMERITUS  PROFESSOR  OP  ANATOMY  IN  UNIVERSITY  COLLEGE,  LOND'ON'. 


FROM  THE 


EIGHTH  AND  REVISED  ENGLISH  EDITION. 


ILLUSTRATED  BY  TWO  HUNDRED  AND  FORTY-NINE  ENGRAVINGS  ON  WOOD. 


/S7? 


PHIL/A  DELPHIA: 

HE\N"EY     0.    LEA 

1879. 


PREFACE 


The  plan  of  this  work  is  designed  to  teach  the  Anatomy  of  the 
Human  Body  by  dissection  in  successive  stages  after  the  following 
manner : — 

In  the  dissection  of  a  Part  the  attention  of  the  Student  is  directed 
first  to  the  superficial  prominences  of  bone  and  muscle,  and  to  the 
hollows  that  point  out  the  situation  of  the  subjacent  vessels.  Next 
the  cutaneous  structures,  and  the  different*  layers  of  muscles  with 
their  appertaining  vessels  and  nerves  are  examined  in  succession,  so 
that  the  several  objects  between  the  surface  of  the  Body  and  the 
bones  may  be  observed  in  much  the  same  order  as  they  would  be 
met  with  in  a  Surgical  operation.  And,  lastly,  the  joints  and  liga- 
ments receive  due  notice. 

In  the  dissection  also  of  the  viscera  and  the  organs  of  the  senses 
the  manner  in  which  the  composition  of  each  may  be  shown,  is  fully 
indicated  for  the  guidance  of  the  Student. 

The  Anatomical  description  of  the  Part  under  examination  is 
arranged  in  conformity  with  the  dissection  in  regions,  and  each 
muscle,  bloodvessel,  nerve,  or  other  structure,  is  described  only  to 
such  an  extent  as  it  may  be  laid  bare. 

Since  the  publication  of  the  last  edition  great  changes  have  been 
made  in  textural  Anatomy;  and  the  chief  of  these,  for  which  I  am 
indebted  to  Quain's  Anatomy,  I  have  introduced  into  my  account  of 
the  microscopic  structure  of  the  diflferent  organs. 

In  this  edition,  as  in  the  preceding  ones,  I  have  endeavored  to 
make  the  work  more  complete  by  the  correction  of  inaccuracies,  and 
to  render  it  morfe  efficient  as  a  guide  to  practical  work. 

G.  V.  ELLIS. 

October,  1878. 


CONTENTS 


CHAPTER  I. 


DISSECTION  OF  THE  HEAD  AND  NECK, 

Section  1.  External  Parts  of  tlie  Head 

2.  Internal  Parts  of  the  Head 

3.  The  Face       .... 

4.  The  Orbit      .... 

5.  The  Neck,  right  side 

Posterior  triangular  space 
Front  of  the  Neck 
Anterior  triangular  space 

6.  Pterygo-maxillary  Region    . 

7.  Submaxillary  Region 

8.  Superior  Maxillary  Nerve  and  Vessels 

9.  Deep  Vessels  and  Nerves  of  the  Neck 

10.  Left  side  of  the  Neck 

11.  The  Pharynx 

12.  The  Mouth    .     "*      . 

13.  Cavity  of  the  Nose  . 

14.  Spheno-palatine  and  Otic  Ganglia,  Facial 

Internal  Maxillary  Artery 

15.  The  Tongue  .... 

16.  The  Larynx  .... 

17.  Hyoid  Bone,  Cartilages  and  Ligaments  of  the  Larnyx,  Structure 

of  the  Trachea      .... 

18.  Prevertebral  Muscles  and  the  Vertebral  Vessels 

19.  Ligaments  of  the  first  two  Cervical  Vertebrae,  and  of  the  Clavicle 


and  Nasal  Nerves,  and 


PAGE 

17 

24 

34 

50 

61 

63 

67 

69 

87 

97 

103 

105 

118 

122 

132 

133 

138 
146 
151 

158 
163 
166 


CHAPTER  II. 

DISSECTION  OF  THE  BRAIN. 


Sectiox  1.  Membranes  and  Vessels 

2.  Origin  of  the  Cranial  Nerves 

3.  Medulla  Oblongata  and  Pons  Varolii 


172 
177 

182 


VI 

CONTENTS. 

PAGE 

Section  4. 

The  Cerebnim,  or  Great  Brain        .            .            .            .            .189 

The  under  surface,  or  the  Base 

.     190 

The  upper  surface  and  lobes    . 

.     193 

Convolutions    . 

.     195 

The  Interior 

.     199 

Ventricles  of  the  Brain 

.     200 

Floor  of  the  lateral  Ventricle  . 

.     203 

Central  Parts  of  the  Cerebrum 

.     205 

Structure  of  the  Cerebrum 

209 

5. 

The  Cerebellum,  or  little  Brain 
Surfaces  and  Lobes 

211 
212 

Structure  of  the  Mass  . 

215 

Fourth  Ventricle 

, 

217 

CHAPTER  III. 


DISSECTION  OF  THE  UPPER  LIMB. 


Section  1.  The  Wall  of  the  Thorax      .... 
The  Axillary  Space      .... 

2.  Scapular  Muscles,  Vessels,  Nerves,  and  Ligaments 

3.  The  Front  of  the  Arm  .... 

Back  of  the  Arm  .... 

4.  The  Front  of  the  Forearm  .... 

5.  The  Palm  of  the  Hand         .... 

6.  The  Back  of  the  Forearm    .... 

7.  Ligaments  of  the  Shoulder,  Elbow,  Wrist,  and  Hand" 


224 
228 
240 
248 
257 
260 
272 
282 
290 


CHAPTER  IV. 


DISSECTION  OF  THE  THORAX. 


Section  1.  Cavity  of  the  Thorax           ......  305 

The  Pleurae       .  .  .  .  .  .  .307 

Connections  of  the  Lungs         .....  308 

The  Pericardium           ......  310 

The  Heart  and  its  large  Vessels           ....  312 

Nerves  of  the  Thorax  ......  329 

The  Trachea  and  the  Characters  and  Structure  of  the  Lung  333 

•Parts  in  Front  of  the  Spine,  and  the  Cord  of  the  Sympathetic  336 

Parieties  of  the  Thorax            .....  342 

2.  Ligaments  of  the  Trunk      ......  343 

Articulation  of  the  Ribs  to  the  Vertebrae         .             .             .  343 

Articulation  of  the  Ribs  to  the  Sternum         .             .             .  346 

Articulations  of  the  Sternum  .....  346 

Articulations  of  the  Vertebrae               ....  346 


CONTENTS, 


vn 


CHAPTER  V. 

DISSECTION  OF  THE  BACK. 


First  Layer  of  Muscles  .... 

Second  Layer  of  Muscles 

Third  Layer  of  Muscles 

Fourth  Layer  of  Muscles  with  Vessels  and  Nerves 

Fifth  Muscular  Layer,  and  the  Sacral  Nerves 


PAGE 

354 

358 
359 
361 
369 


CHAPTER  VI. 

DISSECTION  OF  THE  SPINAL  CORD. 

Membranes  of  the  Cord  .... 

Roots  of  the  Spinal  Nerves  .... 
Vessels  of  the  Cord  ..... 
Form  and  Divisions  of  .the  Cord 

Structure  of  the  Cord,  and  the  deep  Origin  of  the  Nerves 
Intraspinal  Vessels         ..... 


374 

377 
379 
380 
382 
384 


CHAPTER  VII. 

DISSECTION  OF  THE  PERINEUM. 


Section  1.  Perinseum  of  the  Male 

Posterior  Half  of  the  Space 
Anterior  Half  of  the  Space 
Lateral  Operation  of  Lithotomy 
2.  Perinseum  of  the  Female 


386 
387 
391 
399 
400 


CHAPTER  YIII. 

DISSECTION  OF  THE  ABDOMEN. 

Section  1.  Wall  of  the  Abdomen  ......     404 

2.  Hernia  of  the  Abdomen       .  .  .  .  .  .420 

3.  Cavity  of  the  Abdomen        .  .  .  .  .  .430 

Connections  of  the  Viscera       .....  431 

Peritoneum  and  its  Folds          .....  435 

Mesenteric  Vessels,  and  Part  of  the  Sympathetic  Nerve         .  439 

Connections  of  the  Aorta  and  Vena  Cava        .             .             .  444 

Connections  of  the  Duodenum  and  Pancreas  .             .             .  445 

Coeliac  Axis  and  Vena  Portae    .....  446 

Sympathetic  and  Vagus  Nerves            ....  450 

4.  Anatomy  of  the  Abdominal  Viscera             ....  452 

The  Stomach      .  .  .  .  .  .  .452 

The  Small  Intestine      .  .  .  .  .  .456 

The  Large  Intestine      ......     461 


Vlll 


CONTENTS. 


Section  4.  Anatomy  of  the  Abdominal  Viscera — continued. 
The  Pancreas     . 
The  Spleen 
The  Liver 
The  Gall  Bladder 
The  Kidney  and  the  Ureter 
The  Suprarenal  Body    . 
The  Testis  and  the  Vas  Deferens 

5.  Diaphragm  with  Aorta  and  Vena  Cava 

Deep  Muscles  of  the  Abdomen 

6.  Lumbar  Plexus  and  the  Cord  of  the  Sympathetic  Nerve 


PAGE 

464 
465 
466 
472 
473 
478 
479 
484 
492 
495 


DISSECTION  OF  THE  PELVIS. 

Section  1.  Fascia  of  the  Cavity  and  the  Muscles  of  the  Pelvic  Outlet 

2.  Connections  of  the  Viscera  in  the  Male 

3.  Connections  of  the  Viscera  in  the  Female  . 

4.  Vessels  and  Nerves  of  the  Pelvis    . 

5.  Anatomy  of  the  Viscera  of  the  Male  .  .   . 

The  Prostate  (Hand  and  the  Seminal  Vesicles 
The  Urinary  Bladder     .... 
The  Urethra  and  the  Penis 
The  Rectum       ..... 

6.  Anatomy  of  the  Viscera  of  the  Female 

Genital  Organs  ..... 
The  Vagina        ..... 
The  Uterus         ..... 
Ovaries  and  Fallopian  Tubes    . 
Bladder,  Urethra,  and  Rectum 

7.  Internal  Muscles  of  the  Pelvis 

Articulations  of  the  Pelvis 


499 
503 
509 
513 
520 
521 
524 
526 
532 
533 
533 
535 
537 
539 
541 
542 
543 


CHAPTER  IX. 


DISSECTION  OF  THE  LOWER  LIMB. 

Section  1.  The  Front  of  the  Thigh       .  .  .  .        *    .  .552 

Femoral  Hernia  ......     559 

Scarpa's  Space  .......     563 

Deep  Muscles,  Vessels,  and  Nerves  on  the  Front  of  the  Thigh     565 
Deep  parts  on  the  inner  Side  of  the  Thigh      .  .  .574 

2.  The  Buttock,  or  the  Gluteal  Region  .  .  .  .581 

3.  The  Back  of  the  Thigh         .  .  .  .  .  .592 

The  Popliteal  Space       .             .  .             .             .             .593 

Hamstring  Muscles  and  Vessels  ....     597 

The  Hip-Joint   .             .             .  .             .             .             .600 

4.  The  Back  of  the  Leg            .             .  .            .             .            .     605 

5.  The  Sole  of  the  Foot             .             .  .             .             .             .614 

6.  The  Front  of  the  Leg  and  the  Dorsum  of  the  Foot              .             .     626 

7.  Ligaments  of  the  Knee,  Ankle,  and  Foot  ....     634 


CONTENTS. 


IX 


CHAPTER  X. 


DISSECTION    OF    THE    EYE. 


Sclerotic  Coat  and  Cornea 
Clioroid  Coat  and  Ciliary  Processes 
Ciliary  Muscle    . 
The  Iris 

Ciliary  Vessels  and  Nerves 
Chamber  of  the  Aqueous  Humor 
The  Retina  and  Jacob's  Membrane 
Vitreous  Body,  and  Hyaloid  Membrane 

the  Canal  of  Petit. 
Crystalline  Lens  and  its  Capsule 


with 


the  Suspensory  Ligament  and 


PAGE 

655 
659 
660 
661 
663 
663 
663 

66Q 
668 


CHAPTER  XI. 


DISSECTION    OF    THE    EAK. 


The  Auditory  Canal 

The  Tympanum,  with  its  Vessels  and  Nerves 
Ossicles  of  the  Tympanum  andftheir  Muscles 
The  Osseous  Labyrinth  of  the  Inner  Ear 

Vestibule     .... 

Semicircular  Canals 

Cochlea,  its  Septum  and  Passages 

Organ  of  Corti 
The  Membranous  Sacs,  or  Labyrinth    . 

Utricle  .  .  •  . 

Saccule 
Bloodvessels  of  the  Labyrinth  . 
Nerves  of  the  Cochlea  and  Membranous  Sacs 


. 

.  670 

. 

.  671 

and  Ligaments 

.  674 

. 

.  679 

.  679 

. 

.  680 

.  681 

. 

.  684 

.      . 

.  685 

. 

.  685 

. 

.  686 

.  687 

.      .      . 

.  687 

LIST  OF  ILLUSTRATIONS. 


FIG. 

1.  Extrinsic  muscles  of  the  ear  .  . 

2.  Cutaneous  nerves  and  arteries  of  the  scalp 

3.  Some  of  the  sinuses  of  the  skull 

4.  Cranial  nerves  in  the  base  of  the  skull 

5.  Muscles  of  the  nose 

6.  Muscles  of  the  mouth 

7.  Lateral  cartilages  of  the  nose 

8.  Muscles  on  the  outer  and  inner  surface  of  the  ear  cartilage 

9.  Cutaneous  branches  of  the  fifth  nerve  in  the  face 

10.  First  view  of  the  orbit 

11.  Second  view  of  the  orbit    . 

12.  Third  view  of  the  orbit 

13.  The  eyelids  and  lachrymal  apparatus 

14.  Part  of  the  posterior  triangle  of  the  neck 

15.  View  of  the  anterior  triangular  space  of  the  neck 

16.  A  vievv  of  the  common  carotid  and  subclavian  arteries 

17.  External  carotid  and  its  superficial  branches 

18.  Superficial  view  of  the  pterygoid  region 

19.  Ligaments  of  the  jaw — an  inner  view 

20.  A  view  of  the  interior  of  the  compound  temporo-maxillary  joint 

21.  Deep  view  of  the  pterygoid  region 

22.  Muscles  of  the  tongue        ..... 

23.  Deep  view  of  the  submaxillary  region 

24.  Diagram  of  the  upper  maxillary  nerve  and  its  branches 

25.  Deep  vessels  and  nerves  of  tlie  neck 

26.  Diagram  of  the  eighth  nerve         .... 

27.  Diagram  of  the  ending  of  the  lymj)h  duct  and  the  thoracic  duct  in  the 

veins        ..... 

28.  External  view  of  the  pharynx 

29.  Internal  view  of  the  pharynx 

30.  Muscles  of  the  soft  palate 

31.  Spongy  bones  and  meatuses  of  the  nasal  cavity 

32.  Magnified  vertical  section  of  the  mucous  membrane  of  the  nose 

33.  Nerves  of  the  septum  of  the  nose 

34.  Nerves  of  the  nose  and  palate 

35.  Nerves  joining  the  enlargement  of  the  facial  nerve 

36.  Inner  view  of  the  otic  ganglion     . 

37.  Muscles  on  the  surface  of  the  tongue 

38.  Intrinsic  muscles  of  the  tongue     . 

39.  Front  view  of  the  larynx  .... 

40.  Hinder  view  of  the  larynx 

41.  View  of  the  internal  muscles  of  the  larynx 


Xll 


LIST    OF    ILLUSTRATIONS 


FIG. 

42. 
43. 
44. 
45. 
46. 


48. 
49. 
50. 

51. 

52. 
53. 
54. 
55. 
56. 
57. 
58. 

59. 
60. 

61. 
62. 

63. 
64. 
65. 

66. 
67. 
68. 
69. 
70. 
71. 
72. 
73. 
74. 

75. 

76. 

77. 
78. 
79. 

80. 
81. 


Vocal  apparatus,  on  a  vertical  section  of  the  larynx 

Hyoid  bone  and  the  laryngeal  cartilages 

View  of  the  vocal  cords  and  crico- thyroid  ligaments 

Deep  muscles  of  the  front  of  the  neck  and  the  scaleni  muscles 

External  ligaments  in  front  between  the  atlas  and  axis  and  the  occipital 

bone         ...... 

External  ligaments  behind  between  the  atlas  and  axis  and  the  occipital 

bone         ........ 

Internal  ligament  between  occipital  bone  and  axis 

Internal  ligaments  between  the  occipital  bone  and  the  atlas  and  axis 

First  vertebra  with   the  odontoid  process   removed   from  the   socket 

formed  by  the  bone  and  the  transverse  ligament 
Ligaments  of  the  inner  end  of  the  clavicle,  and  of  the  cartilage  of  the 

second  rib  ....  . 

Arteries  at  the  base  of  the  brain  . 
Origin  of  the  cranial  nerves 

Anterior  view  of  the  medulla  oblongata  and  pons 
Hinder  view  of  the  medulla  oblongata     . 
Fibres  of  the  medulla,  pons,  and  crus  cerebri 
Fibres  of  the  lateral  tract  and  of  the  olivary  body 
Tranverse  section  of  the  medulla  oblongata  above  the  middle  of  the 

olivary  body        ..... 
Under  surface  of  the  brain 
Lobes  of  the  hemisphere,  and  convolutions  and  fissures  of  the  outer 

surface  of  the  brain        ..... 
View  of  the  orbital  lobule  and  the  central  lobe  of  the  brain 
Convolutions  and  fissures  on  the  inner  face  of  the  hemisphere  of  the 

brain       ........ 

View  of  the  lateral  ventricles  of  the  brain 
Second  view  of  the  dissection  of  the  brain 
Connection  posteriorly  between  the  cerebrum,  the  medulla  oblongata 

and  cerebellum  ....... 

Under  part  of  the  cerebellum,  seen  from  behind 

View  from  behind  of  the  under  surface  of  the  cerebellum 

View  of  the  third  and  fourth  ventricles  of  the  brain 

View  of  the  dissected  axilla  ..... 

Second  view  of  the  dissection  of  the  thorax 

Diagram  of  the  serratus  magnus  muscle  .... 

View  from  behind  of  the  attachments  of  the  triangularis  sterni  muscle 

View  of  the  subscapularis  and  the  surrounding  muscles 

View  of  the  muscles  of  the  dorsum  of  the  scapula,  and  of  the  circumflex 

vessels  and  nerve  ...... 

Ligaments  of  the  clavicle  and  scapula,  and  of  the  shoulder  joint 

Cutaneous  veins  and  nerves  at  the  bend  of  the  elbow     . 

Axillary  and  brachial  arteries  and  their  branches 

Muscles  and  deep  vessels  and  nerves  of  the  arm 

Dissection  of  the  dorsal  scapular  vessels  and  nerve,  and  of  the  triceps 

muscle  of  the  arm  .... 

Superficial  view  of  the  forearm     . 
Dissection  of  the  deep  layer  of  muscles  of  the  forearm,  and  of  the  vessels 

and  nerves  between  the  two  layers  of  muscles  of  the  forearm 


268 


LIST    OF    ILLUSTRATIONS, 


Xlll 


FIG. 

82. 
83. 

84. 


87. 


89. 
90. 
91. 
92. 

93. 

94. 

95. 
96. 
97. 


99. 
100. 
101. 
102. 
103. 

104. 

105. 
106. 
107. 

108. 
109. 
110a 
110b 
111. 
112. 
113. 
114. 

115. 
116. 
117. 
118. 
119. 


The  extensor  tendon  of  the  finger  with  its  accessory  muscles  and  the 

sheatli  of  the  flexor  tendons       ...... 

Dissection  of  the  superficial  vessels  and  nerves  of  the  palm  of  the  hand 

with  some  of  the  superficial  muscles      .... 
Deep  dissection  of  the  palm  of  the  hand  ... 

Three  palmar  interosseous  muscles  .... 

Four  dorsal  interosseous  muscles  .... 

Superficial  layer  of  muscles  on  the  back  of  the  forearm,  with  some  ves 

sols  ........ 

Dissection  of  the  deep  layer  of  muscles,  and  the  vessels  and  nerve  on 

the  back  of  tlie  forearm  ...... 

View  of  the  interior  of  the  shoulder-joint 

The  ligaments  of  the  elbow  joint,  and  the  shaft  of  the  radius  and  ulna 

View  of  the  orbicular  ligament  of  the  radius     . 

Front  view  of  the  articulations  of  the  wrist  joint,  and  carpal  and  me 

tacarpal  bones    ....... 

The  wrist  joint  opened  to  show  the  arch  formed  by  the  bones  of  the 

forearm  with  the  uniting  fibro-cartilage 
Articulations  of  the  carpal  bones  .... 

Posterior  ligaments  of  the  wrist,  and  carpal  and  metacarpal  bones 
Union  of  metacarpal  bone  and  first  phalanx 
Diagram  to  show  the  difi"erence  in  the  anterior  border  of  the  right  and 

left  lung  ....... 

Diagram  showing  the  position  of  the  heart  to  the  ribs  and  sternum 
Back  of  the  heart  with  the  coronary  sinus  and  its  veins 
Diagram  of  the  two  cavities  of  the  right  side  of  the  heart 
Diagram  of  the  two  cavities  of  the  left  side  of  the  heart 
Muscular  fibres  of  the  auricles    ..... 

A  diagram  of  the  arrangement  of  the  fibres  in  layers  in  the  left  ven 

tricle        ........ 

The  formation  of  the  septum  ventriculorum  by  the  fibres  of  both  ven 

tricles     ......... 

Arch  of  the  aorta  and  its  great  vessels   .... 

View  of  the  thoracic  duct,  and  the  intercostal  veins 

Scheme  to  illustrate  the  connection  between  the  spinal  and  sympathetic 

nerves     ........ 

Ligaments  of  the  ribs  and  vertebra         .... 

Anterior  common  ligament  of  the  bodies  of  the  vertebrje 

.  View  of  the  posterior  common  ligament  of  the  vertebrae  of  the  neck 

,  View  of  the  posterior  common  ligament  of  the  vertebrae  of  the  loin 

Intervertebral  substance  in  the  lumbar  region  ... 

Vertical  section  of  the  int,ervertebral  substance 

A  horizontal  cut  through  an  intervertebral  fibro-cartilage 

An  inner  view  of  the  neural  arches  of  the  vertebrae,  with  their  inter 

posed  ligaments  ...... 

Ligaments  of  the  processes  of  the  vertebrae,  and  of  the  ribs     . 
Muscles  of  the  back  .  .  . 

Part  of  the  third  layer  of  the  back-muscles 
Dissection  of  the  muscles  underneath  the  splenius 
Deep  dissection  of  the  back  of  the  neck 


273 


XIV 


LIST    OF    ILLUSTRATIONS 


FIG. 

120.  Dissection  of  sacral  nerves  ..... 

121.  Lower  end  of  the  dura  mater,  with  its  central  and  lateral  processes 

122.  View  of  the  membranes  of  the  spinal  cord 

123.  Roots  of  the  spinal  nerves  ..... 

124.  Membranes  of  the  spinal  cord  laid  open 

125.  A  section  of  the  spinal  cord,  to  show  its  composition,  and  its  divisions 

126.  Tlie  gray  substance  in  the  interior  of  tlie  spinal  cord    . 

127.  Intraspinal  arteries  in  the  loins  .... 

128.  Intraspinal  veins  in  the  loins       .... 

129.  A  view  of  the  dissection  of  the  rectal  half  of  the  perinaeum 

130.  Superficial  dissection  of  the  anterior  half  of  the  perinseum 

131.  Deep  dissection  of  the  perinaeum 

132.  The  symphysis  pubis  seen  from  behind  . 

133.  The  female  perinseum       ..... 

134.  The  muscles  of  the  female  perinseum 

135.  Dissection  of  the  first  lateral  muscle  in  the  wall  of  the  belly 

136.  Internal  oblique  muscle  of  the  abdominal  wall 

137.  The  lower  part  of  the  internal  oblique  with  the  Cremaster  muscle  and 

the  testicle  ...... 

138.  Dissection  of  the  third  lateral  muscle  in  the  wall  of  the  belly 

139.  Rectus  muscle  of  the  abdomen    .... 

140.  Dissection  for  inguinal  hernia      .... 

141.  View  of  the  parts  concerned  in  femoral  hernia  . 

142.  Connections  of  the  liver,  stomach,  spleen,  and  large  intestine 

143.  Superior  mesenteric  artery  and  its  branches 

144.  The  lower  mesenteric  artery,  and  the  aorta 

145.  View  of  the  coeliac  axis,  and  of  the  viscera  to  which  its  branches  are 

supplied  ...... 

146.  Vena  portae  and  the  veins  joining  it        . 

147.  Diagram  representing  the  arrangement  of  the  muscular  fibres  of  the 

stomach  ....... 

148.  Alveolar  depressions  of  the  mucous  membrane  of  the  stomach 

149.  Enlarged  representation  of  the  tubes  of  the  stomach     . 

150.  The. duodenum   opened   showing   the  valvulse   conniventes,  and  the 

opening  of  the  bile  duct  ..... 

151a.  Vessels  of  the  villi  in  the  mouse,  injected  by  Gerlach 
151b    Lacteals  and  plexus  of  vessels  in  two  villi,  injected  by  Teichman 
152a.  Patch  of  Peyer's  glands  four  times  enlarged    . 
152b.  Magnified  representation  of  an  injection  of  the  vessels  surrounding 

and  penetrating  the  follicles  in  a  patch  of  Peyer  in  the  rabbit 
153a.  A  piece  of  mucous  membrane  enlarged 
153b.  a  piece  of  mucous  membrane  enlarged  «  . 

154.  Magnified  view  of  the  mucous  membrane  of  the  duodenum 

155.  Interior  of  the  caecum  dried  and  laid  open 
156a.  Enlarged  view  of  *' a  solitary  gland"    . 
156b.  Enlarged  view  of  "  a  solitary  gland"    . 

157.  A  drawing  of  the  trabecular  structure  of  the  spleen  of  the  ox 

158.  Under  surface  of  the  liver  .... 

159.  A  magnified  representation  of  the  hepatic  cells  . 
160a..  Lobules  of  the  liver,  magnified 


PAGE 

372 
375 
375 


380 


LIST    OP    ILLUSTRATIONS 


XV 


FIG. 

160b.  Lobules  of  the  liver,  magnified  .... 

161.  Vessels  in  a  portal  canal,  and  the  lobules  of  the  liver  . 

162.  Gall-bladder  and  its  duct  ..... 

163.  Section  through  the  kidney  ..... 

164.  Plan  of  the  arrangement  of  the  uriniferal  tubes 

165.  Plan  of  contorted  urine  tubes  ending  in  Malpighlan  corpuscles 
166a.  Plan  of  the  vessels  connected  with  the  urine  tubes 
166b.  Plan  of  the  vessels  connected  with  the  urine  tubes 

167.  Vertical  section  of  the  suprarenal  body  .... 

168.  The  testis  with  the  tunica  vaginalis  laid  open    . 

169.  Vertical  and  horizontal  sections  of  the  testis     . 

170.  Under  surface  of  the  diaphragm     ...  .  . 

171.  Deep  view  of  the  muscles,  vessels,  and  nerves  of  the  abdominal  cavity 

172.  Dissection  of  the  lumbar  plexus  and  its  branches 

173.  Side  view  of  the  muscles  in  the  outlet  of  the  pelvis 

174.  Side  view  of  the  dissected  male  pelvis    .... 

175.  Side  view  of  the  female  pelvis     ..... 

176.  Dissection  of  the  internal  iliac  artery     .... 

177.  Dissection  of  the  sacral  nerves  and  plexus 

178.  View  of  the  under  part  of  the  bladder  with  the  vesiculae  seminales 

and  vasa  deferentia         ...... 

179.  Muscular  fibres  of  the  bladder,  prostate,  and  urethra   . 

180.  Section  through  the  bladder,  prostate,  and  urethra 

181.  View  of  the  lower  part  of  the  bladder  and  of  the  urethra  laid  open 

182.  View  of  the  fibres  of  the  case  of  the  corpus  cavernosum 

183.  Pectiniform  septum  of  the  penis  .... 

184.  Magnified  view  of  the  trabecular  structure  and  arteries  of  the  penis 

185.  RejDresentation  of  the  clitoris      ..... 

186.  Venous  plexuses  of  the  genital  organs  and  opening  of  the  vagina 

187.  Interior  of  the  uterus,  with  a  posterior  view  of  the  broad  ligamen 

and  the  uterine  appendages     ..... 

188.  Ovary  during  the  child-bearing  period  laid  open 

189.  Irregular  piece  of  cartilage  in  the  sacro-iliac  articulation 

190.  Sacro-sciatic  ligaments     ...... 

191.  Ligaments  of  the  symphysis  pubis,  thyroid  hole,  and  acetabulum 

192.  Cutaneous  nerves  on  the  front  of  the  thigh 

193.  Dissection  of  the  superficial  parts  of  the  thigh 

194.  Dissection  of  the  crural  sheath    ..... 

195.  Dissection  on  Scarpa's  triangular  space 

196.  Surface  view  of  the  front  of  the  thigh,  the  teguments  and  fascia  being 

removed  ....... 

197.  Deep  part  of  the  femoral  artery  and  its  branches,  with  muscles  of  the 

thigh         ........ 

198.  Deep  dissection  of  the  adductor  muscles  with  their  vessels  and  nerves 

199.  Superficial  view  of  the  buttock  of  the  left  side 

200.  Second  view  of  the  dissection  of  the  buttock 

201.  Third  view  of  the  dissection  of  the  buttock 

202.  View  of  the  popliteal  space         ..... 

203.  Dissection  of  the  back  of  the  thigh         .... 

204.  Fore  part  of  the  capsule  of  the  hip  joint  .  .  • 


PAGE 

470 
471 
473 

474 
476 
476 
477 
477 
479 
480 
482 
485 
488 
496 
501 
505 
511 
514 
519 


XVI 


LIST    OF    ILLUSTRATIONS, 


e  patella  thrown  down 


tilages 


attached 


and  the  met  a 


FIG. 

205.  Hinder  part  of  the  hip-joint  capsule? 

206.  Hip  joint  opened 

207.  First  view  of  the  back  of  the  leg 

208.  Second  view  of  the  back  of  the  leg 

209.  Deep  dissection  of  the  back  of  the  leg   . 

210.  First  view  of  the  sole  of  the  foot 

211.  Second  view  of  the  sole  of  the  foot 

212.  Third  view  of  the  sole  of  the  foot 

213.  Fourth  view  of  the  sole  of  the  foot 

214.  Cutaneous  nerves  of  the  front  of  the  leg  and  foot 

215.  Anterior  tibial  vessel  and  muscles 

216.  External  ligament  of  the  knee-joint 

217.  Internal  ligament  of  the  knee-joint      '  . 

218.  The  capsule  of  the  knee-joint  cut  across,  andtl 

to  show  the  named  folds  of  the  synovial  sac 

219.  Interarticular  ligaments  of  the  knee-joint 

220.  View  of  the  head  of  the  tibia  with  the  fibro-ca 

221.  Internal  lateral  ligament  of  the  ankle    . 

222.  External  lateral  ligament  of  the  ankle  . 

223.  View  of  the  dorsal  ligaments  of  the  tarsus 

224.  Plantar  ligaments  of  the  foot 

225.  View  of  the  inferior  ligaments  of  the  tarsal  bones 

226.  Dorsal  ligaments  uniting  the  tarsus  to  the  metatarsus 

tarsal  bones  to  each  other  behind 

227.  Diagram  of  a  horizontal  section  of  the  eyeball 

228.  Vertical  section  of  the  cornea 

229.  Inner  view  of  the  front  of  the  choroid  coat 

230.  Pigment  cells  of  the  eyeball 

231.  View  of  the  front  of  the  choroidal  coat  and  iris 

232.  Distribution  of  the  nerves  and  vessels  of  the  iris 

233.  Objects  on  the  inner  surface  of  the  retina 

234.  Magnified  vertical  section  of  the  retina 

235.  Enlarged  representation  of  the  parts  of  the  eyeball  on  one  side  opposit 

the  lens  ..... 

236.  A  representation  of  the  laminae  in  hardened  lens 

237.  Views  of  the  lens  fibres  after  Henle 

238.  Vertical  section  of  the  meatus  auditorium  and  tympanum 

239.  View  of  the  inner  wall  of  the  tympanum  enlarged 

240.  Inner  view  of  the  membrana  tympani  in  the  foetus 

241.  The  three  ossicles  of  the  tympanum 

242.  Plan  of  the  ossicles  in  position  in  the  tympanum 

243.  Jacobson's  nerve  in  the  tympanum 

244.  View  of  the  vestibule  obtained  by  cutting  away  the  outer  boundary 

of  a  foetus  ..... 

245.  Representation  of  the  semicircular  canals  enlarged 

246.  Section  through  the  cochlea 

247.  A  diagram  of  a  section  of  the  tube  of  the  cochlea  enlarged 

248.  Petrous  bone  partly  removed  to  show  the  membranous  labyrinth  in 

place      ...... 

249.  Distribution  of  nerves  to  the  membranous  labyrinth 


DEMONSTRATIONS  OF  ANATOMY, 


CHAPTEE  I. 

DISSECTION  OF  THE  HEAD  AND  NECK. 


Section  I. 

EXTERNAL  PARTS  OF  THE  HEAD. 

Directions.  In  the  dissection  of  the  head  and  neck,  the  student 
should  endeavor  to  learn  the  parts  described  in  the  first  fifty-one  pages, 
before  the  position  of  the  body  is  changed  ;  but  if  want  of  time  necessitates 
an  omission  of  some  part,  the  examination  of  the  facial  nerve  (p.  47)  can 
be  best  deferred  till  a  subsequent  stage.  The  orbit  on  one  side,  the  poste- 
rior triangular  space  on  both  sides  of  the  neck,  and  the  exterior  and  the 
interior  of  the  head,  should  be  examined  whilst  the  body  lies  in  its  first 
position  on  the  Back. 

Position.  The  student  begins  with  the  dissection  of  the  scalp  and  tlie 
muscles  of  the  ear.  To  obtain  the  best  position,  raise  the  head  to  a  suitable 
height,  and  turn  the  face  to  the  right  side.  On  the  left  side  the  muscles 
are  to  be  seen,  and  on  the  opposite  half  the  vessels  and  nerves  are  to  be 
displayed. 

Extrinsic  muscles  of  the  Ear.  Three  muscles  attach  the  ear  to 
the  side  of  the  liead.  Two  are  above  it,  one  elevating,  the  other  drawing 
it  forwards  ;  and  the  third,  a  retrahent  muscle,  is  behind  the  ear.  There 
are  other  special  or  intrinsic  muscles  of  the  cartilage  of  the  ear,  which 
will  be  afterwards  described. 

Dissection.  When  the  ear  has  been  drawn  down  by  hooks,  the  position 
of  the  upper  muscle  will  be  indicated  by  a  slight  prominence  between  it 
and  the  head  ;  and  the  muscular  fibres  may  be  laid  bare  by  means  of  the 
two  following  incisions,  made  no  deeper  than  the  skin  :  One  is  to  be  car- 
ried upwards  on  the  side  of  the  head,  for  about  three  inches,  along  the 
cutaneous  ridge  before  mentioned  ;  and  the  other,  about  the  same  length, 
is  to  be  directed  from  before  backwards  close  above  the  ear,  so  that  the 
two  may  join  at  a  right  angle.  On  carefully  raising  the  flaps  of  skin  from 
below  upwards,  and  removing  the  subjacent  tissue,  a  thin  fan-shaped 
muscular  layer  will  come  into  view — the  more  anterior  fibres  constituting 
the  attrahens,  and  the  posterior  the  attollens  aurem  muscle. 

On  drawing  forwards  the  ear  a  ridge  marks  the  situation  of  the  posterior 
muscle.  To  remove  the  integuments,  let  the  scalpel  be  drawn  about  an 
inch  behind  the  ear,  from  the  transverse  cut  above  as  far  as  to  a  level  with 
2 


18  DISSECTION    OF    THE    HEAD. 

the  lobule  of  the  ear,  and  then  forwards  below  the  lobule.  After  the  piece 
of  skin  included  by  those  cuts  has  been  reflected  towards  the  ear,  the 
retrahent  muscle  must  be  sought  beneath  the  subcutaneous  tissue ;  it 
consists  of  rounded  bundles  of  fibres,  and  is  stronger  and  deeper  than  the 
others. 

The  ATTRAiiENS  AUREM  (fig.  1,  ^^)  is  a  Small  fan-shaped  muscle,  and, 
arises  from  the  fore  part  of  the  aponeurosis  of  the  occipito-frontalis.  Its 
fibres  are  directed  backwards,  and  are  inserted  into  a  projection  on  the 
front  of  the  rim  of  the  ear.  Beneath  it  are  the  superficial  temporal  vessels 
and  nerve. 

The  ATTOLLENS  AUREM  (fig.  1 ,  ^^)  has  the  same  form  as  the  preceding, 
though  its  fibres  are  longer  and  better  marked.  Arising  also  from  the 
tendon  of  tlie  occipito-frontalis,  the  fibres  converge  to  their  insertion  into 
the  inner  or  cranial  surface  of  the  pinna  of  the  ear — into  an  eminence 
corresponding  with  a  fossa  (that  of  the  anti-helix)  on  the  opposite  aspect. 

The  RETRAiTENS  AUREM  (musculi  rctrahcntes,  Alb.,  fig.  1,  ")  consists 
of  two  or  three  roundish  but  separate  bundles  of  fibres,  which  are  stronger 
than  those  of  the  other  muscles.  The  bundles  arise  from  the  root  of  the 
mastoid  process,  and  pass  almost  transversely  forwards  to  be  inserted  by 
aponeurotic  fibres  into  the  lower  part  of  the  ear  (concha)  at  its  cranial 
aspect.  The  posterior  auricular  artery  and  nerve  are  in  contact  with  this 
muscle. 

Action.  The  three  preceding  muscles  will  move  the  outer  ear  slightly  in 
the  directions  indicated  by  their  names :  the  anterior  drawing  it  upwards 
and  forwards,  the  middle  one  upwards,  and  the  posterior  backwards. 

The  OCCIPITO-FRONTALIS  MUSCLK  (fig.  1,  ^)  covcrs  the  arch  of  the  skull, 
and  consists  of  an  anterior  and  a  posterior  fleshy  part,  with  an  intervening 
tendon. 

Dissection.  On  the  same  side  of  the  head  (the  left)  the  occipito-frontalis 
is  to  be  dissected.  To  bring  this  muscle  into  view,  a  cut  may  be  made 
along  the  middle  line  of  the  skull,  from  tlie  root  of  the  nose  to  the  occipital 
protuberance ;  and  it  may  be  connected  in  front  with  the  transverse  incision 
on  tlie  side  of  the  head.  The  flap  of  skin,  thus  marked  out,  is  to  be  raised 
with  the  subjacent  fat  from  before  back;  whilst  doing  this  the  dissector 
will  meet  first  with  the  anterior  fleshy  part  of  the  muscle,  next  with  a 
white  shining  thin  aponeurosis,  and  lastly  with  tlie  posterior  fleshy  belly 
towards  the  lateral  aspect  of  the  cranium.  Tlie  aponeurosis  of  the  muscle 
is  easily  taken  away  with  the  granular  fat  superficial  to  it ;  and  if  the 
under  surface  of  the  flap  of  integuments  presents  a  white  instead  of  a  yel- 
low appearance,  the  student  may  suspect  he  is  removing  that  aponeurosis. 

The  anterior  or  frontal  part  (^)  is  a  thin  muscular  layer  over  the  os 
frontis,  which  is  said  to  take  its  origin  below.  Along  the  line  of  the  eye- 
brow the  fibres  are  blended  with  the  following  muscles,  orbicularis  palpe- 
brarum, corrugator  supercilii,  and  pyramidalis  nasi  ;  and  tiiey  are  also 
fixed  to  the  subjacent  bone,  viz.,  to  the  os  nasi  internally,  and  to  the  outer 
angular  process  of  the  frontal  bone  externally  (Theile).  From  these  at- 
tachments the  fibres  are  directed  upwards  to  the  aponeurosis,  and  end  in  it 
rather  below  the  level  of  tiie  coronal  suture. 

The  posterior  or  occipital  part  (*)  is  stronger  than  the  anterior  ;  it  arises 
from  the  outer  half  or  two-thirds  of  the  upper  curved  line  of  the  occipital 
bone,  and  from  the  mastoid  portion  of  the  temporal  bone.  The  fibres  are 
about  one  inch  and  a  half  in  length,  and  ascend  to  the  aponeurosis. 

The  tendon^  or  epicranial  aponeurosis^  extends  over  the  upper  part  of 


OCCIPITO-FRONTALIS    MUSCLE. 


19 


the  cranium,  and  is  continuous  across  the  middle  line  with  the  same  struc- 
ture of  the  opposite  half  of  the  head.  On  the  side  it  gives  origin  to  the 
jiuricular  muscles  ;  and  a  thin  membrane  is  here  prolonged  from  it  over  the 
fascia  covering  the  temporal  muscle,  to  be  fixed  to  the  side  of  the  head. 


15.  Attollens  atirem. 

16.  Attraheas  aureni. 


Extrinsic  Mcsci.es  op  the  Ear. 

17.  Retrahens  aurem,  only  partly  seen. 


Posteriorly,  the  aponeurosis  is  attached  to  the  superior  curved  ridge  of  the 
occipital  bone  between  the  fleshy  parts  of  the  muscles  of  opposite  sides. 
Tiie  aponeurotic  expansion  is  closely  united  to  the  skin  ;  but  it  is  connected 
to  the  pericranium  only  by  a  loose  areolar  tissue  devoid  of  fat,  so  that  it 
moves  freely  over  the  skull. 

Superficial  to  the  occipito-frontalis  are  the  cutaneous  vessels  and  nerves 
of  the  scalp.  In  front  the  fleshy  fibres  of  opposite  sides  are  joined  above 
tlie  root  of  the  nose. 

Action,  When  the  anterior  belly  contracts  it  elevates  the  eyebrow, 
making  smooth  the  skin  at  the  root  of  the  nose,  and  wrinkling  transversely 
that  of  the  forehead  ;  and  continuing  to  contract,  it  draws  forward  the 
scalp.  The  posterior  belly  will  move  back  the  scalp  ;  and  the  bellies  acting 
in  succession  will  carry  tlie  hairy  scalp  forwards  and  backwards. 

Dissection.  After  the  removal  of  the  superior  auricular  muscles  and  the 
temporal  vessels,  together  with  the  epicranial  aponeurosis  and  its  lateral 
prolongation,  the  attachment  of  the  temporal  fascia  on  the  side  of  the  head 
may  be  seen. 

The  temporal  fascia  is  a  white,  shining  membrane,  which  is  stronger 
tiian  the  epicranial  aponeurosis,  and  gives  attachment  to  the  subjacent 
temporal  muscle.  Superiorly  it  is  inserted  into  the  curved  line  that  limits 
the  temporal  fossa  on  the  side  of  the  skull  ;  and  inferiorly,  where  it  is  nar- 
rower and  thicker,  it  is  fixed   to   the  zygomatic  arch.     By  its   cutaneous 


20  DISSECTION    OF    THE    HEAD. 

surface  the  fascia  is  in  contact  with  the  muscles  already  examined,  and 
with  the  superficial  temporal  vessels  and  nerves. 

An  incision  in  the  fascia,  a  little  above  the  zygoma,  will  show  it  to  con- 
sist there  of  two  layers,  whicli  are  fixed  to  the  edges  of  the  upper  border 
of  the  zygomatic  arch.  Between  the  layers  is  some  fatty  tissue,  with  a 
small  branch  of  the  superficial  temporal  artery,  and  a  slender  twig  of  the 
orbital  branch  of  the  superior  maxillary  nerve  with  its  artery. 

Dissection.  The  temporal  fascia  is  now  to  be  detached  from  the  skull, 
and  to  be  thrown  down  to  the  zygomatic  arch,  in  order  that  the  origin  of 
the  underlying  temporal  muscle  may  be  examined.  A  soft  areolar  tissue 
which  lies  beneath  it  near  the  zygoma  is  to  be  taken  away.  The  difference 
in  thickness  of  parts  of  the  fascia  will  be  evident. 

The  TEMPORAL  MUSCLE  is  laid  bare  only  in  part.  Wide  and  thin  above, 
it  becomes  narrower  and  thicker  at  the  lower  end.  The  muscle  arises 
from  the  temporal  fascia,  and  from  all  the  surface  of  the  impression  on  the 
side  of  the  skull,  which  is  named  the  temporal  fossa.  From  this  origin  tlie 
fibres  descend,  converging  to  a  tendon,  whicli  is  inserted  into  the  under 
surface  and  fore  part  of  the  coronoid  process  of  the  lower  jaw. 

On  the  cutaneous  surface  is  the  temporal  fascia,  with  tiie  parts  superfi- 
cial to  that  membrane ;  and  concealed  by  the  muscle  are  the  deep  tempo- 
ral vessels  and  nerves  which  ramify  in  it.  The  insertion  of  the  muscle 
underneath  the  zygomatic  arch  will  be  afterwards  followed. 

The  temporal  belongs  to  the  group  of  masticatory  muscles ;  and  its 
action  will  be  referred  to  with  the  description  of  the  pterygoid  region. 

Dissection.  For  the  dissection  of  the  vessels  and  nerves,  let  the  face 
be  now  turned  to  the  left  side,  and  let  an  incision  be  carried  along  the 
eyebrow  and  the  zygomatic  arch  to  a  little  behind  the  ear,  so  as  to  allow 
the  skin  on  the  right  half  of  the  head  to  be  reflected.  The  flap  of  skin 
is  to  be  raised  from  before  backwards,  but  the  subcutaneous  fat  should  be 
left  till  the  nerves  are  found. 

Behind  the  ear  the  skin  should  be  raised  as  on  the  other  side,  to  un- 
cover the  posterior  auricular  vessels  and  nerve. 

Along  the  eyebrow  seek  the  branches  of  vessels  and  nerves  which  come 
from  the  orbit  (fig.  2),  viz.,  the  supra-orbital  vessels  and  nerve  opposite 
the  middle,  and  the  supra-trochlear  nerve  and  frontal  vessels  near  the 
inner  part  of  the  orbit ;  they  lie  at  first  beneath  the  occipito-frontalis,  and 
the  muscular  fibres  must  be  cut  through  to  find  them. 

On  the  side  of  the  head,  in  front  of  the  ear,  the  superficial  temporal 
vessels  and  nerve  are  to  be  traced  to  the  vertex ;  and  above  the  zygomatic 
arch  the  branches  of  the  facial  which  join  an  offset  (^*')  of  the  superior 
maxillary  nerve,  are  to  be  sought. 

Behind  the  ear  the  posterior  auricular  vessels  and  nerve,  and  below  it 
branches  from  the  great  auricular  nerve  to  the  tip  and  back  of  tiie  ear,  are 
to  be  found  ;  one  or  more  offsets  of  the  last  should  be  followed  to  their 
junction  with  the  posterior  auricular  nerve. 

At  the  back  of  the  head  the  ramifications  of  the  occipital  vessels,  also 
the  large  and  small  occipital  nerves,  should  be  denuded  ;  the  former  nerve 
lies  by  the  side  of  tlie  artery,  and  the  latter  about  midway  between  this 
vessel  and  the  ear. 

Cutaneous  Arteries.  The  arteries  of  the  scalp  (fig.  2),  are  fur- 
nished by  the  internal  and  external  carotid  trunks,  and  anastomose  freely 
over  the  side  of  the  head.     Only  two  small  branches,  the  supra-orbital 


CUTANEOUS    NERVES.  21 

and  frontal,  come  from  the  former ;  whilst  three,  viz.,  the  temporal,  occi- 
pital, and  posterior  auricular,  belong  to  the  latter. 

The  supra-orbital  artery  (c)  leaves  the  orbit  throucrh  the  notch  in  the 
margin  of  the  orbit,  and  is  distributed  on  the  forehead.  Some  of  its 
branches  are  superficial  to  the  occipito-frontalis,  and  ascend  to  the  top  of 
the  head  ;  whilst  others  lie  beneath  the  muscle,  and  supply  it,  the  peri- 
cranium, and  the  bone. 

The  frontal  branch  (b)  is  close  to  the  inner  angle  of  the  orbit,  and  is 
much  smaller  than  tlie  preceding.  It  ends  in  branches  for  the  supply  of 
the  muscles,  integuments,  and  pericranium. 

The  superficial  temporal  artery  {d)  is  one  of  the  terminal  branches  of 
the  external  carotid.  After  ascending  above  the  zygomatic  arch  for 
about  two  inches,  the  vessel  divides  on  the  temporal  fascia  into  anterior 
and  posterior  : — 

The  anterior  branch  runs  forwards  with  a  serpentine  course  to  the  fore- 
head, supplying  muscular,  cutaneous,  and  pericranial  offsets,  and  anasto- 
moses with  the  supra-orbital  artery  :  this  is  the  branch  that  is  opened 
when  blood  is  taken  from  the  temporal  artery. 

The  posterior  branch  is  larger  than  the  other,  and  arches  backwards 
above  the  ear  towards  the  occipital  artery,  with  which  it  anastomoses. 
Its  offsets  to  the  parts  around  are  similar  to  those  of  the  anterior,  and  it 
communicates  with  the  artery  of  the  opposite  side  over  the  top  of  the 
liead. 

Occipital  artery  (a).  The  terminal  part  of  this  artery,  after  perforat- 
ing the  trapezius,  divides  into  large  and  tortuous  branches,  which  spread 
over  the  back  of  the  head  and  the  occipito-frontalis  muscle.  Communi- 
cations take  place  with  the  artery  of  the  opposite  side,  with  the  posterior 
part  of  the  temporal,  and  with  the  following  artery.  Some  offsets  pass 
deeply  to  supply  the  occipito-frontalis  muscle,  the  pericranium,  and  the 
bone. 

The  posterior  auricular  artery  ( f)  appears  in  front  of  the  mastoid 
I)rocess,  and  divides  into  two  branches.  One  (mastoid)  is  directed  back- 
wards to  supply  the  occipito-frontalis,  and  anastomose  with  the  occipital 
artery.  The  other  (auricular)  is  furnished  to  the  retrahent  muscle  and 
tlie  back  of  the  pinna  of  the  ear ;  and  an  offset  from  this  pierces  the  pinna 
to  be  distributed  on  the  opposite  surface. 

The  VEINS  of  the  exterior  of  the  head  are  so  similar  to  the  arteries, 
that  a  full  notice  of  each  is  not  required.  All  the  veins  corresponding 
with  branches  of  the  internal  carotid  artery  enter  the  facial  vein,  whilst 
the  rest  open  into  the  jugular  veins.  These  superficial  veins  communi- 
cate both  with  the  sinuses  in  the  interior  of  the  skull  by  means  of  small 
branches  named  emissary,  and  with  the  veins  occupying  the  spongy  sub- 
stance (diploe)  of  the  cranial  bones. 

'The  frontal  vein  is  directed  towards  the  inner  angle  of  the  orbit,  where 
it  receives  the  supra-orbital  vein,  the  two  giving  rise  to  the  angular  vein 
of  the  face  :  near  its  ending  it  receives  small  veins  from  the  eyebrow,  and 
from  the  upper  eyelid  and  the  nose.  Both  the  superficial  temporal  and 
posterior  auricular  veins  open  into  the  external  jugular;  and  the  occipital 
joins  the  internal  jugular  vein. 

Cutaneous  Nerves  (fig.  2).  The  nerves  of  the  scalp  are  furnished 
from  cutaneous  offsets  of  both  cranial  and  spinal  nerves.  The  half  of  the 
head  anterior  to  the  ear  receives  branches  from  three  trunks  Oi"  the  fifth 
cranial  nerve,  and  a  few  twigs  from  the  facial  nerve.     All  the  rest  of  the 


22 


DISSECTION    OF    THE    HEAD. 


head  is  supplied  by  spinal  nerves  (anterior  and  posterior  primary  branches), 
except  close  behind  the  ear,  where  there  is  an  offset  of  the  I'acial  or  seventh 
cranial  nerve. 

The  stipra-orhital  nerve  (fig.  2,  *)  comes  from  the  first  trunk  of  the 
fifth  nerve,  and  escapes  from  tlie  orbit  with  its  companion  artery ;  whilst 


Fig.  2. 


COTAUEOUS  Nerves  of  the  Scalp. 

5.  Supra-trochlear. 


1.  Great  auricular  nerve. 

2.  Small  occipital. 
.3.  Great  occipital. 
4,  I'osteiior  auricular  of  the  facial. 

Auriculo-temporal  (not  nuniberod)  in  front 
of  the  ear,  by  the  side  of  the  temporal  ar- 
tery, d. 

Cutaneous  Arteries  of  the  Scalp. 

d.  Superficial  temporal 


6.  Supra-orbital. 
10.  Superficial  temporal  of  the  upper  maxil- 
lary, and  crossing  it  are  the  superficial 
temporal  brandies  of  the  temporal  nerve. 


n.  Occipital  artery, 

h.   Frontal. 

c.   Supra-orbital. 


/.    Posterior  auricular. 

h.  Lateral  superficial  temporal. 


beneath  the  occipito-frontalis  muscle,  the  nerve  gives  offsets  to  it  and  tlie 
orbicularis  palpebrarum,  as  well  as  to  the  pericranium.     In  the  orbicularis 


CUTANEOUS    NERVES.  23 

a  communication  is  established  between  this  and  the  facial  nerve.  Fi- 
nally the  nerve  ends  in  two  cutaneous  branches,  which  ramify  in  the  tegu- 
ments : — 

One  of  these  (inner)  soon  pierces  the  occipito-fron talis,  and  reaches 
upwards  as  high  as  the  parietal  bone.  The  other  branch  (outer)  is  of 
larger  size,  and,  perforating  the  muscle  higher  up,  extends  over  the  arch 
of  the  head  as  far  as  the  ear. 

As  the  nerve  escapes  from  the  supra-orbital  notch  it  furnishes  some 
palpebral  filaments  to  the  upper  eyelid. 

At  the  inner  angle  of  the  orbit  is  the  small  supra-trochlear  branch 
(fig.  2,  ^)  of  the  same  nerve.  It  ascends  to  the  forehead  close  to  the 
bone,  and  piercing  the  muscular  fibres  ends  in  the  integument.  Branches 
are  given  from  it  to  the  orbicularis  and  corrugp.tor  supercilii,  and  some 
palpebral  twigs  enter  the  eyelid. 

The  superficial  temporal  nerves  are  derived  from  the  second  and  third 
trunks  of  the  fifth  nerve,  and  from  the  facial  nerve. 

The  temporal  branch  of  the  superior  maxillary  nerve  (second  trunk  of 
the  fifth)  is  usually  a  slender  twig  (fig.  2,  ^®),  which  perforates  the  tempo- 
ral aponeurosis  about  a  finger's  breadth  above  the  zygomatic  arch.  When 
cutaneous,  the  nerve  is  distributed  on  the  temple,  and  communicates  with 
the  facial  nerve,  also  sometimes  with  the  next. 

The  auricula-temporal  branch  (fig.  2  d)  of  the  inferior  maxillary  nerve 
(third  trunk  of  tlie  fifth)  lies  near  the  ear,  and  accompanies  the  temporal 
artery  to  the  top  of  the  head.  As  soon  as  the  nerve  emerges  from  beneath 
the  parotid  gland,  it  divides  into  two  terminal  branches : — The  more  pos- 
terior is  the  smaller  of  the  two,  and  supplies  the  attrahens  aurem  muscle 
and  the  integument  above  the  ear.  The  other  branch  ascends  vertically 
in  the  teguments  to  the  top  of  the  head.  The  nerve  also  furnishes  an 
auricular  branch  (upper)  to  the  anterior  part  of  the  ear  above  the  audi- 
tory meatus. 

The  temporal  branches  of  the  facial  nerve  are  directed  upwards  over 
the  zygomatic  arch  and  the  temporal  aponeurosis  to  the  orbicularis  palpe- 
brarum muscle  :  they  will  be  described  with  the  dissection  of  the  trunk  of 
the  facial  nerve. 

The  posterior  auricular  nerve  (fig.  2,  *)  lies  behind  the  ear  with  th(; 
artery  of  tlie  same  name.  It  arises  from  the  facial  nerve  close  to  the 
stylo-mastoid  foramen,  and  ascends  in  front  of  the  mastoid  process.  Soon 
after  the  nerve  becomes  superficial  it  comm^unicates  with  the  great  auri- 
cular nerve,  and  divides  into  an  occipital  and  an  auricular  branch,  which 
are  distributed  as  their  names  express : — 

The  occipital  branch  is  long  and  slender,  and  ends  in  the  posterior 
belly  of  the  occipito-fron  talis  muscle.  It  lies  near  the  occipital  bone, 
enveloped  in  dense  fibrous  structure,  and  furnishes  ofl^'sets  to  the  integu- 
ments. 

The  auricular  branch  ascends  to  the  back  of  the  ear,  supplying  the 
retrahent  muscle  and  tlie  posterior  surface  of  the  pinna. 

The  great  auricular  nerve  of  the  cervical  plexus  (fig.  2,  ^)  is  seen  to 
some  extent  at  the  lower  part  of  the  ear,  but  its  anatomy  will  be  after- 
wards given  with  the  description  of  the  cervical  plexus. 

The  great  occipital  (fig.  2,  ^)  is  the  largest  cutaneous  nerve  at  the  back 
of  the  head,  and  is  recognized  by  its  proximity  to  tlie  occipital  artery. 
Springing  from  the  posterior  primary  branch  of  the  second  cervical  nerve, 
it  perforates  the  muscles  of  the  back  of  the  neck,  and  divides  on  the  occi- 


24  DISSECTION    OF    THE    HEAD. 

put  into  numerous  large  offsets ;  these  spread  over  the  posterior  part  of 
the  occipito-frontalis  muscle,  ending  mostly  in  the  integument.  As  soon 
as  the  nerve  pierces  the  trapezius,  it  is  joined  by  an  offset  from  the  third 
cervical  nerve  ;  and  on  the  back  of  the  head  it  communicates  with  the 
small  occipital  nerve. 

The  small  occipital  nerve  of  the  cervical  plexus  (fig.  2,  '^)  lies  midway 
between  the  ear  and  the  preceding  nerve,  and  is  continued  upwards  in  the 
integuments  higher  than  the  level  of  the  ear.  It  communicates  with  the 
nerve  on  each  side,  viz.,  the  posterior  auricular  and  the  great  occipital. 
Usually  this  nerve  furnishes  an  auricular  branch  to  the  upper  part  of  the 
ear  at  the  cranial  aspect,  which  supplies  also  the  attoUens  aurem  muscle. 


Section  II. 

INTERNAL  PARTS  OF  THE  HEAD. 


Dissection.  The  skull  is  now  to  be  opened,  but  before  sawing  the  bone 
the  dissector  should  detach,  on  the  right  side,  the  temporal  muscle  nearly 
down  to  the  zygoma,  without  separating  the  fascia  of  the  same  name  from 
the  fleshy  fibres ;  and  all  the  remaining  soft  parts  are  to  be  divided  by  an 
incision  carried  around  the  skull,  about  one  inch  above  the  margin  of  the 
orbit  at  the  forehead,  and  as  low  as  the  protuberance  of  the  occiput. 

The  cranium  is  to  be  sawn  in  the  same  line  as  the  incision  through  the 
soft  parts,  but  the  saw  is  to  cut  only  through  the  outer  osseous  plate.  The 
inner  plate  is  to  be  broken  through  with  a  chisel,  in  order  that  tlie  subja- 
cent membrane  of  the  brain  (dura  mater)  may  not  be  injured.  The  skull- 
cap is  next  to  be  forcibly  detached  by  inserting  the  fingers  between  the 
cut  surfaces  in  front,  and  the  dura  mater  will  then  come  into  view. 

The  DURA  MATER  is  the  most  external  of  the  membranes  investing  the 
brain.  It  is  a  strong,  fibrous  structure,  which  serves  as  an  endosteum  to 
the  bones,  and  supports  the  cerebral  mass.  Its  outer  surface  is  rough, 
and  presents,  now  the  bone  is  separated  from  it,  numerous  small  fibrous 
and  vascular  processes ;  but  these  are  most  marked  along  the  line  of  the 
sutures,  where  the  attachment  of  the  dura  mater  to  the  bone  is  the  most 
intimate.  Ramifying  on  the  upper  part  of  the  membrane  are  branches  of 
the  large  meningeal  vessels. 

Small  granular  bodies,  glands  of  Pacchioni,  are  also  seen  along  the 
middle  line.  The  number  of  these  bodies  is  very  variable  ;  they  are  found 
but  seldom  before  the  third  year,  but  generally  after  the  seventh,  and 
they  increase  with  age.  Occasionally  the  surface  of  the  skull  is  indented 
by  these  so-called  glands. 

Dissection.  For  the  purpose  of  seeing  the  interior  of  the  dura  mater, 
divide  this  membrane  with  a  scissors  close  to  the  margin  of  the  skull, 
except  in  the  middle  line  before  and  behind  where  tlie  superior  longitudi- 
nal sinus  lies.  The  cut  membrane  is  then  to  be  raised  towards  the  top  of 
the  head ;  and  on  the  right  side  the  veins  connecting  it  with  the  brain 
may  be  broken  through. 

The  inner  surface  of  the  dura  mater  is  smooth  and  polished  ;  and  this 
appearance  is  due  to  an  epithelial  layer  similar  to  that  lining  serous 
membranes. 


REMOVAL    OF    BRAIN.  25 

This  external  envelope  of  the  brain  consists  of  white  fibrous  and  elastic 
tissues  so  disposed  as  to  give  rise  to  two  strata,  viz.,  an  external  or  en- 
dosteal, and  an  internal  or  supporting.  At  certain  spots  those  layers  are 
slightly  separated,  and  form  thereby  the  spaces  or  sinuses  for  the  passage 
of  the  venous  blood.  Moreover,  the  innermost  layer  sends  processes  be- 
tween different  parts  of  the  brain,  forming  the  falx,  tentorium,  etc. 

The  falx  cerebri  is  the  process  of  the  dura  mater,  in  shape  like  a  sickle, 
which  dips  in  the  middle  line  between  the  hemispheres  of  the  large  brain. 
Its  form  and  extent  will  be  evident  if  the  right  half  of  the  brain  is  gently 
separated  from  it.  Narrow  and  pointed  in  front,  where  it  is  attached  to 
the  crista  galli  of  the  ethmoid  bone,  it  widens  posteriorly,  and  joins  a 
horizontal  piece  of  the  dura  mater  named  the  tentorium  cerebelli.  The 
upper  border  is  convex,  and  is  fixed  to  the  middle  line  of  the  skull  as  far 
backwards  as  the  occipital  protuberance ;  and  the  lower  or  free  border, 
concave,  is  turned  towards  the  central  part  of  the  brain  (corpus  callosum), 
with  which  it  is  in  contact  posteriorly. 

In  this  fold  of  the  dura  mater  are  contained  the  following  sinuses  : — the 
superior  longitudinal  along  the  convex  border,  the  inferior  longitudinal  in 
the  hinder  part  of  the  lower  edge,  and  the  straight  sinus  at  the  line  of 
junction  between  it  and  the  tentorium. 

The  superior  longitudinal  sinus  (fig.  3,  5)  extends  from  the  ethmoid 
bone  to  the  occipital  protuberance.  Its  position  in  the  convex  border  of 
the  falx  will  be  made  manifest  by  the  escape  of  blood  through  numerous 
small  veins,  when  pressure  is  made  from  before  back  with  the  finger  along 
the  middle  line  of  the  brain. 

When  the  sinus  is  opened  it  is  seen  to  be  narrow  in  front,  and  to  widen 
behind,  where  it  ends  in  a  common  point  of  union  of  certain  sinuses  (tor- 
cular  Herophili)  at  the  centre  of  the  occipital  bone.  Its  cavity  is  trian- 
gular in  form,  with  the  apex  of  the  space  turned  to  the  falx  ;  and  across  it 
are  stretched  small  tendinous  cords — chordae  Willisii — near  the  openings 
of  some  of  the  cerebral  veins.  Occasionally  small  glandulae  Pacchioni  are 
present  in  the  sinus. 

The  sinus  receives  small  veins  from  the  substance  and  exterior  of  the 
skull,  and  larger  ones  from  the  brain  ;  and  the  blood  flows  backw^ards  in 
it.  The  cerebral  veins  open  chiefly  at  the  posterior  part  of  the  brain,  and 
lie  for  some  distance  against  the  w^all  of  the  sinus  before  they  perforate  the 
dura  mater ;  tlieir  course  is  directed  from  behind  forwards,  so  that  the 
current  of  the  blood  in  them  is  evidently  opposed  to  that  in  the  sinus  :  this 
disposition  of  the  veins  may  be  seen  on  the  left  side  of  the  brain,  where 
the  parts  are  undisturbed. 

Directions.  Before  tlie  rest  of  the  dura  mater  can  be  examined,  the 
brain  must  be  taken  from  the  head.  To  facilitate  its  removal,  let  the 
head  incline  backwards,  whilst  the  shoulders  are  raised  on  a  block,  so  that 
the  brain  may  be  separated  somewhat  from  the  base  of  the  skull.  For  the 
division  of  the  cranial  nerves  a  sharp  scalpel  will  be  necessary ;  and  the 
nerves  are  to  be  cut  longer  on  the  one  side  than  on  the  other. 

Removal  of  the  brain.  As  a  first  step  cut  across  the  anterior  part  of 
the  falx  cerebri,  and  the  different  cerebral  veins  entering  the  longitudinal 
sinus  ;  raise  and  throw  backwards  the  falx,  but  leave  it  uncut  in  the 
middle  line  behind.  Gently  raise  with  the  fingers  the  frontal  lobes  and 
the  olfactory  bulbs  of  the  large  brain.  Next  cut  through  the  internal  car- 
otid artery  and  the  second  and  third  nerves,  wiiich  then  appear;  the  large 
second  nerve  is  placed  on  the  inner,  and  the  round  third  nerve  on  the 


26  DISSECTION    OF    THE    HEAD. 

outer  side  of  the  artery.  A  small  branch  of  artery  to  the  orbit  sliould 
likewise  be  divided  at  this  time. 

Tlie  brain  is  now  to  be  supported  in  the  left  hand,  and  the  pituitary  body 
to  be  dislodged  wMtii  the  knife  from  the  hollow  in  the  centre  of  the  sphe- 
noid bone.  A  strong  horizontal  process  of  the  dura  mater  (tentorium  cere- 
belli)  comes  into  view  at  the  back  of  the  cranium.  Along  its  free  margin 
lies  the  small  fourth  nerve,  wiiich  is  to  be  cut  at  this  stage  of  the  proceed- 
ing. Make  an  incision  through  the  tentorium  on  each  side,  close  to  its 
attachment  to  the  temporal  bone,  without  injuring  the  parts  underneath  ; 
the  following  nerves,  which  will  be  then  visible,  are  to  be  divided  in  suc- 
cession. Near  the  inner  margin  of  the  tentorium  is  the  fifth  nerve,  consist- 
ing of  a  large  and  small  root;  whilst  towards  the  middle  line  of  the  skull 
is  the  long  slender  sixth  nerve.  Below  the  fifth,  and  somewhat  external 
to  it,  is  the  seventh  nerve  with  its  facial  and  auditory  parts,  the  former 
being  anterior  and  the  smaller  of  the  two.  Directly  below  the  seventh  are 
the  three  trunks  of  the  eighth  nerve  in  one  line : — of  these,  the  upper 
small  piece  is  the  glosso- pharyngeal ;  the  flat  band  next  below,  the  pneu- 
mogastric  ;  and  the  long  round  nerve  ascending  from  the  spinal  canal,  the 
spinal  accessory.  The  remaining  nerve  nearer  the  middle  line  is  the  ninth, 
which  consists  of  two  small  pieces. 

After  dividing  the  nerves,  cut  through  the  vertebral  arteries  as  they 
wind  round  the  upper  part  of  the  spinal  cord.  Lastly,  cut  across  the 
spinal  cord  as  low  as  possible,  as  well  as  the  roots  of  the  spinal  nerves  that 
are  attached  on  each  side.  Then  on  placing  the  first  two  fingers  of  the 
right  hand  in  the  spinal  canal,  the  cord  may  be  raised,  and  the  whole  brain 
may  be  taken  readily  from  the  skull  in  the  left  hand. 

Preservation  of  the  hrain.  After  removing  some  of  the  membranes 
from  the  upper  part,  and  making  a  few  apertures  through  them  on  the 
under  surface,  the  brain  may  be  immersed  in  spirit  to  harden  the  texture  ; 
and  methylated  spirit  may  be  used  on  account  of  its  cheapness.  Placing 
the  brain  upside  down  on  a  piece  of  calico  long  enough  to  Avrap  over  it, 
put  it  in  the  spirit. 

Examination  of  the  hrain.  At  the  end  of  two  or  three  days  the  dissec- 
tor should  examine  the  other  membranes,  and  the  vessels.  As  soon  as  the 
vessels  have  been  learnt,  the  membranes  are  to  be  carefully  removed  from 
the  surface  of  tiie  brain,  without  detaching  the  different  cranial  nerves  at 
the  under  surface.  The  brain  may  remain  in  the  spirit  till  the  dissection 
of  the  head  and  neck  has  been  completed,  but  it  should  be  turned  over 
occasionally  to  allow  the  spirit  to  penetrate  its  substance. 

The  description  of  the  brain  and  its  vessels  will  be  found  after  that  of 
the  head  and  neck. 

Directions.  After  setting  aside  the  brain,  the  anatomy  of  the  dura  mater, 
and  tlie  vessels  and  nerves  in  the  base  of  the  skull  should  be  proceeded 
with.  For  this  purpose  raise  the  head  to  a  convenient  height,  and  fasten 
the  tentorium  in  its  natural  position  with  a  few  stitches.  The  dissector 
should  be  furnished  with  the  base  of  a  skull  while  studying  the  following 
parts. 

Dura  mater.  At  the  base  of  the  cranium  the  dura  mater  is  much  more 
closely  united  to  the  bones  than  it  is  at  the  top  of  the  skull.  Here  it  dips 
into  the  different  inequalities  of  the  osseous  surfaces  ;  and  it  sends  processes 
througli  the  several  foramina,  wliich  join  for  the  most  part  the  pericra- 
nium, and  furnish  sheatlis  to  tlie  nerves. 

Beginning  the  examination  in  front,  the  membrane  will  be  found  to  send 


SINUSES    OF    CRANIUM.  27 

a  prolongation  into  the  foramen  caecum,  as  well  as  a  series  of  tubes  tlirougli 
the  a[)ertures  in  tlie  cribriform  plate  of  the  ethmoid  bone.  Througli  the 
sphenoidal  fissure  it  joins  the  periosteum  of  the  orbit ;  and  through  the 
oi)tic  foramen  a  covering  is  continued  on  the  optic  nerve  to  the  eyeball. 
Behind  the  sella  Turcica,  the  dura  mater  adheres  closely  to  the  basilar 
process  of  the  occipital  bone ;  and  it  may  be  traced  into  the  spinal  canal 
through  the  foramen  magnum,  to  the  margin  of  which  it  is  very  firmly 
united. 

The  tentorium  cerehelli  is  the  piece  of  the  dura  mater  which  is  interposed 
in  a  somewhat  horizontal  position  between  the  small  brain  (cerebellum), 
and  the  posterior  part  of  the  large  brain  (cerebrum). 

Its  upper  surface  is  i-aised  along  the  middle,  where  it  is  joined  by  the 
falx  cerebri,  and  is  hollowed  laterally  for  the  reception  of  the  back  part  of 
the  cerebral  hemispheres.  Its  under  surface  touches  the  little  brain,  and 
is  joined  by  the  falx  cerebelli. 

The  anterior  concave  margin  is  free,  except  at  the  ends  where  it  is  fixed 
by  a  narrow  slip  to  each  anterior  clinoid  process.  The  posterior  or  con- 
vex part  is  connected  to  the  following  bones : — occipital  (transverse  groove), 
inferior  angle  of  the  parietal,  petrous  portion  of  the  temporal  (upper  border), 
and  posterior  clinoid  process  of  the  sphenoid. 

Along  the  centre  of  the  tentorium  is  the  straight  sinus;  and  in  the  at- 
tached edge  are  the  lateral  and  the  superior  petrosal  sinus  on  each  side. 

Falx  cerebri.     The  characters  of  this  fold  have  been  given  in  page  25. 

The  Falx  cerehelli  has  the  same  position  below  the  tentorium  as  the  falx 
cerebri  above  that  fold.  It  is  much  smaller  than  the  falx  of  the  cerebrum, 
and  will  appear  on  detaching  the  tentorium.  Triangular  in  form,  this 
fold  is  adherent  to  the  middle  ridge  of  the  occipital  bone  below  the  pro- 
tuberance, and  projects  between  the  hemispheres  of  the  small  brain.  Its 
base  is  directed  to  the  tentorium  ;  and  the  apex  reaches  the  foramen  mag- 
num, to  each  side  of  which  it  gives  a  small  slip.  In  it  is  contained  the 
occipital  sinus. 

The  SINUSES  are  venous  spaces  between  the  layers  of  the  dura  mater, 
into  which  blood  is  received.  All  the  sinuses  open  either  into  a  large 
space  named  torcular  Herophili,  opposite  the  occipital  protuberance;  or 
into  the  two  cavernous  sinuses  on  the  sides  of  the  body  of  the  sphenoid 
bone. 

A.  The  TORCULAR  Herophili  (fig.  3,  a)  is  placed  in  the  tentorium, 
opposite  the  centre  of  the  occipital  bone.  It  is  of  an  irregular  shape,  and 
numerous  sinuses  open  into  it,  viz.,  the  superior  longitudinal  above,  and  the 
occipital  below  ;  the  straight  in  front,  and  the  lateral  sinus  on  each  side. 

The  superior  longitudinal  sinus  has  been  already  described  (see  p.  25). 

The  inferior  longitudinal  sinus  (fig.  3,  c)  resembles  a  small  vein,  and 
is  contained  in  the  lower  border  of  the  falx  cerebri  at  the  posterior  part. 
This  vein  receives  blood  from  the  falx  and  the  larger  brain,  and  ends  in 
the  straight  sinus  {d)  at  the  edge  of  tlie  tentorium. 

The  straight  sinus  (fig.  3,  d)  lies  along  the  middle  of  the  tentorium, 
and  seems  to  continue  the  [)receding  sinus  to  the  common  point  of  union. 
Its  form  is  triangular,  like  the  superior  longitudinal.  Joining  it  are  the 
inferior  longitudinal  sinus,  the  veins  of  Galen  from  the  interior  of  the 
large  brain,  and  some  small  veins  from  the  upper  part  of  the  cerebellum. 

The  occipital  sinus  (fig.  3,  g^  is  a  small  space  in  the  falx  cerebelli, 
which  reaches  to  the  foramen  magnum,  and  collects  the  blood  from  the 
occipital  fossie.     This  sinus  may  be  double. 


28 


DISSECTION    OF    THE    HEAD. 


The  lateral  sinus  (fig.  3,  e)  is  the  channel  by  which  most  of  the  blood 
passes  from  the  skull.  There  is  one  on  each  side,  right  and  left,  which 
extends  from  the  occipital  protuberance  to  the  foramen  jugulare,  where  it 
ends  in  the  internal  jugular  vein.  In  this  extent  tiie  sinus  occupies  the 
winding  groove  in  the  interior  of  the  skull  between  the  two  points  of  bone 
before  mentioned :  and  the  right  is  frequently  larger  than  the  left. 

Fig.  3. 


a.  Torcular  Herophili. 

h.  Superior  loQKUudinal  sinus. 

c.  Inferior  longitudinal. 

d.  Straight  sinus. 

e.  Lateral  sinus. 
g.  Occipital  sinus. 

/.  Superior,  and  h,  inferior  petrosal  sinus. 


SOMK   OF   THE    SiNUSES    OP   THE    SkULL. 

Besides  small  veins  from  the  brain,  it  is  joined  by  the  superior  petrosal 
sinus  (/),  opposite  the  upper  edge  of  the  petrous  portion  of  the  temporal 
bone ;  and  by  the  inferior  petrosal  (h)  at  tlie  foramen  jugulare.  Often- 
times it  communicates  with  the  occipital  vein  through  the  mastoid  fora- 
men, and  sometimes  with  veins  of  the  diploe  of  the  skull. 

The  foramen  jugulare  is  divided  into  three  compartments  by  bands  of 
the  dura  mater.  Through  the  posterior  interval  the  lateral  sinus  passes  ; 
through  the  anterior  the  inferior  petrosal  sinus ;  and  through  the  central 
one  the  pieces  of  the  eighth  nerve. 

Dissection.  To  examine  the  cavernous  sinus  on  the  left  side,  cut 
through  the  dura  mater  by  the  side  of  the  body  of  the  sphenoid  bone  from 
the  anterior  to  the  posterior  clinoid  process,  and  internal  to  the  position  of 
the  third  nerve  :  behind  the  clinoid  process,  let  the  knife  be  directed  in- 
wards for  about  half  the  width  of  the  basilar  part  of  tlie  occipital  bone. 
By  placing  the  handle  of  the  scalpel  in  the  opening  thus  made,  the  extent 
of  the  space  will  be  defined.  A  probe  or  a  blow-pipe  will  be  required,  in 
order  that  it  may  be  passed  into  the  different  sinuses  joining  the  cavernous 
centre. 

B.  The  CAVERNOUS  sinus,  which  has  been  so  named  from  the  reticu- 
late structure  in  its  interior,  is  situate  on  the  side  of  the  body  of  the 
sphenoid  bone.  This  space,  resulting  from  the  separation  of  the  two 
layers  of  th(i  dura  mater,  is  of  an  irregular  shape,  and  extends  from  the 
sphenoidal  fissure  to  the  tip  of  the  petrous  portion  of  the  temporal  bone. 

The  piece  of  dura  mater  bounding  the  sinus  externally  is  of  some  tliick- 
ness,  and  contains  in  its  substance  the  third  and  fourtli  nerves,  with  the 
ophthalmic  trunk  of  the  fifth  nerve ;  these  lie  in  their  numerical  order 
from  above  down. 

The  cavity  of  the  sinus  is  larger  behind  than  before,  and  in  it  are 
shreds  of  fibrous  tissue  with  small  vessels.     Tiirough  the  space  winds  the 


MENINGEAL    ARTERIES.  29 

trunk  of  the  internal  carotid  artery  surrounded  by  the  sympathetic,  with 
the  sixth  nerve  on  the  outer  side  of"  the  vessel ;  but  all  these  are  shut  out 
from  the  blood  in  tlie  space  by  a  thin  lining  membrane. 

The  cavernous  sinus  receives  the  ophthalmic  vein  of  the  orbit,  some 
inferior  cerebral  veins,  and  twigs  from  tlie  pterygoid  veins  outside  the 
skulL  It  communicates  with  its  fellow  on  the  opposite  side  by  the  circular 
and  transverse  sinuses ;  and  its  blood  is  transmiited  to  the  lateral  sinus  by 
the  superior  and  inferior  petrosal  channels. 

The  circular  sinus  lies  around  the  pituitary  body,  and  reaches  from  the 
one  cavernous  sinus  to  the  other  across  the  middle  line.  Besides  serving 
as  the  means  of  communication  between  those  sinuses,  it  receives  small 
veins  from  the  pituitary  body.  This  sinus  is  usually  destroyed  by  tlie 
removal  of  the  pituitary  body. 

Tlie  transverse  or  basilar  sinus  crosses  the  basilar  process  of  the  occipi- 
tal bone,  on  a  level  with  the  petrous  part  of  the  temporal  bone,  and  unites 
the  opposite  cavernous  sinuses.  A  second  transverse  sinus  is  sometimes 
found  nearer  the  foramen  magnum. 

The  superior  petrosal  siiius  (fig.  3,/)  lies  in  a  groove  in  the  upper 
edge  of  the  petrous  part  of  the  temporal  bone,  and  extends  between  the 
cavernous  and  lateral  sinuses.  A  small  vein  from  the  cerebellum,  and  an- 
other from  the  internal  ear,  are  received  into  it. 

The  inferior  petrosal  sinus  (fig.  3,  h)  extends  between  the  same  sinuses 
as  the  preceding,  and  lies  in  a  groove  along  the  line  of  junction  of  the 
petrous  part  of  the  temporal  with  the  basilar  process  of  the  occipital  bone; 
it  is  joined  by  a  small  vein  from  the  outside  of  the  skull,  through  the  fora- 
men lacerum  in  the  base  of  the  cranium.  This  sinus  passes  through  the 
anterior  compartment  of  the  jugular  foramen,  and  ends  in  the  internal 
jugular  vein. 

Meningeal  Arteries.  These  arteries  supplying  the  cranium  and  the 
dura  mater  come  through  the  base  of  the  skull ;  they  have  been  named 
from  their  situation  in  the  three  fossae,  anterior,  middle,  and  posterior 
meningeal. 

The  anterior  meningeal  are  very  small  branches  of  the  ethmoidal  arteries 
(p.  56),  which  enter  the  skull  by  apertures  between  the  frontal  and  eth- 
moid bones  ;  they  are  distributed  to  the  dura  mater  over  and  near  the 
ethmoid  bone. 

The  middle  meningeal  arteries  are  three  in  number :  two,  named  large 
and  small,  are  derived  from  the  internal  maxillary  trunk  ;  and  the  third  is 
an  offset  of  the  ascending  pharyngeal  artery. 

a.  The  large  meningeal  branch  of  the  internal  maxillary  artery  appears 
through  the  foramen  spinosum  of  the  sphenoid  bone,  and  ascends  towards 
the  anterior  inferior  angle  of  the  parietal  bone.  At  this  spot  the  vessel 
enters  a  deep  groove  in  the  cranium,  and  ends  in  ramifications  which 
spread  over  the  side  of  the  head,  some  of  them  reaching  to  the  top  and  the 
occiput,  whilst  others  perforate  the  bone,  and  end  on  the  exterior  of  the 
head.     Two  veins  accompany  the  artery. 

Branches.  As  soon  as  the  artery  comes  into  the  cranial  cavity,  it 
furnishes  branches  to  the  dura  mater  and  osseous  structure,  and  to  the 
ganglion  of  the  fifth  nerve.  One  small  offset,  petrosal,  enters  the  hiatus 
Fallopii,  and  supplies  the  surrounding  bone  (Hyrtl;.  One  or  two  branches 
pass  into  the  orbit,  and  anastomose  with  the  ophthalmic  artery. 

6.  The  small  meningeal  branch  is  an  offset  of  the  large  one  outside  the 


30  DISSECTION    OF    THE    HEAD. 

skull,  and  is  transmitted  through  the  foramen  ovale  to  the  membrane  lining 
the  middle  cranial  fossa. 

c.  Another  meningeal  branch  from  the  ascending  pharyngeal  artery 
comes  through  the  foramen  lacerum  (basis  cranii).  This  is  seldom  in- 
jected, and  is  not  often  visible. 

The  posterior  meningeal  branches  are  small,  and  are  furnished  by  the 
occipital  and  vertebral  arteries. 

That  from  the  occipital,  one  on  each  side,  enters  the  skull  by  the  jugu- 
lar foramen  ;  and  that  from  the  vertebral  arises  opposite  the  foramen  mag- 
num.    Both  vessels  ramify  in  the  posterior  fossa  of  the  skull. 

Meningeal  Nerves.  Offsets  to  the  dura  mater  are  said  to  be  derived 
from  the  fourth,  fifth,  glosso-pharyngeal,  and  vagus,  cranial  nerves,  and 
from  the  sympathetic  nerve.  To  make  these  nerves  apparent,  it  would  be 
necessary  to  steep  the  dura  mater  in  diluted  nitric  acid. 

Cranial  Nerves  (fig.  4).  The  cranial  nerves  pass  from  the  encepha- 
lon  through  apertures  in  the  base  of  the  skull.  As  each  leaves  the  cranium 
it  is  invested  by  processes  of  the  membranes  of  the  brain,  which  are  thus 
disposed : — those  of  the  dura  mater  and  pia  mater  are  lost  on  the  nerve  ; 
whilst  that  of  the  arachnoid  membrane  is  reflected  back,  after  a  short  dis- 
tance, to  the  interior  of  the  skull.  Some  of  the  nerves,  those  in  the  middle 
fossa  of  the  skull  for  instance,  receive  sheaths  of  the  dura  mater  before 
they  approach  the  foramina  of  transmission.  The  nerves  will  be  referred 
to  now  as  nine  pairs,  but  notice  will  be  subsequently  taken  of  a  different 
mode  of  enumerating  them.  Only  part  of  the  course  of  each  nerve  will  be 
seen  at  this  stage,  the  rest  will  be  learnt  in  the  dissection  of  the  base  of 
the  brain. 

The  FIRST  NERVE  (fig.  33)  ends  anteriorly  in  the  enlargement  of  the 
olfactory  bulb.  This  swelling  lies  on  the  cribriform  plate  of  the  ethmoid 
bone,  and  supplies  about  twenty  branches  to  the  nose  through  the  small 
foramina  in  the  subjacent  bone.  These  delicate  nerves  are  surrounded  by 
prolongations  of  the  membranes  of  the  brain,  and  their  arrangement  will 
be  noticed  in  the  dissection  of  the  nose. 

The  SECOND  NERVE  (fig.  4,  ^)  diverging  from  its  commissure  to  the  eye- 
ball, enters  the  orbit  through  the  optic  foramen  ;  accompanying  the  nerve 
is  the  ophthalmic  artery. 

Dissection,  The  third  and  fourth  nerves,  and  the  ophthalmic  trunk  of 
the  fifth  nerve,  lie  in  the  outer  wall  of  the  cavernous  sinus ;  and  to  see 
them,  it  will  be  necessary  to  trace  them  through  the  dura  mater  towards 
the  orbit. 

Afterwards  the  student  should  follow  outwards  the  roots  of  the  fifth 
nerve  into  the  middle  fossa  of  the  skull,  as  in  fig.  4,  taking  away  the  dura 
mater  from  them,  and  from  the  surface  of  the  large  Gasserian  ganglion 
which  lies  on  the  point  of  the  petrous  portion  of  the  temporal  bone.  From 
the  front  of  the  ganglion  arise  other  two  large  trunks  besides  the  ophthalmic, 
viz.,  superior  and  inferior  maxillary,  and  these  should  also  be  traced  to 
their  apertures  of  exit  from  the  skull.  If  the  dura  mater  is  removed  en- 
tirely from  the  bone  near  the  nerves  a  better  dissection  will  be  obtained. 

The  THIRD  NERVE  (fig.  4,  ^)  is  destined  for  the  muscles  of  the  orbit. 
It  enters  the  wall  of  the  cavernous  sinus  near  the  anterior  clinoid  process, 
and  is  deprived  at  that  spot  of  its  tube  of  arachnoid  membrane.  In  the 
wall  of  the  sinus  it  is  placed  above  the  other  nerves  ;  but  when  it  is  about 
to  enter  the  orbit  through  the  sphenoidal  fissure,  it  sinks  below  the  fourth 
and  a  part  of  the  fifth,  and  divides  into  two  branches. 


NERVES  IN  BASE  OF  SKULL, 


31 


Near  the  orbit  the  nerve  is  joined  by  one  or  two  delicate  filaments  of 
the  cavernous  plexus  (p.  33). 

The  FOURTH  nerve  (fig.  4,  *)  courses  forwards,  like  the  preceding,  to 
one  muscle  in  the  orbit.  It  is  the  smallest  of  the  nerves  in  the  wall  of  the 
sinus,  and  is  placed  below  the  third  ;  but  as  it  is  about  to  pass  through  the 
s[)henoidal  fissure  it  rises  higher  than  all  the  other  nerves. 

Fig.  4. 


The  dura  mater  has  been  remoyed 
iu  the  middle  fossa,  on  the  left  side, 
to  show  the  nerves  in  the  wall  of  the 
cavernous  sinus,  and  especially  the 
ganglion,  and  the  three  trunks  of  the 
fifth  nerve.  Each  nerve,  except  the 
first  which  is  absent,  is  marked  by  its 
corresponding  numeral.  On  the  right 
side  the  dura  mater  is  untouched, 
t  Offsets  to  the  dura  mater  from  the 
fifth  nerve. 


Cranial  Nerves  in  the  Base  of  the  Skull. 


In  the  wall  of  the  sinus  the  fourth  nerve  is  joined  by  twigs  of  the  sym- 
pathetic ;  and  it  is  sometimes  united  with  the  ophthalmic  trunk  of  the 
fifth. 

Fifth  Nerve  (fig.  4,  ^).  This  nerve  is  distributed  to  the  face  and 
head,  and  consists  of  two  parts  or  roots — a  large  or  sensory,  and  a  small  or 
motory. 

The  large  root  of  the  nerve  passes  through  an  aperture  in  the  dura 
mater  into  the  middle  fossa  of  the  base  of  the  skull,  where  it  ends  imme- 
diately in  the  Gasserian  ganglion. 

The  ganglion  of  the  root  of  the  fifth  nerve  (Gasserian  ganglion),  placed 
in  a  depression  on  the  point  of  the  petrous  part  of  the  temporal  bone,  is 
flattened,  and  is  nearly  as  wide  as  the  thumb-nail.  The  upper  surface  of 
the  ganglion  is  closely  united  to  the  dura  mater,  and  presents  a  semilunar 
elevation,  wliose  convexity  looks  forwards.  Some  filaments  from  the 
plexus  of  the  sympathetic  on  the  carotid  artery  join  its  inner  side. 

Branches.  From  the  front  of  the  ganglion  proceed  the  three  following 
trunks: — The  ophthalmic  nerve,  the  first  and  highest,  is  destined  for  the 
orbit  and  forehead.  Next  in  order  is  the  su))erior  maxillary  nerve,  which 
leaves  the  skull  by  the  foramen  rotundum,  and  ends  in  the  face  below  the 


32  DISSECTION    OF    THE    HEAD. 

orbit.  And  the  last,  or  the  inferior  maxillary  nerve,  passes  through  the  fora- 
men ovale  to  reach  the  lower  jaw,  the  lower  part  of  the  face,  and  the  tongue. 

The  smaller  root,  entering  the  same  tube  of  the  dura  mater  as  the  large 
one,  passes  beneath  the  ganglion,  without  communicating  with  it,  and  joins 
only  one  of  the  three  trunks  derived  from  the  ganglion  ;  if  the  ganglion  be 
raised,  this  root  will  be  seen  to  enter  the  inferior  maxillary  nerve. 

Those  branches  of  the  ganglion  which  are  unconnected  with  the  smaller 
or  motor  root,  viz.,  the  ophthalmic  and  superior  maxillary,  are  solely  nerves 
of  sensibility ;  but  the  inferior  maxillary,  which  is  compounded  of  both 
roots,  is  a  nerve  of  sensibility  and  motion.  But  the  whole  of  the  inferior 
maxillary  nerve  has  not  this  double  function,  for  the  motor  root  is  mixed 
almost  exclusively  with  the  part  which  supplies  the  muscles  of  the  lower 
jaw ;  and  it  is,  therefore,  chiefly  that  small  piece  of  the  nerve  which  pos- 
sesses a  twofold  action,  and  resembles  a  spinal  nerve. 

The  ophthalmic  nerve  is  the  only  one  of  the  three  trunks  which  needs  a 
more  special  notice  in  this  stage  of  the  dissection.  It  is  continued  through 
the  sphenoidal  fissure  and  the  orbit  to  the  forehead.  In  form  it  is  a  flat 
band,  and  is  contained  in  the  wall  of  the  cavernous  sinus  below  the  third 
and  fourth  nerves.     Near  the  orbit  it  divides  into  three  branches  (p.  51). 

In  this  situation  it  is  joined  by  filaments  of  the  cavernous  plexus  of  the 
sympathetic,  and  gives  a  small  recurrent  filament  (fig.  4,  f)  to  that  part  of 
the  dura  mater  which  forms  the  tentorium  cerebelli  (Arnold). 

The  SIXTH  NERVE  (fig.  4,  ^)  enters  the  orbit  through  the  sphenoidal  fis- 
sure, and  supplies  one  of  the  orbital  muscles.  It  pierces  the  dura  mater 
behind  the  body  of  the  sphenoid  bone,  and  crosses  the  space  of  the  caver- 
nous sinus,  instead  of  lying  in  the  outer  wall  with  the  other  nerves. 

In  the  sinus  the  nerve  is  placed  close  against  the  outer  side  of  the 
carotid  artery ;  and  it  is  joined  by  one  or  two  large  branches  of  the  sym- 
pathetic nerve  surrounding  that  vessel. 

Seventh  Nerve  according  to  Willis  (fig.  4,  ^).  This  cranial  nerve 
consists  of  two  trunks,  fascial  and  auditory,  and  both  enter  the  meatus 
auditorius  internus.  In  the  bottom  of  the  meatus  they  separate  ;  the  facial 
nerve  courses  through  the  aqueduct  of  Fallopius  to  the  face,  and  the  audi- 
tory nerve  is  distributed  to  the  internal  ear. 

Eighth  Nerve  (fig.  4,  *).  'Three  trunks  are  combined  in  the  eighth 
cranial  nerve  of  Willis,  viz.,  glosso- pharyngeal,  pneumogastric,  and  spinal 
accessory.  All  three  pass  through  the  central  compartment  of  the  foramen 
jugulare,  but  all  are  not  contained  in  one  tube  of  the  membranes  of  the 
brain.  The  glosso-pharyngeal  nerve  is  external  to  the  other  two,  being 
separated  from  them  by  the  inferior  petrosal  sinus,  and  lias  distinct  sheaths 
of  the  dura  mater  and  the  arachnoid  membrane ;  but  the  pneumo-gastric 
and  spinal  accessory  nerves  are  inclosed  in  the  same  tube  of  the  dura 
mater,*  only  a  piece  of  the  arachnoid  intervening  between  them. 

The  NINTH  nerve  (fig.  4,  ^)  is  the  motor  nerve  of  the  tongue,  and  con- 
sists of  two  small  pieces,  which  pierce  separately  the  dura  mater  opposite 
the  anterior  condyloid  foramen ;  these  unite  after  passing  through  that 
aperture. 

Dissection.  The  dissector  may  now  return  to  the  examination  of  the 
trunk  of  the  carotid  artery  as  it  winds  through  the  cavernous  sinus. 

On  the  o[)posite  side  of  the  head,  viz.,  that  on  which  the  nerves  in  the 
wall  of  the  cavernous  sinus  are  untouched,  an  attempt  may  be  made  to  find 
two  small  plexuses  of  the  sympathetic  on  the  carotid  artery,  though  in  an 
injected  body  this  dissection  is  scarcely  possible. 


INTERNAL  CAROTID  ARTERY.  33 

One  of  these  (cavernous)  is  near  the  root  of  the  anterior  clinoid  pro- 
cess ;  and  to  bring  it  into  view  it  will  be  necessary  to  cut  off  tliat  piece  of 
bone,  and  to  dissect  out  with  care  the  third,  fourth,  fifth,  and  sixth  nerves, 
looking  for  filaments  between  them  and  the  plexus.  Another  plexus 
(carotid),  joining  the  fifth  and  sixth  nerves,  surrounds  the  artery  as  this 
enters  the  sinus. 

The  INTERNAL  CAROTID  ARTERY  appears  in  the  base  of  the  skull  at 
the  apex  of  the  petrous  part  of  the  temporal  bone.  In  its  ascent  to  the 
brain  the  vessel  lies  in  the  space  of  the  cavernous  sinus,  along  the  side 
of  the  body  of  the  sphenoid  bone,  and  makes  two  remarkable  bends,  so  as 
to  look  like  the  letter  S  reclined.  At  first,  the  artery  ascends  to  the 
posterior  clinoid  process  ;  it  is  then  directed  forwards  to  the  root  of  the 
anterior  process  of  the  same  name  ;  and  lastly  it  turns  upwards  internal 
to  this  last  point  of  bone,  perforates  the  dura  mater  bounding  the  sinus, 
and  divides  into  cerebral  arteries  at  the  base  of  the  brain.  In  this 
course  the  artery  is  enveloped  by  nerves  derived  from  the  sympathetic  in 
the  neck. 

The  hrmiches  of  the  artery  here  are  few.  In  the  sinus  there  are  some 
small  arteries  (arteriaa  receptaculi)  for  the  supply  of  the  dura  mater  and 
the  bone,  the  nerves,  and  the  pituitary  body ;  and  at  the  anterior  clinoid 
process  the  ophthalmic  branch  arises. 

The  terminal  brandies  of  the  carotid  will  be  seen  in  the  dissection  of 
the  base  of  the  brain. 

Sympathetic  Nerve.  Around  the  carotid  artery  is  a  prolongation  of 
the  sympathetic  nerve  of  the  neck,  which  forms  the  following  plexuses  : — 

The  carotid  plexus  is  situate  on  the  outer  side  of  the  vessel,  at  its  en- 
trance into  the  cavernous  sinus,  and  communicates  with  the  sixth  nerve 
and  the  Gasserian  ganglion. 

The  small  cavernous  plexus  is  placed  below  the  bend  of  the  artery  which 
is  close  to  the  anterior  clinoid  process,  and  is  connected  with  that  offset 
of  the  upper  cervical  ganglion  which  courses  along  the  inner  side  of  the 
carotid  artery.  Filaments  from  the  plexus  unite  with  the  third,  fourth, 
and  ophthalmic  nerves.  One  filament  is  also  furnished  to  the  lenticidar 
ganglion  in  the  orbit,  either  separately  from,  or  in  conjunction  with,  the 
nasal  nerve. 

After  forming  those  plexuses,  the  nerves  surround  the  trunk  of  the 
carotid,  and  are  lost  chiefly  in  the  cerebral  membrane  named  pia  mater ; 
but  some  ascend  on  the  cerebral  and  ophthalmic  branches  of  that  vessel, 
and  one  offset  is  said  to  enter  the  eyeball  with  the  central  artery  of  the 
retina. 

Petrosal  nerves  (fig.  34).  Beneath  the  Gasserian  ganglion  is  the  large 
superficial  petrosal  nerve  (fig.  34, 2)  entering  the  hiatus  Fallopii  to  join 
the  facial  nerve.  Externally  to  this  is  occasionally  seen  another- small 
petrosal  nerve  (fig.  34,  *)  (^external  super jiciaV)^  which  springs  from  the 
sym[)athetic  on  the  middle  meningeal  artery,  and  enters  the  bone  to  join 
the  facial  nerve.  A  third,  the  small  petrosal  nerve  (fig.  34,  ^),  is  con- 
tained in  the  substance  of  the  temporal  bone.  The  source,  and  the  desti- 
nation of  those  three  small  nerves  will  be  afterwards  learnt.  It  will  suffice 
now  for  the  student  to  note  the  two  first,  and  to  see  that  they  are  kept 
moist  and  fit  for  examination  at  a  future  time. 

Directions.  Now  the  base  of  the  skull  has  been  completed,  a  preserva- 
tive fluid  or  salt  should  be  applied,  and  the  flaps  of  the  teguments  should 
be  stitched  together  over  all. 
3 


34  DISSECTION    OF    THE    FACE. 

Section  III. 

DISSECTION  OF  THE  FACE. 

Directions.  The  left  side  of  the  face  may  be  used  for  learning  the  mus- 
cles and  vessels,  and  the  right  side  is  to  be  reserved  for  the  nerves. 

Position.  The  previous  position  of  the  body  for  the  examination  of  the 
base  of  the  skull  will  require  to  be  changed : — the  head  is  to  be  lowered, 
and  the  side  of  the  face  to  be  dissected  is  to  be  placed  upwards. 

Dissection.  As  a  preparatory  step,  the  muscular  fibres  of  the  apertures 
may  be  made  slightly  tense  by  inserting  a  small  quantity  of  tow  or  cotton- 
wool between  the  eyelids  and  the  eyeball,  and  between  the  lips  and  the 
teeth. 

First  lay  bare  the  sphincter  muscle  of  the  eyelids  by  a  skin-deep  circular 
incision  over  the  margin  of  the  orbit,  and  by  raising  the  skin  of  the  lids 
towards  the  aperture  of  the  eye.  Much  care  must  be  taken  in  detaching 
the  skin  from  tlie  thin  and  oftentimes  pale  fibres  of  the  orbicular  muscle  in 
the  lids,  else  they  will  be  cut  away  in  consequence  of  the  little  areolar 
tissue  between  the  two. 

Next  the  integument  is  to  be  removed  from  the  side  of  the  face  by  one 
incision  in  front  of  the  ear,  from  above  the  zygomatic  arch  to  the  angle  of 
the  jaw,  and  then  along  the  base  of  the  jaw  to  the  chin  ;  and  by  another 
cut  carried  backwards  horizontally  from  the  corner  of  the  mouth  into  the 
first.  The  flaps  of  skin  are  to  be  raised  from  behind  forwards,  and  left 
adherent  along  the  middle  line.  On  the  side  of  the  nose  the  skin  is  closely 
united  to  the  subjacent  parts,  and  must  be  detached  with  caution.  Around 
the  mouth  are  many  fleshy  slips  extending  both  upwards  and  downwards 
from  the  orbicular  muscle,  but  they  are  all  marked  so  distinctly  as  to  escape 
injury,  with  the  exception  of  the  small  risorius  muscle  which  goes  from 
the  corner  of  the  mouth  towards  the  ramus  of  the  lower  jaw.  While 
removing  the  fat  from  the  muscles,  each  fleshy  slip  may  be  made  tense 
with  hooks. 

Tlie  facial  vessels  and  their  branches  will  come  into  view  as  tlie  muscles 
are  cleaned ;  but  the  nerves  may  be  disregarded  on  this  side. 

In  front  of  the  ear  is  the  parotid  gland,  whose  duct  is  to  be  preserved ; 
this  is  on  a  level  with  the  meatus  auditorius,  and  pierces  the  middle  of  the 
cheek. 

Muscles  of  the  Face  (fig.  6).  The  superficial  muscles  of  tlie  face 
are  gathered  around  the  apertures  of  the  nose,  eye,  and  mouth.  An  orbi- 
cular or  sphincter  muscle  encircles  the  apertures  of  the  eye  and  mouth  ; 
and  other  muscles  .are  blended  with  each  to  enlarge  the  opening  in  the 
centre  of  the  fibres.  There  are  three  distinct  groups  of  muscles  :  one  of 
the  eyelids ;  another  of  the  nostril ;  and  a  third  of  the  aperture  of  the 
mouth.  One  of  the  muscles  of  mastication,  viz.,  the  masseter,  is  seen 
between  the  jaws. 

Muscles  of  the  Nose.  These  muscles  are  the  following :  pyra- 
midalis  nasi,  compressor  naris,  levator  alte  nasi,  dilator  naris,  and  depressor 
alai  nasi. 

The  PYiiAMiDALis  NASI  (fig.  5,  ^)  is  a  small  fleshy  slip  that  covers  the 
nasal  bone,  and  is  continuous  above  with  the  occipito-fron talis  muscle. 
Over  the  cartilaginous  part  of  the  nose  its  fibres  end  in  an  aponeurosis, 


MUSCLES    OF    NOSE, 


36 


which  joins  that  of  the  compressor  naris.  Along  its  inner  border  is  the 
muscle  of  the  opposite  side. 

Action.  Tliis  muscle  makes  tijfht  the  skin  over  the  nasal  cartilages, 
but  renders  lax,  and  sometimes  wrinkles  transversely  the  skin  towards  the 
root  of  the  nose. 

Compressor  Naris.  This  muscle  (fig.  5,  ^)  is  not  well  seen  till  after 
the  examination  of  tlie  following  one.  Triangular  in  shape,  it  arises  by 
its  apex  from  the  canine  fossa  of  the  u{)per  maxillary  bone.  The  fibres 
are  directed  inwards,  spreading  out  at  the  same  time,  and  end  in  an 
aponeurosis,  which  covers  the  cartilaginous  part  of  the  nose,  and  joins  the 
tendon  of  the  opposite  muscle.  This  muscle  is  partly  concealed  by  the 
next — the  common  elevator  of  the  ala  of  the  nose  and  the  upper  lip. 

Action.     It  stretches  the  skin  over  the  cartilaginous  part  of  the  nose. 

The  LEVATOR  LABii  suPERiORis  AL^EQUE  NASI  (fig.  5,  ^)  is  placed  by 
the  side  of  the  nose,  and  arises  from  the  top  of  the  nasal  process  of  the 
upper  maxillary  bone,  internal  to  the  attachment  of  the  orbicularis.  As 
the  fibres  descend  from  the  inner  part  of  the  orbit  the  most  internal  are 

Fig.  5. 


1.  Pyramidalis  nasi. 

2.  Common  elevator  of  the  nose  and  lip. 

3.  Compressor  naris. 

4  and  5.  The  two  slips  of  the  dilatator  naris. 

6.  Depressor  alse  nasi. 

7.  Orbicularis  oris,  attached  to  the  septum  nasi. 


Muscles  of  the  Nose. 


attached  by  a  narrow  slip  to  the  wing  of  the  nose,  whilst  tlie  rest  are 
blended  inferiorly  with  the  orbicularis  oris.  Near  its  origin  the  muscle  is 
partly  concealed  by  the  orbicularis  palpebrarum,  but  in  the  rest  of  its 
extent  it  is  subcutaneous.  Its  outer  border  joins  the  elevator  of  the 
upper  lip. 

Action.  As  the  name  expresses,  it  can  raise  the  upper  lip,  and  draw 
outwards  the  wing  of  the  nose,  dilating  tlie  aperture  ;  but  when  the  mouth 
is  shut  it  can  enlarge  the  nostril  independently  of  the  lip. 

Dilatator  Naris.  In  the  dense  tissue  on  the  outer  side  of  the  nostril 
are  a  few  muscular  fibres,  both  at  the  fore  and  back  part  of  that  aperture 
(fig.  5,*,  and  *),  to  which  the  above  name  has  been  given  by  Theile:  they 
are  seldom  visible  without  a  lens.  The  anterior  slip,  *,  j  asses  from  the 
cartilage  of  the  aperture  to  the  integument  of  the  margin  of  the  nostril ; 
and  the  posterior^  °,  arising  from  the  upper  jawbone  and  the  small  sesa- 
moid cartilages,  ends  also  in  the  integuments  of  the  nostril. 


36  DISSECTION    OF    THE    FACE. 

Action.  The  fibres  enlarge  the  nasal  opening  by  raising  and  everting 
the  outer  edge. 

The  DEPRESSOR  AL^  NASI  (fig.  5,  *)  will  be  seen  if  the  upper  lip  is 
everted,  and  the  mucous  membrane  is  removed  from  the  side  of  the  frtenum 
of  the  lip.  It  arises  below  the  nose  from  a  depression  of  the  upper  jaw- 
bone above  the  roots  of  the  second  incisor  and  canine  teeth  ;  and  ascends  to 
be  inserted  into  the  septum  nasi  and  the  posterior  part  of  the  ala  of  the  nose. 

Action.  By  drawing  down  and  turning  in  the  edge  of  the  dilated  nostril, 
it  restores  the  aperture  to  its  usual  size. 

Muscles  of  the  Eyelids.  The  muscles  of  the  eyelids  and  eyebrow 
are  four  in  number,  viz.,  orbicularis  palpebrarum,  corrugator  supercilii, 
levator  palpebrfe  superioris,  and  tensor  tarsi  :^  the  two  latter  are  dissected 
in  the  orbit,  and  will  be  described  with  it. 

The  orbicularis  palpebrarum  (fig.  6,  ^)  is  the  sphincter  muscle 
closing  the  opening  between  the  eyelids.  It  is  a  flat  and  thin  layer, 
which  extends  from  the  margin  of  the  lids  beyond  the  circumference  of 
the  orbit.  From  a  difference  in  the  characters  of  the  fibres,  a  division 
has  been  made  of  them  into  two  parts — outer  and  inner. 

The  external  fibres  (orbital  part),  the  best  marked,  are  fixed  only  at 
one  point,  viz.,  the  inner  angle  of  the  orbit.  This  attachment  (origin)  is 
connected  with  the  surface  and  borders  of  the  small  tendo  palpebrarum ; 
above  that  tendon  with  the  nasal  process  of  the  upper  maxillary,  and  the 
internal  angular  process  of  the  frontal  bone  ;  and  below  the  tendon  with 
the  superior  maxillary  bone,  and  the  margin  of  the  orbit.  From  this 
origin  the  fibres  are  directed  outwards,  giving  rise  to  ovals,  which  lie  side 
by  side,  and  increase  in  size  towards  the  outer  edge  of  the  muscle  where 
they  project  beyond  the  margin  of  the  orbit. 

The  internal,  fibres  (palpebral  part),  paler  and  finer  than  the  outer, 
occupy  the  eyelids,  and  are  fixed  at  both  the  outer  and  inner  angles  of 
the  orbit.  Internally  (origin)  they  are  united  with  the  tendo  palpebrarum, 
and  externally  (insertion)  with  the  external  tarsal  ligament  and  the  malar 
bone,  and  some  few  may  blend  with  the  orbital  part.  Close  to  the  cilia 
or  eyelashes  the  fibres  form  a  small  pale  bundle,  which  is  sometimes  called 
ciliary. 

The  muscle  is  subcutaneous ;  and  its  circumference  is  blended  above 
with  the  occipito-frontalis.  Beneath  the  upper  half  of  the  orbicularis,  as 
it  lies  on  the  margin  of  the  orbit,  is  the  corrugator  supercilii  muscle  with 
the  supra-orbital  vessels  and  nerve  ;  and  beneath  the  lower  half  is  part  of 
the  elevator  of  the  upper  lip.  The  outer  fibres  are  joined  occasionally  by 
slips  to  other  contiguous  muscles  below  the  orbit. 

Action.  The  inner  fibres  cause  the  lids  to  approach  each  other,  shut- 
ting tlie  eye  ;  and  in  forced  contraction  the  outer  commissure  is  drawn 
inwards.  In  closure  of  the  eye  the  lids  move  unequally — the  upper  being 
much  depressed,  and  the  lower  slightly  elevated  and  moved  horizontally 
inwards. 

When  the  outer  fibres  contract,  the  eyebrow  is  depressed,  and  the  skin 
over  the  edge  of  the  orbit  is  raised  around  the  eye,  so  as  to  protect  the 
ball.  Elevation  of  the  upper  lip  follows  contraction  of  the  outer  part  of 
the  orbicularis,  in  consequence  of  fibres  being  prolonged  to  the  levator 
labii  superioris. 

'  The  tensor  tarsi  muscle  (p.  59)  is  sometimes  described  as  a  part  of  the  orbicu- 
laris. 


MUSCLES    OF    MOUTH 


37 


The  CORRUGATOR  suPKRCiLii  IS  beneath  the  orbicularis,  near  the  inner 
angle  of  the  orbit.  Its  fibres  arise  from  the  inner  part  of  the  superciliary 
ridge  of  the  frontal  bone,  and  are  directed  outwards  to  join  the  orbicular 
muscle  about  the  middle  of  the  orbital  arch.  It  is  a  short  muscle,  and  is 
distinguished  by  the  closeness  of  its  fibres. 

Action.  It  draws  inwards  and  downwards  the  mid-part  of  the  eyebrow, 
wrinkling  vertically  the  skin  near  the  nose,  and  stretching  that  outside  its 
point  of  insertion. 

Muscles  of  the  Mouth.  The  muscles  of  the  aperture  of  the  mouth 
consist  of  a  S[)hincter  ;  an  elevator  of  the  upper  lip  and  angle  of  the  mouth  ; 
ixn  elevator  and  depressor  of  the  lower  lip  and  angle  of  the  mouth  ;  and 
retractors  of  the  corner.  Lastly,  a  wide  muscle  of  the  cheek  closes  the 
space  between  the  jaws. 


Fi2:.  6. 


1.  Occipito-frontalis,    anterior    belly. 

4.  Posterior  belly. 

2.  Orbicularis  palpebrarum. 

3.  Levator    labii     superioris     alaeque 

nasi. 

5.  Compressor  nasi. 

6.  Levator  labii  superioris. 

7.  Zygomaticus  minor  (too  large). 

8.  Zygomaticus  major. 

9.  Risorius. 

10.  Masseter. 

11.  Orbicularis  oris. 

12.  Depressor  labii  inferioris. 
\'^.  Depressor  anguli  oris. 
14.  Buccinator. 

•f  Levator  auguli  oris.     See  fig.  1. 


The  ORBICULARIS  ORIS  MUSCLE  (fig.  6,  ")  suiTOunds  the  opening  of 
the  mouth,  and  is  united  \\\i\\  the  several  muscles  acting  on  that  aperture. 
It  consists  of  two  parts,  inner  and  outer,  which  differ  in  the  appearance 
and  arrangement  of  the  fibres,  like  the  sphincter  muscle  of  the  eyelids. 

The  iiiner  part  (fig.  5,  ^),  whose  fibres  are  pale  in  color  and  fine  in 
texture,  forms  a  rounded  thick  fasciculus,  which  corresponds  with  the  red 
margin  of  the  lip.  The  fibres  of  this  portion  of  the  muscle,  unattached  to 
bone,  blend  with  the  buccinator  at  the  corner  of  the  mouth,  and  some  pass 
from  lip  to  lip. 

The  outer  part  is  thin,  wide,  and  more  irregular  in  form,  and  is  con- 
nected with  the  subjacent  bone,  besides  its  union  with  the  adjacent  muscles. 
In  the  upper  lip  it  is  attached,  on  each  side  of  the  middle  line,  by  one 
slip  (naso-labial)  to  the  back  of  the  septum  of  the  nose  (fig.  5,  ^)  ;  and  by 
a  thin  stratum  to  the  outer  surface  of  the  upper  jaw,  opposite  the  canine 
tooth,  and  external   to   the  depressor  of  the   wing  of  the  nose.     In  the 


38  DISSECTION    OF    THE    FACE. 

lower  lip  it  is  fixed  on  each  side  into  the  inferior  jawhone,  opposite  the 
canine  tooth,  external  to  the  levator  lahii  inf'erioris  musck\  To  see  these 
attachments  the  lip  must  be  everted,  and  the  mucous  membrane  carefully- 
raised. 

The  inner  margin  of  the  muscle  is  free,  and  bounds  the  aperture  of  the 
mouth  ;  whilst  the  outer  edge  blends  with  the  different  muscles  that  ele- 
vate or  depress  the  lips  and  the  angle  of  the  mouth.  Beneath  the  orbicu- 
laris in  each  lip  is  the  coronary  artery,  with  the  mucous  membrane  and 
the  labial  glands. 

Action.  Both  parts  of  the  muscle  contracting,  the  lips  are  pressed  to- 
gether and  projected  forwards,  and  the  aperture  of  the  mouth  is  diminished 
transversely  by  the  approximation  of  the  corners  towards  each  other. 

The  inner  fibres  acting  alone  will  turn  inwards  the  red  part  of  the  lip, 
and  diminish  the  width  of  the  buccal  opening. 

Tiie  outer  fibres  press  the  lips  against  the  dental  arches,  the  free  edges 
being  protruded  and  somewhat  everted.  At  the  same  time  the  centre  part 
of  the  nose  is  depressed  and  the  chin  raised  by  means  of  tlie  fleshy  slips 
connected  with  those  parts. 

The  LEVATOR  LABii  SUPERIORJS  (fig.  6,  ^)  cxteuds  vertically  from  the 
lower  margin  of  the  orbit  to  the  orbicularis  oris.  It  arises  from  the 
upper  maxillary  and  malar  bones  above  the  infra-orbital  foramen,  and 
blends  inferiorly  with  the  orbicularis  oris.  Near  the  orbit  the  muscle  is 
overlapped  by  the  orbicularis  palpebrarum,  but  below  that  spot  it  is  sub- 
cutaneous. By  its  inner  side  it  joins  the  common  elevator  of  the  ala  of 
the  nose  and  upper  lip ;  and  to  its  outer  side  lie  the  zygomatic  muscles,  the 
small  one  joining  it.     Beneath  it  are  the  infra-orbital  vessels  and  nerve. 

Action.  By  the  action  of  this  muscle  the  upper  lip  is  raised,  and  the 
skin  of  the  cheek  is  bulged  below  the  eye. 

The  DEPRESSOR  LABII  iNFERiORis  (fig.  6,  ^'^)  is  Opposite  the  elevator 
of  the  upper  lip,  and  has  much  yellow  fat  mixed  with  its  fibres.  The 
muscle  has  a  wide  origin  from  a  depression  on  the  front  of  the  lower  jaw, 
reaching  backwards  from  near  the  symphysis  to  a  little  beyond  the  hole 
for  the  labial  vessels  and  nerve  ;  ascending  thence  it  is  united  with  the 
orbicularis  in  the  lower  lip.  Its  inner  border  joins  the  muscle  of  the  oppo- 
site side  above,  and  its  outer  is  overlapped  below  by  the  depressor  anguli 
oris. 

Action.  If  one  muscle  contracts,  the  half  of  the  lip  of  the  same  side  is 
depressed  and  everted  ;  but  by  the  use  of  both  muscles,  tlie  whole  lip  is 
lowered  and  turned  outwards,  and  rendered  tense  at  the  centre. 

The  LEVATOR  LABii  INFERIORIS  (levator  menti)  is  a  small  muscle  on 
the  side  of  the  frainum  of  the  lower  lip,  which  is  opposite  the  depressor  of 
the  ala  of  the  nose  in  the  upper  lip.  When  the  lip  has  been  everted  and 
the  mucous  membrane  removed,  the  muscle  will  be  seen  to  arise  from  a 
fossa  near  the  symphysis  of  the  lower  jaw,  and  to  descend  to  its  insertion 
into  the  integument  of  the  chin.  Its  position  is  internal  to  the  depressor 
of  the  lip  and  the  attachment  of  the  orbicularis. 

Action.  It  indents  the  skin  of  the  chin  opposite  its  insertion,  and 
assists  in  raising  the  lower  lip. 

The  LEVATOR  ANGULI  ORIS  (fig.  G,  f)  has  well-marked  fibres,  and  is 
partly  concealed  by  the  levator  labiisuperioris.  Arising  from  the  canine 
fossa  beneath  the  infi-a-orbital  foramen,  its  fibres  spread  out  towards  the 
angle  of  the  mouth  where  they  are  superficial  to  the  buccinator,  and  mix 


MUSCLES    OF    MOUTH.  39 

with  the  rest  of  the  muscles,  but  the  greater  number  are  continued  into 
the  depressor  anguli  oris  and  the  lower  lip. 

Action.  This  muscle  elevates  the  corner  of  the  mouth,  and  acts  as  an 
antagonist  to  the  depressor. 

The  DEPRESSOR  ANGULI  ORIS  (fig.  6,  ^*)  is  triangular  in  shape ;  it 
arises  from  the  oblique  line  on  the  outer  surface  of  the  lower  jaw,  and 
ascending  to  the  angle  of  the  mouth,  its  fibres  are  prolonged  into  the  ele- 
vator of  the  angle.  The  muscle  conceals  the  labial  branch  of  the  inferior 
dental  vessels  and  nerve.  At  its  origin  the  depressor  is  united  with  the 
platysma  myoides,  and  near  its  insertion  with  the  risorius  muscle. 

Action.  The  angle  of  the  mouth  is  drawn  downwards  and  backwards 
by  it,  as  is  exemplified  in  a  sorrowful  countenance. 

The  ZYGOMATIC  MUSCLES  (fig.  6)  are  directed  obliquely  from  the  arch 
of  the  same  name  towards  the  angle  of  the  mouth  and  the  upper  lip. 
One  is  longer  and  larger  than  the  other ;  they  are  therefore  named  major 
and  minor. 

The  zygomaticus  major ^  ^,  arises  from  the  outer  part  of  the  malar  bone, 
and  is  inserted  into  the  angle  of  the  mouth. 

The  zygomaticus  misior, ',  is  attached  to  the  malar  bone  anterior  to  the 
other,  and  blends  with  the  fibres  of  the  special  elevator  of  the  upper  lip. 

Action.  The  large  muscle  inclines  upwards  and  backwards  the  corner 
of  the  mouth ;  and  the  small  one  assists  the  levator  labii  superioris  in 
raising  the  upper  lip. 

The  RISORIUS  MUSCLE  (SantoHni)  (fig.  6,^)  is  a  thin  and  narrow  bun- 
dle of  fibres,  sometimes  divided  into  two  or  more  parts,  which  arises 
externally  from  the  fascia  over  the  masseter  muscle,  and  is  connected  in- 
ternally with  the  apex  of  the  depressor  anguli  oris. 

Action.  The  use  of  this  muscle  is  indicated  by  its  name,  as  it  retracts 
the  corner  of  the  mouth  in  laugliing. 

The  BUCCINATOR  (fig.  6,  ^*)  is  the  flat  and  thin  muscle  of  the  cheek, 
and  occupies  the  interval  between  the  jaws.  The  muscle  arises  from  the 
outer  surface  of  the  alveolar  borders  of  the  upper  and  lower  maxillie,  as 
far  forwards  in  each  as  the  first  molar  tooth ;  and  in  the  interval  between 
the  jaws  behind  it  is  attached  to  a  band  of  fascia — the  pterygo-maxillary 
ligament.  From  the  origin  the  fibres  are  directed  forwards  to  the  angle 
of  the  mouth,  where  they  mix  with  the  other  muscles  and  with  both  parts 
of  the  orbicularis ;  and  as  some  of  the  central  fibres  descend  to  the  lower 
lip  whilst  others  ascend  to  the  upper  lip,  a  decussation  takes  place  at  the 
corner  of  the  mouth. 

On  the  cutaneous  surface  of  the  buccinator  are  the  different  muscles 
converging  to  the  angle  of  the  mouth  ;  and  crossing  the  upper  part  is 
the  duct  of  the  parotid  gland,  which  perforates  the  muscle  opposite  the 
second  upper  molar  teeth.  Internally  the  muscle  is  lined  by  the  mucous 
membrane  of  the  mouth,  and  externally  it  is  covered  by  a  fascia  (bucco- 
pliaryngeal)  that  is  continued  to  the  pharynx.  By  its  intermaxillary 
origin  the  buccinator  corresponds  with  the  attachment  of  the  superior 
constrictor  of  the  pharynx. 

Action.  By  one  muscle  the  corner  of  the  mouth  is  retracted,  and  the 
cheek  wrinkled.  By  the  action  of  both  tiie  aperture  of  the  mouth  is 
widened  transversely. 

In  mastication  the  cheek  is  pressed  by  the  muscular  contraction  against 
the  dental  arches,  when  the  corner  of  the  mouth  is  fixed  by  the  sphincter. 

In  the  expulsion  of  air  from  the  mouth,  as  in  whistling,  the  muscle  is 


40  DISSECTION    OF    THE    FACE. 

contracted  so  as  to  prevent  bulging  of  the  cheek  ;  but  in  the  use  of  a 
blow-pipe  it  is  distended  over  the  volume  of  air  contained  in  the  mouth, 
and  drives  out  a  continuous  stream  of  air  by  its  contraction. 

The  VESSELS  OF  THE  FACE  (fig.  17)  are  the  facial  and  transverse  facial 
arteries  with  their  accompanying  veins.  The  arteries  are  branches  of  the 
external  carotid;  and  the  facial  vein  is  received  into  the  internal  jugular 
trunk. 

The  facial  artery  (fig.  17,  f),  a  branch  of  the  carotid,  emerges  from 
the  neck,  and  appears  on  the  lower  jaw  anterior  to  the  masseter  muscle. 
From  this  point  the  artery  ascends  in  a  tortuous  manner,  near  the  angle 
of  the  mouth  and  the  side  of  the  nose,  to  the  inner  angle  of  the  orbit, 
where  it  anastomoses  with  the  ophthalmic  artery.  The  course  of  the  ves- 
sel is  comparatively  superficial  in  the  mass  of  i'at  of  the  inner  part  of  the 
cheek.  At  first  it  is  concealed  by  the  platysma  whilst  crossing  the  jaw, 
but  this  thin  muscle  does  not  prevent  pulsation  being  recognized  during 
life;  and  near  the  mouth  the  large  zygomatic  muscle  is  sui)erficial  to  it. 
The  vessel  rests  successively  on  the  lower  jaw,  buccinator  muscle,  ele- 
vator of  the  angle  of  the  mouth,  and  elevator  of  the  upper  lip.  Accom- 
panying the  artery  is  the  facial  vein,  which  is  nearly  a  straight  tube,  and 
lies  to  the  outer  side. 

Branches.  From  the  outer  side  of  the  vessel  unnamed  branches  are 
furnished  to  the  muscles  and  integuments,  some  of  which  anastomose  with 
the  transverse  facial  artery.  From  the  inner  side  are  given  the  following 
branches : — 

The  inferior  labial  branch  (t)  runs  inwards  beneath  the  depressor 
anguli  oris  muscle,  and  is  distributed  between  the  lower  lip  and  chin;  it 
communicates  with  the  inferior  coronary,  and  with  the  labial  branch  of 
the  inferior  dental  artery. 

Coronary  branches  (r  and  s).  There  is  one  for  each  lip  (superior  and 
inferior),  which  arise  together  or  separately  from  the  facial,  and  are  di- 
rected inwards  between  the  orbicular  muscle  and  the  mucous  membrane 
of  the  lip,  till  they  inosculate  with  the  corresponding  branches  of  the 
opposite  side.  From  the  arterial  arches  thus  formed,  offsets  are  supplied 
to  the  lips  and  labial  glands.  From  the  arch  in  the  upper  lip  a  branch  is 
given  to  each  side  of  the  septum  of  the  nose, — artery  of  the  septum. 

The  lateral  nasal  branch  (p)  arises  opposite  the  ala  nasi,  and  passes 
beneath  the  levator  labii  superioris  aloeque  nasi  to  the  side  of  the  nose, 
where  it  anastomoses  with  the  internal  nasal  branch  of  the  ophthalmic 
artery. 

The  angular  branch  (o)  is  the  terminal  twig  of  the  f^icial  artery  at  the 
inner  angle  of  the  orbit,  and  joins  with  a  branch  (external  nasal)  of  the 
ophthalmic  artery. 

The  facial  vein  commences  at  the  root  of  the  nose  in  a  small  vein 
named  angular  (p.  21).  It  then  crosses  over  the  elevator  of  the  upper  lip, 
and  separating  from  the  artery,  courses  beneath  the  large  zygomatic  mus- 
cle to  the  side  of  the  jaw.  Afterwards  it  has  a  short  course  in  the  neck 
to  join  the  internal  jugular  vein. 

Branches.  At  the  inner  side  of  the  orbit  it  receives  veins  from  the  lower 
eyelid  (inferior  palpebral),  and  from  the  side  of  the  nose.  Below  the 
orbit  it  is  joined  by  the  infra-orbital  vein,  also  by  a  large  branch,  anterior 
internal  maxillary,  that  comes  from  the  pterygoid  region;  and  thence  to 
its  termination  by  veins  corresponding  with  the  branches  of  the  artery  in 
the  face  and  neck. 


PAROTID    GLAND.  41 

The  transverse  facial  artery  (fig.  17)  is  a  branch  of  the  temporal,  and 
appears  in  the  face  at  the  anterior  border  of  tlie  parotid  gland.  It  lies  by 
the  side  of  the  parotid  duct,  with  branches  of  the  facial  nerve,  and  dis- 
tributes offsets  to  the  muscles  and  integuments ;  some  branches  anastomose 
with  the  facial  artery. 

Dissection.  The  parotid  gland  in  front  of  the  ear  may  be  next  displayed. 
To  see  the  gland,  raise  the  skin  from  the  surface  towards  the  ear  by  means 
of  a  cut  from  the  base  of  the  jaw  to  the  anterior  border  of  the  sterno-mas- 
toid  muscle ;  this  cut  may  be  united  with  that  made  for  the  dissection  of 
tlie  posterior  muscle  of  the  ear.  A  strong  fascia  covers  the  gland,  and  is 
connected  above  and  behind  to  the  zygomatic  arch  and  the  cartilage  of  the 
ear,  but  is  continued  over  the  face  in  front;  this  is  to  be  removed,  so  that 
the  gland  may  be  detached  slightly  from  the  parts  around.  The  great 
auricular  nerve  will  be  seen  ascending  to  the  lobe  of  the  ear ;  and  one  or 
two  small  glands  rest  on  the  surface  of  the  parotid. 

The  PAROTID  (fig.  16,  '^^)  is  the  largest  of  the  salivary  glands.  It  occu- 
pies the  space  between  the  ear  and  the  lower  jaw,  and  is  named  from  its 
position.  Its  excretory  duct  enters  the  mouth  through  the  middle  of  the 
cheek. 

The  shape  of  the  gland  is  irregular,  and  is  determined  somewhat  by  the 
bounding  parts.  Thus  inferiorly,  where  there  is  not  any  resisting  struc- 
ture, the  parotid  projects  into  the  neck,  and  comes  into  close  proximity 
with  the  sub-maxillary  gland,  though  separated  from  it  by  a  process  of  the 
cervical  fascia;  a  line  from  the  angle  of  the  jaw  to  the  sterno-mastoid 
muscle  marks  usually  the  extent  of  the  gland  in  this  direction.  Above, 
the  parotid  is  limited  by  the  zygomatic  arch  and  the  temporal  bone. 
Along  the  posterior  part  the  sterno-mastoid  muscle  extends;  but  anteriorly 
the  gland  projects  somewhat  on  the  face,  and  in  this  direction  a  small 
accessory  part,  socia  parotidis^  is  prolonged  from  it  over  the  masseter. 

Connected  with  the  anterior  border  is  the  excretory  duct — duct  of  Sten- 
son  (ductus  Stenonis,  fig.  17),  which  crosses  the  masseter  below  the  socia 
parotidis,  and  perforates  the  cheek  obliquely  opposite  the  second  molar 
tooth  of  the  upper  jaw.  The  duct  lies  between  the  transverse  facial  artery 
and  some  branches  of  the  facial  nerve,  the  latter  being  below  it.  A  line 
drawn  from  the  meatus  auditorius  to  a  little  below  the  nostril  would  mark 
the  level  of  the  duct  in  the  face  ;  and  the  central  point  of  the  line  would 
be  opposite  the  opening  into  the  mouth.  The  length  of  the  duct  is  about 
two  inches  and  a  half;  and  its  capacity  is  large  enough  to  allow  a  small 
probe  to  pass,  but  the  opening  into  the  mouth  is  much  less. 

The  cutaneous  surface  of  the  parotid  is  smooth,  and  one  or  two  lymphatic 
glands  are  seated  on  it ;  but  from  the  deep  part  processes  are  sent  into  the 
inequalities  of  the  space  between  the  jaw  and  the  mastoid  process. 

Dissection.  By  removing  with  caution  the  parotid  gland,  the  hollows 
that  it  fills  wnll  come  into  view  :  at  the  same  time  the  dissector  will  see 
the  vessels  and  nerves  that  pass  through  it.  An  examination  of  the  pro- 
cesses of  the  gland,  and  of  the  number  of  important  vessels  and  nerves  in 
relation  with  it,  will  demonstrate  the  dangers  attending  any  operation  on 
it.  The  duct  may  be  opened,  and  a  pin  may  be  passed  along  it  to  the 
mouth,  to  show  the  diminished  size  of  the  aperture. 

Two  large  processes  of  the  gland  extend  deeply  into  the  neck.  One 
dips  behind  the  styloid  process,  and  projects  beneath  the  mastoid  process 
and  sterno-mastoid  muscle,  whilst  it  reaches  also  tlie  deep  vessels  and 
nerves  of  the  neck.     The  other  piece  is  situate  in  front  of  the  styloid 


42  DISSECTION    OF    THE    FACE. 

process ;  it  passes  into  the  glenoid  hollow  behind  the  articulation  of  the 
lower  jaw  ;  and  sinks  beneath  the  ramus  of"  that  bone  along  the  internal 
maxillary  artery. 

Passing  through  the  middle  of  the  gland  is  the  external  carotid  artery, 
which  ascends  behind  the  ramus  of  the  jaw,  and  furnishes  the  auricular, 
superficial  temporal,  and  internal  maxillary  branches.  Superficial  to  the 
artery  lies  the  trunk  formed  by  the  junction  of  the  temporal  and  internal 
maxillary  veins,  from  which  tlie  external  jugular  vein  springs  ;  and  this 
common  trunk,  receiving  some  veins  from  the  parotid,  is  connected  with 
the  internal  jugular  vein  by  a  branch  through  the  gland.^  Crossing  the 
gland  from  behind  forwards  is  the  trunk  of  the  facial  nerve,  which  passes 
over  the  artery,  and  distributes  its  branches  through  the  parotid.  The 
superficial  temporal  branch. of  the  inferior  maxillary  nerves  lies  above  the 
upper  part  of  the  glandular  mass  ;  and  offsets  of  the  great  auricular  nerve 
pierce  the  gland  at  the  lower  part,  and  join  the  facial. 

The  structure  of  the  parotid  resembles  that  of  the  other  salivary  glands. 
The  glandular  mass  is  divided  into  numerous  small  lobules  by  intervening 
processes  of  fascia ;  and  eacli  lobule  consists  of  a  set  of  the  fine  closed  sac- 
cular extremities  of  the  excretory  duct,  which  are  lined  by  flattened  and 
nucleated  epithelium,  and  surrounded  by  capillary  vessels.  These  little 
sacs  form  by  their  aggregation  the  mass  of  eacli  lobule. 

From  the  lobules  issue  small  ducts,  which  unite  to  form  larger  tubes, 
and  finally  all  the  ducts  of  the  gland  are  collected  into  one.  The  common 
duct  (duct  of  Stenson)  is  composed  of  an  external  fibrous  coat,  consisting 
of  white  and  elastic  fibres  ;  and  of  an  internal  mucous  coat  which  is  clothed 
with  columnar  epithelium. 

The  parotid  receives  its  arteries  from  the  external  carotid  ;  and  its  nerves 
from  the  sympathetic,  auriculo-temporal  of  tlie  fifth,  facial,  and  great  auri- 
cular.    Its  lymphatics  join  those  of  the  neck. 

Two  or  three  small  molar  glands  lie  along  the  origin  of  the  buccinator, 
and  open  into  the  moutli  near  the  last  molar  tooth  by  separate  ducts. 

Cartilages  of  the  Nose  (fig.  7).  These  close  the  anterior  nasal 
aperture  in  the  skeleton,  and  form  part  of  the  outer  nose  and  the  septum. 
Tliey  are  five  in  number,  two  on  each  side — lateral  cartilage  and  cartilage 
of  the  aperture  ;  together  with  a  central  one,  or  the  cartilage  of  the  septum 
of  the  nose.  Only  the  lateral  cartilages  are  seen  in  this  stage  of  the  dis- 
section. 

Dissection.  The  lateral  cartilages  will  be  seen  when  the  muscular  and 
fibrous  structure  of  the  left  side  of  the  nose,  and  the  skin  of  the  lower 
part  of  the  nostril  of  the  same  side,  have  been  taken  away.  By  turning 
aside  the  lateral  cartilages  the  septal  one  will  appear  in  the  middle  line. 

The  upper  lateral  cartilage  (fig.  7,  ^)  is  flattened,  and  is  somewhat 
triangular  in  form.  Posteriorly  it  is  attached  to  the  nasal  and  upper 
maxillary  bones ;  and  anteriorly  it  meets  the  one  of  the  opposite  side  for  a 
short  distance  above,  but  the  two  are  separated  below  by  an  interval,  in 
which  the  cartilage  of  the  septum  appears.     Interiorly  the  lateral  cartilage 

•  Oftentimes  there  is  a  different  arrangement  of  these  veins.  In  such  case  the 
external  jugular  is  continued  from  the  occipital  (half  or  all)  and  posterior  auri- 
cular veins  ;  whilst  the  temporal  and  internal  maxillary  veins  unite  to  form  a 
trunk  (tempo-maxillarj),  which  receives  the  facial  below  the  jaw,  and  opens  into 
the  internal  jugular  vein  opposite  the  upper  Imrder  of  the  thyroid  cartihage. 
When  this  condition  exists,  the  temporo-maxillary  vein  accompanies  the  external 
carotid  artery. 


APPENDAGES    OF    EYE.  43 

is  contiguous  to  the  cartilage  of  the  aperture,  and  is  connected  to  it  by 
fibrous  tissue. 

The  cartilage  of  the  aperture  (fig.  7)  forms  a  ring  around  the  opening 
of  the  nose  except  behind.  It  has  not  any  attacliraent  directly  to  bone  ; 
but  it  is  united  above  to  the  lateral  cartilage  by  fibrous  tissue,  and  below 
with  the  dense  teguments  forming  the  margin  of  the  aperture  of  the 
nostril. 

Fig.  7. 


1.  Triangular  septal  cartilage. 

2.  Upper  lateral  cartilage. 

3.  Lower  lateral,  or  the  cartilage  of  the  aperture,  the  outer  part. 
4'.  Inner  part  of  the  cartilage  of  the  aperture. 

5.  Nasal  boue. 


Lateral  Cartilages  of  the  Nose. 

The  part  of  the  cartilage  (^)  which  bounds  the  opening  externally,  is 
narrow  and  pointed  behind,  wliere  it  ends  in  two  or  three  small  pieces  of 
cartilage — cartilagines  minores  vel  sesamoidece ;  but  swells  out  in  front 
where  it  touches  its  fellow,  and  forms  the  apex  of  the  nose. 

Tiie  inner  part  (*)  projects  backwards  along  the  septum  of  the  nose 
nearly  to  the  superior  maxillary  bone ;  it  assists  in  the  formation  of  the  par- 
tition between  the  nostrils,  and  extends  below  the  level  of  the  septum  nasi. 

The  Appendages  of  the  Eye  include  the  eyebrow,  the  eyelid,  and 
the  lachrymal  apparatus.  Some  of  these  can  be  examined  now  on  the 
opposite  side  of  tlie  face.  The  apparatus  for  the  tears  will  be  dissected 
after  the  orbit  lias  been  completed. 

The  eyebrow  (supercilium)  is  a  curved  eminence  just  above  the  eye, 
which  is  placed  over  the  orbital  arch  of  the  frontal  bone.  It  consists  of 
thickened  integuments,  and  its  prominence  is  in  part  due  to  the  subjacent 
orbicularis  palpebrarum.  It  is  furnished  with  long  coarse  hairs,  which  are 
directed  outwards,  and  towards  one  another. 

The  eyelids  are  two  movable  semilunar  parts  in  front  of  the  eye,  which 
can  be  approached  or  separated  over  the  eyeball.  The  upper  lid  is  the 
largest  and  the  most  movable,  and  descends  below  the  middle  of  the  eye- 
ball when  the  two  meet ;  it  is  also  provided  with  a  special  muscle  to  raise 
it.  The  interval  between  the  open  lids  is  named  Jissura  palpebrarum. 
Externally  and  internally  tliey  are  united  by  a  commissure  or  canthns. 

Tlie  free  margin  is  tliicker  than  the  rest  of  tlie  lid,  and  is  semilunar  in 
form  ;  but  towards  the  inner  side,  about  a  quarter  of  an  inch  from  the 
commissure,  it  becomes  straighter.  At  the  spot  where  the  two  parts  join 
is  a  small  white  eminence  (fig.  13,  ^)  the  papilla  lachrymalis :  and  in  this 
is  the  punctum  lachrymale,  or  the  opening  of  tlie  canal  for  the  tears. 

This  margin  is  provided  anteriorly  with  the  eyelashes,  and  near  the 
posterior  edge  with  a  row  of  small  ojjenings  of  the  Meibomian  glands  ; 
but  both  the  cilia  and  the  glands  are  absent  from  the  part  of  the  lid  which 
is  internal  to  the  opening  of  the  punctum  lachrymale.     The  free   margin 


44  DISSECTION    OF    THE    FACE. 

of  each  lid  is  sharp  at  the  anterior  edge  where  it  touches  its  fellow ;  but  is 
sloped  at  the  posterior,  so  as  to  leave  an  interval  between  it  and  the  eye- 
ball for  the  passage  inwards  of  fluid. 

The  eyelashes  (cilia)  are  two  or  more  rows  of  curved  hairs,  which  are 
fixed  into  the  anterior  edge  of  the  free  border  of  the  lid ;  tliey  are  largest 
in  the  upper  lid,  and  diminish  in  length  from  the  centre  towards  the  sides. 
Tiie  cilia  are  convex  towards  one  another,  and  cross  when  the  lids  are 
shut. 

The  Structure  of  the  Eyelids.  Each  lid  consists  fundamentally 
of  a  piece  of  cartilage  attached  to  the  bone  by  ligaments.  Superficial  to 
this  framework  are  the  integuments  with  a  layer  of  fibres  of  the  orbicularis 
palpebrarum,  and  beneath  it  the  mucous  lining  of  the  conjunctiva.  The 
upper  lid  includes  also  the  tendon  of  the  levator  palpebras.  Vessels  and 
nerves  are  contained  in  the  lids. 

Dissection.  The  student  may  learn  the  structure  of  the  lids  on  the  left 
side,  on  which  the  muscles  are  dissected.  The  bit  of  tow  or  wool  may 
remain  beneath  the  lids;  and  the  palpebral  part  of  the  orbicularis  muscle 
is  to  be  thrown  inwards  by  an  incision  around  the  margin  of  the  orbit. 
In  raising  the  muscle  care  must  be  taken  of  the  thin  membranous  palpe- 
bral ligament  beneath,  and  of  the  vessels  and  nerves  of  the  lid. 

Orbicularis  palpebrarum.  The  palpebral  fibres  of  this  muscle  form  a 
pale  layer  which  reaches  the  free  edge  of  the  eyelids  (p.  36).  A  thin 
stratum  of  areolar  tissue  without  fat  unites  the  muscle  with  the  skin. 

The  palpebral  ligame^it  is  a  stratum  of  fibrous  membrane,  which  is 
continued  from  the  margin  of  the  orbit  to  join  the  lower  or  free  edge  of 
each  tarsal  cartilage.  At  the  inner  part  of  the  orbit  the  ligament  is  thin 
and  loose,  but  at  the  outer  part  it  is  somewhat  thicker  and  stronger. 

The  tarsal  cartilages^  one  for  each  eyelid,  are  elongated  transversely, 
and  give  strength  to  the  lids.  Each  is  fixed  internally  by  the  ligament  of 
the  eyelids,  and  externally  by  a  fibrous  band — external  tarsal  ligament, 
to  the  outer  part  of  the  orbit.  Tiie  margin  corresponding  with  the  edge 
of  the  lid-  is  free,  and  thicker  than  the  rest  of  the  cartilage.  On  the 
inner  surface  each  cartilage  is  lined  by  the  mucous  membrane  or  conjunc- 
tiva. 

The  cartilages  are  not  alike  in  the  two  lids.  In  the  upper  eyelid,  where 
the  cartilage  is  largest,  it  is  crescentic  in  shape,  and  is  about  half  an  inch 
wide  in  the  centre;  and  to  its  fore  part  the  tendon  of  the  levator  [)al[)ebra3 
is  attached.  In  the  lower  lid  the  cartilage  is  a  narrow  band,  about  two 
lines  broad,  with  borders  nearly  straigiit. 

Ligament  of  the  eyelids  (tendo  palpebrarum,  internal  tarsal  ligament) 
is  a  small  fibrous  band  at  the  inner  part  of  the  oubit,  which  serves  to  fix 
the  lids,  and  is  attached  to  the  anterior  margin  of  the  lachrymal  groove 
in  the  upper  jaw.  It  is  about  a  quarter  of  an  inch  long,  and  divides  into 
two  processes,  which  are  united  with  the  tarsal  cartilages,  one  to  each. 
This  ligament  crosses  the  lachrymal  sac,  to  which  it  gives  a  fibrous  expan- 
sion ;  and  the  fleshy  fibres  of  the  orbicularis  palpebrarum  arise  from  it. 

The  Meibomian  glands  or  follicles  are  placed  in  grooves  on  the  ocular 
surface  of  the  tarsal  cartilages.  They  extend,  parallel  to  one  another,  from 
the  thick  towards  the  op[)Osite  margin  of  the  cartilage  ;  and  their  number 
is  about  thirty  in  the  upper,  and  twenty  in  the  lower  lid.  The  apertures 
of  the  glands  open  in  a  line  on  the  free  border  of  the  lid  near  the  pos- 
terior edge. 

Each  gland  is  a  small  yellowish  tube,  closed  at  one  end,  and  having 


AURICLE    OF    THE    EAR.  45 

minute  lateral  coRcal  appendafi;es  connected  with  it.  Each  contains  a  seba- 
ceous secretion,  and  is  lined  by  flattened  epithelium. 

If  the  j)alpebral  ligament  be  cut  through  in  the  upper  lid,  the  tendon  of 
the  levator  palpebrce  will  be  seen  to  be  inserted  into  the  fore  part  of  the 
tarsal  cartilage  by  a  wide  aponeurotic  expansion. 

The  conjunctiva,  or  the  mucous  membrane,  lines  the  interior  of  the 
eyelids,  and  covers  the  anterior  part  of  the  ball  of  the  eye.  Inside  the 
lids  it  is  inseparably  united  to  the  tarsal  cartilages,  and  has  numerous  fine 
papilla?.  At  the  free  margin  of  the  lid  this  membrane  joins  the  common 
integuments.  Through  the  lachrymal  canals  and  sac  it  is  continuous  with 
the  pituitary  membrane  of  the  nose. 

At  the  inner  commissure  of  the  eyelids  the  conjunctiva  forms  a  promi- 
nent and  fleshy-looking  body — caruncula  lachrymalis  (fig.  13,  *),  which 
contains  a  group  of  mucous  follicles,  and  has  a  few^  minute  hairs  on  its 
surface.  External  to  the  carimcle  is  a  small  vertical  fold  of  the  mucous 
membrane — plica  semilunaris ;  this  extends  to  the  ball  of  the  eye,  and 
represents  the  membrana  nictitans  of  birds. 

Bloodvessels  of  the  eyelids.  The  arteries  of  the  eyelids  are  furnished 
by  the  ophthalmic  artery,  and  come  from  the  palpebral  and  lachrymal 
branches : — 

Tiie  palpebral  arteries,  one  for  each  eyelid,  run  outw^ards  from  the  inner 
canthus,  lying  between  the  tarsal  cartilage  and  the  tendon  of  the  special 
elevator  in  the  upper  lid,  and  between  the  cartilage  and  the  palpebral  liga- 
ment in  the  lower  lid  ;  and  they  anastomose  externally  with  the  lachrymal 
artery.  From  the  arch  that  each  forms,  branches  are  distributed  to  the 
eyelids. 

T!ie  lachrymal  artery  furnishes  an  offset  to  each  lid  to  form  arches  with 
the  palpebral  arteries,  and  then  perforates  the  palpebral  ligament  at  the 
outer  part  of  the  orbit  to  end  in  the  upper  lid. 

The  veins  of  the  lids  open  into  the  frontal  and  angular  veins  at  the  root 
of  the  nose  (pp.  21,  40). 

The  nerves  of  the  eyelids  are  supplied  from  the  ophthalmic  and  facial 
nerves. 

The  branches  of  the  ophthalmic  nerve  (of  the  fifth)  which  give  offsets 
to  the  upper  lid,  are  the  following  :  lachrymal,  near  the  outer  part ;  snpra" 
orbital,  about  the  middle ;  and  supra-trochlear  and  infra-trochlear  at  the 
inner  side  (pp.  42,  o4).  In  the  lower  eyelid,  about  its  middle,  is  &.  palpe- 
bral branch  of  the  superior  maxillary  trunk  of  the  fifth  nerve. 

Branches  of  the  facial  nerve  (p.  48)  enter  both  lids  at  the  outer  part, 
and  supply  the  orbicularis  muscle ;  they  communicate  with  the  offsets  of 
the  fiftli  nerve. 

External  Ear.  The  outer  ear  consists  of  a  trumpet-shaped  structure, 
named  pinna  or  auricle,  which  receives  the  undulations  of  the  air  ;  and  of 
a  tube — meatus  auditorius,  wiiich  conveys  them  to  the  inner  ear.  The 
pinna  may  be  examined  on  the  left  side  of  the  head ;  but  the  anatomy  of 
the  meatus  will  be  described  with  tiie  ear. 

The  pinna,  or  auricle^  is  fin  uneven  piece  of  yellow  fibro-cartilag(s 
which  is  covered  with  integument,  and  is  fixed  to  the  margin  of  the  meatus 
auditorius  externus.  It  is  of  an  oval  form,  with  the  margin  folded  and 
the  larger  end  placed  upwards. 

The  surface  next  the  head  is  generally  convex  ;  but  the  opposite  is  ex- 
cavated, and  presents  the  undermentioned  elevations  and  depressions.  In 
the  centre  is  a  deep  hollow  named  concha,  which  is  wide  above  but  narrow 


46 


DISSECTION    OF    THE    FACE. 


below  ;  it  conducts  to  the  meatus  auditorius.  In  front  of  the  narrowed 
part  of  the  hollow  is  a  projection  of  a  triangular  shape — the  tragus,  which 
has  some  hairs  on  the  under  surface  ;  and  on  the  opposite  side  of  the  same 
narrow  end,  rather  below  the  level  of  the  tragus,  is  placed  another  projec- 
tion— the  antitragus. 

The  round  rim-like  margin  of  the  ear,  which  extends  into  the  concha, 
is  called  the  helix;  and  the  depression  internal  to  it  is  the  groove  or  fossa 
of  the  helix.     Within  the  helix,  between  it  and  the  concha,  is  the  large 

Fiff.  8. 


Muscles  on  the  Outer  Surface  of  the  Ear  Cartilaoe, 
1.  Muscle.-!  of  the  tragus.  3.  Large  muscle  of  the  helix. 


2.  Muscles  of  the  antitragus. 


4.  Small  muscle  of  the  helix. 


Muscles  on  the  Inner  Surface  of  the  Ear  Cartilage 
6.  Transverse  muscle.  7.  Oblique  muscle  (Tod)  sometimes  seen. 

eminence  of  the  antihelix,  which  presents  at  its  upper  part  a  well-marked 
depression,  ihoi  fossa  of  the  antihelix. 

Inferiorly  the  external  ear  is  terminated  by  a  soft  pendulous  part,  the 
lobule. 

The  special  muscles  of  the  piniia,  which  ex.tend  from  one  part  of  the 
cartilage  to  another,  are  very  thin  and  pale.  Five  small  muscles  are  to 
be  recognized  ;  and  these  receive  their  names  for  the  most  part  from  the 
several  eminences  of  the  external  ear. 

Dissection.  In  seeking  the  small  auricular  muscles,  let  the  integuments 
be  removed  only  over  the  spot  where  each  muscle  is  said  to  be  placed.  A 
siiarp  knife  and  a  good  light  are  necessary  ibr  the  display  of  the  muscular 
fibres.  Occasionally  the  dissector  will  not  tind  one  or  more  of  the  number 
described  below. 

The  muscle  of  the  tragus  (fig.  8,  ^)  is  always  found  on  the  external 
aspect  of  the  process  from  wiiich  it  takes  its  name.  The  fibres  are  short, 
oblique,  or  transverse,  and  extend  from  the  outer  to  the  inner  part  of  the 
tragus. 

The  muscle  of  the  antitragus  (fig.  8,  ^)  is  the  best  marked  of  all.  It 
arises  from  the  outer  part  of  the  antitragus,  and  the  fibres  are  directed 
U[>wards  to  be  inserted  into  the  pointed  extremity  of  tlie  antihelix. 

The  small  muscle  of  the  helix  (fig.  8,  *)  is  often  indistinct  or  absent. 
It  is  placed  on  the  part  of  the  rim  of  the  ear  that  extends  into  the  concha. 

Tiie  large  muscle  of  the  helix  (fig.  8,  ^)  arises  above  the  small  muscle 


CARTILAGE    OF    AURICLE.  47 

of  the  same  part,  and  is  inserted  into  the  front  of  the  helix,  where  this  is 
about  to  curve  backwards.     It  is  usually  present. 

The  transiyerse  muscle  of  the  auricle  (fig.  8,  ^)  forms  a  wide  layer,  which 
is  situate  at  the  back  of  the  ear  in  the  depression  between  the  helix  and 
the  convexity  of  the  concha.  It  arises  from  the  convexity  of  the  carti- 
lage forming  the  concha,  and  is  inserted  into  the  back  of  the  helix.  The 
muscle  is  mixed  with  much  fibrous  tissue,  but  it  is  well  seen  when  that 
tissue  is  removed. 

Actions,  These  muscles  are  said  to  alter  slightly  the  condition  of  the 
outer  ear;  the  muscles  of  the  helix  assisting,  and  those  of  the  tragus  and 
anti tragus  retarding  the  passage  of  sonorous  undulations  to  the  meatus. 

Dissection.  The  pinna  may  now  be  detached  by  cutting  it  close  to  the 
bone.  When  the  integuments  are  entirely  taken  off,  the  cartilage  of  the 
pinna  will  be  apparent ;  but  in  removing  the  integuments,  the  lobule  of 
the  ear,  which  consists  only  of  skin  and  fat,  will  disappear  as  in  fig.  8. 

The  cartilage  of  the  pinna  (fig.  8)  resembles  much  the  external  ear  in 
form,  and  presents  nearly  the  same  parts.  The  rim  of  the  helix  subsides 
posteriorly  in  the  antihelix  about  the  middle  of  the  pinna ;  whilst  ante- 
riorly a  small  process  projects  from  it,  and  there  is  a  fissure  near  the  pro- 
jection. The  antihelix  is  divided  about  two-thirds  down  into  two  pieces  ; 
one  of  these  is  pointed,  and  is  joined  by  the  helix,  the  other  is  continued 
into  the  antitragus.  On  the  posterior  aspect  of  the  concha  is  a  strong 
vertical  process  of  cartilage. 

Inferiorly  the  cartilage  is  fixed  to  the  margin  of  the  external  auditory 
aperture  in  the  temporal  bone,  and  forms  part  of  the  meatus  auditorius  ; 
but  it  does  not  give  rise  to  a  complete  tube,  for  at  the  upper  and  outer 
part  the  canal  is  closed  by  fibrous  tissue. 

In  the  piece  of  cartilage  forming  the  under  part  of  the  meatus  are  two 
fissures  (Santorini),  one  is  at  the  base  of  the  tragus,  the  other  passes  from 
before  backwards. 

Some  ligaments  connect  the  pinna  with  the  head,  but  others  pass  from 
one  point  of  the  cartilage  to  another. 

The  external  lignments  are  condensed  bands  of  fibrous  tissue,  and  are 
two  in  number,  anterior  and  posterior.  The  anterior  fixes  the  fore  part 
of  the  helix  to  the  root  of  the  zygoma.  The  posterior  passes  from  the 
back  of  the  concha  to  the  mastoid  process.  The  chief  special  ligament 
crosses  the  interval  between  the  tragus  and  the  beginning  of  the  helix, 
and  completes  the  tube  of  the  meatus. 

The  FACIAL  NERVE  (portio  dura,  fig.  9),  or  the  seventh  cranial  nerve, 
confers  contractility  on  the  muscles  of  the  face.  Numerous  communica- 
tions take  place  between  it  and  the  fifth  nerve  ;  the  chief  of  these  are 
found  above  and  below  the  orbit,  and  over  the  body  of  the  lower  jaw. 

Dissection.  The  facial  nerve  is  to  be  displayed  on  the  right  side  of  the 
face  if  there  is  time  sufiicient  before  the  body  is  turned,  otherwise  it  is  to  be 
omitted  for  the  present  (see  p.  17).  Some  of  the  nerve  is  concealed  by  the 
])arotid  gland,  but  the  greater  part  is  anterior  to  the  glandular  mass. 

To  expose  the  ramification  of  the  nerve  beyond  the  parotid  gland,  let 
the  skin  be  raised  from  the  face  in  the  same  manner  as  on  the  left  side. 
The  different  branches  are  then  to  be  sought  as  they  escape  from  beneath 
the  anterior  border  of  the  gland,  and  are  to  be  followed  forwards  to  their 
termination. 

The  highest  branches  to  the  temple  have  been  already  partly  dissected 
above  the  zygomatic  arch  ;  and  their  junctions  with  the  temporal  branch 


48  DISSECTION    OF    THE    FACE. 

of  the  superior  maxillary  and  with  the  supra-orbital  nerve  have  been  seen. 
Other  still  smaller  branches  are  to  be  traced  to  the  outer  part  of  the  orbit, 
where  they  enter  the  eyelids  and  communicate  with  tlie  other  nerves  in 
the  lids ;  as  these  cross  the  malar  bone,  a  junction  is  to  be  found  with  the 
subcutaneous  malar  nerve  of  the  fifth. 

AVith  the  duct  of  the  parotid  are  two  or  more  large  branches,  which  are 
to  be  followed  below  the  orbit  to  their  junction  with  the  infra-orbital,  nasal, 
and  infra-trochlear  nerves. 

The  remaining  branches  to  the  lower  part  of  the  face  are  smaller  in 
size.  One  joins  with  the  buccal  nerve  at  the  lower  part  of  the  buccinator 
muscle ;  and  one  or  two  others  are  to  be  traced  forwards  to  the  lower  lip, 
and  to  the  labial  branch  of  the  inferior  dental  nerve. 

To  follow  backwards  the  trunk  of  the  nerve  through  the  gland,  the  in- 
teguments should  be  taken  from  the  surface  of  the  parotid  as  on  the  other 
side,  and  the  gland  should  be  removed  piece  by  piece.  In  this  proceeding 
the  small  branches  of  communication  of  the  great  auricular  nerve  with 
oiFsets  of  the  facial,  and  the  deep  branches  frora  the  facial  to  the  auriculo- 
temporal nerve,  are  to  be  sought. 

Lastly,  tlie  first  small  branches  of  the  facial  to  the  ear  and  the  digastric 
and  stylo-hyoid  muscles,  are  to  be  looked  for  close  to  the  base  of  the  skull 
before  the  nerve  enters  the  parotid. 

The  Nerve  outside  the  Skull  (fig.  9,  ^').  The  nerve  issues  from 
the  stylo-mastoid  foramen,  after  traversing  the  aqueduct  of  Fallopius,  and 
furnishes  immediately  the  three  following  small  branches  : — 

The  posterior  auricular  branch  (fig.  9,  *)  turns  upwards  in  front  of  the 
mastoid  process,  where  it  communicates  with  an  offset  of  the  great  auricu- 
lar, and  is  said  to  be  joined  by  a  branch  to  tiie  ear  from  the  pneumogastric 
(cranial)  nerve  ;  it  ends  in  auricular  and  mastoid  offsets  (p.  23). 

The  branch  to  the  digastric  muscle  generally  arises  in  common  with  the 
next.  It  is  distributed  by  many  offsets  to  the  posterior  belly  of  the  mus- 
cle near  the  skull. 

The  branch  to  the  stylo-hyoideus  is  a  long  slender  nerve,  which  is 
directed  inwards  and  enters  its  muscle  about  the  middle.  This  branch 
communicates  with  the  sympathetic  nerve  on  the  external  carotid  artery. 

As  soon  as  the  facial  nerve  has  given  off  those  branches,  it  is  directed 
forwards  through  the  gland,  and  divides  near  the  ramus  of  the  jaw  into 
two  large  trunks — temporo-facial  and  cervico-facial. 

The  temporo-facial  trunk  furnishes  offsets  to  the  side  of  the  head 
and  face,  whose  ramifications  extend  as  low  as  the  meatus  auditorius.  As 
this  trunk  crosses  over  the  external  carotid  artery,  it  sends  downwards 
branches  to  join  the  auriculo-temporal  portion  of  the  inferior  maxillary 
nerve  ;  and  in  front  of  the  ear  it  gives  some  filaments  to  the  tragus  of  the 
pinna.  Three  sets  of  terminal  branches,  temporal,  malar,  and  infra-orbi- 
tal, are  derived  from  the  temporo-facial  part. 

The  temporal  branches  ascend  obliquely  over  the  zygomatic  arch  to 
enter  the  orbicular  muscle,  the  corrugator  supercilii,  and  the  anterior  belly 
of  the  occipito-frontalis  ;  they  are  united  with  offsets  of  the  supra-orbital 
nerve  (®).  The  attrahens  aurem  muscle  receives  a  branch  from  this  set ; 
and  a  junction  takes  ))lace  above  the  zygoma  with  the  temporal  branch  of 
the  superior  maxillary  nerve  ('"). 

The  malar  branches  are  directed  to  the  outer  angle  of  the  orbit,  and 
are  distributed  to  the  orbicularis  muscle.  In  the  eyelids  communications 
take  place  with  the  palpebral  filaments  of  the  fifth  nerve ;  and  near  the 


FACIAL    NERVE 


49 


outer  part  of  the  orbit,  with  the  small  subcutaneous  malar  branch  of  the 
superior  maxillary  nerve  (®). 

The  infra-orhital  branches  are  longer  than  the  rest,  and  are  furnished 
to  the  muscles  and  the  integument  between  the  eye  and  mouth.  Close  to 
tlie  orbit,  and  beneath  the  elevator  of  the  upper  lip,  a  remarkable  commu- 
nication— infra-orbital  plexus,  is  formed  between  these  nerves  and  the 


Fig.  9. 


Na^a)  nerve. 
Tufra-trochlear. 
Subcutaneous  malar. 
Infra-orbital. 


12.  Buccal. 


Cutaneous  Branches  of  the  Fifth  Nerve  in  the  Face. 

13.  Labial  of  inferior  dental. 

15.  Facial  or  seventh  cranial,  sending  back  the 
posterior  auricular  branch,  4,  and  forwards 
its  numerous  ofisets  to  join  the  branches  of  the 
fifth  nerve  above  enumerated. 


infra-orbital  branches  of  the  superior  maxillary  (^^).  After  crossing  the 
branches  of  the  fifth  nerve,  some  small  offsets  of  tlie  facial  nerve  pass  in- 
wards to  the  side  of  the  nose,  and  others  upwards  to  the  inner  angle  of 
tlie  orbit,  to  supply  the  muscles,  and  to  join  tlie  nasal  (^)  and  infra-trochlear 
C*)  branches  of  the  ophthalmic  nerve. 
4 


50  DISSECTION    OF    THE    ORBIT. 

The  CERVico-FACiAL  IS  Smaller  than  the  other  trunk,  and  distributes 
nerves  to  the  lower  part  of  the  face  and  the  upper  part  of  the  neck.  Its 
highest  branches  join  the  lowest  offsets  of  the  temporo-facial  nerve,  and 
thus  complete  the  network  on  the  face.  This  trunk,  whilst  in  the  parotid, 
jrives  twigs  to  the  gland,  and  is  united  with  the  gi*eat  auricular  nerve. 
The  terminal  branches  distributed  from  it  are,  buccal,  supra-maxillary, 
and  infra-maxillary. 

The  buccal  branches  pass  forwards  towards  the  angle  of  the  mouth, 
giving  offsets  to  the  buccinator  muscle,  and  terminate  in  the  orbicularis 
oris.  On  the  buccinator  they  join  the  branch  Q'^)  of  the  inferior  maxillary 
nerve  to  that  muscle. 

The  supra-maxillary  branches  course  inwards  above  the  base  of  the 
lower  jaw  to  the  middle  line  of  the  chin,  and  supply  the  muscles  and  tlie 
integument  between  the  chin  and  mouth.  Beneath  the  depressor  anguli 
oris  the  branches  of  the  facial  join  offsets  of  the  labial  branch  of  the  in- 
ferior dental  nerve  Q^)  in  their  course  to  the  middle  line. 

The  infra-maxillary  branches  lie  below  the  jaw,  and  are  distributed  to 
the  upper  part  of  the  neck.  The  anatomy  of  these  nerves  will  be  given 
with  the  dissection  of  the  anterior  triangle  of  the  neck. 


Section  IV. 

DISSECTION  OF  THE  ORBIT. 


Directions.  The  orbit  should  be  learnt  on  that  side  on  which  the  mus- 
cles of  the  face  have  been  seen. 

Position.  In  the  examination  of  the  cavity*  the  head  is  to  be  placed  in 
the  same  position  as  for  the  dissection  of  the  sinuses  of  the  base  of  the 
skull. 

Dissection.  For  the  display  of  the  contents  of  the  orbit,  it  will  be  neces- 
sary to  take  away  the  cotton  w^ool  from  beneath  the  eyelids.  To  remove 
the  bones  forming  the  roof  of  the  space,  two  cuts  may  be  made  with  a  saw 
through  the  margin  of  the  orbit,  one  being  placed  at  the  outer,  the  other 
near  the  inner  angle  of  the  cavity ;  and  these  should  be  continued  back- 
ward with  a  chisel,  along  the  roof  of  the  orbit,  so  as  to  meet  near  the  optic 
foramen.  The  piece  of  bone  included  in  the  incisions  is  now  to  be  tilted 
forwards,  but  is  not  to  be  taken  away. 

Afterwards  the  rest  of  the  roof  of  the  orbit,  which  is  formed  by  the 
small  wing  of  the  sphenoid  bone,  is  to  be  cut  away  w^ith  the  bone  forceps, 
except  a  narrow  ring  around  the  optic  foramen  ;  and  any  overhanging 
bone  on  the  outer  side,  which  may  interfere  with  the  dissection,  may  be 
likewise  removed.  During  the  examination  of  the  cavity  the  eye  is  to 
be  pulled  gently  forwards. 

The  periosteum  of  the  orbit,  which  has  been  detached  from  the  bone  in 
the  dissection,  surrounds  the  contents  of  the  orbital  cavity,  and  joins  the 
dura  mater  of  the  brain  through  the  sphenoidal  fissure.  It  encases  the 
contents  of  the  orbit  like  a  sac,  and  adheres  but  loosely  to  the  bones. 
Apertures  exist  posteriorly  in  the  membrane  for  the  entrance  of  the  dif- 
ferent nerves  and  vessels  ;  and  laterally  prolongations  of  the  periosteum 
accompany  the  vessels  and  nerves  leaving  the  cavity. 


OPHTHALMIC    NERVE.  51 

Dissection.  The  periosteum  is  next  to  be  divided  along  the  middle  of 
the  orbit,  and  to  be  taken  away.  After  the  removal  of  a  little  fat,  the 
following  nerves,  vessels,  and  museles  come  into  view  ;  but  it  is  not  need- 
ful to  remove  much  of  the  fat  in  this  stage  of  the  dissection. 

The  frontal  nerve  and  the  supra-orbital  vessels  lie  in  the  centre ;  the 
lachrymal  nerve  and  vessels  close  to  the  outer  wall ;  and  the  small  fourth 
nerve  at  the  back  of  the  orbit :  all  these  nerves  enter  the  cavity  above  the 
muscles.  The  superior  oblique  muscle  is  recognized  by  the  fourth  nerve 
entering  it :  the  levator  palpebrie  and  superior  rectus  lie  beneath  the 
frontal  nerve ;  and  the  external  rectus  is  partly  seen  below  the  lachrymal 
nerve.  In  the  outer  part  of  the  orbit,  near  the  front,  is  the  lachrymal 
gland. 

The  frontal  and  lachrymal  nerves  should  be  followed  forwards  to  their 
exit  from  the  orbit,  and  backwards  with  the  fourth  nerve,  through  the 
sphenoidal  fissure,  to  the  wall  of  the  cavernous  sinus.  In  tracing  them 
back,  it  will  be  expedient  to  remove  the  projecting  clinoid  process,  should 
this  still  remain  ;  and  some  care  will  be  required  to  follow  the  lachrymal 
nerve  to  its  commencement. 

Contents  of  the  orbit.  The  eyeball  and  the  lachrymal  gland,  and  a  great 
quantity  of  granular  fat,  are  lodged  in  the  orbit.  Connected  with  the  eye 
are  six  muscles — four  straight  and  two  oblique  ;  and  there  is  also  an  ele- 
vator of  the  upper  eyelid  in  the  cavity. 

The  nerves  in  this  small  space  are  numerous,  viz.,  the  second,  third, 
fourth,  ophthalmic  of  the  fifth,  and  the  sixth  nerve,  together  with  the  small 
temporo-malar  branch  of  the  superior  maxillary  nerve,  and  offsets  of  the 
sympathetic  ;  their  general  distribution  is  as  follows  : — The  second  nerve 
penetrates  the  eyeball ;  the  third  is  furnished  to  all  the  muscles  of  the 
cavity  but  two  ;  the  fourth  enters  the  superior  oblique  (one  of  the  two  ex- 
cepted) ;  and  the  sixth  is  spent  in  the  external  rectus  muscle.  The  fifth 
nerve  supplies  some  filaments  to  the  eyeball  with  the  sympathetic,  but  the 
greater  number  of  its  branches  pass  through  the  orbital  cavity  to  the  face. 
The  ophthalmic  vessels  are  also  contained  in  the  orbit. 

The  lachrymal  gland  (fig.  10,  f)  secretes  the  tears,  and  is  situate  in 
the  hollow  on  the  inner  side  of  the  external  angular  process  of  the  frontal 
bone.  It  is  of  a  lengthened  form,  something  like  an  almond,  and  lies 
across  the  eye.  From  its  anterior  part  a  thin  accessory  piece  projects  be- 
neath the  upper  eyelid.  The  upper  surface  is  convex,  and  in  contact  with 
the  periosteum,  to  which  it  is  connected  by  fibrous  bands  that  constitute  a 
ligament  for  the  gland  ;  the  lower  surface  rests  on  the  eyeball  and  the 
external  rectus  muscle. 

In  structure  the  lachrymal  resembles  the  salivary  glands ;  and  its  very 
fine  ducts,  from  eight  to  twelve  in  number,  open  by  as  many  apertures  in 
a  semicircular  line  on  the  inner  aspect  of  the  upper  eyelid  towards  the 
outer  canthus. 

The  FOURTH  NERVE  (fig.  10,  ^)  is  the  most  internal  of  the  three  nerves 
entering  the  orbit  above  the  muscles.  After  reaching  this  space,  it  is 
directed  inwards  to  the  superior  oblique  muscle,  which  it  pierces  at  the 
orbital  surftice,  contrary  to  the  general  mode  of  distribution  of  the  nerves 
on  the  ocular  surface  of  tlie  muscles. 

The  oriiTiiALMic  trunk  of  the  fifth  nerve  (fig.  10,  p.  52),  as  it  ap- 
proaches the  sphenoidal  fissure,  furnishes  from  its  inner  side  tlie  nasal 
branch,  and  then  divides  into  the  frontal  and  lachrymal  branches ;    the 


62 


DISSECTION    OF    THE    ORBIT. 


former  passes  into  the  orbit  between  the  heads  of  the  external  rectus,  but 
the  other  two  lie,  as  before  said,  above  the  muscles. 

The  frontal  7ierve  (fig.  10,  ^)  is  close  to  the  outer  side  of  the  fourth  as 
it  enters  the  orbit,  and  is  much  larger  than  the  lachrymal  branch.  In  its 
course  to  the  foreliead  the  nerve  lies  along  the  middle  of  the  orbit,  and 
supplying  anteriorly  a  supra-trochlear  brancli  (*),  leaves  that  cavity  by 
the  supra-orbital  notch.  Taking  the  name  supra-orbital,  it  ascends  on 
the  forehead,  and  supplies  the  external  part  of  the  head  (p.  21). 

Fig.  10. 


Muscles : 
a.  Superior  oblique. 
&.  Levator  palpebrse. 

c.  External  rectus. 

d.  Superior  rectus. 
/.  Lachrymal  glaud. 

Nerves  : 

1.  Fourth. 

2.  Frontal. 

3.  Lachrymal. 

4.  Snpra-trochlear. 

6.  Offset  of  lachrymal  to  join  tera- 
poro-malar. 


First  View  of  the  Okbit  (Illustrations  of  Dissections). 

Whilst  in  the  notch  tlie  nerve  gives  palpebral  filaments  to  the  upper  lid. 

The  supra-trochlear  branch  {*)  passes  inwards  above  the  pulley  of  the 
upper  oblique  muscle,  and  leaves  the  orbit  to  end  in  the  eyelid  and  fore- 
head (p.  23).  Before  the  nerve  turns  round  the  margin  of  the  frontal  bone, 
it  sends  downwards  a  branch  of  communication  to  the  infra-trochlear 
branch  of  the  nasal  nerve.  Frequently  there  are  two  supra-trochlear 
branches ;  in  such  instances  one  arises  near  the  back  of  tlie  orbit. 

The  lachrymal  nerve  (fig.  10,  ^)  after  entering  the  orbit  in  a  separate 
tube  of  the  dura  mater,  is  directed  forwards  in  tlie  outer  part  of  the  cavity, 
and  beneath  the  lachrymal  gland  to  the  upper  eyelid,  where  it  pierces  the 
palpebral  ligament,  and  is  distributed  to  the  structure  of  the  lid. 

The  nerve  furnishes  branches  to  the  lachrymal  gland  ;  and  near  the 
gland  it  sends  downwards  one  or  two  small  filaments  (^)  to  communicate 
with  the  temporo-malar  or  orbital  branch  of  tlie  superior  maxillary  nerve. 


SUPERIOR    OBLIQUE    MUSCLE.  63 

Occasionally  it  has  a  communicating  filament  behind  with  the  fourth 
nerve. 

The  nasal  nerve  is  not  visible  at  this  stage  of  the  dissection  :  it  will  be 
noticed  afterwards  at  p.  43. 

Dissection.  Divide  the  frontal  nerve  about  its  middle,  and  throw  the 
ends  forwards  and  backwards  :  by  raising  the  posterior  part  of  the  nerve, 
the  separate  origin  of  the  nasal  branch  from  the  ophthalmic  trunk  will 
appear.     The  lachrymal  nerve  may  remain  uncut. 

The  LEVATOR  PALPEBR^  supERiORis  (fig.  10,  b)  is  the  most  superfi- 
cial muscle,  and  is  attached  posteriorly  to  the  roof  of  the  orbit  in  front  of 
the  optic  foramen.  The  muscle  widens  in  front,  and  bends  downwards  in 
the  eyelid  to  be  inserted  by  a  wide  tendon  into  the  fore  part  of  the  tarsal 
cartilage. 

By  one  surface  the  muscle  is  in  contact  with  the  frontal  nerve  and  the 
periosteum ;  and  by  the  other,  with  the  superior  rectus  muscle.  If  it  is 
cut  across  about  the  centre  a  small  branch  of  the  third  nerve  will  be  seen 
entering  the  posterior  half  at  the  under  surface. 

Action.  The  lid-cartilage  is  made  to  glide  upwards  over  the  ball  by  this 
muscle,  so  that  the  upper  edge  is  directed  back  and  the  lower  forwards, 
the  teguments  of  the  lid  being  bent  inwards  at  the  same  time.  If  the  eye- 
ball is  directed  down,  the  movement  of  the  lid  is  less  free,  because  the 
conjunctiva  is  put  on  the  stretch. 

The  RECTUS  SUPERIOR  (fig.  10,  ^)  is  the  upper  of  four  muscles  that  lie 
arouud  the  globe  of  the  eye.  It  arises  from  the  upper  part  of  the  optic 
foramen,  and  is  connected  with  the  other  recti  muscles  around  the  optic 
nerve.  In  front  the  fleshy  fibres  end  in  a  tendon,  which  is  inserted,  like 
the  other  recti,  into  the  sclerotic  coat  of  the  eyeball  about  a  quarter  of  an 
inch  behind  the  transparent  cornea. 

The  under  surface  of  the  muscle  is  in  contact  with  the  globe  of  the  eye, 
and  with  some  vessels  and  nerves  to  be  afterwards  seen ;  the  other  surface 
is  covered  by  the  preceding  muscle.  The  action  of  the  muscle  will  be 
given  with  the  other  recti  (p.  57). 

The  SUPERIOR  OBLIQUE  MUSCLE  (fig.  10,  ^)  is  thin  and  narrow,  and 
passes  through  a  fibrous  loop  at  the  inner  angle  of  the  orbit  before  reach- 
ing the  eyeball.  The  muscle  arises  behind  from  the  inner  part  of  the 
optic  foramen,  and  ends  anteriorly  in  a  rounded  tendon,  which,  after  pass- 
ing through  the  loop  before  referred  to  (fig.  11)  is  reflected  backwards  and 
outwards  between  the  superior  rectus  and  the  globe  of  the  eye,  and  is  in- 
serted into  the  sclerotic  coat  behind  the  middle  of  the  ball. 

The  fourth  nerve  is  supplied  to  the  orbital  surface  of  the  muscle,  and 
the  nasal  nerve  lies  below  it.  The  thin  insertion  of  the  muscle  lies  between 
the  superior  and  the  external  rectus,  and  near  the  tendon  of  the  inferior 
oblique. 

The  pulley,  or  trochlea  (fig.  11),  is  a  fibro-cartilaginous  ring  nearly  a 
quarter  of  an  inch  wide,  which  is  attached  by  fibrous  tissue  to  the  depres- 
sion of  the  frontal  bone  at  the  inner  angle  of  the  orbit.  A  fibrous  layer  is 
prolonged  from  the  margins  of  the  pulley  on  the  tendon  ;  and  a  synovial 
membrane  lines  the  ring,  to  facilitate  the  movement  of  the  tendon  through 
it.  To  see  the  synovial  membrane  and  the  motion  of  the  tendon,  this  pro- 
longation must  be  cut  away. 

For  the  use  of  the  muscle,  see  the  description  of  the  inferior  oblique, 
p.  59. 


54  DIHSECTION    OF    THE    ORBIT. 

Dissection.  The  superior  rectus  muscle  is  next  to  be  divided  about  the 
middle,  and  turned  backwards  (fig.  11),  when  a  brancli  of  the  third  nerve 
to  its  under  surface  will  be  found.  At  the  same  time  the  nasal  nerve  and 
the  ophthalmic  artery  and  vein  will  come  into  view  as  they  cross  inwards 
above  the  optic  nerve  :  these  should  be  traced  forwards  to  the  inner  angle, 
and  backwards  to  the  posterior  part  of  the  orbit. 

By  taking  away  the  fat  between  the  optic  nerve  and  the  external  rectus, 
at  the  back  of  the  orbit,  the  student  will  find  easily  fine  nerve-threads 
(ciliary)  with  small  arteries  lying  along  the  side  of  the  optic  nerve ;  and 
by  tracing  the  ciliary  nerves  backwards,  they  will  guide  to  the  small  len- 
ticular ganglion  (the  size  of  a  pin's  head)  and  its  branches.  The  dissector 
should  find  then  two  branches  from  the  nasal  and  third  nerves  to  the 
ganglion  :  the  nasal  branch  is  slender,  and  enters  the  ganglion  behind,  and 
that  of  the  third  nerve,  short  and  thick,  joins  the  lower  part. 

Lastly,  the  student  should  separate  from  one  another  the  nasal,  third, 
and  sixth  nerves,  as  they  pass  between  the  heads  of  the  external  rectus 
muscle  into  the  orbit. 

The  THIRD  NERVE  is  placed  highest  in  the  wall  of  the  cavernous  sinus 
(fig.  4,  ^)  ;  but  at  the  sphenoidal  fissure  it  descends  b^low  the  fourth,  and 
the  two  superficial  branches  (frontal  and  laclirymal)  of  the  ophthalmic 
nerve.  It  comes  into  the  orbit  between  the  heads  of  the  outer  rectus, 
having  previously  divided  into  two  parts. 

The  tipper  piece  (fig.  11,  ^),  the  smallest  in  size,  ends  in  the  under  sur- 
face of  the  levator  palpebral  and  superior  rectus  muscles. 

The  lower  piece  supplies  some  of  the  other  muscles,  and  will  be  dissected 
afterwards  (p.  57). 

The  nasal  branch  of  the  ophthalmic  nerve  (fig.  11/)  enters  the  orbit 
between  the  heads  of  the  rectus,  lying  between  *the  two  parts  of  the  third 
nerve.  In  the  orbit  the  nerve  is  directed  obliquely  inwards  to  reach  the 
anterior  of  the  two  foramina  in  the  inner  wall.  Passing  through  this 
aperture  with  the  anterior  ethmoidal  (nasal)  artery,  the  nerve  appears  in 
the  cranium  at  the  outer  margin  of  the  cribriform  plate  of  the  ethmoid 
bone.  Finally,  it  enters  the  nasal  cavity  by  an  aperture  at  the  front  of 
the  cribriform  plate  :  and  after  passing  behind  the  nasal  bone,  it  is  directed 
outwards  between  that  bone  and  the  cartilage,  to  end  on  the  outer  side  of 
the  nose. 

In  the  orhit  the  nasal  crosses  over  the  optic  nerve,  but  beneath  the 
superior  rectus  and  levator  jjalpebrag  muscles,  and  lies  afterwards  below 
the  superior  oblique  ;  in  this  part  of  its  course  it  furnishes  tlie  following 
branches : — 

The  branch  to  the  lenticular  ganglion  (^)  is  about  half  an  inch  long  and 
very  slender,  and  arises  as  soon  as  the  nerve  comes  into  the  orbit :  this  is 
the  long  root  of  the  lenticular  ganglion. 

Long  ciliary  branches.  As  the  nasal  crosses  the  optic  nerve,  it  supplies 
two  or  more  ciliary  branches  (fig.  11)  to  the  eyeball.  These  lie  on  the 
inner  side  of  the  optic,  and  join  the  ciliary  branches  of  the  lenticular 
ganglion. 

The  infra-trochlear  branch  Q)  arises  as  the  nasal  nerve  is  about  to  leave 
the  cavity,  and  is  directed  forwards  below  the  pulley  of  the  superior  oblique 
muscle,  to  end  in  the  upper  eyelid,  the  conjunctiva,  and  the  side  of  the 
nose.  Before  this  branch  leaves  the  orbit  it  receives  an  offset  of  commu- 
nication from  the  supra-troclilear  nerve. 

In  the  nose  (fig.  34).     Whilst  in  the  nasal  cavity  the  nerve  furnishes 


OPHTHALMIC    ARTERY 


55 


branches  to  the  lining  membrane  of  the  septum  narium  and  outer  wall ; 
these  will  be  subsequently  referred  to  with  the  nose. 

Fig.  11. 


Second  View  of  the  Orbit  (Illustrations  of  Dissections). 
Nerve  ft  : 


Muscles : 

a.  Superior  oblique. 

b.  Levator  palpebne  and  upper  rectus  thrown 

back  together. 

c.  External  rectus. 

d.  Fore  part  of  upper  rectus. 
/.   Lachrymal  gland. 


1.  Nasal  nerve  beginning  outside  of  the  orbit. 

2  Its  infra-trochlear  branch. 

.3.  Lenticular  ganglion  : — 

4.  Its  branch  to  the  third  nerve  ; 

5.  Its  branch  to  the  nasal  nerve  (too  large). 

6.  Branch  of  third  to  inferior  oblique  muscle. 

7.  Ciliary  branches  of  the  nasal  nerve. 

8.  Upper  branch  of  the  third. 

9.  Sixth  nerve. 

10.  Third  nerve,  outside  the  orbit. 

Termination  of  the  nasal  nerve  (fig.  9).  After  the  nerve  becomes 
cutaneous  on  the  side  of  the  nose,  as  seen  in  the  dissection  of  the  facial 
nerve  (p.  47),  it  descends  beneath  the  compressor  naris  muscle,  and  ends 
in  the  integuments  of  the  wing  and  tip  of  the  nose. 

The  OPHTHALMIC  or  LENTICULAR  GANGLION  of  the  Sympathetic  nerve 
(fig.  11,  ^)  is  a  small  round  body,  of  the  size  of  a  pin's  head,  and  of  a 
slight  red  color.  It  is  placed  at  the  back  of  the  orbit  between  the  optic 
nerve  and  the  external  rectus,  and  commonly  on  the  outer  side  of,  and 
close  to  the  ophthalmic  artery.  By  its  posterior  part  the  ganglion  has 
branches  of  communication  with  other  nerves  (its  roots)  ;  and  from  the 
anterior  part  proceed  the  ciliary  nerves  to  the  eyeball.  The  ganglion 
communicates  with  sensory,  motory,  and  sympathetic  nerves. 

Tlie  off'sets  of  communication  are  tliree  in  number.  One,  the  long 
root  (^),  is  the  branch  of  the  nasal  nerve  before  noticed,  which  joins  the 


bi)  DISSECTION    OF    THE    ORBIT. 

superior  angle.  A  second  branch  of  considerable  thickness  (short  root  *) 
passes  from  the  inferior  angle  to  join  the  branch  of  the  third  nerve  that 
supplies  the  inferior  oblique  muscle.  And  the  third  root  is  derived  from  the 
sympathetic  (the  cavernous  plexus),  either  in  union  with  the  long  root,  or 
as  a  distinct  branch  to  the  posterior  border  of  the  ganglion. 

Branches.  The  short  ciliary  nerves  (fig.  11)  are  ten  or  twelve  in 
number,  and  are  collected  into  two  bundles,  which  leave  the  upper  and 
lower  angles  of  the  front  of  the  ganglion.  In  the  upper  bundle  are  four  or 
five,  and  in  the  lower,  six  or  seven  nerves.  As  they  extend  along  the 
optic  nerve  to  the  eyeball  they  occupy  the  outer  and  under  parts,  and  com- 
municate with  the  long  ciliary  branches  of  the  nasal  nerve. 

The  OPHTHALMIC  ARTERY,  a  branch  of  the  internal  carotid,  is  trans- 
mitted into  the  orbit  through  the  optic  foramen.  At  first  the  vessel  is 
outside  the  optic  nerve,  but  it  then  courses  inwards,  over  or  under  the 
nerve,  to  the  inner  angle  of  the  orbit,  where  it  ends  in  a  nasal  brancli 
(external)  on  the  side  of  the  nose  (fig.  17,  **),  and  anastomoses  with  tlie 
angular  and  nasal  branches  of  the  facial. 

The  branches  of  the  artery  are  numerous,  though  inconsiderable  in  size, 
and  may  be  arranged  in  three  sets  : — one  arising  outside  the  optic  nerve, 
another  above  it,  and  a  third  set  on  the  inner  side. 

The  lachrymal  artery  accompanies  the  nerve  of  the  same  name  to  the 
upper  eyelid,  where  it  ends  by  supplying  that  part,  and  anastomosing  witli 
the  palpebral  arches.  It  supplies  branches,  like  the  nerve,  to  the  lachry- 
mal gland  and  the  conjunctiva ;  and  it  anastomoses  with  the  middle  men- 
ingeal by  an  offset  through  the  sphenoidal  fissures. 

At  the  front  of  the  orbit  it  sends  a  small  branch  with  each  of  the  ter- 
minal pieces  of  the  temporo-malar  nerve  ;  and  these  join  the  temporal  an<l 
transverse  facial  arteries. 

The  central  artery  of  the  retina  is  a  very  small  branch  which  pierces 
the  optic  nerve,  and  so  reaches  its  destination  in  the  eyeball. 

The  swpra-orbital  branch  arises  beneath  the  levator  palpebral  and  supe- 
rior rectus  muscles ;  it  then  takes  the  course  of  the  nerve  of  the  same 
name  through  the  notch  in  the  margin  of  the  orbit,  and  ends  in  branches 
on  tlie  forehead  (p.  21).  As  it  winds  round  the  margin  of  the  orbit  it  suj)- 
plies  the  eyelid  and  the  orbicularis  muscle. 

The  ciliary  branches  are  uncertain  in  their  place  of  origin  and  enter 
the  eyeball  at  the  front  and  back  : — 

The  posterior  ciliary^  about  twelve  in  number,  are  continued  to  the 
eyeball  around  the  optic  nerve,  and  perforate  the  sclerotic  coat  at  the  pos- 
terior part.  Two  of  this  set  (one  on  each  side  of  the  optic  nerve),  named 
long  ciliary,  pierce  the  sclerotic  farther  out  than  the  others,  and  lie  along 
the  middle  of  the  eyeball. 

The  anterior  ciliary  arteries  arise  from  muscular  branches  of  the  oph- 
thalmic, and  perforate  the  sclerotic  coat  near  the  cornea  :  in  the  eyeball 
they  anastomose  with  the  posterior  ciliary.  For  the  ending  of  these  vessels, 
see  the  eyeball. 

The  muscular  branches  are  not  fixed  in  their  place  of  origin  ;  and  those 
to  the  lower  muscles  often  arise  together  as  one  trunk. 

The  ethmoidal  branches  are  two,  anterior  and  posterior,  and  are  directcMl 
through  the  foramina  in  the  inner  wall  of  the  orbit: — 

The  posterior  is  the  smaller  of  the  two,  and  furnishing  small  meningeal 
offsets  (anterior)  to  the  dura  mater  of  the  base  of  the  skull,  descends  into 


RECTI    MUSCLES.  67 

the  nose  cavity  through  the  openings  in  the  cribriform  plate  of  the 
ethmoid. 

The  anterior  branch  (internal  nasal)  accompanies  the  nasal  nerve  to 
the  cavity  of  the  nose  (Section  XIV.),  and  gives  likewise  meningeal  off- 
sets to  the  dura  mater,  and  the  fore  part  of  the  falx  cerebri. 

The  palpebral  branches^  one  for  each  eyelid,  generally  arise  together 
opposite  the  pulley  of  the  superior  oblique  muscle,  and  then  separate  from 
one  another.  Tlie  arches  they  form  have  been  dissected  with  the  eyelids 
(p.  45). 

The  frontal  branch  turns  round  the  margin  of  the  orbit,  and  is  distrib- 
uted on  the  forehead  (p.  21). 

The  ophthalmic  vein  corresponds  in  its  course  and  most  of  its  branches 
with  the  artery  of  the  same  name.  It  begins  at  the  inner  angle  of  the 
orbit,  where  it  joins  the  facial  vein,  and  receives  tributary  branches  in  its 
progress  to  the  back  of  the  cavity.  Posteriorly  it  leaves  the  artery,  and 
escapes  from  the  orbit  by  the  sphenoidal  fissure  between  the  heads  of  the 
external  rectus,  to  end  in  the  cavernous  sinus. 

The  OPTIC  NERVE  in  the  orbit  extends  from  the  optic  foramen  to  the 
back  of  the  eyeball.  As  the  nerve  leaves  the  foramen  it  is  surrounded  by 
the  recti  muscles  ;  and  beyond  that  spot  the  ciliary  arteries  and  nerves 
entwine  around  it.     It  terminates  in  the  retinal  expansion  of  the  eye. 

Dissection  (fig.  12).  Take  away  the  ophthalmic  artery,  and  divide  the 
optic  nerve  about  its  middle,  together  with  the  small  ciliary  vessels  and 
nerves.  Turn  forwards  the  eyeball,  and  fasten  it  in  that  position  with 
hooks.  On  removing  some  fat  the  three  recti  muscles — inner,  inferior, 
and  outer,  will  appear ;  and  lying  on  the  two  first,  are  the  offsets  of  the 
lower  branch  of  the  third  nerve. 

The  lower  branch  of  the  third  nerve  (fig.  12)  supplies  three  muscles  in 
the  orbit.  Whilst  entering  this  space  between  the  heads  of  the  external 
rectus,  it  lies  below  the  nasal,  and  rather  above  the  sixth  nerve.  Almost 
immediately  afterwards  the  nerve  divides  into  three  branches.  One  Q) 
enters  the  internal  rectus  ;  another  (*)  the  inferior  rectus  ;  and  the  third 
(•''),  the  longest  and  most  external,  is  continued  forwards  to  the  inferior 
oblique  muscle  which  it  pierces  at  the  hinder  border. 

Soon  after  its  origin  the  last  branch  communicates  with  the  lenticular 
ganglion,  forming  the  short  root  (fig.  11,  ^)  of  that  body;  and  it  furnishes 
two  or  more  filaments  to  the  inferior  rectus. 

The  SIXTH  NERVE  (fig.  12,  ^)  lies  below  the  other  nerves,  and  above 
the  ophthalmic  vein,  in  the  interval  between  the  heads  of  the  external 
rectus.     In  the  orbit  it  is  distributed  to  the  external  rectus  muscle. 

Recti  Muscles.  The  internal  d,  inferior  c,  and  external  rectus  b 
(fig.  12)  are  placed  with  reference  to  the  eyeball  as  their  names  express. 
They  arise  i)Osteriorly  from  the  circumference  of  the  optic  foramen  by  a 
common  attachment,  which  partly  surrounds  the  optic  nerve.  But  the 
external  rectus  differs  from  the  others  in  having  two  heads : — The  upper 
joins  the  superior  rectus  in  the  common  origin.  The  lower  and  larger  head 
blends  on  the  one  side  with  the  inferior  rectus  in  the  common  origin,  and 
is  attached  in  addition  to  a  bony  point  on  the  lower  border  of  the  sphenoidal 
fissure,  near  the  inner  end ;  whilst  some  of  its  muscular  fibres  are  con- 
nected with  a  tendinous  band  between  the  heads.  All  the  muscles  are 
directed  forwards,  but  the  lower  obliquely  outwards,  and  have  a  tendinous 
insertion  into  the  ball  of  the  eye  about  a  quarter  of  an  inch  from  the 
cornea,  and  in  front  of  the  transverse  diameter  of  the  ball. 


58 


DISSECTION    OF    THE    ORBIT. 


Between  the  heads  of  origin  of  the  external  rectus,  the  different  nerves 
before  mentioned  are  transmitted  into  the  orbit,  viz.,  tlie  tliird,  the  nasal 
branch  of  the  fifth,  and  the  sixth,  together  with  the  ophtlialmic  vein. 

Action.  The  four  recti  muscles,  attaclu^d  to  the  eyeball  at  opposite 
sides  in  front  of  the  transverse  diameter,  are  able  to  turn  the  pupil  in 
opposite  directions. 

The  inner  and  outer  recti  move  the  ball  horizontally  around  a  vertical 
axis,  the  former  directing  the  pupil  towards  tlie  nose  and  the  latter  towards 
the  temple. 

Fiff.  12. 


Third  View  of  the  Orbit  (Illustrations  of  Dissections). 
Nerves : 


Mu-s-cles  : 

a.  Upper  rectus  and  levator  palpebrsc  thrown 
back  together. 

b.  External  rectus; 

c.  Inferior  rectus. 
(i.  Internal  rectus. 

/.  Upper  oblique  cut,  showing  the  insertion. 
h.  Insertion  of  inferior  oblique. 


1.  Upper  branch  of  the   bird. 

2.  Sixth  nerve. 

3.  Inferior  oblique  branch  of  the  third. 

4.  Branch  of  third  to  inferior  rectus. 

5.  Branch  of  third  to  internal  rectus. 


The  upper  and  lower  recti  elevate  and  depress  the  fore  part  of  the  ball 
around  a  transverse  axis  ;  but  as  their  fibres  are  directed  obliquely  out- 
wards, the  upper  muscle  turns  the  pupil  up  and  in,  and  the  lower  muscle 
turns  it  down  and  in. 

By  the  simultaneous  action  of  two  contiguous  recti,  the  ball  will  be 
moved  to  a  point  intermediate  to  that  to  which  it  would  be  directed  by 
either  muscle  singly. 

Dissection.  By  opening  the  optic  foramen,  the  attachment  of  the  recti 
muscles  will  be  more  fully  laid  bare.  To  dissect  out  the  inferior  oblicpie 
muscle,  let  the  eyeball  be  replaced  in  its  natural  position  ;  then  by  taking 


ACTION  OF  OBLIQUE  MUSCLES.  69 

away  the  conjunctival  lining  of  the  lower  eyelid  near  the  inner  part  of  the 
orbit,  and  removing  some  fat,  the  muscle  will  appear  beneath  the  eyeball, 
bending  from  the  inner  to  the  outer  side  ;  it  may  be  followed  outwards  to 
its  insertion  into  the  ball. 

The  INFERIOR  OBLIQUE  MUSCLE  (fig.  12,  n)  is  situate  near  the  anterior 
margin  of  the  orbit,  and  differs  from  the  other  muscles  in  being  directed 
across,  instead  of  parallel  to  the  axis  of  the  orbit.  It  arises  from  the 
superior  maxillary  bone  betwixt  the  margin  of  the  orbit  and  the  groove 
for  the  lachrymal  sac.  From  this  spot  the  muscle  passes  outwards  between 
the  inferior  rectus  and  the  bone,  and  between  the  eyeball  and  the  external 
rectus,  to  be  inserted  into  the  sclerotic  coat  between  the  outer  and  upper 
recti. 

The  borders  of  the  muscle  look  forwards  and  backwards,  and  the  pos- 
terior receives  the  branch  of  the  third  nerve.  The  tendon  of  insertion  is 
near  that  of  the  superior  oblique  muscle,  but  rather  closer  to  the  optic 
nerve. 

Action.  The  oblique  muscles  rotate  the  eyeball  around  an  antero-poste- 
rior  axis,  and  are  supposed  to  be  used  in  maintaining  the  parallelism  of 
the  axes  of  the  two  eyes. 

The  upper  muscle,  acting  by  itself,  would  rotate  the  ball  in  such  a  way 
as  to  cause  the  inner  end  of  the  transverse  axis  to  sink,  and  the  pupil  to 
be  directed  down  and  out,  as  in  looking  to  the  shoulder. 

The  lower  muscle  would  produce  by  itself  rotation  of  the  ball  in  the  op- 
posite direction,  viz.,  the  inner  end  of  the  transverse  axis  would  be  raised, 
and  the  pupil  would  be  inclined  up  and  out,  as  in  looking  to  the  outer 
part  of  the  orbit. 

During  life  the  rotary  movement  is  supposed  to  be  chiefly  employed  in 
controlling  the  oblique  action  of  the  upper  and  lower  recti.  For  instance, 
as  the  upper  rectus  alone  would  turn  the  pupil  upwards  and  too  much  in- 
wards, the  iilner  movement  will  be  counteracted  by  the  rotation  out  of  the 
inferior  oblique.  And  as  the  lower  rectus  will  incline  the  pupil  down  and 
too  much  in,  the  motion  inwards  will  be  checked  by  the  rotation  out  of 
the  superior  oblique. 

Dissection.  To  expose  the  small  tensor  tarsi  muscle,  the  palpebral  liga- 
ment uniting  the  eyelids  to  the  margin  of  the  orbit  is  to  be  cut  through, 
where  this  has  not  been  done  ;  but  the  lids  must  be  left  attached  at  the 
inner  commissure  by  means  of  the  tendo  palpebrarum.  By  looking  to  the 
posterior  aspect  of  the  tendo  palpebrarum,  after  the  lids  have  been  placed 
across  the  nose,  the  pale  fibres  of  the  tensor  tarsi  will  be  recognized. 

The  TENSOR  TARSI  MUSCLE  arisBS  from  the  ridge  on  the  os  unguis,  and 
slightly  from  the  bone  behind  the  ridge.  Its  fibres  are  pale,  and  form  a 
very  small  flat  band,  behind  the  ligamentum  palpebrarum,  whicli  divides 
like  that  structure  into  a  slip  for  each  eyelid.  In  the  lid  the  slip  lies  by 
the  side  of  the  lachrymal  canal,  and  blends  with  the  fibres  of  the  orbicu- 
laris along  the  free  margin  of  the  tarsal  cartilage. 

Action.  By  its  contraction  the  muscle  draws  inwards  and  backwards 
the  puncta  of  the  lids,  so  as  to  favor  the  reception  and  passage  of  the 
tears. 

Dissection.  A  small  nerve,  the  temporo-malar  or  orbital  branch  of  the 
superior  maxillary  trunk,  lies  along  the  outer  angle  of  the  floor  of  the 
orjjit,  and  may  be  brought  into  view  after  the  removal  of  the  eyeball  and 
its  muscles.  This  nerve  is  very  soft  and  easily  broken,  and  is  covered  by 
pale  fleshy  fibres  (orbitalis  muscle).     Two  branches,  temporal  and  malar. 


60  DISSECTION    OF    THE    ORBIT. 

are  to  be  traced  forwards  from  it :  and  tlie  junction  of  a  filament  of  the 
laclirymal  nerve  with  the  former  is  to  be  sought  in  the  bone  ;  the  outer 
wall  of  the  orbit  may  be  cut  away,  bit  by  bit,  to  follow  the  temporal 
branch  to  the  surface  of  the  head. 

The  temporo-malar  or  orbital  branch  of  the  superior  maxillary  nerve 
(fig.  26)  arises  in  the  spheno-maxillary  fossa,  and  divides  at  the  back  of 
the  orbit  into  malar  and  temporal  branches,  whicli  ramify  in  the  face  and 
the  side  of  the  head  with  companion  vessels. 

The  malar  branch  (r.  subcutaneus  malae)  is  directed  forwards  through 
a  foramen  in  the  malar  bone :  after  emerging  from  its  foramen,  this 
branch  supplies  the  orbicularis,  and  communicates  with  the  facial  nerve 
(p.  48). 

The  temporal  branch  ascends  in  a  groove  in  the  bone  on  the  outer  wall 
of  the  orbit ;  and  being  joined  by  a  filament  from  the  lachrymal  nerve, 
passes  into  the  temporal  fossa  through  a  foramen  in  the  malar  bone  :  it  is 
then  directed  upwards  between  the  temporal  muscle  and  the  skull,  and 
perforates  the  temporal  fascia  near  the  orbit  (p.  23). 

Orbitalis  muscle.  At  the  low^er  and  outer  angle  of  the  orbit  a  thin  fleshy 
layer  is  sometimes  well  seen.  The  fibres  cross  the  spheno-maxillary  fis- 
sure, being  attached  to  the  edges,  and  are  pierced  by  the  malar  branch  of 
the  temporo-malar  nerve. 

Lachrymal  Apparatus  (fig.  13).  The  lachrymal  glands,  puncta, 
canals,  and  sac,  constitute  the  apparatus  by  which  the  tears  are  formed, 
and  conveyed  to  the  nose.     The  gland  has  been  already  described  (p.  51). 

Dissection.  A  bristle  should  be  introduced  into  each  lachrymal  canal 
through  the  punctum  of  the  eyelid.  The  lachrymal  sac  will  appear  by 
removing  the  tensor  tarsi  and  the  areolar  tissue  from  its  surface,  as  it  lies 
on  the  OS  unguis.  The  prolongation  from  the  ligamentum  palpebrarum 
over  the  sac  should  be  defined. 

The  puncta  lachrymalia  Q)  are  two  small  apertures,  one  for  each  lid, 
by  which  the  lachrymal  canals  receive  the  tears.  Elach  is  situate  in  the 
free  margin  of  the  lid,  about  a  quarter  of  an  inch  from  the  inner  canthus, 
and  in  the  elevation  of  the  papilla  lachrymalis. 

Fig.  13. 


1.  Puncta  lachrymalia. 

3.  Upper,  and  3,  Lower  lachrymal  canal. 

4.  Caruncula  lachrymalis. 
.5.  Lachrymal  sac. 

6.  Lachrymal  duct. 


The  Eyemds  and  Lachrymal  Appauatl'9. 

The  lachrymal  canals  (fig.  13,  ^  ^""^  "')  lead  from  the  puncta,  and  convey 
the  tears  to  the  lachrymal  sac  ;  their  situation  is  marked  by  the  bristles 
inserted  in  them.  In  their  course  inwards  the  canals  lie  along  the  liga- 
mentum palpebrarum,  one  (^)  above  and  the  other  (^)  below  it,  and  they 
are  somewhat  arched  with  the  concavity  towards  each  other.  Internally 
they  open  near  together  into  the  lachrymal  sac  rather  above  its  middle. 


DISSECTION    OF    THE    NECK.  61 

The  canal  in  the  upper  eyelid  is  longer  and  more  arched  than  that  in  the 
lower  lid. 

The  lachrymal  sac  and  duct  (fig.  13)  extend  from  the  inner  part  of  the 
orbit  to  the  nose,  and  convey  the  tears  into  the  latter  cavity.  Tliey  form 
one  tube,  of  which  the  upper  dilated  part  is  the  sac,  and  the  lower  con- 
stricted end  the  duct. 

The  sac,  ^,  is  situate  in  the  hollow  formed  by  the  os  unguis  and  nas^l 
}>rocess  of  the  superior  maxillary  bone,  pjxternally  it  is  crossed  by  the 
ligament  of  the  eyelids,  and  is  covered  by  an  expansion  derived  from  that 
band,  which  is  fixed  to  the  margin  of  the  bony  groove.  If  the  aponeurotic 
covering  be  removed,  the  mucous  membrane  lining  the  interior  will  be 
seen.     Into  the  outer  side  of  the  sac  the  lachrymal  canals  open. 

The  duct,  ®  (ductus  ad  nasum),  is  the  narrowed  part  of  the  tube,  and  is 
about  half  an  inch  long.  It  is  entirely  encased  by  bone,  and  corresponds 
with  the  passage  of  the  same  name  in  the  dried  skull.  In  the  nasal  cavity 
it  .opens  into  the  front  of  the  inferior  meatus,  where  its  opening  is  guarded 
by  a  piece  of  the  mucous  membrane.  A  bent  probe  introduced  through 
the  nostril  may  be  passed  into  the  duct  from  the  meatus,  but  with  destruc- 
tion of  the  valve. 

As  the  duct  is  continuous  with  the  mucous  membrane  of  the  nose  it  has 
the  same  structure,  viz.,  a  fibrous  external  layer  with  a  mucous  lining.  The 
epithelium  of  the  sac  and  duct  is  ciliated  as  in  the  nose,  but  in  the  lachry- 
mal canals  it  is  scaly. 

Directions.  The  examination  of  the  eyeball  may  be  omitted  with  more 
advantage  to  the  student  till  the  dissection  of  the  liead  and  neck  has  been 
completed.  The  description  of  the  eye  will  be  found  at  the  end  of  the 
book. 


Section  V. 

DISSECTION  OF  THE  NECK. 


Position.  For  the  dissection  of  the  right  side  of  the  neck  let  the  head 
be  supported  at  a  moderate  height  on  a  block,  and  let  the  face  be  turned 
to  the  left  side  and  fastened  in  that  position  with  hooks.  To  obtain  a  good 
view  of  the  region,  the  right  arm  may  be  drawn  under  the  body,  with  the 
object  of  depressing  the  point  of  the  shoulder,  and  putting  the  neck  parts 
on  the  stretch.  In  some  bodies,  owing  to  a  difference  in  the  form  of  the 
neck,  the  best  position  will  be  obtained  by  placing  the  upper  limb  over 
the  chest. 

Surface-marking.  The  side  of  the  neck  presents  a  somewhat  square  out- 
line, and  is  limited  in  the  following  way: — Below  is  the  prominence  of 
the  clavicle  ;  and  above  is  the  base  of  the  lower  jaw  with  the  skull.  In 
front  the  boundary  is  a  line  from  the  chin  to  the  sternum  ;  and  behind, 
another  line  from  the  occiput  to  tlie  acromial  end  of  the  clavicle.  The 
part  thus  included  is  divided  into  two  triangular  spaces  (anterior  and  pos- 
terior) by  the  diagonal  line  of  the  projecting  sterno-mastoid  muscle.  And 
in  consequence  of  the  position  of  that  muscle  the  base  of  the  anterior  space 
is  at  the  jaw,  and  the  apex  at  tlie  sternum ;  whilst  the  base  of  the  posterior 
one  is  at  the  clavicle,  and  the  apex  at  the  head. 

The  surface  in  front  of  the  sterno-mastoid  is  depressed  at  the  upper  part 


62  DISSECTION    OF    THE    NECK. 

of  the  neck,  near  the  position  of  the  carotid  vessels ;  and  behind  the  muscle, 
just  above  the  clavicle,  is  another  slight  hollow  which  points  to  the  situa- 
tion of  the  subclavian  artery. 

Along  the  middle  line  of  the  neck  the  following  parts  can  be  recognized 
through  the  skin  : — About  two  inches  and  a  half  from  the  base  of  the  jaw 
is  the  eminence  of  the  os  hyoides,  with  its  cornu  extending  laterally  on 
each  side.  Below  this  may  be  felt  the  wide  prominence  of  the  thyroid 
cartilage,  called  pomum  Adami,  which  is  most  marked  in  man  :  and  be- 
tween the  cartilage  and  the  hyoid  bone  is  a  slight  interval,  corresponding 
with  the  thyro-hyoid  membrane. 

Inferior  to  the  thyroid,  is  the  narrow^  prominent  ring  of  the  cricoid  car- 
tilage ;  and  between  the  two  the  linger  may  distinguish  another  interval, 
which  is  opposite  the  crico-thyroid  membrane.  In  some  bodies,  especially 
in  women,  the  swelling  of  the  thyroid  gland  may  be  felt  by  the  side  of  the 
trachea. 

From  the  cricoid  cartilage  to  the  sternum,  and  between  the  sterno-mas- 
toid  muscles,  is  a  depression,  whose  depth  is  much  increased  in  emaciated 
persons,  in  which  the  tube  of  the  trachea  can  be  recognized. 

Direction.  As  the  time  for  turning  the  body  will  not  allow  tlie  examina- 
tion of  the  whole  side  of  the  neck,  the  student  should  lay  bare  in  this  stage 
only  the  parts  behind  the  sterno-mastoid  muscle. 

Dissection.  To  raise  the  skin  from  the  posterior  triangle  of  the  neck, 
make  an  incision  along  the  sterno-mastoid  muscle  from  the  one  end  to  the 
other,  and  afterwards  along  the  clavicle  as  far  as  the  acromion.  The  tri- 
angular flap  of  skin  is  to  be  reflected  from  before  back  towards  the  trapezius 
muscle.  The  superficial  fascia  which  will  then  be  brought  into  view,  con- 
tains the  platysma  ;  and  to  see  that  muscle,  it  will  be  necessary  to  take  the 
subcutaneous  fat  from  the  surface  of  the  fibres. 

The  PLATiSMA  MYOiDES  is  a  thin  subcutaneous  muscular  layer,  which 
is  now  seen  only  in  its  lower  half.  The  muscle  is  placed  across  the  side 
of  the  neck,  and  extends  from  the  top  of  the  shoulder  to  the  face.  Its 
fleshy  fibres  take  origin  by  fibrous  bands  from  the  clavicle  and  the  acro- 
mion, and  below  those  bones  from  the  superficial  fatty  layer  covering  the 
pectoral  and  deltoid  muscles ;  ascending  through  the  neck,  the  fibres  are 
inserted  into  the  jaw. 

The  lower  part  of  the  muscle  is  more  closely  united  to  the  skin  than  the 
upper,  and  covers  the  external  jugular  vein  as  well  as  the  lower  part  of 
the  posterior  triangle.  At  first  the  fibres  of  the  muscle  are  thin  and  scat- 
tered, but  they  increase  in  strength  as  they  ascend.  The  oblique  direc- 
tion of  the  fibres  should  be  noted,  because  in  venesection  in  the  external 
jugular  vein  the  incision  is  to  be  so  made  as  to  divide  them  across. 

The  use  will  be  found  with  the  description  of  the  remainder  of  the 
muscle. 

Dissection.  The  platysma  is  now  to  be  cut  across  near  the  clavicle, 
and  to  be  reflected  upwards  as  far  as  the  incision  over  the  sterno-mastoid 
muscle,  but  it  is  to  be  left  attached  at  that  spot.  In  raising  the  muscle 
the  student  must  be  careful  of  tlie  deep  fascia  of  the  neck  ;  and  he  should 
dissect  out  the  external  jugular  vein,  and  the  superficial  descending 
branches  of  the  cervical  plexus,  which  are  close  beneath  the  platysma. 

The  external  jucfidar  vein  (fig.  14,  ^)  commences  in  the  parotid  gland 
(p.  42),  and  is  directed  backwards  beneath  the  platysma  to  the  lower  part 
of  the  neck,  where  it  pierces  the  deep  cervical  fascia  to  open  into  the  sub- 
clavian vein.     Its  course  down  the  neck  will  be  marked  by  a  line  from 


POSTERIOR    TRIANGULAR    SPACE.  63 

the  angle  of  the  jaw  to  the  middle  of  the  clavicle.  Beyond  the  sterno- 
mastoid  muscle  the  vien  is  dilated,  and  the  swollen  part  {sinus)  is  limited 
by  two  pairs  of  valves — one  being  situate  below  at  the  mouth  of  the  vein, 
and  the  other  near  the  muscle.  Small  superficial  branches  join  the  vein, 
and  an  offset  connects  it  with  the  anterior  jugular  vein.  Its  size,  and  the 
height  at  which  it  crosses  the  sterno-mastoid  muscle,  are  very  uncertain. 

The  deep  cervical  fascia  consists,  like  the  aponeuroses  in  other  regions 
of  the  body,  of  a  superficial  layer  which  surrounds  the  neck  continuously, 
and  of  processes  that  are  prolonged  inwards  between  the  muscles.  In 
some  bodies  this  fascia  is  thin  and  indistinct. 

In  its  extent  round  the  neck  the  membrane  incases  the  sterno-mas- 
toideus,  and  presents  a  different  disposition  before  and  behind  that  muscle. 
As  now  seen  passing  backwards  from  the  muscle,  the  fascia  continues  over 
the  posterior  triangular  space,  and  incloses  the  trapezius  in  its  progress  to 
the  spines  of  the  vertebrae.  At  the  lower  part  of  the  neck  it  is  attached 
to  the  clavicle  and  is  perforated  by  the  external  jugular  vein,  and  the 
cutaneous  nerves. 

After  the  superficial  layer  has  been  removed  near  the  clavicle,  a  deep 
process  may  be  observed  to  surround  the  small  omo-hyoid  muscle,  and  to 
extend  under  the  clavicle,  where  it  is  fixed  to  the  back  of  that  bone,  and 
the  inner  end  of  the  first  rib. 


POSTERIOR  TRIANGULAR  SPACE. 

This  space  (fig.  14),  having  the  form  and  position  before  noted,  is  about 
eight  inches  in  length.  It  contains  the  cervical  and  brachial  plexuses,  with 
the  portion  of  the  subclavian  artery  on  which  a  ligature  is  usually  placed, 
and  some  offsets  of  the  vessel  and  the  nerves. 

Dissection.  By  the  removal  of  the  cervical  fascia  and  the  fat  between 
the  sterno-mastoid  and  trapezius  muscles,  the  posterior  triangle  of  the 
neck  will  be  displayed.  In  the  execution  of  this  task,  the  student  may 
obtain  some  assistance  by  attending  to  the  following  remarks  : — 

Crossing  the  space  obliquely  about  an  inch  above  the  clavicle,  and 
dividing  it  into  two,  is  the  small  omo-hyoid  muscle  (fig.  14,  ').  Close  to 
or  under  the  upper  border  of  the  muscle  lie  the  small  nerve  and  vessels  to 
it :  the  nerve  being  traceable  to  the  descendens  noni,  and  the  artery  to  the 
supra-scapular. 

Above  the  omo-hyoid  muscle  will  be  found  the  ramifications  of  the 
branches  of  the  cervical  plexus,  together  with  the  spinal  accessory  nerve  ; 
the  latter  will  be  recognized  by  its  piercing  sterno-mastoid  muscle.  The 
greater  number  of  the  branches  of  the  cervical  plexus  descend  in  the  space 
to  the  shoulder ;  but  the  small  occipital  and  great  auricular  nerves  ascend 
to  the  head,  and  the  superficial  cervical  branch  is  directed  forwards  over 
the  sterno-mastoid  muscle. 

Below  the  omo-hyoideus  are  the  subclavian  artery  and  the  brachial 
plexus,  which  have  a  deep  })Osition.  In  this  part  also  the  following  ves- 
sels and  nerve  are  to  be  sought,  viz.,  the  supra-scapular  vessels  behind  the 
clavicle;  the  transverse  cervical  vessels  which  are  higher  in  the  neck,  but 
take  an  outward  direction  beneath  the  omo-hyoid  muscle ;  and,  lastly,  the 
small  branch  of  nerve  to  the  subclavius  muscle,  which  lies  about  the  mid- 
dle of  the  space  between  the  clavicle  and  omo-hyoideus. 

Underneath  the   trapezius,  where  it  is  attached  to   the  clavicle,   the 


64 


DISSECTION    OF    THE    NECK. 


v^eiTatus  magnus  muscle  appears ;  and  behind  the  large  cervical  nerves, 
towards  the  lower  part  of  the  space,  is  placed  the  middle  scalenus  muscle. 
Ulirough  the  scalenus  issue  two  muscular  nerves  ;  one,  formed  by  two 
roots,  for  the  serratus  magnus ;  the  otiier  smaller,  and  higher  up,  for  the 
rhomboidei. 

Fig.  14. 


Part  of  the  Posterior  Triangle  op  the  Neck  is  here  displayed, 
but  the  student  should  carry  the  dissection  as  high  as  the  head,  so  as  to  lay  bare  the  whole  of 
that  space. 


1.  Steruo-mastoideus. 
1    Trapezius. 

3.  Posterior  belly  of  the  omo-hyoid  miiscle. 

4.  Anterior  scalenus,  with  the  phrenic  nerve 

oil  it. 
;').  Middle  scalenus  muscle. 


Elevator  of  the  angle  of  the  scapula. 
Third  part  of  the  subclavian  artery. 
External  jugular  vein  joining  the  subcl: 

vian  below. 
Nerves  of  the  brachial  plexus. 
Spinal  accessory  nerve. 

(Blandin's  Surgical  Anatomy.) 


Limits  of  the  space.  The  space  is  bounded  in  the  front  by  the  sterno- 
mastoid  muscle,  ^ ;  and  behind  by  the  trapezius,  '•'.  Its  base  corresponds 
with  the  middle  third  of  the  clavicle,  and  its  apex  is  at  the  skull.     In  its 


POSTERIOR    TRIANGULAR    SPACE.  65 

area  are  several  muscles,  which  are  placed  in  the  following  order  from 
above  down,  viz.,  splenius  capitis,  levator  anguli  scapulae  * ;  and  the  mid- 
dle scalenus  * ;  and  at  the  lower  and  outer  angle,  somewhat  beneath  the 
trapezius  lies  the  upper  part  of  the  serratus  magnus.  Covering  the  space 
are  the  structures  already  examined,  viz.,  the  skin  and  superficial  fascia, 
the  platysma  over  the  lower  half  or  two-thirds,  and  the  deep  fascia. 

The  small  omo-hyoid  muscle,  ',  crosses  the  lower  part  of  the  space,  so 
as  to  subdivide  it  into  two — a  lower  or  clavicular,  and  an  upper  or  occi- 
pital. 

The  clavicular  part  is  small  in  size  and  close  to  the  clavicle,  and  con- 
tains the  subclavian  artery.  It  is  triangular  in  form,  with  its  base  directed 
forwards ;  and  is  bounded  in  front  by  the  sterno-mastoid,  ^ ;  above  by  the 
omo-liyoid  muscle,  ' ;  and  below  by  the  clavicle.  This  small  space  meas- 
ures commonly  about  one  inch  and  a  half  from  before  backwards,  and 
about  half  that  in  front  at  its  base. 

Crossing  the  area  of  this  portion,  rather  above  the  level  of  the  clavicle, 
is  the  trunk  of  the  subclavian  artery,  ^  (its  third  part),  which  issues  from 
beneath  the  anterior  scalenus  muscle,  and  is  directed  over  the  first  rib  to 
the  axilla.  In  the  ordinary  condition  of  the  vessel  the  companion  subcla- 
vian vein  is  seldom  seen,  owing  to  its  situation  being  lower  down  beneath 
the  clavicle.  Above  the  artery  are  the  large  cords  of  tlie  brachial  plexus, ', 
which  accompany  the  vessel,  and  become  closely  applied  to  it  beneath  the 
clavicle.  Behind  the  artery  and  the  nerves  is  the  middle  scalenus 
muscle,  ^.     And  below  the  vessel  is  the  first  rib. 

Along  the  lower  boundary  of  the  space,  and  rather  beneath  the  clavicle 
lie  tlie  supra-scapular  vessels ;  and  crossing  the  upper  angle,  at  the  meet- 
ing of  the  omo-hyoid  and  sterno-mastoid  muscles,  are  tlie  transverse  cer- 
vical vessels.  Entering  the  space  from  above  is  the  external  jugular 
vein,  ®,  which  descends  over  or  under  the  omo-hyoideus  near  the  anterior 
part,  and  opens  into  the  subclavian  vein  ;  in  this  spot  the  vein  receives 
the  supra-scapular  and  transverse  cervical  branches,  and  sometimes  a  small 
vein,  over  the  clavicle,  from  the  cephalic  vein  of  the  arm. 

The  size  of  the  clavicular  part  of  the  space  from  before  back  is  influ- 
enced by  the  attachment  of  the  trapezius  and  sterno-mastoid  muscles  along 
the  clavicle :  in  some  bodies  these  muscles  occupy  nearly  the  whole  length 
of  that  bone,  leaving  but  a  small  interval  between  them ;  and  in  others 
they  meet  so  as  to  cover  the  underlying  vessels.  This  space  may  be  fur- 
ther increased  or  diminished  from  above  down  by  the  position  of  the  omo- 
hyoideus  in  the  neck  ;  for  this  muscle  may  lie  close  to  the  clavicle,  being 
attached  thereto,  or  it  may  be  distant  one  inch  and  a  half  from  that  bone. 

In  depth  the  space  varies  naturally ;  and  in  a  short  thick  neck  with  a 
prominent  clavicle,  the  artery  is  farther  from  the  surface  than  in  the  op- 
posite condition  of  the  parts.  But  the  depth  may  be  altered  much  more 
by  the  position  of  the  clavicle,  according  as  the  limb  may  be  raised  or  de- 
pressed. And  lastly,  the  artery  may  be  concealed  entirely  in  its  usual 
position  by  forcing  upwards  the  arm  and  shoulder,  as  the  collar  bone  can 
be  raised  above  the  level  of  the  omo-hyoid  muscle. 

The  situation  of  the  trunk  of  the  subclavian  artery  may  vary  much,  for 
the  vessel  may  be  one  inch  and  a  half  above  the  clavicle,  or  at  any  point 
intermediate  between  this  and  its  usual  level  just  above  the  prominence  of 
that  bone.  Further,  its  position  to  the  anterior  scalenus  may  be  changed  ; 
and  instead  of  the  vessel  being  beneath,  it  may  be  in  front  of,  or  even 
between  the  fibres  of  that  muscle. 


66  DISSECTION    OF    THE    NECK. 

Commonly  there  is  not  any  branch  connected  with  the  artery  in  this 
part  of  its  course;  but  the  posterior  scapular  branch  (fig.  14)  may  take 
origin  from  it  at  different  distances  from  the  scalenus,  or  there  may  be 
more  than  one  branch  (Quain). 

The  subclavian  vein  rises  upwards  not  unfrequently  as  high  as  the 
artery,  or  it  may  even  lie  with  the  artery  beneath  the  anterior  scalenus  in 
some  rare  instances.  The  position  of  the  external  jugular  vein  with 
regard  to  the  subclavian  artery  is  very  uncertain  ;  and  the  branches 
connected  with  the  lower  end  may  form  a  kind  of  plexus  over  the  arterial 
trunk. 

The  occipital  part  of  the  posterior  triangle  is  larger  than  the  other.  Its 
boundaries  in  front  and  behind  are  the  sterno-mastoid  and  tlie  trapezius ; 
and  it  is  separated  from  the  clavicular  portion  by  the  omo-hyoid  muscle. 

In  it  are  contained  chiefly  the  ramifications  of  the  cervical  plexus ;  and  a 
chain  of  lymphatic  glands  lies  along  the  sterno-mastoid  muscle.  The 
spinal  accessory  nerve,  ^®,  is  directed  obliquely  across  this  interval  from 
the  sterno-mastoid  muscle,  which  it  pierces,  to  the  under  surface  of  the 
trapezius  ;  and  a  communication  takes  place  between  this  cranial  and  the 
spinal  nerves  in  the  space. 

Superficial  Branches  of  the  Cervical  Plexus.  Behind  the 
sterno-mastoid  muscle  appear  some  of  the  ramifications  of  the  cervical 
nerves  in  the  plexus  of  the  same  name  ;  and  superficial  branches  are  fur- 
nished from  these  both  upwards  and  downwards. 

The  ASCENDING  SET  (fig.  14)  are  three  in  number,  viz.,  small  occipital, 
great  auricular,  and  superficial  cervical. 

The  small  occipital  branch  (fig.  2,  ^)  comes  from  the  second  cervical 
nerve,  and  is  directed  upwards  to  the  head  along  the  posterior  border  of 
the  sterno-mastoid  muscle.  At  first  the  nerve  is  beneath  the  fascia  ;  but 
near  the  occiput  it  becomes  cutaneous,  and  is  distributed  between  the  ear 
and  the  great  occipital  nerve  (p.  24).  Occasionally  there  is  a  second  cuta- 
neous nerve  to  the  head. 

The  great  auricular  nerve  (fig.  2,  ^)  is  a  branch  of  the  part  of  the 
plexus  formed  by  the  second  and  third  cervical  nerves.  Perforating  the 
deep  fascia  at  the  posterior  border  of  the  sterno-mastoid  muscle,  the  nerve 
is  directed  upwards  beneath  the  platysma  to  the  lobule  of  the  ear,  where 
it  ends  in  the  following  branches  : — 

The  facial  branches  are  sent  forwards  to  the  integuments  over  the 
parotid,  and  a  few  slender  filaments  pass  through  the  gland  to  join  the 
facial  nerve. 

The  auricular  branches  ascend  to  the  external  ear,  and  are  chiefly  dis- 
tributed on  its  cranial  aspect ;  one  or  more  reach  the  opposite  surface  by 
piercing  the  pinna.  On  the  ear  they  communicate  with  branches  furnished 
from  the  facial  and  pneumogastric  nerves. 

The  mastoid  branch  is  directed  backwards  to  the  integuments  between 
the  ear  and  the  mastoid  process  ;  and  it  joins  the  posterior  auricular  branch 
of  the  facial  nerve  (p.  23). 

The  superjicial  cervical  nerve  (fig.  2,  '*)  springs  from  the  same  source 
as  the  preceding,  and  turns  forwards  round  the  sterno-mastoid  muscle 
about  the  middle.  Afterwards  it  pierces  the  fascia  and  platysma,  and 
ramifies  over  the  anterior  triangular  space  (see  p.  68).  There  may  be 
more  than  one  branch  to  represent  this  nerve. 

The  DESCENDING  SET  of  branches  (fig.  2)  (supra-clavicular),  are  de- 
rived from  the  third  and  fourth   nerves  of  the   plexus,  and  are  directed 


FORE    PART    OF    NECK.  67 

towards  the  clavicle  over  the  lower  part  of  the  triangular  space.  Their 
number  is  somewhat  uncertain,  but  usually  there  are  about  tliree  on  the 
clavicle. 

The  most  internal  branch  (sternal)  crOvSses  the  clavicle  near  its  inner 
end  ;  the  middle  branch  lies  about  the  middle  of  that  bone  ;  and  the 
posterior  (acromial)  turns  over  the  attachment  of  the  trapezius  to  the 
acromion.     All  are  distributed  in  the  integuments  of  the  chest  and  shoulder. 

Derived  from  the  descending  set  are  two  or  more  posterior  cutaneous 
cervical  nerves,  wiiich  ramify  in  the  integument  over  tl»e  lower  two  thirds 
of  the  fore  part  of  the  trapezius. 

The  lymphatic  glands  (glandulae  concatenatae)  lie  along  the  sterno- 
mastoid  muscle,  and  are  continuous  at  the  low^er  part  of  the  neck  with  the 
glands  in  the  cavity  of  the  thorax.  There  is  also  a  superficial  chain  along 
the  external  jugular  vein. 

Dissection.  The  dissection  of  the  posterior  triangle  should  be  repeated 
on  the  left  side  of  the  neck,  in  order  that  the  difference  in  the  vessels  may 
be  observed.  Afterwards  the  reflected  parts  are  to  be  replaced  and  care- 
fully fastened  in  their  natural  position  with  a  few  stitches,  preservative 
fluid  or  salt  having  been  previously  applied. 

Directions.  It  is  supposed  that  the  body  will  now  be  turned  on  the  fore 
part  for  the  examination  of  the  Back  ;  and  during  the  time  allotted  for 
this  position  the  dissector  of  the  head  is  to  learn  the  posterior  part  of  the 
neck.     (Dissection  of  the  Back.) 

After  the  completion  of  the  Back,  the  student  should  take  out  the  spinal 
cord,  and  then  return  to  the  dissection  of  the  front  of  the  neck,  which  is 
described  below. 


FRONT  OF  THE  NECK. 

Directions.  Supposing  the  thorax  and  Back  finished,  the  head  and 
neck  may  be  detached  from  the  trunk  by  dividing  the  spinal  column  be- 
tween the  second  and  third  dorsal  vertebrte,  and  cutting  through  the  arch 
of  the  aorta  beyond  its  large  branches  (if  this  is  not  done),  so  as  to  take 
that  piece  of  tlie  vessel  with  the  head.  The  dissector  continues  his  work 
on  the  remainder  of  the  right  side  of  the  neck  ;  but  if  the  facial  nerve 
has  been  omitted,  it  should  be  first  learnt  (p.  47). 

Position.  Supposing  the  facial  nerve  completed,  a  small  narrow  block 
is  to  be  placed  beneath  the  left  side  of  the  neck,  and  the  face  is  to  be 
turned  from  the  dissector.  Further,  the  neck  is  to  be  made  tense  by 
means  of  hooks,  the  chin  being  well  raised  at  the  same  time. 

Dissection.  An  incision  along  the  base  of  the  jaw  on  the  right  side  (if 
it  has  not  been  made  already)  will  readily  allow  the  piece  of  integument 
in  front  of  the  sterno-mastoideus  to  be  raised  towards  the  middle  line. 
Beneath  the  skin  is  the  superficial  fascia,  containing  very  fine  offsets  of 
the  superficial  cervical  nerve. 

To  define  the  platysma  muscle,  remove  the  fat  which  covers  it,  carrying 
the  knife  down  and  back  in  the  direction  of  the  fleshy  fibres. 

Platysma  Myoides.  Tlie  anterior  part  of  the  platysma,  viz.,  from 
the  sterno-mastoid  muscle  to  the  lower  jaw,  covers  the  greater  portion  of 
the  anterior  triangular  space.  At  the  base  of  the  jaw  it  is  inserted  be- 
tween the  symphysis  and  the  masseter  muscle ;  while  other  and  more 
posterior  fibres  are  continued  over  the  face,  joining  the  depressor  anguli 


68  DISSECTION    OF    THE    NECK. 

oris  find  risorius,  as  far  as  the  fascia  covering  the  parotid  gland,  or  even 
to  tlie  cheek  bone. 

The  fibres  have  the  same  appearance  in  this  as  in  the  lower  lialf  of  the 
muscle,  but  they  are  rather  stronger.  Below  the  chin  the  inner  fibres  of 
opposite  muscles  cross  for  a  distance  of  about  an  inch,  but  those  which 
are  superficial  do  not  belong  always  to  the  same  side. 

Action.  The  ordinary  action  of  this  muscle  is  confined  to  the  skin  of 
the  neck,  which  it  throws  into  longitudinal  wrinkles;  but  it  can  depress 
the  corner  of  the  mouth  by  the  slip  prolonged  to  the  face.  Tlirough  its 
attachment  to  the  jaw  it  will  assist  in  opening  the  mouth. 

Dissection.  Raise  the  platysma  to  the  base  of  the  jaw,  and  dissect  out 
the  branches  of  the  superficial  cervical  nerve,  and  the  cervical  branches 
of  the  facial  nerve  that  are  beneath  it.  Clean  also  the  deep  fascia  of  the 
neck,  and  the  anterior  jugular  vein  which  is  placed  near  the  middle  line. 

The  superficial  cervical  nerve  has  been  traced  from  its  origin  in  the 
cervical  plexus  to  its  position  on  the  deep  fascia  of  the  neck  (p.  G6) ;  but 
the  nerve  may  arise  from  the  plexus  by  two  pieces.  Beneath  the  platysma 
it  divides  into  an  ascending  and  a  descending  branch  : — 

The  ascending  branch  perforates  the  platysma,  supplying  it,  and  ends 
in  the  integuments  over  the  anteriqr  triangle,  about  half  way  down  the 
neck.  Whilst  this  branch  is  beneath  the  platysma  it  joins  the  facial 
nerve. 

The  descending  branch  likewise  passes  through  the  platysma,  and  is 
distributed  to  the  teguments  below  the  preceding,  reaching  as  low  as  the 
sternum. 

The  infra-maxillary  branches  of  the  facial  or  seventh  cranial  nerve 
(rami  subcutanei  colli)  (p.  50)  pierce  the  deep  cervical  fascia,  and  pass 
forwards  beneath  the  platysma,  forming  arches  across  the  side  of  the  neck 
(fig.  9),  which  reach  as  low  as  the  hyoid  bone.  Most  of  the  branches  end 
in  the  platysma,  but  a  few  filaments  perforate  it,  and  reach  the  integu- 
ments. Beneath  the  muscle  there  is  a  communication  between  the  branches 
of  the  facial  and  the  offsets  of  the  superficial  cervical  nerve. 

Dissection.  Cut  across  the  external  jugular  vein  about  the  middle, 
and  throw  the  ends  up  and  down.  Afterwards  the  superficial  nerves  of 
the  neck  may  be  divided  in  a  line  with  the  angle  of  the  jaw,  the  anterior 
ends  being  removed,  and  the  posterior  reflected.  The  great  auricular 
nerve  may  be  cut  through  and  the  ends  reflected. 

The  part  of  the  deep  cervical  fascia  in  front  of  the  sterno-mastoideus  is 
stronger  than  that  behind  the  muscle,  and  has  the  following  arrangement. 
Near  the  sternum  the  fascia  forms  a  white  firm  membrane,  which  is  at- 
tached to  that  bone ;  but  higher  in  the  neck  it  becomes  thinner,  and  is 
fixed  above  the  lower  jaw  and  the  zygoma,  covering  also  the  parotid 
gland.  From  the  ramus  of  the  jaw  a  piece  is  prolonged  downwards,  be- 
tween the  parotid  and  submaxillary  glands,  to  join  the  styloid  j)rocess ; 
this  piece  is  named  the  stglo-maxillary  ligament.  And  from  the  angle  of 
the  jaw  a  strong  piece  is  continued  to  the  sterno-mastoideus,  which  fixes 
forwards  the  anterior  border  of  that  muscle. 

Layers  of  the  membrane  are  prolonged  between  the  muscles ;  and  that 
beneath  the  sterno-mastoid  is  connected  with  the  sheath  of  the  cervical 
vessels.  One  of  these  beneath  the  sterno-thyroid  muscle,  descends  in 
front  of  the  great  vessels  at  the  root  of  the  neck  to  the  arch  of  the  aorta, 
and  the  pericardium. 


ANTERIOR    TRIANGULAR    SPACE.  69 


ANTERIOR    TRIANGULAR    SPACE. 

This  space  (fig.  15)  contains  the  carotid  vessels  and  their  branches,  with 
many  nerves ;  and  it  corresponds  with  the  hollow  on  the  surface  of  the 
neck  in  front  of  the  sterno-mastoid  muscle. 

Dissection.  To  define  the  anterior  triangular  space  and  its  contents, 
take  away  the  deep  fascia  of  the  neck,  and  the  fat,  but  without  injuring 
or  displacing  the  several  parts.  First  clean  the  surface  of  the  hyoid  mus- 
cles that  appear  along  the  middle  line,  leaving  untouched  the  anterior 
jugular  vein. 

The  trunks  into  which  the  large  carotid  artery  bifurcates  are  to  be  fol- 
lowed upwards,  especially  the  more  superficial  one  (external  carotid), 
whose  numerous  branches  are  to  be  traced  as  far  as  they  lie  in  the  space. 
In  removing  the  sheath  from  the  vessels,  as  tliese  appear  from  beneath  the 
muscles  at  the  lower  part  of  the  neck,  the  dissector  should  be  careful  of 
the  small  descending  branch  of  the  hypo-glossal  nerve  in  front  of  it.  In 
the  slieath  between  the  vessels  (carotid  artery  and  jugular  vein)  will  be 
found  the  pneumogastric  nerve,  and  behind  the  sheath  is  the  sympathetic 
nerve. 

Crossing  the  space,  in  the  direction  of  a  line  from  the  mastoid  process 
to  the  hyoid  bone,  are  the  digastric  and  stylo-hyoid  muscles,  with  several 
nerves  directed  transversely.  Thus  lying  below  them  is  the  hypo-glossal 
nerve,  which  gives  one  branch  (descendens  noni)  in  front  of  the  sheath, 
and  another  to  the  thyroid-hyoid  muscle.  Above  the  muscles,  and  taking  a 
similar  direction  between  the  two  carotid  arteries,  are  the  glosso-pharyn- 
geal  nerve  and  the  stylo-pharyngeus  muscle.  Directed  downwards  and 
backwards  from  beneath  the  same  muscles  to  the  sterno-mastoideus,  is  the 
spinal  accessory  nerve. 

On  the  inner  side  of  the  vessels,  between  the  hyoid  bone  and  the  thy- 
roid cartilage,  the  dissector  will  find  the  superior  laryngeal  nerve  ;  and 
by  the  side  of  the  larynx,  with  tlie  descending  part  of  the  superior  thyroid 
artery,  the  small  external  laryngeal  branch. 

Clean  then  the  submaxillary  gland  close  to  the  base  of  the  jaw  ;  and  on 
partly  displacing  it  from  the  surface  of  the  mylo-hyoid  muscle,  the  student 
will  expose  the  small  branch  of  nerve  to  that  muscle  with  the  submental 
artery. 

The  interval  between  the  jaw  and  the  mastoid  process  is  supposed  to  be 
already  cleaned  by  the  removal  of  the  parotid  gland  in  the  dissection  of  the 
facial  nerve. 

Limits  of  the  space.  Behind,  is  the  sterno-mastoid  muscle,  ^ ;  and  in 
front,  a  line  from  the  chin  to  the  sternum,  along  the  middle  of  the  neck. 
Above,  at  the  base  of  the  space,  would  be  the  lower  jaw,  the  skull,  and 
the  ear ;  and  below,  at  the  apex,  is  the  sternum.  Over  this  space  are 
placed  the  skin,  the  superficial  fascia  with  the  platysma,  the  deep  fascia, 
and  the  ramifications  of  the  facial  and  superficial  cervical  nerves. 

Muscles  in  the  space.  In  the  area  of  the  triangular  interval,  as  it  is 
above  defined,  are  seen  the  larynx,  and  pharynx  in  part,  and  many  mus- 
cles converging  towards  the  hyoid  bone  as  a  centre,  some  being  above 
and  some  below  it.  Below  are  the  depressors  of  that  bone,  viz.,  omo- 
hyoid, sterno-hyoid,  and  sterno-thryoid,  ^  to  *;  and  above  the  os  hyoides 
are  the  elevator  muscles,  viz.,  mylo-hyoid,  digastric,,and  stylo-hyoid.    Con- 


70  DISSECTION    OF    THE    NECK. 

nected  with  the  back  of  the  hyoid  bone  and  the  layrnx  are  some  of  the 
constrictor  muscles  of  the  gullet. 

Vessels  in  the  triangular  space.  The  carotid  bloodvessels,  ^  and  '', 
occupy  the  hinder  and  deeper  part  of  the  space  along  the  side  of  the 
sterno-mastoid  muscle ;  and  their  course  would  be  marked  on  the  surface 
by  a  line  from  the  sterno-clavicular  articulation  to  a  point  midway  between 
the  jaw  and  the  mastoid  process.  As  high  as  the  level  of  the  cricoid  car- 
tilage they  are  buried  beneath  the  depressor  muscles  of  the  os  hyoides ; 
but  beyond  that  spot  they  are  covered  by  the  superficial  layers  over  the 
space,  and  by  the  sterno-mastoid  muscle  which,  before  the  parts  are  dis- 
placed, conceals  the  vessels  as  far  as  the  parotid  gland. 

For  a  short  distance  after  its  exit  from  beneath  the  muscles  at  the  root 
of  the  neck,  the  common  carotid  artery  remains  a  single  trunk,  ^;  but 
opposite  the  upper  border  of  the  thyroid  cartilage  it  divides  into  two  large 
vessels,  external  and  internal  carotid.  From  the  place  of  division  these 
trunks  are  continued  onwards,  beneath  the  digastric  and  stylo-hyoid  mus- 
cles, to  the  interval  between  the  jaw  and  the  mastoid  process. 

At  first  the  trunks  lie  side  by  side,  the  vessel  destined  for  the  internal 
parts  of  the  head  (internal  carotid)  being  the  more  posterior  or  external 
of  the  two;  but  above  the  digastric  muscle  it  becomes  deeper  than  the 
other.  The  more  superficial  artery  (external  carotid)  furnishes  many 
branches  to  the  neck  and  the  outer  part  of  the  head,  vi?.,  some  forwards 
to  the  larynx,  tongue,  and  face;  others  backwards  to  the  occiput  and  the 
ear;  and  others  upwards  to  the  head. 

But  the  common  carotid  does  not  always  divide,  as  here  said.  For 
the  point  of  branching  of  the  vessel  may  be  moved  from  the  upper  border 
of  the  thyroid  cartilage,  either  upwards  or  downwards,  so  that  the  trunk 
may  remain  undivided  till  it  is  beyond  the  os  hyoides,  or  end  in  branches 
opposite  the  cricoid  cartilage.  The  division  beyond  the  usual  place  is 
more  frequent  than  the  branching  short  of  that  spot.  It  may  ascend  as 
an  undivided  trunk  (though  very  rarely),  furnishing  offsets  to  the  neck 
and  head. 

In  close  contact  with  the  outer  side  of  both  the  common  and  the  internal 
carotid  artery,  and  incased  in  a  sheath  of  fascia  with  them,  is  the  large 
internal  jugular  vein,  which  receives  branches  in  the  neck  corresponding 
with  some  of  the  branches  of  the  superficial  artery.  In  some  bodies  the 
vein  may  cover  the  artery,  and  the  branches  joining  it  above  may  form  a 
kind  of  plexus  over  the  upper  part  of  the  common  carotid. 

Nerves  in  the  space.  In  connection,  more  or  less  intimate,  with  the 
large  vessels,  are  the  following  nerves  with  a  longitudinal  direction : — In 
front  of  the  sheath  lies  the  descending  branch  of  the  hypo-glossal  nerve ; 
within  the  sheath,  between  the  carotid  artery  and  jugular  vein,  is  the 
pneumogastric  nerve;  and  behind  the  sheath  is  the  sympathetic  nerve. 
Along  the  outer  part  of  the  vessels  the  spinal  accessory  nerve  extends  for 
a  short  distance,  till  it  {)ierces  the  sterno-mastoid  muscle. 

Several  nerves  are  placed  across  the  vessels : — thus,  directed  transversely 
over  the  two  carotids,  so  as  to  form  an  arch  below  the  digastric  muscle,  is 
the  hypoglossal  nerve,  which  gives  downwards  its  branch  (descendens  noni) 
most  commonly  in  front  of  the  sheath.  Appearing  on  the  inner  side  of  the 
carotid  arteries,  close  to  the  base  of  the  space,  is  the  glosso-pharyngeal 
nerve,  which  courses  forwards  between  them.  Inside  the  internal  carotid 
artery,  opposite  the  hyoid  bone,  the  superior  laryngeal  nerve  comes  into 


STERNO-CLEIDO-MASTOJDEUS.  71 

sight;  whilst  a  little  lower  down,  with  the  descending  branches  of  the 
tliyroid  artery,  is  the  external  laryngeal  branch  of  that  nerve. 

Glands  in  the  space.  Two.  glandular  bodies,  the  submaxillary,  ",  and 
thyroid,  ^^,  have  their  seat  in  this  triangular  space  of  the  neck.  The  sub- 
maxillary gland  is  situate  altogether  in  front  of  the  vessels,  and  is  partly 
concealed  by  the  jaw  ;  and  beneath  it  on  the  surface  of  the  mylo-hyoideus 
is  the  small  nerve  to  that  muscle;  with  the  submental  artery.  By  the  side 
of  the  thyroid  cartilage,  between  it  and  the  common  carotid  artery,  lies  the 
thyroid  body  beneath  the  sterno-thyroid  muscle :  in  the  female  this  body 
is  more  largely  developed  than  in  the  male. 

At  the  base  of  the  space,  if  the  parts  were  not  disturbed,  w^ould  be  the 
parotid  gland,  which  is  wedged  into  the  hollow  between  the  jaw  and  the 
mastoid  process,  and  projects  somewhat  below  the  level  of  the  jaw.  Its 
connections  have  been  noticed  at  p.  41. 

Directions.  The  student  has  to  proceed  next  with  the  examination  of 
the  individual  parts  that  have  been  referred  to  with  the  triangular  spaces. 

Anterior  jugular  vein.  This  small  vein  occupies  the  middle  line  of  the 
neck,  and  its  size  is  dependent  upon  the  degree  of  development  of  the  ex- 
ternal iugrular.  Beginning  in  some  small  branches  below  the  chin,  the 
vein  descends  to  the  sternum,  and  then  bends  outwards  beneath  the  sterno- 
mastoid  muscle,  to  open  into  the  subclavian  vein,  or  into  the  external 
jugular.  In  the  neck  the  anterior  and  external  jugular  veins  communicate. 
There  are  two  anterior  veins,  one  for  each  side,  though  one  is  usually 
larger  than  the  other;  and  at  the  bottom  of  the  neck  they  are  joined  by  a 
transverse  branch. 

The  STERNo-CLEiDO-MASTOiD  MUSCLE  (fig.  15,  ')  forms  the  superficial 
prominence  of  the  side  of  the  neck.  It  is  narrower  in  the  centre  than  at 
the  ends,  and  is  attached  below  by  two  heads  of  origin,  which  are  separated 
by  an  elongated  interval.  The  inner  head  is  fixed  by  a  narrowed  tendon 
to  the  anterior  surface  of  the  first  piece  of  the  sternum ;  and  the  outer  head 
lias  a  wide  fleshy  attachment  to  the  sternal  third  of  the  clavicle.  From 
this  origin  the  heads  are  directed  upwards,  the  internal  passing  backwards, 
and  the  external  almost  vertically,  and  are  blended  about  the  middle  of 
the  neck  in  a  roundish  belly.  Near  tlie  skull  the  muscle  ends  in  a  tendon, 
which  is  inserted  into  the  mastoid  process  at  the  outer  aspect  from  base  to 
tip,  and  by  a  thin  aponeurosis  into  a  rough  surface  behind  that  process, 
and  into  the  outer  part  of  the  upper  curved  line  of  the  occipital  bone. 

The  muscle  divides  the  lateral  surface  of  the  neck  into  two  triangular 
spaces.  On  its  cutaneous  aspect  the  sterno-mastoid  is  covered  by  the  com- 
mon integuments,  by  the  platysma  and  deep  fascia,  and  by  the  external 
jugular  vein  and  the  superficial  branches  of  the  cervical  plexus  (across  the 
middle).  If  the  muscle  be  cut  through  below  and  raised,  it  w^ill  be  seen 
to  lie  on  the  following  parts :  The  clavicular  origin  is  superficial  to  the 
anterior  scalenus  and  omo-hyoid  muscles  ;  and  the  sternal  head  conceals 
the  depressors  of  the  hyoid  bone,  and  the  common  carotid  artery  with  its 
vein  and  nerves.  After  the  union  of  the  heads,  the  muscle  is  placed  over 
the  cervical  plexus,  and  the  middle  scalenus  and  elevator  of  the  angle  of 
the  scapula  ;  and  near  the  skull,  on  the  digastric  and  splenius  muscles,  the 
occii)ital  artery,  and  part  of  the  parotid  gland.  The  spinal  accessory  per- 
forates the  muscular  fibres  about  the  u|)per  third. 

Action.  Both  muscles  acting  bend  tlie  head  forwards ;  but  one  muscle 
turns  the  face  to  the  opposite  side.     In  conjunction  w'ith  the  muscles  at- 


72 


DISSECTION    OF    THE    NECK. 


taclied  to  the  mastoid  process  one  steriio-rnastoideus  will  incline  the  head 
towards  the  shoulder  of  the  same  side. 


Fig.  15. 


View  of  the  Anterior  Triangular  Space  of  the  Neck  (Quain's  "Arteries"). 

1.  Sterno-rnastoideus.  7    Internal  juy:ular  veia. 

2.  Sterno-hyoideus.  8.  External    jugular    vein.— In    the    Drawing 

3.  Anterior  belly  of  the  omo-hyoideus.  from  which  this  cut  is  copied  the  steruo-raas- 
i.  Thyro-hyoideus.  toid  is  partly  cut  through. 

6.  Common  carotid  artery  dividing. 


In  laborious  respiration  the  two  muscles  will  assist  in  elevating  the  ster- 
num. 

The  OMO-iiYOiD  MUSCLE  crosses  beneath  the  sterno-mastoideus,  and 
consists  of  two  fleshy  bellies  united  by  a  small  round  intermediate  tendon 
(fig.  14, ').  The  origin  of  the  muscle  from  the  scapula,  and  the  connec- 
tions of  the  posterior  part,  are  to  be  studied  in  the  dissection  of  the  Back. 
From  the  intervening  tendon  the  anterior  fleshy  belly  (fig.  15,  *)  is  directed 
upwards  along  the  outer  border  of  the  sterno-liyoid  nuiscle,  and  is  inserted 
into  the  lower  part  of  the  body  of  the  hyoid  bone,  close  to  the  great  cornu. 

The  anterior  belly  is  in  contfict  with  the  fascia,  after  escaping  from  be- 
neath the  sterno-mastoid  ;  and  rests  on  the  sterno-thyroideus.  This  part 
of  the  muscle  crosses  the  common  carotid  artery  and  internal  jugular  vein 
on  a  level  with  the  cricoid  cartilage. 

Action.  The  anterior  belly  depresses  the  hyoid  bone  ;  and  the  posterior 


DEPRESSORS  OF  OS  HYOIDES.  73 

is  said  by  Theile  to  make  tense  tlie  deep  fascia  of  the  neck  with  which  it 
is  connected. 

The  STERNO-iiYOiD  MUSCLE  (fig.  15,  ^)  is  a  flat  thin  band  nearer  the 
middle  line  than  the  preceding.  It  arises  from  the  posterior  surface  of  the 
sternum  and  the  cartilage  of  the  first  rib.  From  this  spot  the  fibres  ascend, 
and  are  inserted  into  the  lower  border  of  the  body  of  the  os  hyoides,  inter- 
nal to  the  preceding  muscle. 

One  surface  is  in  contact  with  the  fascia,  and  is  often  marked  by  a  ten- 
dinous intersection  near  the  clavicle.  When  the  muscle  is  divided  and 
turned  aside,  the  deep  surface  will  be  found  to  touch  the  sterno-thyroideus, 
and  the  superior  thyroid  vessels.  The  muscles  of  opposite  sides  are  sepa- 
rated by  an  interval  which  is  largest  below. 

Action.  It  draws  the  os  hyoides  downwards  after  swallowing ;  and  in 
laborious  respiration  it  will  act  as  an  elevator  of  the  sternum. 

The  STERNO-TiiYROiD  MUSCLE  is  wider  and  shorter  than  the  sterno- 
hyoid, beneath  which  it  lies.  Like  the  other  hyoid  muscle,  it  arises  from 
the  posterior  surface  of  the  sternum,  and  the  cartilage  of  the  first  rib  below 
the  former ;  and  it  is  inserted  into  the  oblique  line  on  the  side  of  the  thy- 
roid cartilage,  where  it  is  continuous  with  the  thyro-hyoid  muscle. 

The  inner  border  touches  its  fellow  for  about  an  inch,  along  the  middle 
line  of  the  neck,  whilst  the  outer  reaches  over  the  carotid  artery.  The 
superficial  surface  is  concealed  by  the  preceding  hyoid  muscles  ;  and  the 
opposite  surface  is  in  contact  with  the  lower  part  of  the  common  carotid 
artery,  the  trachea,  and  the  larynx  and  thyroid  body.  A  transverse,  ten- 
dinous line  crosses  the  muscle  near  the  sternum. 

Action.  Its  chief  use  is  to  aid  the  preceding  muscle  in  lowering  rapidly 
the  hyoid  bone  after  deglutition  ;  but  it  can  draw  down  and  forwards  the 
thyroid  cartilage,  and  assist  in  rendering  tight  the  vocal  cords. 

Like  the  sterno-hyoid  it  participates  in  the  movement  of  the  chest  in 
laborious  breathing. 

The  THYRO-HYOiDEus  (fig.  15,  *)  is  a  continuation  in  direction  of  the 
last  muscle.  Beginning  on  the  side  of  the  thyroid  cartilage,  the  fibres 
ascend  to  the  inner  half  of  the  great  cornu  of  the  os  hyoides,  and  to  the 
outer  part  of  the  body  of  the  bone. 

On  the  muscle  lies  the  omo-hyoideus  ;  and  beneath  it  are  the  superior 
laryngeal  nerve  and  vessels.  It  is  sometimes  considered  one  of  the  special 
muscles  of  the  larynx. 

Action.  Raising  the  thyroid  cartilage  towards  the  os  hyoides,  it  renders 
lax  the  vocal  cords,  and  assists  in  placing  the  cartilage  under  the  tongue 
preparatory  to  swallowing. 

Directions. — The  remaining  parts  included  in  this  section  are  the 
scaleni  muscles  and  the  subclavian  bloodvessels,  with  the  cervical  nerves 
and  the  carotid  bloodvessels.  The  student  may  examine  them  in  the  order 
here  given. 

Dissection  (fig.  IG).  Supposing  the  sterno-mastoid  cut,  the  fiit  and 
fascia  are  to  be  taken  away  from  tlie  lower  part  of  the  neck,  so  as  to  pre- 
pare the  scaleni  muscles  with  the  subclavian  vessels  and  their  branches. 
By  means  of  a  little  dissection  the  anterior  scalenus  muscle  will  be  seen 
ascending  from  the  first  rib  to  the  neck,  having  the  phrenic  nerve  and  sub- 
clavian vein  in  front  of  it,  the  latter  crossing  it  near  the  rib. 

The  part  of  the  subclavian  artery  on  the  inner  side  of  the  scalenus  is 
then  to  be  cleaned,  care  being  taken  not  only  of  its  branches,  but  of  the 
branches  of  the  sympathetic  nerve  which  course  over  and  along  it  from  the 


74 


DISSECTION    OF    THE    NECK. 


neck  to  the  chest.     Tliis  dissection  will  be  facilitated  by  the  removal  of  a 
part  or  the  whole  of  the  clavicle. 

All  the  branches  of  the  artery  are  in  general  easily  found,  except  the 
superior  intercostal,  which  is  to  be  sought  in  the  tliorax  in  front  of  the 
neck  of  the  first  rib.     On  the  branch  (inferior  thyroid)  ascending  to  the 


Fig.  16. 


A  VIEW  OF  THB  Common  Carotid  akd  Subclavian  Arteries  (Quain's  "  Arteries"). 


1.  Anterior  scalenus,  with  the  phrenic  nerve 

on  it. 

2.  Middle  scalenus. 

.3.  Levator  anguli  scapulse. 

4.  Oinohyoideus. 

5.  Rectus  capitis  anticus  major. 

6.  Common  carotid  artery. 


7.  Subclavian  vein. 

8.  Subclavian  artery. 

9.  Digastric  muscle. 

10.  Parotid  gland. 

11.  Submaxillary  gland. 

12.  Thyroid  body. 

13.  Trapezius  muscle,  reflected. 


thyroid  body,  or  near  it,  is  the  middle  cervical  ganglion  of  the  Sympathetic ; 
and  the  dissector  should  follow  downwards  from  it  a  small  cardiac  nerve 
to  the  thorax.  Only  the  origin  and  first  part  of  the  course  of  the  arterial 
branches  can  be  now  seen  ;  their  termination  is  met  with  in  other  stages 
of  this  dissection,  or  in  tlie  dissection  of  other  parts  of  the  body. 

Now  the  student  should  seek  the  small  right  lympliatic  duct  that  opens 
into  the  subclavian  vein  near  its  junction  with  the  jugular.  A  notice  of  it 
will  be  given  with  the  lympliatics  of  the  thorax. 


SCALENI    MUSCLES.  75 

The  outer  part  of  the  subclavian  artery  having  been  already  prepared, 
let  the  dissector  remove  more  completely  the  fibrous  tissue  from  the  nerves 
of  the  brachial  plexus.  From  the  plexus  trace  the  small  branch  to  the 
subclavius  muscle ;  and  the  branches  to  the  rhomboid  and  serratus  muscles, 
which  pierce  the  middle  scalenus.  If  it  is  thought  necessary,  the  anterior 
scalenus  may  be  cut  through  after  the  artery  has  been  studied. 

Clean  the  cervical  plexus,  and  seek  its  muscular  branches,  the  small 
twigs  to  join  the  descendens  noni,  and  the  roots  of  the  phrenic  nerve. 
Lastly,  let  the  middle  scalenus  muscle  be  defined,  as  it  lies  beneath  the 
cervical  nerves. 

The  SCALENI  muscles  are  usually  described  as  three  in  number,  and  are 
named  from  their  relative  position,  anterior,  middle,  and  posterior ;  they 
extend  from  the  first  two  ribs  to  the  transverse  processes  of  the  cervical 
vertebrae. 

The  SCALENUS  ANTicus  (fig.  16,  ^)  extends  from  the  first  rib  to  the 
lower  cervical  vertebras,  and  is  somewhat  conical  in  shape.  It  is  attached 
by  its  apex  to  the  inner  border  and  the  upper  surface  on  the  first  rib,  so  as 
to  surround  the  rough  surface  or  projection  on  this  aspect  of  the  bone  ;  and 
by  its  base  it  is  inserted  into  the  anterior  transverse  processes  of  four  of 
the  cervical  vertebrae,  viz.,  sixth,  fifth,  fourth,  and  third  (fig.  45,  ^). 

More  deeply  seated  below  than  above,  the  muscle  is  concealed  by  the 
clavicle  and  the  subclavius,  and  by  the  clavicular  part  of  the  sterno-mas- 
toid :  the  phrenic  nerve  lies  along  its  cutaneous  surface,  and  the  subclavian 
vein  crosses  over  it  near  the  rib.  Along  the  inner  border  is  the  internal 
jugular  vein.  Beneath  the  scalenus  are  the  pleura,  the  subclavian  artery, 
and  the  nerves  of  the  brachial  plexus.  The  insertion  into  the  vertebrae 
corresponds  with  the  origin  of  the  rectus  capitus  anticus  major  muscle. 

Action.  The  anterior  of  these  muscles  raises  strongly  the  first  rib,  in 
consequence  of  its  forward  attachment.  If  the  rib. is  fixed,  it  bends  for- 
ward the  lower  part  of  the  neck. 

The  scALENius  MEDius  MUSCLE  (fig.  16,  ^)  is  larger  than  the  anterior, 
and  extends  farthest  of  all  on  the  vertebrae.  Inferiorly  it  is  attached  to  a 
groove  on  the  upper  surface  of  the  first  rib,  extending  obliquely  forwards 
from  the  tubercle  to  the  outer  border  for  one  inch  and  a  half.  The  muscle 
ascends  behind  the  spinal  nerves,  and  is  inserted  into  the  tips  of  the  poste- 
rior transverse  processes  of  all  the  cervical  vertebra  (fig.  45,  ^). 

In  contact  with  the  anterior  surface  are  the  subclavian  artery  and  the 
spinal  nerves,  together  with  the  sterno-mastoid  muscle ;  whilst  the  poste- 
rior surface  touches  the  posterior  scalenus,  and  the  deep  lateral  muscles  of 
the  back  of  the  neck.  The  outer  border  is  perforated  by  the  nerves  of  the 
rhomboid  and  serratus  muscles. 

Action.  Usually  it  elevates  the  first  rib.  With  the  rib  fixed,  the  cer- 
vical part  of  the  spine  will  be  inclined  laterally  by  one  muscle. 

Tiie  SCALENUS  POSTICUS  (fig.  45,  ^)  is  considerable  in  size,  and  appears 
to  be  but  part  of  the  preceding.  It  is  attached  below  by  a  slip,  about  half 
an  inch  wide,  to  the  second  rib,  in  front  of  the  serratus  posticus  superior; 
and  it  is  inserted  above  with  the  scalenus  medius  into  two  or  three  of  the 
lower  cervical  transverse  processes. 

Action.  It  acts  as  an  elevator  of  the  second  rib  ;  and  its  fibres  having 
the  same  direction  as  those  of  the  medius,  it  will  incline  the  neck  in  the 
same  way. 

Tiie  SUBCLAVIAN  ARTERY  (fig.  16)  is  the  first  part  of  the  large  vessel 
supplying  the  upper  limb  with  blood,  which  is  thus  designated  from  its 


76  DISSECTION    OF    THE    NECK. 

position  beneath  the  clavicle.  This  vessel  (^)  is  derived  from  the  branch- 
ing of  the  innominate  artery  behind  the  sterno-clavicular  articulation,  and 
the  part  of  it  named  subclavian  extends  as  far  as  the  lower  border  of  the 
first  rib.  To  reach  the  limb  the  artery  crosses  the  lower  part  of  the  neck, 
taking  an  arched  course  over  the  bag  of  the  pleura  and  the  first  rib,  and 
between  the  scaleni  muscles.  For  the  purpose  of  describing  its  numerous 
connections  the  vessel  may  be  divided  into  three  parts  :  the  first  extending 
from  the  sterno-clavicular  articulation  to  the  inner  border  of  the  interior 
scalenus ;  the  second,  beneath  the  scalenus ;  and  the  third,  from  the  outer 
border  of  that  muscle  to  the  lower  edge  of  the  first  rib. 

First  part.  Internal  to  the  anterior  scalenus  the  artery  lies  deep  in  the 
neck,  and  ascends  slightly  from  its  origin.  Between  the  vessel  and  the 
surface  will  be  found  the  common  integumentary  coverings  with  the  pla- 
tysma  and  the  deep  fascia,  the  sterno-mastoid,  sterno-hyoid  and  sterno- 
thyroid muscles,  and  a  strong  deep  process  of  fascia  from  the  inner  border 
of  the  scalenus  muscle.  This  part  of  the  subclavian  lies  over  the  longus 
colli  muscle,  though  at  some  distance  from  it,  and  separated  from  it  by  fat 
and  nerves.  Below  the  artery  is  the  pleura,  which  ascends  into  the  arch 
formed  by  the  vessel. 

Veins.  The  innominate  vein,  and  the  ending  of  the  subclavian  C),  form 
an  arch  below  that  of  the  artery.  The  large  internal  jugular  vein  crosses 
the  arterial  trunk  close  to  the  scalenus ;  and  underneath  this  vein,  with 
the  same  direction,  lies  the  vertebral  vein.  Much  more  superficial,  and 
separated  from  the  artery  by  muscles,  is  the  deep  part  of  the  anterior  jugu- 
lar vein. 

Nerves.  In  front  of  the  artery  lies  the  pneumogastric  nerve,  near  to  the 
internal  jugular  vein  ;  and  inside  this,  the  lower  cardiac  branch  of  the 
same  nerve  trunk.  Behind  the  subclavian  artery  winds  the  recurrent 
branch  of  the  [)neumogastric  ;  and  still  deeper  is  the  cord  of  the  sympa- 
thetic nerve  with  its  cardiac  branches,  one  or  more  of  its  offsets  entwining 
round  the  vessel. 

Second  part.  Beneath  the  scalenus  the  vessel  is  less  deep  than  when 
placed  internal  to  that  muscle,  and  at  this  spot  it  rises  highest  above  the 
clavicle.  The  second  part,  like  the  first,  is  covered  by  the  integuments, 
platysma,  and  deep  fascia ;  then  by  the  clavicular  origin  of  the  st  tuo- 
mastoideus ;  and  lastly  by  the  anterior  scalenus.  Behind  the  vessel  is  the 
middle  scalenus.  Below  the  artery  is  the  bag  of  the  pleura,  which  ascends 
between  the  scalena. 

Veins.  Below  the  level  of  the  artery,  and  separated  from  it  by  the  an- 
terior scalenus  muscle,  lies  the  arch  of  the  subclavian  vein. 

Nerves.  In  front  of  the  scalenus  descends  the  phrenic  nerve.  Above 
the  vessel,  in  the  interval  between  the  scalena,  are  placed  tlie  large  cervical 
nerves ;  and  the  trunk  formed  by  the  last  cervical  and  first  dorsal  is  inter- 
posed between  the  artery  and  the  middle  scalenus. 

Third  part.  Beyond  the  scalenus  the  artery  is  contained  in  the  clavicu- 
lar part  of  the  posterior  triangular  sjjace  (p.  64),  and  is  nearer  the  surface 
than  in  the  rest  of  its  course :  this  part  of  the  vessel  is  inclosed  in  a  tube 
of  the  deep  cervical  fascia,  which  it  receives  as  it  passes  from  between  the 
scaleni.  It  is  comparatively  superficial  whilst  in  the  space  before  men- 
tioned, for  it  is  covered  only  by  the  integuments,  the  platysma,  and  deep 
fascia. ;  but  near  its  termination  the  vessel  gets  under  cover  of  the  suj)ra- 
scapular  artery  and  vein,  and  the  clavicle  and  subclavius  muscle.     In  this 


SUBCLAVIAN    ARTERY.  77 

part  of  its  course  tlie  artery  rests  on  the  surface  of  the  first  rib,  which  is 
interposed  between  it  and  the  pleura. 

Veins.  The  arch  of  the  subclavian  vein  is  closfe  to  the  artery,  not  being 
separated  by  muscle,  but  lies  commonly  at  a  lower  level.  The  external 
jugular  vein  crosses  it  near  the  scalenus  muscle  ;  and  the  suprascapular 
and  transverse  cervical  branches,  which  enter  the  jugular,  form  sometimes 
a  plexus  over  the  third  part  of  the  artery. 

Nerves.  Tlie'  large  cords  of  the  brachial  plexus  are  placed  above  and 
close  to  the  vessel ;  and  the  small  nerve  of  the  subclavius  crosses  it  about 
the  middle.  Superficial  to  the  cervical  fascia  lie  the  descending  cutaneous 
branches  of  the  cervical  plexus. 

Pecaliaritles.  The  artery  may  spring  as  a  separate  trunk  from  the  arch 
of  the  aorta ;  and  in  such  a  deviation  the  vessel  takes  a  deeper  place  than 
usual  to  reach  the  scaleni  muscles. 

It  has  been  before  said  (p.  66)  that  the  subclavian  may  be  in  front  of 
the  scalenus  or  in  its  fibres ;  and  that  it  may  be  placed  one  inch  and  a  half 
above  the  level  of  the  clavicle. 

Branches  of  subclavian.  Usually  there  are  four  chief  branches  on  the 
subclavian  artery.  Three  branches  arise  from  the  first  part  of  the  arterial 
trunk  ;  one  (vertebral)  ascends  to  the  head ;  another  (internal  mammary) 
descends  to  the  chest;  and  the  remaining  one  (thyroid  axis)  is  a  short 
thick  trunk,  which  furnishes  branches  inwards  and  outwards  to  the  thyroid 
body  and  shoulder.  These  arise  commonly  near  the  scalenus  muscle,  so 
as  to  leave  an  interval  at  the  origin  free  from  ofisets.  This  interval  varies 
in  length  from  half  an  inch  to  an  inch  in  the  greater  number  of  cases  ;  and 
its  extremes  range  from  somewhat  less  than  half  an  inch  to  an  inch  and 
three  quarters.  But  in  some  instances  the  branches  are  scattered  over  the 
first  part  of  the  artery  (Quain).^ 

The  fourth  branch  (superior  intercostal)  arises  beneath  the  anterior 
scalenus  from  the  second  part  of  the  artery,  and  gives  off  the  deep  cervical 
branch  ;  a  small  spinal  artery  comes  sometimes  from  this  part  of  the  trunk. 

If  there  is  a  branch  present  on  the  third  part  of  tlie  artery,  it  is  com- 
monly the  posterior  scapular ;  if  more  than  one,  this  same  branch  with 
the  external  mammary  ;  and  if  more  than  two,  an  offset  belonging  to  the 
thyroid  axis  will  be  added. 

The  vertebral  artery  is  generally  the  first  and  largest  branch  of  the  sub- 
clavian, and  arises  from  the  upper  and  posterior  part.  Ascending  between 
the  contiguous  borders  of  the  scalenus  and  longus  colli  muscles,  this  branch 
enters  the  aperture  in  the  lateral  mass  of  the  sixth  cervical  vertebra,  and 
is  continued  upwards  to  the  skull  through  the  foramina  in  the  other  cervical 
vertebrae.  Before  the  artery  enters  its  aperture  it  is  partly  concealed  by 
the  internal  jugular  vein,  and  passes  beneath  the  thyroid  artery  ;  it  is  ac- 
companied by  branches  of  the  sympathetic  nerve,  and  supplies  small  mus- 
cular offsets.     Its  course  and  distribution  will  be  given  afterwards. 

The  vertebral  vein  issues  with  its  accompanying  artery,  to  which  it  is 
superficial  in  the  neck,  and  is  directed  over  the  subclavian  artery  to  join 
tlie  subclavian  vein  ;  it  receives  the  deep  cervical  vein,  and  the  branch 
that  accompanies  the  ascending  cervical  artery. 

The  internal  mammary  branch  leaves  the  lower  part  of  the  subclavian 

'  The  student  is  referred  for  fuller  information  respecting  the  peculiarities  of 
the  vessel,  and  the  practical  applications  to  be  deduced  from  them,  to  the  original 
and  valuable  work  on  the  Anatomy  of  the  Arteries  of  the  Human  Body,  by  Richard 
Quain,  F.R.S. 


78  DISSECTION    OF    THE    NECK. 


artery,  and  coursing  downwards  beneath  the  cLavicle,  subchivius,  and  the 
riglit  innominate  vein,  enters  tlie  thorax  between  tlie  lirst  rib  and  the  bag 
of  the  pleura.  As  the  artery  disappears  in  the  chest,  it  is  crossed  (super- 
ficially) by  the  phrenic  nerve.  The  vessel  is  distributed  to  the  walls  of 
the  chest  and  abdomen  ;  and  its  anatomy  will  be  given  with  the  dissection 
of  those  parts. 

Thyroid  axis.  This  is  a  short  thick  trunk  (fig.  10)  which  arises  from 
the  front  of  the  artery  near  the  anterior  scalenus  muscle,  and  soon  divides 
into  three  branches — one  to  the  thyroid  body,  and  two  to  the  sca{)ula. 

The  suprascapular  branch  courses  outwards  across  the  lower  part  of  the 
neck,  behind  the  clavicle  and  subclavius  muscle,  to  the  superior  costa  of 
the  scapula,  and  entering  the  supraspinal  fossa  is  distributed  on  the  dorsum 
of  that  bone.  The  connections  of  this  artery  are  more  fully  seen  in  the 
dissection  of  the  Back. 

The  transverse  cervical  branch,  usually  larger  than  the  preceding,  takes 
a  similar  direction,  though  higher  in  the  neck,  and  ends  beneath  the  bor- 
der of  the  trapezius  muscle  in  the  superficial  cervical  and  posterior  scapular 
arteries.  ("  Dissection  of  the  Back.")  In  its  course  outwards  through 
the  s[)ace  containing  the  third  part  of  the  subclavian  artery,  this  branch 
crosses  the  anterior  scalenus,  the  phrenic  nerve,  and  the  brachial  plexus. 
Some  small  offsets  are  supplied  by  it  to  the  posterior  triangular  space  of 
the  neck. 

Though  the  transverse  cervical  artery  supplies  ordinarily  the  posterior 
scapular  branch,  there  are  many  bodies  in  which  it  is  too  small  to  give 
origin  to  so  large  an  offset.  In  such  instances  the  diminished  artery  ends 
in  the  trapezius  muscle  ;  whilst  the  posterior  scapular  branch  arises  sepa- 
rately from   the  third,  or  even  the  second  part  of  the  subclavian  artery 

The  inferior  thyroid  branch  is  the  largest  offset  of  the  thyroid  axis. 
Directed  inwards  with  a  flexuous  course  to  the  thyroid  body,  the  branch 
passes  beneath  the  common  carotid  artery  and  the  accompanying  vein  and 
nerves,  and  in  front  of  the  longus  colli  muscle  and  the  recurrent  nerve. 
At  the  lower  part  of  the  thyroid  body  it  divides  into  branches  which  ramify 
in  the  under  surface,  and  communicate  with  the  superior  thyroid,  and  its 
fellow,  forming  a  very  free  anastomosis  between  those  vessels. 

Nea-r  the  larynx  a  laryngeal  branch  is  distributed  to  that  tube,  and  other 
offsets  are  furnished  to  the  trachea. 

The  ascending  cervical  branch  of  the  thyroid  is  directed  upwards  be- 
tween the  scalenus  and  rectus  capitis  anticus  major,  and  ends  in  branches 
to  those  muscles  and  the  posterior  triangle  of  the  neck.  Some  small  spinal 
offsets  are  conveyed  along  the  spinal  nerves  to  the  cord  and  its  membranes. 

The  veins  corresponding  with  the  branches  of  the  thyroid  axis  have  the 
following  destination  :  those  with  the  su[)rascapular  and  transverse  cervical 
arteries  oi)en  into  the  external  jugular  vein.  But  the  inferior  thyroid  vein 
begins  in  the  tliyroid  body,  and  descends  in  front  of  the  trachea,  beneath 
the  muscles  covering  this  tube,  to  the  innominate  vein. 

The  superior  intercostal  artery  arises  from  the  posterior  })art  of  the  sub- 
clavian, and  bends  downwards  over  the  neck  of  the  first  rib :  its  distribu- 
tion to  the  first  two  intercostal  spaces  will  be  seen  in  the  thorax. 

Arising  in  common  with  this  branch  is  the  deep  cervical  artery  (art.  pro- 
funda cervicis).  Analogous  to  the  dorsal  branch  of  an  intercostal  artery 
(Quain),  it  passes  backwards  between  the  transverse  process  of  the  last 
cervical  vertebra  and  the  first  rib,  lying  internal  to  or  beneath  the  two 


the  ™ 


SUBCLAVIAN    VEIN.  79 

hinder  scaleni  muscles  and  the  fleshy  slips  continued  upwards  from  the 
erector  spini«,  to  end  beneath  the  complexus  muscle  at  the  posterior  part  of 
the  neck. 

A  spinal  branch  (Quain)  is  frequently  given  from  the  second  part  of  the 
artery  ;  its  offsets  are  continued  into  the  spinal  canal  through  the  inter- 
vertebral foramina. 

The  SUBCLAVIAN  VEIN  has  not  the  same  limits  as  the  companion  artery, 
reaching  only  from  the  lower  edge  of  the  first  rib  to  the  inner  border  of  the 
anterior  scalenus.  It  is  a  continuation  of  the  axillary  vein,  and  ends  by 
joining  the  internal  jugular  in  the  innominate  trunk.  Its  course  is  arched 
below  tlie  level  of  the  artery,  from  which  it  is  separated  by  the  scalenus. 

The  anterior  and  external  jugular  join  the  subclavian  vein  outside  the 
scalenus,  and  the  vertebral  vein  enters  it  inside  that  muscle.  Into  the 
angle  of  union  of  the  subclavian  and  jugular  veins  the  right  lym[)hatic  duct 
opens  (fig.  27,^)  ;  and  at  the  like  spot,  on  the  left  side,  the  large  lymphatic 
or  thoracic  duct  ends  (fig.  27,^).  The  highest  pair  of  valves  in  the  sub- 
clavian trunk  is  placed  outside  the  opening  of  the  external  jugular  vein.^ 

It  should  be  borne  in  mind  that  not  unfrequently  the  vein  is  as  high  in 
the  neck  as  the  third  part  of  its  companion  artery  ;  and  that  the  vein  has 
been  seen  twice  with  the  artery  beneath  the  anterior  scalenus. 

The  ANTERIOR  PRIMARY  BRANCHES  OF   THE  CERVICAL  NERVES    Spring 

from  the  common  trunks  in  the  intervertebral  foramina,  and  appear  on  the 
side  of  the  neck  between  the  intertransverse  muscles.  These  nerves  are 
eight  in  number,  and  are  equally  divided  between  the  cervical  and  the 
brachial  plexus  ;  the  highest  four  being  combined  in  the  former,  and  the 
remaining  nerves  in  the  latter  plexus.  The  nerves  receive  offsets  of  com- 
munication from  the  sympathetic  at  their  beginning,  and  intermix  by  means 
of  numerous  branches  near  the  spine. 

To  this  general  statement  some  addition  is  needed  for  the  first  two  nerves  ; 
and  their  peculiarities  will  be  noticed  in  Section  18. 

Brachial  Plexus.  The  four  lower  cervical  nerves  and  part  of  the  first 
intercostal  are  blended  in  this  plexus;  and  a  fasciculus  is  added  to  them 
from  the  lowest  nerve  entering  the  cervical  plexus.  Thus  formed,  the  plexus 
reaches  from  the  neck  to  the  axilla,  where  it  ends  in  nerves  for  the  upper 
limb.  Only  the  part  of  it  above  the  clavicle  can  now  be  seen.  In  the 
neck  the  nerves  have  but  little  of  a  plexiform  disposition :  they  lie  at  first 
between  the  scaleni  muscles,  opposite  the  four  lower  cervical  vertebrae,  and 
have  the  following  arrangement: — 

The  fifth  and  sixth  nerves  unite  near  the  vertebrae ;  the  seventh  remains 
distinct  as  far  as  the  outer  border  of  the  middle  scalenus ;  and  the  last  cer- 
vical and  the  piece  of  the  first  intercostal  are  blended  in  one  trunk  beneath 
the  anterior  scalenus ;  so  that  they  make  at  first  three  cords.  Near  the 
attachment  of  the  middle  scalenus  to  the  rib,  the  seventh  nerve  throws 
itself  into  the  trunk  of  the  united  fifth  and  sixth,  and  then  there  result  two 
cords  to  the  plexus: — the  one  (upper)  formed  by  tlie  fifth,  sixth,  and  sev- 
enth cervical  nerves;  and  the  other  (lower)  by  tlie  eighth  cervical  and  the 
first  intercostal  nerve.  These  two  trunks  accompany  the  subclavian  artery, 
lying  to  its  acromial  side,  and  are  continued  to  the  axilla  where  they  are 
more  intimately  blended. 

Branches.  The  branches  of  the  plexus  may  be  classed  into  those  above 

'  See  a  paper  on  the  Valves  in  the  Veins  of  the  Neck  in  the  Edin.  Med.  Journal, 
of  Nov.,  1856,  by  Dr.  Struthers. 


80  DTSSECTIOX    OF    THE    NECK. 

the  clavicle,  and  tliose  below  that  bone.  The  highest  set  end  mostly  in 
muscles  of  the  lower  part  of  the  neck  and  of  the  scapula ;  whilst  tlie  other 
set  consist  of  the  terminal  branches,  and  are  furnished  to  the  upper  limb, 
with  which  they  will  be  referred  to. 

Branches  above  the  Clavice.  The  branch  of  the  suhclaviiis  mus- 
cle is  a  slender  twig,  which  arises  from  the  trunk  formed  by  the  fifth  and 
sixth  nerves,  and  is  directed  downwards  over  the  subclavian  artery  to  the 
under  surface  of  the  muscle ;  it  is  often  united  with  the  phrenic  nerve  at 
the  lower  part  of  the  neck. 

The  branch  of  the  rhomboid  muscles  springs  from  the  fifth  nerve  in  the 
substance  of  the  middle  scalenus,  and  perforates  the  fibres  of  that  muscle; 
it  is  directed  backwards  beneath  the  levator  anguli  scapulie  to  its  destina- 
tion. Branches  are  given  usually  from  this  nerve  to  the  levator  anguli 
scapulae. 

The  nerve  of  the  serratus  (posterior  thoracic  nerve)  is  contained  in  the 
scalenus,  like  the  preceding,  and  arises  from  the  fifth  and  sixth  nerves 
near  the  intervertrebral  foramina.  Piercing  the  fibres  of  the  scalenus 
lower  than  the  preceding  branch,  tlie  nerve  is  continued  behind  the  brachial 
plexus,  and  enters  the  serratus  magnus  muscle  on  the  axillary  surface. 

Branches  of  the  scaleni  and  longus  colli  muscles.  These  small  twigs 
are  seen  when  the  anterior  scalenus  is  divided;  they  arise  from  the  begin- 
ning of  the  trunks  of  the  nerves. 

The  suprascapular  nerve  is  larger  than  either  of  the  others.  It  arises 
near  the  subclavian  branch  from  the  cord  of  the  plexus  formed  by  the  fifth 
and  sixth  nerves.  Its  destination  is  to  the  muscles  on  the  dorsum  of  the 
scapula,  and  it  will  be  dissected  with  tlie  arm. 

Occasionally  an  offset  from  the  fifth  cervical  trunk  joins  the  phrenic 
nerve  on  the  anterior  scalenus  muscle. 

The  CERVICAL  PLEXUS  is  formed  by  the  first  four  cervical  nerves. 
Situate  at  the  upper  part  of  the  neck,  it  lies  beneath  the  sterno-mastoid 
muscle,  and  on  the  middle  scalenus  and  the  levator  anguli  scapulae.  It 
diflfers  much  from  the  brachial  plexus,  for  it  resembles  a  network  more 
than  a  bundle  of  large  cords.  The  following  is  the  general  arrangement  of 
the  nerves  in  the  plexus  :  Each  nerve,  except  the  first,  divides  into  an 
ascending  and  a  descending  branch,  and  these  unite  with  similar  parts  of 
the  contiguous  nerves,  so  as  to  give  rise  to  a  series  of  arches.  From  these 
loops  or  arches  the  different  branches  arise: — 

The  branches  are  superficial  and  deep.  The  superficial  set  has  been 
described  with  the  triangular  space  of  the  neck,  as  consisting  of  ascending 
and  descending  (p.  66).  The  ascending  brandies  may  be  now  seen  to 
spring  from  the  union  of  the  second  andtliird  nerves;  and  the  descending, 
to  take  origin  from  the  loop  between  the  third  and  fourtli  nerves.  The 
deep  set  of  branches  remains  to  be  examined  :  they  are  muscular  and  com- 
municating, and  may  be  arranged  into  an  internal  and  an  external  series. 

Internal  Series The  phrenic  or  muscular  nerve  of  the  diaphragm 

(fig.  16)  is  derived  from  the  fourth,  or  third  and  fourth  nerves  of  the 
plexus  ;  and  it  may  be  joined  by  a  fasciculus  fi-om  the  fifth  cervical  nerve. 
Descending  obliquely  on  the  surface  of  the  anterior  scalenus  from  the  outer 
to  the  inner  edge,  it  enters  the  chest  in  front  of  the  internal  mammary 
artery,  but  behind  the  subclavian  vein,  and  traverses  that  cavity  to  reach 
the  diaphragm.  At  the  lower  part  of  the  neck  the  phrenic  nerve  is  joined 
by  a  filament  of  the  sympathetic,  and  sometimes  by  an  ofliset  of  the  nerve 
of  the  subclavius  muscle. 


CERVICAL    PLEXUS.  81 

On  the  left  side  the  nerve  crosses  over  the  first  part  of  the  subclavian 
artery. 

The  branches  communicating  loith  the  descendens  noni  are  two  in  num- 
ber. One  arises  from  the  second,  and  the  other  from  the  third  cervical 
nerve  ;  they  are  directed  inwards  over  the  internal  jugular  vein,  and  com- 
municate in  front  of  the  carotid  sheath  with  the  descending  muscular 
branch  (descendens  noni)  of  the  hypoglossal  nerve.  Sometimes  these 
nerves  pass  under  the  jugular  vein. 

Muscular  branches  are  furnished  to  the  anterior  recti  muscles ;  they 
arise  from  the  loop  between  the  first  two  nerves,  and  from  the  trunks  of 
the  other  nerves  close  to  the  intervertebral  foramina. 

Some  connecting  branches  pass  from  the  loop  between  the  first  two 
nerves,  and  unite  with  the  sympathetic  and  some  cranial  nerves  near  the 
base  of  the  skull:  these  will  be  afterw^ards  described. 

External  or  Posterior  Series.  Muscular  branches  are  given 
from  the  second  nerve  to  the  sterno-mastoideus ;  from  the  third  nerve  to 
the  levator  anguli  scapulas ;  and  from  the  third  and  fourth  nerves  to  the 
trapezius.  Further,  some  small  branches  supply  the  substance  of  the  mid- 
dle scalenus. 

Connecting  branches  with  the  spinal  accessory  nerve  exist  in  three 
places.  First,  in  the  sterno-mastoid  muscle;  next,  in  the  posterior  trian- 
gular space ;  and  lastly,  beneath  the  trapezius.  The  union  with  the  branches 
distributed  to  the  trapezius  has  the  appearance  of  a  plexus. 

The  COMMON  CAROTID  ARTERY  is  the  leading  vessel  for  the  supply  of 
blood  to  the  neck  and  head  (fig.  16,  *).  The  origin  of  the  vessel  differs  on 
opposite  sides  of  the  body,  beginning  at  the  lower  part  of  the  neck  on  the 
right,  and  in  the  thorax  on  the  left  side. 

The  right  vessel  commences  opposite  the  sterno-clavicular  articulation 
in  the  bifurcation  of  the  innominate  artery,  and  ends  at  the  upper  border 
of  the  thyroid  cartilage  by  dividing  into  the  external  and  internal  carotid. 
The  course  of  the  artery  is  along  the  side  of  the  trachea  and  larynx,  gradu- 
ally diverging  from  the  vessel  on  the  opposite  side  in  consequence  of  the 
increasing  size  of  the  larynx;  and  its  position  will  be  marked  by  a  line 
from  the  sterno-clavicular  articulation  to  a  point  midAvay  between  the 
angle  of  the  jaw  and  the  mastoid  process. 

Contained  in  a  sheath  of  cervical  fascia  with  the  internal  jugular  vein 
and  the  pneumo-gastric  nerve,  the  carotid  artery  has  the  following  connec- 
tions w^ith  the  surrounding  parts: — As  high  as  the  cricoid  cartilage  the 
vessel  is  deeply  placed,  and  is  concealed  by  the  common  coverings  of  the 
skin,  platysma,  and  fasciae,  and  by  the  muscles  at  the  low^er  part  of  the 
neck,  viz.,  sterno-mastoid  (sternal  origin),  sterno-hyoid,  omo-hyoid,  and 
sterno-thyroid.  But  above  the  circoid  cartilage  to  its  termination  the 
artery  is  less  deep,  being  covered  only  by  the  sterno-mastoid  with  the 
common  investments  of  the  part.  The  vessel  rests  mostly  on  the  longus 
colli  muscle,  but  close  to  its  ending  on  the  rectus  capitis  anticus  major. 
To  the  inner  side  of  the  carotid  lie  the  trachea  and  larynx,  the  ojsophagus 
and  pharynx,  and  the  thyroid  body,  the  last  overhanging  the  vessel  by  the 
side  of  the  larynx.  Along  the  outer  side  of  the  carotid  sheath  is  a  chain 
of  lymphatic  glands. 

Veins.  The  large  internal  jugular  lies  on  the  outer  side  and  close  to  the 

carotid  at  the  upper  end,  but  separated  from  it  below  by  an  interval  of 

about  half  an  inch :  on  the  left  side  the  vein  is  over  the  artery  below^,  as 

will  be  afterwards  seen.     One  or  two  upper  thyroid  veins  and  their  branches 

6 


82  DISSECTION    OF    THE    NECK. 

cross  the  upper  part  of  the  arterial  *  trunk ;  and  opposite  the  thyroid  body 
anotlier  small  vein  (middle  (thyroid)  is  directed  back  over  the  vessel. 
Near  the  clavicle  the  anterior  jugular  vein  passes  out  under  the  sterno- 
mastoid :  it  is  superficial  to  the  artery,  and  separated  from  it  by  the  sterno- 
hyoid and  thyroid  muscles. 

Arteries.  Offsets  of  the  upper  thyroid  artery  descend  over  the  top  of 
the  sheath  ;  and  the  inferior  thyroid  crosses  under  it  below  the  level  of  the 
cricoid  cartilage. 

Nerves.  The  descendens  noni  lies  in  front  of  the  sheath,  crossing  from 
the  outer  to  the  inner  side,  and  is  joined  there  by  the  cervical  nerves.  The 
pueumogastric  lies  within  the  sheath,  behind  and  between  the  artery  and 
the  vein.  The  sympatlietic  cord  and  branches  rest  on  the  spine  behind 
the  sheath.  All  the  nerves  above  mentioned  have  a  longitudinal  direction; 
but  the  inferior  laryngeal  or  recurrent  crosses  obliquely  inwards  behind 
the  sheath  towards  the  lower  end  of  the  artery. 

Branches  of  carotid.  As  a  rule,  the  common  carotid  artery  does  not 
furnish  any  collateral  branch,  though  it  is  very  common  for  the  superior 
thyroid  to  spring  from  its  upper  end.  At  the  terminal  bifurcation  into  the 
two  carotids  the  artery  is  slightly  bulged. 

The  INTERNAL  JUGULAR  VEIN  cxtcuds  upwards  to  the  base  of  the  skull, 
but  only  the  part  of  it  that  accompanies  the  common  carotid  is  now  seen. 
Placed  behind  or  external  to  its  artery,  the  vein  ends  below  by  uniting 
with  the  subclavian  in  the  innominate  vein.  Its  proximity  to  the  carotid 
is  not  equally  close  throughout,  for  at  the  lower  part  of  the  neck  the  vein 
inclines  backwards,  leaving  a  space  between  it  and  the  artery,  in  which 
the  vagus  nerve  is  seen  about  midway  between  the  two.  Sometimes  the 
vein  is  superficial  to  the  carotid,  as  on  the  left  side. 

The  lower  part  of  the  vein  is  marked  by  a  dilatation  or  sinus.  Near 
its  ending  it  becomes  contracted,  and  is  provided  with  a  pair  of  valves 
(Struthers). 

In  this  part  of  its  course  the  vein  receives  the  superior  and  middle  thy- 
roid branches. 

Peculiarities  of  the  carotid.  The  origin  of  the  artery  on  the  right  side 
may  be  above  or  below  the  point  stated.  Mention  has  been  made  of  the 
difference  in  the  place  of  bifurcation,  and  of  the  fact  that  the  common 
carotid  may  not  be  divided  into  two  (p.  70).  Instead  of  one,  there  may 
be  two  trunks  issuing  from  beneath  the  hyoid  muscles. 

Dissection.  The  dissector  may  next  trace  out  completely  the  trunk  of 
the  external  carotid  (fig.  17),  and  follow  its  branches  until  they  disappear 
beneath  different  parts.  Afterwards  he  may  separate  from  one  anotlier 
the  digastric  and  stylo-hyoid  muscles,  which  cross  the  carotid  ;  and  may 
define  their  origin  and  insertion. 

The  DIGASTRIC  MUSCLE  (fig.  15^)  cousists  of  two  fleshy  bellies,  united 
by  an  intervening  tendon,  whence  its  name.  The  posterior,  the  larger  of 
the  two,  arises  from  the  groove  beneath  the  mastoid  process ;  wliilst  the 
anterior  belly  is  fixed  on  the  side  of  the  sym[)hysis  of  the  lower  jaw. 
From  these  attachments  the  fibres  are  directed  to  the  intervening  tendon, 
which  is  surrounded  by  fibres  of  the  stylo-hyoideus,  and  is  united  to  its 
fellow,  and  to  the  body  and  part  of  the  great  cornu  of  the  os  hyoides  by  an 
aponeurotic  expansion. 

The  arch  formed  by  the  digastric  is  superficial,  except  at  the  outer  end, 
where  it  is  beneath  the  sterno-mastoid  and  s[)lenius  muscles.  The  poste- 
rior belly  covers  the  carotid  vessels  and   the    accompanying  veins  and 


DISSECTION    OF    THE    NECK.  83 

nerves  ;  and  is  placed  across  tlie  anterior  triangular  space  of  the  neck*  in 
the  position  of  a  line  from  the  mastoid  process  to  a  little  above  the  hyoid 
bone  :  along  its  lower  border  lie  the  occipital  artery  and  the  hypoglossal 
nerve ;  the  former  passing  backwards,  the  latter  forwards.  The  anterior 
belly  rests  on  the  mylo-hyoid  muscle. 

The  muscle  forms  the  lower  boundary  of  a  space  between  the  jaw  and 
the  base  of  the  skull,  which  is  subdivided  into  two  by  the  stylo-maxillary 
ligament.  In  the  posterior  portion  are  contained  the  parotid  gland  (^"j, 
and  the  vessels  and  nerves  in  connection  with  it  (p.  41)  ;  in  the  anterior, 
are  the  submaxillary  gland  ("),  w^ith  the  facial  and  submental  vessels,  and 
deeper  still,  the  muscles  between  the  chin  and  the  hyoid  bone. 

Action.  The  lower  jaw  being  movable,  the  muscle  depresses  that  bone 
and  opens  the  mouth.  If  the  jaw  is  fixed,  the  two  bellies  acting  will  ele- 
vate the  hyoid  bone. 

It  is  supposed  that  the  posterior  belly  may  assist  in  moving  back  the 
head  when  the  jaw  is  fixed. 

The  STYLO-HYOiD  MUSCLE  is  thin  and  slender,  and  has  the  same  posi- 
tion as  the  posterior  belly  of  the  digastric.  It  arises  from  the  outer  sur- 
face of  the  styloid  process,  near  the  base,  and  is  inserted  into  the  body  of 
the  OS  hyoides. 

The  muscle  has  the  same  connections  as  the  posterior  belly  of  the  digas- 
tric ;  and  its  fleshy  fibres  are  usually  perforated  by  the  tendon  of  that 
muscle.     In  some  bodies  the  stylo-hyoideus  is  absent. 

Action.  This  muscle  elevates  the  os  hyoides  preparatory  to  swallowing, 
and  checks,  with  the  posterior  belly  of  the  digastric,  the  too  forward  move- 
ment of  that  bone  by  the  otiier  elevators. 

The  HYPOGLOSSAL  NERVE  (ninth  cranial)  appears  in  the  anterior  tri- 
angle at  the  lower  edge  of  the  digastric  muscle,  where  it  hooks  round  the 
occipital  artery;  it  is  then  directed  forwards  to  the  tongue  below  that 
muscle,  and  disappears  in  front  beneath  the  mylo-hyoideus.  In  this  course 
the  nerve  passes  over  the  two  carotids  ;  and  near  the  cornu  of  the  os 
hyoides  it  crosses  also  the  lingual  artery,  so  as  to  become  higher  than  the 
vessel.  From  this  part  arise  the  descendens  noni  branch,  and  a  small 
muscular  offset  to  the  thryo-hyoideus. 

The  descending  branch  (ram.  descend,  noni)  leaves  the  trunk  of  the 
hypoglossal  on  the  outer  side  of  the  carotid  artery,  and  descends  on  the 
front  of  (sometimes  in)  the  sheath  of  the  vessel  to  about  the  middle  of  the 
neck,  where  it  is  joined  by  the  communicating  branches  of  the  cervical 
nerves.  After  the  union  of  the  spinal  nerves,  offsets  are  su{)plied  to  the 
depressor  muscles  of  the  os  hyoides,  viz.,  omo-hyoid  (both  bellies),  sterno- 
hyoid, and  sterno-thyroid :  sometimes  another  offset  is  continued  to  the 
thorax,  wiiere  it  joins  the  phrenic  and  cardiac  nerves. 

The  connection  between  the  descendens  noni  and  the  spinal  nerves  is 
formed  by  two  or  more  cross  filaments,  so  as  to  construct  an  arch  with  the 
concavity  upwards ;  and  an  interchange  of  fibrils  between  the  two  nerves 
is  supposed  to  take  place. 

The  EXTERNAL  CAROTID  ARTERY  (fig.  17,  d)  spHngs  from  the  bifurca- 
tion of  the  common  carotid  at  the  upper  border  of  the  thyroid  cartilage, 
and  furnishes  branches  to  the  neck,  the  face,  and  the  outer  parts  of  the 
head. 

From  the  place  of  origin  it  ascends  in  front  of  the  mastoid  process,  and 
ends  near  the  condyle  of  the  jaw  in  the  internal  maxillary  and  temporal 
branches.    The  artery  lies  at  first  to  the  inner  side  of  the  internal  carotid,  but 


84 


DISSECTION    OF    THE    NECK 


it  afterwards  becomes  superficial  to  that  vessel ;  and  its  direction  is  some- 
what arched  forwards,  though  the  position  would  be  marked  sufficiently 
by  a  line  from  the  front  of  tlie  meatus  of  the  ear  to  the  cricoid  cartihige. 

At  first  the  external  carotid  is  overlaid  by  the  sterno-mastoideus,  and 
by  the  common  coverings  of  the  anterior  triangular  space,  viz.,  the  skin, 
and  the  superficial  and  deep  fascia  with  the  platysma.     But  above  the 


Fig.  17. 


ExTBKKAL  Carotid  and  its  Superficial  Branches  ("Anatomy  of  the  Arteries,"  Quain). 


a.  Common  carotid. 

m. 

Supra-orbital. 

b.  Internal  jugular  vein. 

n. 

External  nasal. 

c.  Internal  carotid. 

o. 

Angular  branch  of  facial. 

d.  External  carotid. 

V- 

Lateral  nasal. 

e.  Upper  thyroid  branch. 

r. 

Superior  coronary. 

/.  Lingual. 

s. 

Inferior  coronary. 

g.  Facial. 

t. 

Inferior  labial. 

h.  Internal  maxillary. 

u. 

,  Submental  artery. 

i.  Superficial  temporal. 

level  of  a  line  from  the  mastoid  process  to  the  hyoid  bone,  the  artery  is 
crossed  by  the  digastric  and  stylo-hyoid  muscles,  and  still  higher  the  2)arotid 
gland  conceals  it.  At  its  beginning  the  artery  rests  against  the  pharynx  ; 
but  above  the  angle  of  the  jaw  it  is  placed  over  the  styloid  process  and 
stylo-pharyngeus  muscle,  wliich  separates  it  from  the  internal  carotid.  To 
the  inner  side  of  the  vessel  at  first  is  the  pharynx  ;  and  still  higher,  are 
the  ramus  of  the  jaw  and  the  stylo-maxillary  ligament. 


EXTERNAL  CAROTID  ARTERY.  85 

Veins.  There  is  not  any  companion  vein  with  the  external  carotid  as 
witli  most  arteries  ;  but  sometimes  a  vein,  formed  by  the  union  of  the  tem- 
poral and  internal  maxillary  branches  (p.  42),  will  accompany  it.  Near 
tlie  beginnino;  it  is  crossed  by  the  facial  and  lingual  branches  joining  the 
internal  jugular  vein  ;  and  near  the  ending  the  external  jugular  vein  lies 
over  it. 

Nerves  are  directed  from  behind  forwards  over  and  under  the  artery. 
At  the  lower  border  of  the  digastric  muscle  the  hypoglossal  lies  over  the 
vessel,  and  near  tlie  ending  the  ramifications  of  the  facial  nerve  are  super- 
ficial to  it.  Three  nerves  lie  beneath  it :  beginning  below,  the  small  ex- 
ternal laryngeal ;  a  little  higher,  the  superior  laryngeal ;  and  near  the  base 
of  the  jaw,  the  glosso-pharyngeal. 

Tlie  branches  of  the  external  carotid  are  numerous,  and  are  classed  into 
an  anterior,  posterior,  and  ascending  set.  The  anterior  set  comprise 
branches  to  the  thyroid  body,  the  tongue,  and  the  face,  viz.,  superior  thy- 
roid, lingual,  and  facial  arteries.  In  the  posterior  set  are  the  occipital 
and  ]iosterior  auricular  branches.  And  the  ascending  set  include  the  as- 
cending pharyngeal,  temporal,  and  internal  maxillary  arteries.  Besides 
these,  the  carotid  gives  other  branches  to  the  sterno-mastoid  muscle  and 
the  ]mrotid  gland. 

Tlie  origin  of  the  branches  of  the  carotid  may  be  altered  by  their  closer 
aggregation  on  the  trunk.  The  usual  number  may  be  diminished  by  two 
or  more  uniting  into  one  ;  or  the  number  may  be  increased  by  some  of  the 
secondary  offsets  being  transferred  to  the  parent  trunk. 

Directions.  All  the  branches,  except  the  ascending  pharyngeal,  lingual, 
and  internal  maxillary,  may  be  now  examined ;  but  those  three  will  be 
described  afterwards  with  the  regions  they  occupy. 

The  superior  thyroid  artery  (e)  arises  near  the  cornu  of  the  os  hyoides, 
and  passes  beneath  the  omo-hyoid,  sterno-hyoid,  and  sterno-thyroid  mus- 
cles to  the  thyroid  body,  to  w^hich  it  is  distributed  on  the  anterior  aspect. 
This  artery  is  superficial  in  the  anterior  triangle,  and  furnishes  offsets  to 
the  lowest  constrictor  and  the  muscle  beneath  which  it  lies,  in  addition  to 
the  following  named  branches  : — 

a.  The  hyoid  branch  is  very  inconsiderable  in  size,  and  runs  inwards 
below  the  hyoid  bone :  it  supplies  the  muscles  attached  to  that  bone,  and 
anastomoses  with  the  vessel  of  the  opposite  side. 

b.  A  branch  for  the  sterno-mastoid  muscle  lies  in  front  of  the  sheath  of 
the  common  carotid  artery,  and  is  distributed  chiefly  to  the  muscle  from 
which  it  takes  its  name. 

c.  The  laryngeal  branch  pierces  the  membrane  between  the  hyoid  bone 
and  the  thyroid  cartilage,  with  the  superior  laryngeal  nerve,  and  ends  in 
the  interior  of  the  larynx. 

d.  A  small  crico-thyroid  branch  is  placed  on  the  membrane  between  the 
cricoid  .and  the  thyroid  cartilage,  and  communicates  with  the  corresponding 
artery  of  the  opposite  side,  forming  an  arch. 

The  superior  thyroid  vein  commences  in  the  larynx  and  the  thyroid 
body,  and  crosses  the  end  of  the  common  carotid  artery  to  open  into  the 
internal  jugular  vein. 

The  facial  artery  (g)  arises  above  the  lingual,  and  is  directed  upwards 
over  the  lower  jaw  to  the  face.  In  the  neck  the  artery  passes  beneath  the 
digastric  and  stylo-hyoid  muscles,  and  is  afterwards  lodged  on  the  sub- 
maxillary gland,  on  which  it  makes  a  sigmoid  turn.     Its  anatomy  in  the 


hU  DISSECTION    OF    THE    NECK. 

face  has  been  examined  (j).  40).  From  the  cervical  part  branches  are 
given  to  the  pharynx,  and  to  tlie  structures  below  the  jaw,  viz. : — 

a.  Tiie  inferior  palatine  branch  ascends  to  the  j)harynx  beneath  the 
jaw,  passing  between  the  stylo-glossus  and  stylo-pharyngeus  muscles,  and 
is  distributed  to  the  soft  ])alate,  after  furnishing  a  brancli  to  the  tonsil. 
This  branch  frequently  arises  from  the  ascending  })haryngeal  artery. 

6.  The  tonsillar  branch  is  smaller  than  the  preceding,  and  passes  be- 
tween the  internal  pterygoid  and  stylo-glossus  muscles.  Opj)Osite  the  ton- 
sil it  perforates  the  constrictor  muscle,  and  ends  in  offsets  to  that  body. 

c.  Glandular  branches  are  supplied  to  the  submaxillary  gland  from  the 
part  of  the  artery  in  contact  with  it. 

d.  The  submental  branch  arises  near  the  inferior  maxilla,  and  courses 
forwards  on  the  mylo-hyoideus  to  the  anterior  belly  of  the  digastric  muscle, 
where  it  ends  in  offsets  :  some  of  these  turn  over  the  jaw  to  the  chin  and 
lower  lip ;  and  the  rest  supply  the  muscles  between  the  jaw  and  the  hyoid 
bone — one  or  two  perforating  the  mylo-hyoideus  and  anastomosing  with 
the  sublingual  artery. 

Thoi  facial  vein  (p.  40)  joins  the  internal  jugular.  In  the  cervical  part 
of  its  course  it  receives  branches  corresponding  with  the  offsets  of  the 
artery.     It  often  throws  itself  into  the  temjjoro-maxillary  trunk. 

The  occipital  artery  is  of  considerable  size,  and  is  destined  for  the  back 
of  the  head.  It  arises  from  the  carotid  opposite  the  facial  branch,  near 
the  lower  border  of  the  digastric  muscle,  and  ascends  to  the  inner  part  of 
the  mastoid  process  of  the  temporal  bone.  Next  it  turns  horizontally 
backwards  on  the  occipital  bone,  passing  above  the  transverse  process  of 
the  atlas  ;  and  finally  becomes  cutaneous  near  the  middle  line  (p.  21).  In 
the  neck  this  artery  passes  beneath  the  digastric  muscle  and  a  part  of  the 
parotid  gland  ;  and  crosses  over  the  internal  carotid  artery,  the  jugular 
vein,  and  the  spinal  accessory  and  liypoglossal  nerves. 

The  only  ofJ'set  from  the  artery  in  the  front  of  the  neck  is  a  small  poste- 
rior meningeal  branch:  this  ascends  along  the  internal  jugular  vein,  and 
enters  the  skull  by  the  foramen  jugulare  (p.  30).  The  branches  at  the 
back  of  the  neck  will  be  afterwards  seen. 

The  occipital  vein  begins  at  the  back  of  the  head  (p.  21),  and  has  the 
same  course  as  the  artery ;  it  communicates  with  the  lateral  sinus  through 
the  mastoid  foramen,  also  with  the  diploic  veins,  and  coalesces  with  the  in- 
ternal (sometimes  the  external)  jugular  vein. 

The  posterior  auricular  artery  is  smaller  than  the  preceding  branch, 
and  takes  origin  above  the  digastric  muscle.  Between  the  ear  and  the 
mastoid  process,  it  divides  into  two  branches  for  the  ear  and  occiput  (p.  21). 

A  small  branch,  stylo-mastoid  enters  the  foramen  of  the  same  name, 
and  supplies  the  tympanum  of  the  ear. 

The  vein  with  the  artery  receives  a  stylo  mastoid  branch,  and  terminates 
in  the  trunk  formed  by  the  temporal  and  internal  maxillary  veins. 

The  temporal  artery  (?)  is  in  direction  the  continuation  of  the  external 
carotid  trunk,  and  is  one  of  the  terminal  branches  of  that  artery.  As- 
cending under  the  parotid  gland  it  divides  on  the  temporal  fascia  into  an- 
terior and  posterior  branches,  about  two  inches  above  the  zygoma ;  these 
are  distributed  to  the  front  and  side  of  the  head  (p.  21).  The  trunk  of  the 
artery  gives  offsets  to  the  surrounding  [)arts,  viz. : — 

a.  Parotid  branches  are  furnislied  to  the  gland  of  the  same  name. 
Articular  twigs  are  supplied  to  the  articulation  of  the  lower  jaw  ;   and 


MASSETER    MUSCLE.  87 

Other  muscular  branches  enter  the   masseter.     Some  anterior  auricular 
offsets  are  distributed  to  the  pinna  and  meatus  of  the  external  ear. 

h.  The  transverse  facial  branch  quits  the  temporal  artery  opposite  the 
condyle  of  the  jaw,  and  is  directed  forwards  over  the  masseter  muscle 
(p.  41)  ;  on  the  side  of  the  face  it  supplies  the  muscles  and  integuments, 
and  anastomoses  with  the  facial  artery. 

c.  The  middle  temporal  branch  arises  just  above  the  zygoma,  and  pierces 
the  temporal  aponeurosis  to  enter  the  substance  of  tlie  temporal  muscle  :  it 
anastomoses  with  branches  of  the  internal  maxillary  artery. 

d.  A  small  branch  of  the  temporal  artery  is  likewise  found  between  the 
layers  of  the  temporal  fascia ;  this  anastomoses  with  an  offset  of  the  lachry- 
mal. 

The  temporal  vein  commences  on  the  side  of  the  head  (p.  21)  and  is  con- 
tiguous to  its  companion  artery.  Near  the  zygoma  it  is  joined  by  the 
middle  temporal  vein ;  next  it  receives  branches  which  are  companions  of 
the  offsets  of  the  artery ;  and  it  ends  by  uniting  with  the  internal  maxil- 
lary vein. 

Directions.  The  lower  part  of  the  neck  w^ill  not  be  used  again  for  some 
days,  so  that  the  dissector  may  stitch  together  the  flaps  of  skin,  when  he 
has  applied  salt  to  preserve  it. 


Section  VI. 

PTERYGO-MAXILLARY  REGION. 


In  this  region  are  included  the  muscles  superficial  to  and  beneath  the 
ramus  of  the  lower  jaw,  together  with  the  articulation  of  that  bone.  In 
contact  with  the  muscles  (pterygoid)  beneath  the  jaw,  are  the  internal 
maxillary  bloodvessels,  and  the  inferior  maxillary  trunk  of  the  fifth  nerve. 

Dissection.  The  masseter  muscle,  which  is  superficial  to  tlie  bones,  has 
been  ])artly  laid  bare  in  the  dissection  of  the  facial  nerve.  To  see  it  more 
fully  tlie  branches  of  the  facial  nerve,  and  the  transverse  facial  artery  should 
be  cut  through,  and  turned  backwards  oif  the  face.  A  little  cleaning  will 
suffice  to  define  the  origin  and  insertion  of  the  muscle. 

Should  there  be  any  tow  or  cotton  wool  in  the  mouth  let  it  be  removed. 

The  MASSETER  (fig.  6,  ^")  is  partly  aponeurotic  at  the  upper  attachment. 
It  arises  from  all  the  lower  border  of  the  zygomatic  arch,  extending  for- 
wards to  the  upper  jaw  ;  and  from  the  inner  surface  of  the  arch  by  fine 
fleshy  fibres.  Most  of  the  fibres  are  inclined  down  and  somewhat  back, 
and  are  inserted  into  the  outer  surface  of  the  coronoid  process,  ramus,  and 
angle  of  the  lower  jaw  ;  but  a  few  are  fixed  into  the  contiguous  part  of 
the  body  of  the  bone  as  far  as  the  second  molar  tooth.  Some  of  the 
hinder  and  deeper  fibres  are  inclined  downwards  and  forwards  across  the 
others. 

The  lower  part  of  the  masseter  is  subcutaneous,  but  the  upper  is  partly 
concealed  by  the  parotid  gland  (socia  parotidis),  and  is  crossed  by  Sten- 
son's  duct,  and  by  the  transverse  facial  vessels  and  the  facial  nerve.  The 
anterior  border  projects  over  the  buccinator  muscle,  and  a  quantity  of  fat 
resembling  that  in  the  orbit  is  found  beneath  it.     The  muscle  covers  the 


88  DISSECTION    OF    THE    PTERYGOID    REGION- 

ramus  of  the  jaw,  and  the  masseteric  branches  of  nerve  and  arterj  enter- 
ing it  at  the  under  surface. 

Action.  It  raises  the  lower  jaw  with  the  internal  pterygoid  in  the  mas- 
tication of  the  food. 

Dissection.  To  lay  bare  the  temporal  muscle  to  its  insertion,  the  follow- 
ing dissection  may  be  made  :  Tiie  temporal  fascia  is  to  be  detached  from 
tiie  upper  border  of  the  zygomatic  arch,  and  to  be  removed  from  the  sur- 
face of  the  muscle.  Next,  the  arch  of  the  zygoma  is  to  be  sawn  through 
in  front  and  behind,  so  as  to  include  all  its  length  ;  and  is  to  be  tlirown 
down  (without  being  cut  off)  with  the  masseter  muscle  still  attached  to  it, 
by  separating  the  fibres  of  that  muscle  from  the  ramus  of  the  jaw.  In 
detaching  the  masseter  muscle,  its  nerve  and  artery,  which  pass  through 
the  sigmoid  notch,  will  be  found. 

The  surface  of  the  temporal  muscle  may  be  then  cleaned ;  and  to  ex- 
pose its  insertion  and  deep  origin,  let  the  coronoid  process  be  sawn  off  by 
a  cut  passing  from  the  centre  of  the  sigmoid  notch  nearly  to  the  last  molar 
tooth,  so  as  to  include  the  whole  insertion  of  the  muscle.  Before  sawing 
tlie  bone  let  the  student  find  and  separate  from  the  muscle  the  buccal  ves- 
sels and  nerve  issuing  from  beneath  it.  Lastly,  the  coronoid  process  sliould 
be  raised  and  the  fat  removed,  in  order  that  the  lower  fibres  of  the  tem- 
poral muscle,  and  their  contiguity  to  the  external  pterygoid  close  below 
them,  may  be  observed. 

The  temporal  muscle  (fig.  18,  ^)  takes  its  origin  from  the  whole  of  the 
temporal  fossa  (p.  20),  reaching  up  to  the  semicircular  line  on  the  side  of  the 
skull,  and  downwards  to  the  crest  on  the  outer  aspect  of  the  great  wing  of 
the  sphenoid  bone.  From  this  extensive  attachment,  as  well  as  from  the 
fascia  over  it,  the  fibres  converge  to  a  superficial  tendon,  which  is  inserted 
into  the  inner  surface  of  the  coronoid  process,  as  well  as  into  a  groove  on 
the  same  process  which  reaches  from  the  apex  to  near  the  last  molar  tooth. 

Behind  the  posterior  border  of  the  tendon  are  the  masseteric  vessels  and 
nerve,  and  in  front  of  it  the  buccal  vessels  and  nerve  :  the  last  nerve  per- 
forates occasionally  some  of  the  fibres  of  the  muscle. 

Action.  All  the  fibres  contracting  the  muscle  will  raise  the  mandible 
and  press  it  forcibly  against  the  upper  jaw  ;  but  the  hinder  fibres  may  re- 
tract the  lower  jaw  after  it  has  been  moved  forwards  by  the  external  ptery- 
goid. 

Dissection.  For  the  display  of  the  pterygoid  muscles  (fig.  18),  it  will 
be  necessary  to  remove  a  piece  of  the  ramus  of  the  jaw.  But  the  greater 
part  of  the  temjjoral  muscle  is  to  be  first  detached  from  the  subjacent  bone 
with  the  handle  of  tlie  scalpel,  and  the  deep  temporal  vessels  and  nerves 
are  to  be  sought  in  its  fibres. 

A  piece  of  the  ramus  is  next  to  be  taken  away  by  sawing  across  the 
bone  close  to  the  condyle,  and  again  close  above  the  dental  foramen ;  and 
to  make  the  dental  vessels  and  nerve  in  contact  with  its  inner  surface 
secure  from  injury,  the  luuulle  of  the  scalpel  may  be  inserted  between  them 
and  the  bone,  and  carried  downwards  to  their  entrance  into  the  foramen. 
The  masseteric  artery  and  nerve  are  liable  to  be  cut  in  sawing  the  bone ; 
should  these  be  divided,  turn  them  upwards  for  the  present,  and  afterwards 
tie  together  the  ends. 

After  the  loose  piece  of  l)one  has  been  removed,  and  the  subjacent  parts 
freed  from  much  fat,  the  pterygoid  muscles  will  appear, — the  external  (^) 
being  directed  outwards  to  the  condyle  of  the  jaw,  and  the  internal  (''), 
wliich  is  parallel  in  direction  to  the  masseter,  being  inclined  to  the  angle 


POSITION    OF    VESSELS    AND    NERVES. 


89 


of  tlie  jaw.  In  removing  the  fatty  tissue,  the  student  must  be  careful  not 
to  take  away  the  thin  lateral  ligament,  which  lies  on  the  internal  pterygoid 
muscle  beneath  the  ramus. 

Position  of  vessels.     Crossing   inwards   over   the   external   pterygoid 
muscle,  is  the  internal  maxillary  artery,  which  distributes  offsets  upwards 


Superficial  View  of  the  Pterygoid  Region  (Quain's  "Arteries"). 


1.  Temporal  muscle. 

2.  Extei'nal  pterygoid. 
.3.  Internal  pterygoid. 

4.  Buccinator. 

5.  Digastric  and  stylo-hyoid  muscles  cut  and 

thrown  back. 


Common  carotid  dividing  into  external  and 

internal  trunks. 
8.  Internal   maxillary  artery   (beneath   the 

pterygoid   instead   of  over  it)   and    its 

branches. 
The  nerves  are  omitted  in  this  woodcut. 


and  downwards:  sometimes  the  artery  will  be  placed  beneath  the  muscle. 
The  veins  with  the  artery  are  large  and  plexiform :  and  may  be  taken 
away. 

Position  of  nerves.  Most  of  the  branches  of  the  inferior  maxillary 
nerve  appear  in  this  dissection.  Thus,  issuing  from  beneath  the  lower 
border  of  the  external  pterygoid  are  the  large  dental  and  gustatory  nerves, 
the  latter  being  the  more  internal  of  the  two;  and  coming  out  behind  the 
joint  of  the  jaw  is  the  auriculo-temporal  nerve.  Appearing  between  the 
upper  border  of  the  muscle  and  the  cranium,  are  tlie  small  masseteric  and 
deep  temporal  nerves.  Tlie  buccal  branch  of  the  nerve  perforates  tlie  fibres 
of  the  same  muscle  near  the  inner  attachment.  Branches  of  the  above- 
mentioned  artery  accompany  the  nerves.  Coursing  along  tlie  posterior 
part  of  the  upper  jaw,  is  the  small  posterior  dental  nerve  with  an  artery. 

Between  the  jaws  is  the  whitish  narrow  band  of  the  pterygo-maxillary 
ligament,  to  which  the  buccinator  and  superior  constrictor  muscles  are 
connected. 

The  EXTERNAL  PTERYGOID  MUSCLE  (fig.  18,  ^)  cxtcuds  almost  horizon- 
tally from  the  zygomatic  fossa  to  the  neck  of  the  lower  jaw.     Its  origin  is 


90  DISSECTION    OF    THE    PTERYGOID    REGION. 

from  the  outer  surface  of  the  great  wing  of  the  sphenoid  bone  below  the 
crest,  and  from  the  outer  surface  of  the  external  pterygoid  plate.  The 
fibres  are  directed  outwards  and  somewhat  backwards,  those  attached  to 
the  upper  margin  of  the  spheno-maxillary  fissure  forming  at  first  a  separate 
bundle,  and  are  inserted  into  the  hollow  in  front  of  the  neck  of  the  lower 
jaw  bone,  and  into  the  interarticular  fibro-cartilage  of  the  joint. 

Externally  the  pterygoid  is  concealed  by  the  temporal  muscle  and  the 
lower  jaw,  and  the  internal  maxillary  artery  lies  on  it.  By  the  deep  sur- 
face it  is  in  contact  with  the  inferior  maxillary  nerve,  with  a  plexus  of 
veins,  and  with  the  internal  lateral  ligament  of  tlie  joint  of  the  jaw.  The 
parts  in  contact  with  the  borders  of  the  muscle  have  been  enumerated 
before. 

Sometimes  the  slip  of  the  muscle,  which  is  attached  to  the  margin  of  tlie 
spheno-maxillary  fissure  and  the  root  of  the  external  pterygoid  plate,  is 
described  as  a  separate  head  with  an  insertion  into  the  interarticular  car- 
tilage. 

Action.  If  both  muscles  act  the  jaw  is  moved  forwards,  so  that  the 
lower  dental  arch  is  placed  in  front  of  the  upper,  and  the  grinding  teeth 
are  rubbed  together  in  an  antero-posterior  direction.  In  order  that  the 
lower  front  teeth  may  be  able  to  pass  the  others  the  jaw  is  depressed. 

One  muscle  contracting  (say  the  right),  the  condyle  of  the  same  side  is 
drawn  inwards  and  forwards,  and  the  grinding  teeth  of  the  lower  jaw  are 
moved  horizontally  to  the  left  across  those  oF  the  upper.  By  the  alternate 
action  of  the  two  muscles  the  trituration  of  tlie  food  is  effected. 

The  INTERNAL  PTERYGOID  MUSCLE  (fig.  18,  ')  is  nearly  parallel  to  the 
ramus  of  the  jaw,  and  its  fibres  are  longer  than  those  of  the  preceding 
muscle.  Arising  in  the  pterygoid  fossa,  and  chiefly  from  the  inner  sur- 
face of  the  external  pterygoid  plate,  the  nmscle  is  further  attached  below, 
outside  the  fossa,  to  the  outer  surface  of  the  tuberosity  of  the  palate  bone, 
and  to  the  tuberosity  of  the  upper  jaw  bone.  The  fibres  descend  to  be 
inserted  into  the  angle,  and  into  the  inner  surface  of  the  ramus  of  the  jaw 
as  high  as  the  inferior  dental  foramen. 

On  tlie  muscle  are  placed  the  dental  and  gustatory  nerves,  the  dental 
artery,  and  the  internal  lateral  ligament  of  the  jaw.  The  deep  surface  is 
in  relation  below  with  the  superior  constrictor,  and  at  its  origin  with  the 
tensor  palati  muscle. 

Action.  From  the  direction  and  attachment  of  the  fibres  the  muscle 
will  unite  with  the  masseter  in  elevating  the  jaw. 

Directions.  Before  proceeding  further  in  the  dissection,  the  student 
may  learn  the  anatomy  of  the  articulation  of  the  lower  jaw. 

TEMroRO-MAXiLLARY  ARTICULATION.  In  tliis  articulation  are  com- 
bined the  condyle  of  the  jaw  and  the  anterior  part  of  the  glenoid  fossa  of 
the  temporal  Ixme ;  but  the  osseous  surfaces  are  not  in  contact,  for  a  piece 
of  fibro-cartilage  with  two  synovial  sacs  is  interposed  between  them.  The 
bones  are  retained  in  apposition  mostly  by  the  strong  muscles  of  the  lower 
jaw  ;  but  the  following  ligaments  serve  to  unite  them. 

Capsule.  This  is  a  thin  fibrous  tube  inclosing  the  bones,  and  is  wider 
above  than  below.  By  the  upper  end  it  is  fixed  around  the  articular 
surface  of  the  temporal  bone  in  front  of  the  Glaserian  fissure  ;  and  it  is  in- 
serted below  around  the  condyle  of  the  lower  jaw.  The  space  in  the 
interior  is  divided  into  two,  u{)per  and  lower,  by  a  piece  of  fibro-cartilage, 
which  is  united  to  the  capsule  l)y  its  circumfennice. 

The  external  lateral  is  a  short  ligamentous  band,  being  but  a  part  of  the 


TEMPORO-MAXILLARY    JOINT. 


91 


capsule,  which  is  attached  above  to  the  tubercle  at  the  root  of  the  zygoma, 
and  below  to  the  outer  side  of  the  neck  of  the  inferior  maxilla. 

The  internal  lateral  ligament  (fig.  19,  ^)  is  a  long,  thin,  membranous 
band,  which  is  not  in  contact  with  the  joint.  Su[>eriorly  it  is  connected 
to  a  projection  inside  the  glenoid  fossa,  which  consists  of  the  spinous  pro- 
cess of  the  sphenoid  and  the  vaginal  process  of  the  temporal  bone ;  and 
inferiorly  it  is  inserted  into  the  orifice  of  the  dental  canal  in  the  lower  jaw. 
The  ligament  lies  between  the  jaw  and  the  internal  pterygoid ;  and  its 
origin  is  concealed  by  the  external  pterygoid  muscle.  Between  the  liga- 
ment and  the  jaw  the  internal  maxillary  artery  intervenes. 


Fis:.  19. 


Fig.  20. 


Ligaments  of  the  Jaw — ax  isxer  view 
(Bonrgery  and  Jacob). 

1.  Internal  lateral  ligament. 

2    Stylo-maxillary. 

3.  Stylo-maxillary  ligament. 


A  VIEW  OP  THE  IXTBKIOR  OF  THE  COMPOrXD 

Tempoko-maxillabt   Joist   (Bourgery  and 
Jacob) . 
4.  Interarticular  fibro-cartilage — the  dark  inter- 
vals above    and  below  are  the   hollows  con- 
taining the  synovial  membranes. 


Dissection.  After  the  external  lateral  ligament  and  the  capsule  of  the 
joint  have  been  examined,  an  interarticular  fibro-cartilage,  with  a  hollow 
above  and  below  it,  will  be  exposed  by  taking  away  the  capsule  on  the 
outer  side  (fig.  20). 

The  interarticular  Jihro-cartilage  (fig.  20,  *)  is  adapted  to  the  surfaces 
of  the  bones.  It  is  elongated  transversely,  is  thinner  in  the  centre  than  at 
the  margins,  and  an  aperture  is  sometimes  present  in  the  middle.  The 
upper  surface  fits  into  the  glenoid  fossa,  being  concavo-convex  from  before 
backwards,  and  the  lower  is  moulded  on  the  convexity  of  the  condyle  of 
the  jaw.  By  the  circumference  it  is  connected  with  the  capsule  and  the 
external  lateral  ligament ;  and  in  front  the  external  pterygoid  muscle  i3 
attached  to  it. 

This  interarticular  pad  allows  greater  freedom  of  movement  in  the  joint 
without  dislocation  ;  diminishes  the  injurious  effect  of  pressure  ;  and  dead- 
ens the  sound  of  the  jaw  striking  the  skull. 

Two  synovial  membranes  are  present  in  the  articulation — one  above, 
and  one  below  the  fibro-cartilage.     The  lower  one  is  the  smaller  of  the  two. 

Another  structure — the  stylo-maxillary  ligament  (fig.  20,  ')  is  described 
as  a  uniting  band  to  this  articulation.  It  is  a  process  of  the  deep  cervical 
fascia,  which  extends  from  the  styloid  process  to  the  hinder  part  of  the 
ramus  of  the  jaw:  it  gives  attachment  to  the  stylo-glossus  muscle,  and 
separates  the  parotid  and  submaxillary  glands. 


92  DISSECTION    OF    THE    PTERYGOID    REGION. 

Articular  surfaces  of  the  bones.  The  lower  jaw  possesses  a  thin  narrow 
condyle,  which  is  elongated  transversely,  and  directed  backwards  and 
inwards. 

On  the  temporal  bone  is  a  narrow  deep  articular  hollow  (glenoid  fossa), 
which  is  lengthened  from  without  in,  and  is  placed  in  front  of  the  Glaserian 
fissure.  In  front  of  this  is  a  prominence  of  bone  (transverse  root  of  the 
zygomatic  process),  which  is  convex  from  before  back  and  rather  hollowed 
from  side  to  side. 

Movements  of  the  joint.  This  condyloid  articulation  is  provided  with 
an  up  and  down,  a  to  and  fro,  and  a  lateral  movement. 

In  depressing  the  jaw,  as  in  opening  the  mouth,  the  articular  condyle 
moves  forwards  till  it  is  placed  under  the  convexity  at  the  fore  part  of  the 
articular  hollow,  but  the  interposed  concave  fibro-cartilage  gives  security 
to  the  joint.  Even  with  this  provision,  a  slight  degree  more  of  sudden 
motion  throws  the  condyle  off  the  prominence  of  the  temporal  bone  into 
the  zygomatic  fossa,  and  gives  rise  to  dislocation. 

In  this  movement  the  fore  and  lateral  parts  of  the  capsule  are  made 
tight ;  and  the  fibro-cartilage  is  drawn  forwards  with  the  condyle  by  the 
external  pterygoid  muscle. 

When  the  jaw  is  elevated  and  tlie  mouth  closed,  the  condyle  and  the 
fibro-cartilage  glide  back  into  the  glenoid  fossa.  In  this  position  the  jaw 
is  placed  in  the  state  of  greatest  security  against  dislocation. 

The  ligaments  and  the  surrounding  muscles,  which  were  stretched  in 
the  previous  movement,  are  then  set  at  rest.       ^ 

During  the  horizontal  motion  forwards  and  backwards  the  condyle  is 
moved  successively  to  the  front  and  back  of  the  temporal  articular  surface ; 
and  the  lower  jaw  is  slightly  depressed,  in  order  that  the  fore  teeth  in  the 
upper  dental  arch  should  not  im[)ede  those  of  the  lower. 

By  turns  the  front  and  back  of  the  ca[)sule  will  be  stretched;  and  the 
fibro-cartilage  always  follows  the  condyle  of  the  jaw,  even  in  dislocation. 

Too  great  motion  forwards  will  be  prevented  by  the  coronoid  process  of 
the  jaw  striking  against  the  zygomatic  arch ;  and  that  backwards,  by  the 
meeting  of  the  condyle  and  the  auditory  process  of  the  os  temporis. 

Lateral  horizontal  movement  puts  tlie  jaw  first  to  one  side  and  then  to 
the  other.  When  the  jaw  is  forced  to  the  left  side,  the  right  condyle  sinks 
into  its  articular  hollow,  whilst  the  left  is  projected ;  and  the  grinding  teeth 
of  the  lower  dental  arch  are  moved  to  the  left  across  those  of  the  upper. 
By  the  alternate  action  to  opposite  sides  the  food  is  triturated. 

The  inner  part  of  the  capsule  on  the  right,  and  the  outer  part  on  the 
left  side,  will  be  put  on  the  stretch  when  the  jaw  is  carried  to  the  left  of 
the  middle  line ;  and  the  opposite. 

With  old  edentulous  jaws  the  capsule  is  much  enlarged,  and  permits  the 
condyle  to  wander  backwards  behind  the  Glaserian  fissure.  Without  this 
provision  the  altered  lower  jaw  would  not  meet  the  upi)er  to  crush  the  food. 

Dissection.  The  condyle  of  the  jaw  is  next  to  be  disarticulated,  the 
external  pterygoid  muscle  being  still  uncut;  and  it  with  the  attached  mus- 
cle is  to  be  drawn  forwards  so  as  to  allow  tlie  fifth  nerve  to  be  seen.  Whilst 
cutting  through  the  joint  capsule,  the  dissector  must  be  careful  of  the 
auriculo-tem})oral  nerve  close  beneath  (fig.  21). 

On  drawing  forwards  the  j)terygoid  muscle,  and  removing  some  fat,  the 
dissector  will  find  the  trunk  of  the  inferior  maxillary  nerve.  All  the  small 
muscular  branches  of  the  nerve  before  noted  should  be  traced  to  the  trunk 
in  the  foramen  ovale  of  the  sphenoid  bone.     The  auriculo-temporal  branch 


INTERNAL    MAXILLARY    ARTERY.  93 

should  be  followed  backwards  with  care  behind  the  articulation,  and  the 
dental  and  gustatory  nerves  beneath  the  muscle  should  be  cleaned.  The 
small  cliorda  tympani  is  then  to  be  found  joining  the  posterior  part  of  the 
gustatory  nerve  near  the  skull. 

The  middle  meningeal  artery  is  to  be  sought  beneath  the  external  ptery- 
goid. Sometimes  the  trunk  of  the  internal  maxillary  artery  lies  beneath 
that  muscle,  and  in  such  case,  it  and  its  branches  are  to  be  traced  out. 

The  INTERNAL  MAXILLARY  ARTERY  (fig.  17,  h)  IS  onc  of  the  terminal 
branches  of  the  external  carotid,  and  takes  a  winding  course  beneath  the 
lower  jaw  and  the  temporal  muscle  to  the  spheno-maxillary  fossa,  where  it 
ends  in  branches  for  the  face,  the  interior  of  the  nose,  and  the  palate  and 
pharynx. 

At  first  the  artery  is  directed  inwards  beneath  the  jaw,  between  that 
bone  and  the  internal  lateral  ligament  of  the  joint,  and  crosses  the  dental 
nerve.  Next,  the  vessel  winds  over  the  external  pterygoid  muscle,  being 
placed  between  it  and  the  temporal  muscle.  And  lastly,  the  artery  enters 
the  spheno-maxillary  fossa  between  the  processes  of  origin  of  the  external 
pterygoid.  The  course  of  the  artery  is  sometimes  beneath,  instead  of  over 
the  external  pterygoid :  in  such  a  state  the  artery  gains  the  spheno-maxil- 
lary fossa  by  coming  upwards  through  the  origin  of  the  muscle,  as  in  the 
woodcut. 

The  branches  of  this  artery  are  very  numerous,  and  are  classed  into 
three  sets :  thus  one  set  arises  beneath  the  jaw ;  another  between  the  mus- 
cles ;  and  another  in  the  spheno-maxillary  fossa. 

Two  branches,  viz.,  the  inferior  dental  and  middle  meningeal,  leave  the 
internal  maxillary  artery  whilst  it  is  in  contact  with  the  ramus  of  the  jaw. 

The  inferior  dental  branch  descends  between  the  internal  lateral  liga- 
ment and  the  jaw,  and  enters  the  foramen  on  the  inner  surface  of  the  ramus, 
along  with  the  dental  nerve :  it  supplies  the  teeth,  and  ends  in  the  lower 
part  of  the  face. 

As  this  artery  is  about  to  enter  the  foramen  it  furnishes  a  small  twig, 
mylo-hyoid  branch,  to  the  muscle  of  that  name ;  this  is  conducted  by  a 
groove  on  the  inner  surface  of  the  bone,  in  company  with  a  branch  from 
the  dental  nerve,  to  the  superficial  surface  of  the  mylo-hyoid  muscle,  where 
it  anastomoses  with  the  submental  artery. 

The  great  yneningeal  artery  is  the  largest  branch,  and  arises  opposite 
the  preceding.  It  ascends  beneath  the  external  pterygoid  muscle,  and 
(oftentimes)  between  the  roots  of  the  auriculo-temporal  nerve ;  crossing 
the  internal  lateral  ligament,  it  enters  the  skull  through  the  foramen  spino- 
sum  of  the  sphenoid  bone.  When  in  the  skull  the  artery  ascends  to  the 
vertex  of  the  head,  and  supplies  the  bone  and  the  dura  mater  (p.  29). 
Before  the  meningeal  artery  enters  the  skull,  it  furnishes  the  following 
small  branches : — 

a.  The  tympanic  branch  (inferior)  passes  into  the  tympanum  through 
the  Glaserian  fissure,  and  is  distributed  to  the  membrana  tympani  and  that 
cavity. 

b.  A  deep  auricular  branch  arises  with  the  former  or  separately  enters 
the  meatus  through  the  cartilage,  or  between  this  and  the  bone,  and  rami- 
fies in  the  meatus  and  on  the  membrana  tympani. 

c.  The  small  meningeal  branch  begins  near  the  skull,  and  courses  through 
the  foramen  ovale  with  the  inferior  maxillary  nerve;  it  ramifies  in  the 
dura  mater  in  the  middle  fossa  of  the  skull. 

Another  small  branch  springs  from  the  dental  artery  or  the  internal 


94  DISSECTION    OF    THE    PTERYGOID    REGION. 

maxillary  trunk,  and  accompanying  tlie  gustatory  nerve,  ends  in  the  cheek 
and  the  mucous  membrane  of  tlie  mouth. 

The  branches  from  the  second  part  of  tlie  artery,  viz.,  whilst  it  is  between 
the  temporalis  and  pterygoideus  externus  are  distributed  to  the  temporal, 
masseteric,  buccal,  and  pterygoid  muscles. 

The  deep  temporal  arteries  are  two  in  number  (anterior  and  posterior) ; 
and  each  occupies  the  part  of  the  tem[)oral  fossa  indicated  by  its  name. 
They  ascend  beneath  the  temporal  muscle,  and  anastomose  with  the  super- 
ficial temporal  artery :  the  anterior  communicates,  through  the  malar  bone, 
with  branches  of  the  lachrymal  artery. 

When  the  parent  trunk  has  the  unusual  position  beneath  the  pterygoid, 
the  anterior  branch  lies  under  that  muscle,  instead  of  over  it. 

The  masseteric  artery  is  directed  outwards  with  the  nerve  of  the  same 
name  behind  the  tendon  of  the  temporal  muscle ;  and  passing  through  the 
sigmoid  notch,  enters  the  under  surface  of  the  masse ter  muscle.  Its 
branches  anastamose  with  the  other  offsets  to  the  muscle  from  the  external 
carotid  trunk. 

The  buccal  branch  quits  the  artery  near  the  upper  jaw,  and  in  the  un- 
usual position  of  tlie  artery  it  may  perforate  the  fibres  of  the  pterygoid  ; 
it  descends  beneath  the  coronoid  process  with  its  companion  nerve,  and  is 
distributed  to  the  buccinator  muscle,  the  cheek,  and  the  side  of  the  face, 
joining  the  branches  of  the  facial  artery. 

Tha pterygoid  branches  are  uncertain  in  their  position;  w^hether  derived 
from  the  trunk  or  some  of  the  branches  of  the  internal  maxillary,  they 
enter  both  pterygoid  muscles. 

Of  the  branches  that  arise  from  the  artery  when  it  enters  the  spheno- 
maxillary fossa,  only  one,  the  superior  dental,  will  be  now  described.  The 
remainder  will  be  examined  with  the  superior  maxillary  nerve  and  Meckel's 
ganglion  ;  they  are  infraorbital  (p.  105),  superior  palatine,  naso-palatine, 
vidian,  and  pterygo-palatine  (Section  14). 

The  superior  or  posterior  dental  branch  takes  origin  near  the  top  of  the 
upper  maxilla,  and  descends  with  a  tortuous  course  on  the  outer  surface  of 
that  bone,  along  with  a  small  branch  of  the  superior  maxillary  nerve.  It 
sends  twigs  into  the  foramina  in  the  bone,  and  supplies  the  upper  molar 
and  bicuspid  teeth  ;  but  some  external  offsets  are  furnished  to  the  gums. 
A  few  branches  reach  the  lining  membrane  of  the  antrum. 

The  INTERNAL  MAXILLARY  VEIN  rcccive  the  offsets  accompanying  the 
branches  of  the  artery  in  the  first  two  parts  of  its  course  :  these  veins  form  a 
plexus — pterygoid,  between  the  two  pterygoid  muscles,  and  in  part  be- 
tween the  temporal  and  external  pterygoid  muscles.  This  anastomosis 
communicates  with  the  alveolar  plexus ;  with  the  facial  vein  by  a  large 
branch  (anterior  internal  maxillary)  ;  and  with  the  cavernous  sinus  in  the 
interior  of  the  skull,  by  veinules  that  pass  through  the  base  of  the  cranium. 

Escaping  from  the  plexus,  the  vein  accompanies  the  artery  to  the  paro- 
tid gland,  and  there  joins  the  superficial  tem[)oral  vein, — the  union  of  the 
two  giving  rise  to  the  external  jugular.  Sometimes  this  common  vessel 
enters  the  internal  jugular  vein  (p.  42). 

The  INFERIOR  MAXILLARY  NERVE  (fig.  21)  is  the  largest  of  the  three 
trunks  arising  from  the  Gasserian  ganglion  (p.  32).  It  leaves  the  skull 
by  the  foramen  ovale  in  the  sphenoid  bone,  and  divides  beneath  the  ex- 
ternal pterygoid  muscle  into  two  chief  pieces,  viz.,  an  anterior,  small,  moto- 
sensory  part ;  and  a  large,  posterior,  chiefly  sensory  portion. 


INFERIOR    MAXILLARY    NERVE, 


95 


Directions.  Should  the  internal  maxillary  artery  obstruct  the  view  of 
the  nerve,  it  may  be  cut  through. 

The  SMALLER  PART,  formed  mainly  by  its  contribution  from  the  trunk 
of  the  nerve,  receives  nearly  all  the  fibrils  of  the  motor  root,  and  ends  in 
branches  for  the  muscles  of  the  jaw,  viz.,  temporal,  masseter,  and  one  ptery- 
goid ;  and  for  the  muscle  of  the  cheek,  the  buccinator. 


Fig.  21. 


Muscles  : — 
a.  Temporal  reflected. 
6.  Condyle  of  the  jaw  disarticulated  with 
the  external  pterygoid  attached  to  it. 

c.  Internal  pterygoid. 

d.  Buccinator. 

/.  Massi  ter  thrown  down. 
Nerves  : — 


10. 


Dekp  view  of  the  Pterygoid  Keqion  (Illustra- 
tions of  Dissections). 


Buccal. 

Masseteric,  cut. 

Deep  tcmpoi-al. 

Auriculo-temporal. 

Chorda  tympani. 

Inferior  dental. 

Gustatory. 

Internal  lateral  ligament  of  the  lower 
jaw.  The  arteries  are  not  figured, 
with  the  exception  of  the  internal 
maxillary  trunk  which  is  marked 
with  9  :  the  offsets  of  the  artery  ac- 
company the  nerves,  being  named 
like  them. 


The  deep  temporal  branches  (^)  are  furnished  to  the  under  surface  of  the 
temporal  muscle.  Like  the  arteries,  they  are  two  in  number,  anterior  and 
posterior,  and  course  upwards  beneath  the  external  pterygoid  muscle. 

The  posterior  branch  is  the  smallest,  and  is  often  derived  from  the 
masseteric  nerve  ;  it  is  placed  near  the  back  of  the  temporal  fossa. 

The  anterior  branch  supplies  the  greater  part  of  the  muscle,  and  com- 
municates sometimes  with  the  buccal  nerve. 

The  masseteric  branch  (^)  takes  a  backward  course  above  the  external 
pterygoid  muscle,  and  through  the  sigmoid  notch,  to  the  under  surface  of 
the  masseter  muscle :  in  the  masseter  the  nerve  can  be  followed  to  near 
the  anterior  border.  As  this  branch  passes  by  the  articulation  of  the  jaw 
it  gives  one  or  more  twigs  to  that  joint. 

The  pterygoid  branches  come  from  both  parts  of  the  inferior  maxillary 
nerve. 

The  branch  or  branches  to  the  external  pterygoid  spring  from  the  small 
part,  or  from  the  buccal  nerve,  and  enter  the  under  surface  of  its  muscle. 

The  nerve  to  the  internal  pterygoid  arises  from  the  large  part  of  the 
maxillary  trunk  close  to  the  skull,  and  may  be  followed  beneatli  the  upper 
border  to  the  deep  surface  of  the  muscle;  it  will  be  learnt  in  the  dissection 
of  the  otic  ganglion  (Section  14). 

The  buccal  branch  (^),  longer  and  larger  than  the  others,  peiforates  the 
external  pterygoid,  and  is  directed  inwards,  beneath  the  coronoid  process 
to  the  surface  of  the  buccinator,  where  it  ends  in  terminal  branches.  As 
it  perforates  the  pterygoid  muscle  filaments  are  given  to  the  fleshy  sub- 


96  DISSECTION    OF    THE    PTERYGOID    REGION. 

Stance;  and  after  it  has  passed  through  the  fibres  it  furnishes  a  branch  to 
the  temporal  muscle.  The  nerve  is  directed  towards  tlie  angle  of  the 
mouth,  supplying  the  integument,  the  buccinator  muscle,  and  the  lining 
mucous  membrane.  It  is  united  freely  with  the  facial  nerve,  the  two 
forming  a  plexus. 

The  LARGER  PART  of  the  inferior  maxillary  nerve  divides  into  three 
trunks — auriculo-temporal,  dental,  and  gustatory.  A  few  of  the  fibrils  of 
the  small  (motor)  root  are  applied  to  it,  and  are  conveyed  to  certain  mus- 
cles, viz.,  tensor  tympani,  circumfiexus  palati,  pterygoideus,  internus,  my- 
lohyoideus,  and  digastricus. 

The  AURICULO-TEMPORAL  NERVE  (*)  separates  from  the  others  near 
the  base  of  the  skull,  and  has  commonly  two  roots.  Its  course  to  the  sur- 
face of  the  head  is  directed  first  backwards  beneath  the  external  pterygoid 
muscle,  as  far  as  the  inner  part  of  the  articulation  of  the  jaw ;  and,  then, 
upwards  with  the  temporal  artery  in  front  of  the  ear.  The  nerve  furnishes 
branches  to  the  surrounding  parts,  viz.,  the  joint,  the  ear,  and  the  parotid 
gland;  and  it  communicates  with  the  i'acial  nerve.  Its  ramifications  on 
the  head  are  described  at  page  23.  In  the  part  now  dissected  its  branches 
are  the  following: — 

a.  Branches  of  the  meatus  auditorius.  Two  offsets  are  given  to  the 
meatus  from  the  point  of  union  of  the  branches  of  the  facial  with  the 
auriculo-temporal  nerve,  and  enter  that  tube  between  the  cartilage  and 
bone. 

h.  Articular  branch.  The  branch  to  the  joint  of  the  jaw  arises  near 
the  same  spot  as  the  preceding,  or  from  the  branches  to  tlie  meatus. 

c.  The  inferior  auricular  brarich  supplies  the  external  ear  below  the 
meatus  auditorius:  it  sends  offsets  along  the  internal  maxillary  artery, 
which  communicates  with  the  sympathetic  nerve. 

d.  Parotid  branches.     Tliese  small  filaments  ramify  in  the  gland. 

e.  Communicating  brandies.  Two  or  more  branches  around  the  ex- 
ternal carotid  artery  communicate  wnth  the  facial  and  sympathetic 
nerves. 

The  INFERIOR  DENTAL  Q)  is  the  largest  of  the  three  trunks  into  which 
the  inferior  maxillary  nerve  divides.  In  its  course  to  the  canal  in  the 
lower  jaw,  the  nerve  is  external  to  the  gustatory,  and  lies  at  first  beneath 
the  external  pterygoid  muscle;  it  is  afterwards  placed  on  the  internal 
pterygoid,  and  on  the  internal  lateral  ligament  near  the  dental  foramen. 
After  the  nerve  enters  the  bone,  it  is  continued  forwards  beneath  the  teeth 
to  the  foramen  in  the  side  of  the  jaw,  and  ends  at  that  spot  by  dividing 
into  an  incisor  and  a  labial  branch.  Only  one  muscular  offset  (mylo-hyoid) 
is  supplied  by  the  dental  nerve  before  it  enters  the  bone.  Its  branches 
are: — 

a.  The  mylo-hyoid  branch  arises  from  the  trunk  of  the  nerve  near  the 
dental  foramen,  and  is  continued  along  a  groove  on  the  inner  aspect  of  the 
ramus  of  the  jaw  to  the  cutaneous  surface  of  the  mylo-hyoideus,  and  to  the 
anterior  belly  of  the  digastric  muscle. 

b.  The  dental  branches  arise  in  the  bone,  and  supply  the  molar  and 
bicuspid  teeth.  If  the  bone  is  soft,  the  canal  containing  the  nerve  and 
artery  may  be  laid  open  so  as  to  expose  these  branches. 

c.  The  incisor  branch  continues  the  trunk  of  the  nerve  onwards  to  the 
middle  line,  and  furnishes  ofl'sets  to  the  canine  and  incisor  teeth,  beneath 
which  it  lies. 

d.  The  labial  branch  (mental?)  (fig.  9,  '^)  issues  on  the  face  beneath 


DISSECTION    OF    THE    SUBMAXILLARY    RElUON.  97 

the  depressor  of  the  an^le  of  tlie  mouth.  It  gives  branches  to  the  muscles 
below  the  aperture  of  the  moutli,  and  communicates  with  the  facial  nerve; 
but  the  greater  part  of  tlie  branch  is  directed  upwards  beneath  the  depressor 
labii  inferioris,  and  is  distributed  on  the  inner  and  outer  surfaces  of  the 
lower  lip. 

The  inferior  dental  artery^  after  entering  the  lower  jaw,  has  a  similar 
course  and  distribution  to  the  nerve.  Thus  it  supplies  offsets  to  the  bone, 
dental  branches  to  the  molar  and  bicuspid  teeth,  and  ends  anteriorly  in  an 
incisor  and  a  labial  branch. 

The  incisor  branch  is  continued  to  the  symphysis  of  the  jaw,  where  it 
ends  in  the  bone:  it  lies  beneath  the  canine  and  incisor  teeth,  to  which  it 
furnishes  twigs. 

The  labial  branchy  issuing  by  the  labial  foramen,  ramifies  in  the  struc- 
tures covering  the  lower  jaw,  and  communicates  with  the  branches  of  the 
facial  artery. 

The  GUSTATORY  or  LINGUAL  NERVE  (^)  is  the  remaining  trunk  of  the 
inferior  maxillary,  and  is  concealed  at  first,  like  the  others,  by  the  exter- 
nal pterygoid  muscle.  It  is  then  inclined  inwards  with  a  small  artery 
over  the  internal  pterygoid  muscle,  and  under  cover  of  the  side  of  the  jaw 
to  the  tongue.  The  remainder  of  the  nerve  will  be  seen  in  the  dissection 
of  the  submaxillary  region. 

In  this  course  under  the  jaw  the  nerve  does  not  distribute  any  branch 
to  the  parts  around,  but  the  following  communicating  branch  is  received 
by  it. 

The  chorda  tympani  is  a  branch  of  the  facial  nerve,  and  is  distributed 
to  the  tongue.  P^scaping  from  the  tympanum  by  the  Glaserian  fissure, 
this  small  branch  (*)  is  applied  to  the  gustatory  nerve  at  an  acute  angle. 
At  the  point  of  junction  some  fibrils  communicate  with  the  gustatory,  but 
the  greater  part  of  the  chorda  tympani  is  conducted  along  tliat  nerve  to 
the  tongue. 

The  origin  of  the  nerve,  and  its  course  across  the  tympanum  to  its  posi- 
tion beneath  the  external  pterygoid,  are  described  in  Section  14. 


Section  VII. 

SUBMAXILLARY  REGION. 


The  submaxillary  region  is  situate  between  the  lower  jaw  and  the  hyoid 
bone.  In  it  are  contained  the  muscles  of  the  os  hyoides  and  tongue,  the 
vessels  and  nerves  of  tlie  tongue,  and  the  sublingual  and  submaxillary 
glands. 

Position.  In  this  dissection  the  position  of  the  neck  is  the  same  as  for 
the  examination  of  the  anterior  triangle. 

Dissection.  If  any  fatty  tissue  has  been  left  on  the  submaxillary  gland, 
or  on  the  mylo-hyoid  muscle,  when  the  anterior  triangular  space  was  dis- 
sected, let  it  be  taken  away. 

The  submaxillary  gland  (fig.  16,  ")  lies  below  the  jaw  in  the  anterior 

part  of  the  space  limited  by  that  bone  and  the  digastric  muscle.     Its  shape 

is  irregular,  and  the  facial  artery  winds  over  the  surface.     It  rests  on  the 

mylo-hyoideus,  and  sends  a  deep  process  round  the  posterior  or  free  border 

7 


98  DISSECTION    OF    THE    SUBMAXILLARY    REGION. 

of  that  muscle.  In  front  of  it  is  the  anterior  belly  of  the  digastric  ;  and 
behind  is  the  stylo-maxillary  ligament  separating  it  from  the  parotid. 
Occupying  a  position  somewhat  below  the  side  of  the  jaw,  the  gland  is 
very  near  the  surface,  being  covered  only  by  the  integuments  and  pla- 
tysma,  and  the  deep  fascia. 

In  structure  the  submaxillary  resembles  the  parotid  gland  (p.  42) ;  and 
its  duct — duct  of  Wharton — issuing  from  the  deep  process,  extends  beneath 
the  mylo-hyoid  muscle  to  the  mouth. 

Dissection.  To  see  the  mylo-hyoid  muscle,  detach  the  anterior  belly 
of  the  digastric  from  the  jaw,  and  dislodge  without  injury  the  submaxillary 
gland  from  beneath  the  bone. 

The  MYLO-HYOID  MUSCLE  (fig.  33,  ^)  is  triangular  in  shape,  with  the 
base  at  the  jaw  and  the  apex  at  the  hyoid  bone,  and  unites  along  the 
middle  line  with  its  fellow  of  the  opposite  side.  It  arises  from  the  mylo- 
hyoid ridge  on  the  inner  surface  of  the  lower  jaw  as  far  back  as  the  last 
molar  tooth ;  and  is  inserted  into  the  middle  of  the  body  of  the  os  hyoides, 
as  well  as  into  a  central  tendinous  band  between  that  bone  and  the  jaw. 

On  the  cutaneous  surface  lie  the  digastric  muscle,  and  the  submaxillary 
gland,  the  facial  artery  with  the  submental  offset,  and  its  own  branch  of 
nerve  and  artery.  Its  fibres  are  frequently  deficient  near  the  jaw,  and 
allow  the  next  muscle  to  be  seen.  Only  the  posterior  border  is  unattached, 
and  round  it  a  piece  of  the  submaxillary  gland  winds.  The  parts  in  con- 
tact with  the  deep  surface  of  the  muscle  will  be  perceived  after  the  under- 
mentioned dissection  has  been  made. 

Action.  The  lower  jaw  being  fixed  the  muscle  approaches  the  os  hyoides 
to  the  jaw,  enlarging  the  pharynx  preparatory  to  swallowing. 

With  the  hyoid  bone  immovable,  the  mylo-hyoideus  can  help  in  de- 
pressing the  jaw,  and  opening  the  mouth. 

Dissection.  To  bring  into  view  the  muscles  beneath  the  mylo-hyoid, 
and  to  trace  the  vessels  and  nerves  to  the  substance  of  the  tongue  (as  in 
figure  23),  the  student  should  first  divide  the  facial  vessels  on  the  jaw, 
and  remove  them  with  the  superficial  part  of  the  submaxillary  gland;  but 
he  should  be  careful  to  leave  the  deep  part  of  the  gland  which  turns  be- 
neath the  mylo-hyoideus,  because  the  small  submaxillary  ganglion  is  in 
contact  with  it.  Next  he  should  cut  through  the  small  branches  of  ves- 
sels and  nerve  on  the  surface  of  the  mylo-hyoideus;  and  detaching  that 
muscle  from  the  jaw  and  its  fellow,  should  throw  it  down  to  the  os  hyoides, 
but  w^ithout  injuring  the  genio-hyoid  muscle  beneath  it. 

Afterwards  the  bone  is  to  be  sawn  through  on  the  right  side  of  the 
muscles  attached  to  tiie  symphysis,  the  soft  parts  covering  the  lower  jaw 
having  been  previously  cut.  The  side  of  the  jaw,  which  will  then  be 
loose  (for  the  ramus  of  the  bone  has  been  sawn  before),  is  to  be  raised  to 
see  the  parts  beneath,  and  it  may  be  fastened  u[)  out  of  the  way  with  a 
stitch ;  but  it  should  not  be  detached  from  the  mucous  membrane  of  the 
mouth. 

The  apex  of  the  tongue  is  to  be  now  pulled  well  out  of  the  mouth  over 
the  upper  teeth,  and  fastened  with  a  stitch  to  the  septum  of  the  nose, 
whilst  the  left  half  of  the  jaw  is  to  be  drawn  down  forcibly  with  hooks. 
The  scalpel  should  be  then  passed  from  below  upwards  between  the  sawn 
surfaces  of  the  bone,  for  the  purpose  of  dividing  a  strong  band  of  the 
mucous  membrane  of  the  mouth ;  and  it  should  be  carried  onwards  along 
the  middle  line  of  the  tongue  to  the  tip. 

By  means  of  a  stitch  the  os  hyoides  may  be  fastened  down,  to  make 


IIYOID    AND    STYLOID    MUSCLES.  99 

tight  the  muscular  fibres.  All  the  fat  and  areolar  tissue  are  to  be  removed, 
and  in  doing  this  the  student  is  to  take  care  of  the  Whartonian  duct;  of 
the  hypoglossal  nerve  and  its  brandies,  wliich  lie  on  the  hyo-glossus  mus- 
cle, and  especially  of  its  small  offset  ascending  to  the  stylo-glossus  mus- 
cle ;  also  of  the  gustatory  nerve  nearer  the  jaw.  Between  the  gustatory 
nerve  and  the  deep  part  of  the  submaxillary  gland  the  dissector  should 
seek  the  small  submaxillary  ganglion  (smaller  than  a  pin's  head),  with 
its  offsets;  and  should  endeavor  to  separate  from  the  trunk  of  the  gustatory 
the  small  chorda  tympani  nerve,  and  to  define  the  offset  from  it  to  the 
submaxillary  ganglion. 

At  the  hinder  border  of  the  hyo  glossus  clean  the  lingual  vessels,  the 
stylo-hyoid  ligament,  and  the  glosso-pharyngeal  nerve,  all  passing  beneath 
that  muscle ;  and  at  the  anterior  border  find  the  issuing  ranine  vessels 
which,  with  the  gustatory  and  hypoglossal  nerves,  are  to  be  traced  on  the 
under  surface  of  the  tongue  to  the  tip. 

Parts  beneath  mylo-hyoideus  (fig.  23).  The  relative  position  of  the 
objects  brought  into  view  by  the  steps  of  the  previous  dissection  is  now 
apparent: — Extending  from  the  cornu  of  the  hyoid  bone  to  the  side  of  the 
tongue  is  tlie  hyo-glossus  muscle,  whose  fibres  are  crossed  superiorly  by 
those  of  the  stylo-glossus.  On  the  hyo-glossus  are  placed,  from  below 
upwards,  the  hypoglossal  nerve,  the  Whartonian  duct,  and  the  gustatory 
nerve,  the  latter  crossing  the  duct ;  and  near  the  inner  border  of  the  mus- 
cle the  two  nerves  are  united  by  branches.  Beneath  the  same  muscle  lie, 
from  below  upwards,  the  lingual  artery  with  its  vein,  the  stylo-hyoid 
ligament,  and  the  glosso-pharyngeal  nerve.  Above  the  hyo-glossus  is  the 
mucous  membrane  of  the  mouth,  with  the  sublingual  gland  attached  to  it 
in  front,  and  some  fibres  of  the  superior  constrictor  muscle  covering  it 
behind  near  the  jaw. 

Between  the  chin  ajjd  the  os  hyoides,  along  the  middle  line,  is  situate 
the  genio-hyoid  muscle  ;  and  larger  and  deeper  than  it  is  a  fan-shaped 
muscle,  the  genio-hyo-glossus.  Along  the  outer  side  of  the  last  muscle  lie 
the  ranine  vessels  ;  and  a  sublingual  branch  for  the  gland  of  the  same 
name  springs  from  the  lingual  artery  at  the  inner  border  of  the  hyo-glos- 
sus. On'the  under  surface  of  the  tongue,  near  the  margin,  lies  the  gus- 
tatory nerve ;  and  in  the  fibres  of  the  genio-hyo-glossus  runs  the  hypo- 
glossal nerve. 

The  iiYO-GLOSSus  MUSCLE  (fig.  22,  ^)  is  thin  and  somewhat  square  in 
shape.  The  muscle  arises  from  the  lateral  part  of  the  body  of  the  os 
hyoides  (basio-glossus),  and  from  all  the  great  cornu  of  the  same  bone 
(cerato-glossus).  The  two  pieces  form  a  thin  sheet,  and  enter  the  back 
part  and  side  of  the  tongue ;  they  will  be  seen  afterwards  to  mingle  with 
fibres  of  the  palato-  and  stylo-glossus.^ 

The  parts  in  contact  with  the  surfaces  of  the  hyo-glossus  have  been 
already  enumerated  ;  and  beneath  the  muscle  also  are  portions  of  the 
genio-hyo-glossus  and  middle  constrictor.  Along  the  anterior  border  is 
the  genio-hyo-glossus  muscle. 

Action.  When  the  tongue  is  at  rest,  the  muscle  can  bring  that  organ 
to  the  floor  of  the  mouth,  drawing  down  the  sides  and  giving  a  rounded 

1  A  third  part  (chondro-glossus)  is  distinct  from  the  others,  and  is  not  dissected  ; 
it  ends  on  the  upper  surface  of  the  tongue  near  the  root.  For  further  details  re- 
specting the  anatomy  of  this  and  the  otlier  lingual  muscles,  reference  is  to  be  made 
to  the  dissection  of  the  tongue,  Section  15. 


100 


DISSECTION    OF    THE    SUBMAXILLARY    REGION, 


Fig.  22. 


form  to  the  dorsum  ;  but  if  the  tongue  is  protruded  from  the  mouth,  the 
fibres  will  retract  it  into  that  cavity. 

If  the  tongue  is  fixed  against  tiie  roof  of  the  mouth  by  other  mus- 
cles, even  though  the  lower  jaw  is  depressed,  this  muscle  with  the  genio- 
hyo-glossus  will  elevate  the  os  hyoides,  and  allow  swallowing  to  take 
place. 

The  STYLO-GLOSSUS  (fig.  22,  ^)  is  a  slender  muscle,  whose  attachments 
are  expressed  by  its  name.  Arising  from  the  styloid  process  near  the 
apex,  and  from  the  stylo-maxillary  ligament,  the  muscle  is  continued  for- 
wards to  the  side  of  the  tongue.  Here  it  gives  fibres  to  the  dorsum,  and 
turning  to  the  under  surface,  extends  to  the  tip  of  the  tongue.  Beneath 
the  jaw  this  muscle  is  crossed  by  the  gustatory  nerve. 

Action.  Both  muscles  will  raise  the  back  of  the  tongue  against  the 
roof  of  the  mouth,  but  if  the  tongue  is  protruded  they  will  restore  it  to  the 
cavity. 

One  muscle  can  direct  the  point  of  the  tongue  towards  its  own  side  of 
the  mouth. 

The  GENio-HYOiD  MUSCLE  (fig.  22,  *)  arises  from  the  lower  of  the  two 

lateral  tubercles  on  the  inner  aspect  of 
the  symphysis  of  the  jaw,  and  is  in- 
serted  into  the   middle    of  the    hyoid 

^       bone. 

A^'J  aHyi'^^"'"^ "  Covered  by  the  mylo-hyoideus,  this 

\jirwl       "'^  muscle  rests  on  the  genio-hyo-glossus. 

The  inner  border  touches  the  muscle  of 
the  opposite  side,  and  the  two  are  often 
united. 

Action.  As  long  as  the  mouth  is 
shut  it  raises  the  hyoid  bone ;  but 
acting  from  the  os  hyoides,  and  the 
closers  of  the  mouth  being  relaxed,  it 
can  depress  the  jaw  and  open  the 
mouth. 

The  GENIO-HiO-GLOSSUS  (fig.  22,^) 
is  the  largest  muscle  of  this  region ;  it 
has  a  triangular  form,  with  tiie  apex 
at  the  jaw,  and  the  base  at  the  middle 
line  of  the  tongue.  It  takes  origin 
from  the  upper  tubercle  behind  the 
symphysis  of  the  jaw.  From  this  spot 
the  fibres  radiate,  the  posterior  passing 
downwards  to  their  insertion  into  the 
body  of  the  hyoid  bone,  the  anterior 
forwards  to  the  tip  of  the  tongue,  and  the  intermediate  to  the  tongue  from 
root  to  point. 

Lying  along  the  middle  of  the  tongue,  it  is  in  contact  with  its  fellow. 
The  lower  border  of  the  muscle  corresponds  with  the  genio-hyoideus,  and 
the  upper  with  the  fra3num  linguae  On  its  outer  side  are  the  ranine  ves- 
sels, and  the  hyo-glossus  muscle ;  and  the  hypoglossal  nerve  perforates  the 
posterior  fibres. 

Action.  By  the  simultaneous  action  of  all  the  fibres  the  tongue  is 
depressed  in  the  floor  of  the  mouth,  and  hollowed  along  the  middle.  But 
different  parts  of  the  muscle  are  thought  to  have  difterent  uses  when  they 


Muscles  of  the  TojfauE. 

1.  Hyo-glossus.  4.  Genio-hyoideus. 

2.  Stylo-glossus.        5.  Stylo-pharyngeus. 

3.  Genio-hyo-glossus. 


GUSTATORY    NERVE.  101 

act  from  the  jaw  : — Thus  the  fibres  attached  to  the  os  hyoides  advance 
and  fix  that  bone  before  swallowing ;  the  hinder  tongue  fibres  raise  the 
root  of  the  tongue  and  protrude  the  tip,  and  the  anterior  then  turn  down 
the  tip  of  the  tongue  over  the  teeth. 

When  the  mouth  is  open  swallowing  can  be  performed  if  the  tongue  is 
fixed  against  the  teeth  and  roof  of  the  mouth,  because  this  muscle  and  the 
hyo-glossus  can  then  raise  the  hyoid  bone. 

The  lingual  artery  (fig.  11^  f),  arises  from  the  external  carotid  between 
the  superior  thyroid  and  facial  branches.  At  first  it  is  directed  inwards 
above  the  os  hyoides,  and  then  upwards  beneath  the  hyo-glossus  to  the 
under  part  of  the  tongue  (fig.  23)  ;  it  ends  at  the  anterior  border  of  that 
muscle  in  the  sublingual  and  ranine  branches.  Near  the  hyo-glossus  the 
artery  is  crossed  by  the  ninth  nerve,  and  by  the  digastric  and  stylo-hyoid 
muscles.  Beneath  the  hyo-glossus,  the  vessel  rests  on  the  middle  con- 
strictor and  genio-hyo-glossus  muscles,  and  is  below  the  level  of  the  glosso- 
pharyngeal nerve.     Its  branches  are  these  : — 

a.  A  small  hyoid  branch  is  distributed  on  the  upper  border  of  the  os 
hyoides,  supplying  the  muscles  ;  it  anastomoses  with  its  fellow  of  the  oppo- 
site side,  and  with  the  hyoid  branch  of  the  superior  thyroid  artery  of  the 
same  side. 

b.  A  branch  to  the  dorsum  of  the  tongue  arises  beneath  the  hyo-glossus 
muscle,  and  ascends  to  supply  the  substance  of  the  tongue  and  the  tonsil. 
The  fibres  of  the  hyo-glossus  must  be  divided  to  see  it. 

c.  The  sublingaal  branch  springs  from  the  final  division  of  the  artery 
at  the  edge  of  the  hyo-glossus,  and  is  directed  outwards  to  the  gland  of  the 
same  name.  Some  offsets  supply  the  gums  and  the  contiguous  muscles, 
and  one  continues  behind  the  incisor  teeth  to  join  a  similar  artery  from 
the  other  side. 

d.  The  ranine  branch  (9)  is  the  terminal  part  of  the  lingual  artery,  and 
extends  forwards  along  the  outer  side  of  the  genio-hyo-glossus  to  the  tip 
of  the  tongue  where  it  ends.  Muscular  oflTsets  are  furnished  to  the  sub- 
stance of  the  tongue  of  the  same  side.  This  artery  lies  along  the  frienum 
linguse,  but  is  imbedded  in  the  muscular  fibres. 

The  lingual  vein  commences  on  both  the  upper  and  under  surfaces  of 
the  tongue.  It  lies  with  its  companion  artery,  and  ends  in  the  internal 
jugular  vein. 

The  GUSTATORY  or  LINGUAL  NERVE  (fig.  23,  ^)  has  been  followed  in 
the  pterygo-maxillary  region  to  its  passage  between  the  ramus  of  the 
lower  jaw  and  the  internal  pterygoid  muscle  (p.  97).  In  this  dissection 
the  nerve  is  inclined  forwards  to  the  side  of  the  tongue,  across  the  mucous 
membrane  of  the  mouth  and  the  origin  of  the  superior  constrictor  muscle, 
and  above  the  deep  part  of  the  submaxillary  gland.  Lastly,  it  is  directed 
across  the  Wliartonian  duct,  and  along  the  side  of  the  tongue  to  the  apex. 
Branches  are  furnished  to  the  surrounding  parts,  thus : — 

Two  or  more  offsets  connect  it  with  the  submaxillary  ganglion,  near  the 
gland  of  that  name. 

Farther  forwards  branches  descend  on  the  hyo-glossus  to  unite  in  a  kind 
of  plexus  with  twigs  of  the  hypoglossal  nerve. 

Other  filaments  are  supplied  to  the  mucous  membrane  of  the  mouth,  the 
gums,  and  the  sublingual  gland. 

Lastly,  the  branches  for  the  tongue  ascend  tlirough  the  muscular  sub- 
stance, and  are  distributed  to  the  conical  and  fungiform  papilhe. 

The  submaxillary  ganglion  (fig.   23,   ^)  resembles  the  other  ganglia 


102 


DISSECTION    OF    THE    SUBMAXILLARY    REGION. 


connected  with  the  three  trunks  of  the  fifth  nerve,  and  communicates  with 
sensory,  raotory,  and  sympatlietic  nerves.  It  is  smaller  in  size  than  the 
lenticular  ganglion,  is  sometimes  rather  red,  and  is  placed  above  the  deep 
process  of  the  submaxillary  gland.  Offsets  proceed  upwards  to  connect  it 
with  other  nerves  ;  and  from  the  lower  part  arise  the  branches  to  the  ad- 
jacent structures. 

Connection  with  nerves — roots.     Two  or  three  branches,  in  the  form  of 
loops,  pass  from  the  ganglion  to  the  gustatory  nerve.     At  the  posterior 

Fig.  23. 


Muscles  :  a.  Oenio-hyo-glossus. 

B.  Genio-hyoiileus. 

c.  Hyo-glossus. 

D.  Stylo-glos8us. 

E    Mylo-hyoideus,  reflected. 

H.  Stylo-hyoideiis. 

J.  Posterior  belly  of  digastricus. 

Nerves:  1.  Gustatory. 

2.  Submaxillary  ganglion. 

.3.  Wharton's  duct. 

4.  Glosso-pharyugeal  nerve. 

6.  Hypo-glossal. 

7.  Upper  laryngeal.     The  lingual  ar- 

tery  ramifies  in  this  region,  lying 
by  the  side  of  the  hypoglossal 
nerve :  the  rauine  ofiFset  is  marked 
with  9. 


Deep  view  of  the  Submaxillary  Kegion  (Illustrations  of  Dissections). 

part  the  ganglion  is  further  joined  by  an  offset  from  the  chorda  tympani, 
(of  the  facial  nerve)  which  lies  in  contact  with  the  gustatory.  And  its 
sympathetic  branch  comes  from  the  nerves  around  the  facial  artery. 

Branches.  From  the  lower  part  of  the  ganglion  five  or  six  branches 
descend  to  the  substance  of  the  submaxillary  gland  ;  and  from  the  anterior 
part  other  filaments  are  furnished  to  the  mucous  membrane  of  the  mouth 
and  the  Whartonian  duct. 

Chorda  tympani.  Joining  the  gustatory  above  by  fibrils  (p.  97),  it  is 
applied  to  the  back  of  that  nerve  till  near  the  tongue,  and  can  be  easily 
separated  from  it ;  but  beyond  that  point  it  enters  amongst  the  fibres  of 
the  gustatory  nerve  and  is  conveyed  to  the  tongue.  Near  the  submaxil- 
lary gland  an  offset  is  sent  to  the  submaxillary  ganglion. 

The  HYPO-GLOSSAL  or  NINTH  NERVE  (fig.  23,  ^)  in  the  submaxillary 
region  lies  on  the  hyo-glossus  muscle,  being  concealed  by  the  mylo- 
hyoideus  :  but  at  the  inner  border  of  the  hyo-glossus  it  enters  the  fibres 
of  the  genio-hyo-glossus,  and  is  continued  along  the  middle  line  of  the 
tongue  to  the  tip. 

Branches.  On  the  hyo-glossus  the  ninth  nerve  furnislies  branches  to 
the  muscles  of  the  submaxillary  region,  except  the  mylo-hyoid  and  the 
digastric,  viz.,  to  the  hyo-glossus,  stylo-glossus,  genio-hyoideus,  and  genio- 
hyo-glossus.  Further,  some  offsets  communicate  with  the  gustatory  nerve 
on  the  hyo-glossus. 

Along  the  middle  of  the  tongue  the  nerve  sends  upwards  long  filaments 


UPPER  MAXILLARY  NERVE.  103 

wliich  supply  the  muscular  structure,  and  communicate  with  the  gustatory 
nerve. 

The  glosso-pharyngeal  cranial  nerve  (fig.23,  *),  issuing  between  the 
two  carotid  arteries,  courses  over  the  stylo-pharyngeus  and  the  middle 
constrictor  of  the  pharynx,  and  ends  under  the  hyo-glossus  in  branches  for 
the  tongue.     See  Dissection  of  the  Toxgue. 

The  duct  of  the  submaxillary  gland  (fig.  28,  ^),  Wharton's  duct,  issues 
from  the  deep  part  of  the  glandular  mass  turning  round  the  border  of  the 
mylo-hyoid  muscle.  It  is  about  two  inches  in  length,  and  is  directed  up- 
wards on  the  hyo-glossus  muscle,  and  beneath  the  gustatory  nerve,  to 
open  on  the  side  of  the  frasnum  linguoe  in  the  centre  of  an  eminence  :  its 
opening  in  the  mouth  will  be  seen  if  a  bristle  be  passed  along  it.  The  duct 
has  a  thin  wall,  and  consists  externally  of  a  fibrous  layer  with  much  elastic 
tissue  and  a  few  pale  muscular  fibres,  and  internally  of  a  mucous  lining 
with  flattened  epithelium. 

The  dee[3  part  of  the  submaxillary  gland  extends  along  the  side  of  the 
duct,  reaching  in  some  instances  the  sublingual  gland. 

The  suhlingual  gland  {^g.  23,  ^)  is  somewhat  of  the  shape  of  an  almond, 
and  the  longest  measurement,  which  is  about  one  inch  and  a  half,  is  directed 
backwards.  It  is  situate  beneath  the  anterior  part  of  the  tongue,  in  con- 
tact with  the  inner  surface  of  the  lower  jaw,  and  close  to  the  symphysis. 
Separated  from  the  cavity  of  the  mouth  by  the  mucous  membrane,  the 
gland  is  prolonged  across  the  upper  border  of  the  genio-hyo-glossus  muscle, 
so  as  to  touch  the  one  of  the  opposite  side. 

The  sublingual  is  an  aggregation  of  small  glandular  masses,  each  being 
provided  with  a  separate  duct  (Henle).  The  ducts  (ductus  Riviniani)  are 
from  ten  to  eighteen  in  number.  Some  of  them  open  beneath  the  tongue 
along  a  crescent-shaped  fold  of  the  mucous  membrane,  and  others  join  the 
Whartonian  duct  ;  one  or  more  form  a  larger  tube,  which  either  joins  that 
duct  01-  opens  near  it. 


Section  VIII. 

SUPERIOR  MAXILLARY  NERVE  AND  VESSELS. 

Directions.  The  student  may  examine  next  the  right  orbit,  and  the 
remaining  trunk,  superior  maxillary  of  the  fifth  nerve. 

Supposing  the  right  orbit  to  be  untouched,  the  student  may  vary  his 
former  examination  of  the  left  cavity  (p.  50)  by  dissecting  it  from  the  outer 
side. 

Dissectio7i.  For  this  purpose  divide  the  margin  of  the  orbit  with  a  saw 
through  the  supra-orbital  notch,  and  the  roof  with  a  chisel  back  to  the 
sphenoidal  fissure.  Cut  also  with  a  chisel  (from  the  inside)  along  the 
middle  fossa  of  the  base  of  the  skull  from  the  sphenoidal  fissure  in  front 
to  the  foramen  spinosum  behind,  and  outside  the  line  of  the  foramen  ro- 
tundum  and  foramen  ovale.  The  side  of  the  skull  is  next  to  be  sawn  ver- 
tically in  front  of  the  petrous  part  of  the  temporal  bone,  so  that  the  incision 
shall  end  at  the  posterior  extremity  of  the  cut  made  in  the  base.  After- 
wards the  outer  wall  of  the  orbit  is  to  be  sawn  horizontally  into  the  spheno- 
maxillary fissure.     The  piece  of  bone  forming  part  of  the  cranium  and 


104  DISSECTION    OF    THE    NECK. 

orbit  is  now  loose,  and  is  to  be  removed  with  the  temporal  muscle.  If  the 
part  of  the  roof  of  the  orbit,  which  is  left,  should  interfere  with  tiie  sight 
of  the  contents  of  the  cavity,  let  it  be  taken  away  with  a  bone-forceps. 

The  description  of  the  orbit  (p.  51)  will  serve  in  a  general  way  for  the 
right  cavity. 

The  superior  maxillary  division  of  the  fifth  nerve,  in  its  course  to  the 
face,  occupies  successively  the  skull,  the  spheno-maxillary  fossa,  and  the 
infra-orbital  canal. 

The  beginning  of  the  nerve  in  the  cranium  has  been  already  demon- 
strated (p.  31). 

Dissection.  In  the  spheno-maxillary  fossa  the  nerve  can  be  partly  seen 
by  the  dissection  already  made  for  the  orbit,  and  its  exposure  here  will  be 
completed  by  removing  the  fat,  and  cutting  away  some  of  the  wing  of  the 
sphenoid  bone,  so  as  to  leave  only  an  osseous  ring  round  the  nerve  at  its 
exit  from  the  skull.  In  the  fossa  the  student  seeks  the  following  offsets, 
the  orbital  branch  entering  the  cavity  of  the  orbit ;  branches  to  Meckel's 
ganglion  which  descend  in  the  fossa ;  and  a  dental  branch  along  the  back 
of  the  upper  jaw. 

To  follow  onwards  the  nerve  in  the  floor  of  the  orbit,  the  contents  of 
the  cavity  having  been  taken  away,  the  bony  canal  in  which  it  lies  must 
be  opened  to  tlie  face.  Near  the  front  of  the  orbit  the  anterior  dental 
branch  is  to  be  traced  downwards  for  some  distance  in  the  bone.  The 
infraorbital  vessels  are  prepared  with  the  nerve. 

The  Superior  maxillary  nerve  (fig.  24)  commences  in  the  Gasse- 
rian  ganglion  (p.  31),  and  leaves  the  cranium  by  the  foramen  rotundum. 
The  course  of  the  nerve  is  almost  straight  to  the  face,  across  the  spheno- 
maxillary fossa,  and  along  the  orbital  plate  of  the  superior  maxilla  and  the 
infraorbital  canal.  Issuing  from  tlie  canal  by  the  infraorbital  foramen,  it 
is  concealed  by  the  elevator  of  the  upper  lip,  and  ends  in  branches  to  the 
eyelid,  nose,  and  upper  lip  : — 

a.  The  orbital  hranch  (^)  arises  in  the  spheno-maxillary  fossa,  and  en- 
tering the  orbit,  divides  into  malar  and  temporal  branches  (p.  GO). 

h.  The  spheno -palatine  branches  (^)  descend  from  the  nerve  in  the 
fossa,  and  supply  the  nose  and  the  palate;  they  are  connected  with  Meck- 
el's ganglion,  and  will  be  dissected  with  it  (Section  14). 

c.  A  posterior  dental  branch  (^)  leaves  the  nerve  near  the  upper  jaw. 
It  enters  a  canal  in  the  maxilla,  and  supplies  branches  to  the  molar  teeth 
and  the  lining  membrane  of  the  antrum  ;  it  joins  the  anterior  dental  branch 
near  the  teeth.  Before  entering  the  canal  it  furnishes  one  or  more  offsets 
to  the  gums  and  the  buccinator  muscle. 

d.  The  anterior  dental  branch  (*)  quits  the  nerve  trunk  in  the  floor  of 
the  orbit,  and  descends  to  the  anterior  teeth  in  a  s{)ecial  canal  in  front  of 
the  antrum:  it  is  distributed  by  two  branches.  One  (inner)  gives  nerves 
to  the  incisor  and  canine  teeth,  and  furnishes  one  or  two  fllaments  to  the 
lower  meatus  of  the  nose;  the  other  (outer)  ends  by  supplying  the  bicuspid 
teeth. 

e.  Before  the  trunk  ends  in  the  facial  branches,  it  supplies  a  small  pal- 
pebral o^^gX  to  the  lower  eyelid;  this  is  directed  upwards  to  the  lid  in  a 
groove  in  the  margin  of  the  orbit. 

/.  Infraorbital  or  facial  branches  (^).  These  are  larger  than  the  other 
offsets  of  the  nerve,  and  form  its  terminal  ramifications.  Some  incline 
inwards  to  the  side  of  the  nose,  and  the  rest  descend  to  the  upper  lip. 
Near  the  orbit  they  are  crossed  by  branches  of  the  facial  nerve  (fig.  9,  "), 


UPPER    MAXILLARY    NERVE, 


105 


with  which  they  communicate,  the  whole  forming  the  infraorbital  plexus 
(p.  49). 

g.  The  branches  for  the  side  of  the  nose  supply  the  muscular  and  te^^u- 
mentary  structures. 

Fig.  24. 


2.  Trunk  of  the  nerve  leaving  the 

Gasserian  ganjrlion. 

3.  Spheno-palatine  branches. 

4.  Temporo-malar  branch. 

5.  Posterior  dental  nerves. 

6.  Anterior  dental. 

7.  Facial  branches. 


Diagram  of  the  Upper  Maxillary  Nerve  and  its  Branches. 

h.  The  branches  for  the  upper  Up  are  three  or  four  in  number,  which 
divide  as  they  descend,  and  are  distributed  chiefly  to  the  surfaces  of  the 
lip,  though  they  supply  as  well  the  muscles  and  the  labial  glands. 

The  infraorbital  artery  is  a  branch  of  the  internal  maxillary  (p.  94). 
Taking  the  course  of  the  nerve  through  the  infraorbital  canal,  the  vessel 
appears  in  the  face  beneath  the  elevator  muscle  of  the  upper  lip;  and  it 
ends  in  branches,  which  are  distributed,  like  those  of  the  nerve,  to  the 
parts  between  the  eye  and  mouth.  In  the  face  its  branches  anastomose 
with  the  facial  and  buccal  arteries.  In  the  canal  in  the  maxilla  the  artery 
furnishes  branches  to  the  orbit. 

Another  branch,  anterior  dental^  runs  with  the  nerve  of  the  same  name, 
anf  supplies  the  incisor  and  canine  teeth :  this  gives  offsets  to  the  antrum 
of  the  maxilla,  and  near  the  teeth  it  anastomoses  with  the  posterior  dental 
artery. 

The  vein^  accompanying  the  artery,  communicates  in  front  with  the 
facial  vein;  and  terminates  behind  in  a  plexus  of  veins  (alveolar)  corre- 
sponding with  the  offsets  of  the  internal  maxilla  artery  in  the  spheno- 
maxillary fossa. 


Section  IX. 

DEEP  VESSELS  AND  NERVES  OF  THE  NECK. 


In  this  Section  are  included  the  deepest  styloid  muscle,  the  internal 
carotid  and  ascending  pharyngeal  arteries,  and  some  cranial  and  sympa- 
thetic nerves. 

Position.  The  position  of  the  part  is  to  remain  as  before,  viz.,  the 
neck  is  to  be  fixed  over  a  small  block. 


106  DISSECTION    OF    THE    NECK. 

Dissection.  To  see  the  stylo-pharyngeus  muscle,  the  posterior  belly  of 
the  digastric,  and  the  stylo-hyoid  muscle,  should  be  detached  from  their 
origin  and  thrown  down.  The  trunk  of  the  external  carotid  artery  is  to 
be  removed  by  cutting  it  through  where  the  hypoglossal  nerve  crosses  it, 
and  by  dividing  those  branches  of  it  that  have  been  already  examined; 
the  veins  accompanying  the  arteries  are  to  be  taken  aw^ay.  In  cleaning 
the  surface  of  the  stylo-pharyngeus  muscle,  the  glosso-pharyngeal  nerve 
and  its  branches,  and  the  stylo-hyoid  ligament  may  be  prepared.  The 
side  of  the  jaw  is  to  be  drawn  forwards  on  the  face. 

The  STYLO-PHARYXGEus  MUSCLE  (levator  pharyngis  externus)  resem- 
bles the  other  styloid  muscles  in  its  elongated  form.  The  fibres  arise 
from  the  root  of  the  styloid  process  on  the  inner  surface,  and  descend  be- 
tween the  superior  and  middle  constrictors  to  be  inserted  partly  into  the 
pharynx,  and  partly  into  the  upper  border  (hinder  border,  MerkeP)  of  the 
thyroid  cartilage. 

Tlie  muscle  lies  below  the  stylo-glossus,  and  between  the  carotid  arte- 
ries ;  and  the  glosso-pharyngeal  nerve  turns  over  the  low^er  part  of  its  flesliy 
belly. 

Action.  It  elevates  and  draws  outwards  the  part  of  the  pharynx  above 
the  hyoid  bone,  making  the  tube  ready  for  the  reception  of  the  morsel  to 
be  swallowed.  From  its  attachment  to  the  thyroid  cartilage  it  will  raise 
the  larynx ;  and  by  its  position  it  will  control  the  movement  forwards  of 
the  air  tube. 

The  stylo-hyoid  ligament  is  a  fibrous  band,  which  extends  from  the  tip 
of  the  styloid  process  to  the  small  cornu  of  the  os  hyoides.  Its  position  is 
between  the  stylo-glossus  and  stylo-pharyngeus  muscles,  and  over  the  in- 
ternal carotid  artery ;  whilst  the  lower  end  is  placed  beneath  the  hyo- 
glossus  muscle.  To  the  posterior  border  the  middle  constrictor  muscle  is 
attached  below\  It  is  frequently  cartihiginous  or  osseous  in  part  of,  or  in 
all  its  extent.     Occasionally  a  slij)  of  fleshy  fibres  is  continued  along  it. 

The  INTERNAL  CAROTID  ARTERY  Supplies  parts  within  the  head,  viz., 
the  brain,  the  eye  and  orbit,  and  the  nose  ;  and  takes  a  circuitous  course 
through  and  along  the  base  of  the  skull  before  it  terminates  in  the  brain. 

'I'he  arterial  trunk  in  the  cranium,  and  its  offset  to  the  orbit,  have  been 
already  examined ;  but  the  portion  in  the  neck  and  the  temporal  bone  re- 
mains to  be  dissected.  The  branches  of  the  carotid  to  the  brain  are 
examined  with  the  encephalon. 

Dissection.  For  the  display  of  the  cervical  part  of  the  artery  (fig.  2o) 
there  is  now  but  little  dissection  required.  By  detaching  the  styloid  pro- 
cess at  the  root,  and  throwing  it  with  its  muscles  to  the  middle  line,  the 
internal  carotid  artery  and  the  jugular  vein  may  be  followed  upwards  to 
the  skull.  Only  a  dense  fascia  conceals  them,  but  this  is  to  be  taken  away 
carefully,  so  that  the  branches  of  the  nerves  may  not  be  injured. 

In  the  fascia,  and  directed  inwards  over  the  artery,  seek  the  glosso- 
pharyngeal nerve  and  its  branches  near  the  skull,  and  the  small  pharyn- 
geal branch  of  the  vagus  lower  down  ;  still  lower,  the  superior  laryngeal 
branch  of  the  vagus,  with  its  external  laryngeal  offset  crossing  beneath  the 
carotid.  Between  the  vein  and  artery,  close  to  the  skull,  will  be  found 
the  vagus,  hypoglossal,  and  sympathetic  nerves;  and  crossing  backwards, 
over  or  under  the  vein,  the  spinal  accessory  nerve.     External  to  the  ves- 

'  Anatomie  und  Phisiologie  des  Meuschlichen  Stiinm  und  Sprach  Organs,  Leip- 
zig, 1807.     Von  Dr.  Merkel. 


STYLO-PHARYNGEUS    MUSCLE.  107 

sels  a  loop  of  the  first  and  second  cervical  nerves  over  the  transverse 
process  of  the  atlas  is  to  be  defined  ;  and  from  it  branches  of  communica- 
tion are  to  be  traced  to  the  large  ganglion  of  the  sympathetic  beneath  the 
artery,  and  to  the  vagus  and  hypoglossal  nerves.  Ascending  to  the 
cranium,  on  the  inner  side  of  the  carotid,  the  ascending  pharyngeal  artery 
will  be  met  with. 

To  open  the  carotid  canal  in  the  temporal  bone,  and  to  follow  the  con- 
tained artery  into  the  cranium,  make  a  cut  along  the  side  of  the  skull  in 
the  following  manner  :  the  saw  being  placed  beneath  the  mastoid  process, 
cut  forwards  to  the  foramen  spinosum  in  the  wing  of  the  sphenoid  bone 
(to  whicii  spot  the  side  of  the  skull  has  been  already  taken  away),  and  let 
the  instrument  be  directed  through  the  stylo-mastoid  foramen  and  the  root 
of  the  styloid  process,  but  rather  external  to  the  jugular  foramen  and  the 
carotid  canal.  AVhen  the  piece  of  bone  has  been  detached,  the  carotid 
canal  may  be  opened  with  the  bone  forceps. 

In  cleaning  the  artery  in  the  canal,  large  and  rather  red  branches  of  the 
superior  cervical  ganglion  of  the  sympathetic  will  be  found  on  it ;  and  in  a 
fresh  part  two  small  filaments  may  be  recognized  with  care — one  from 
Jacobson's  nerve,  joining  the  sympathetic  at  the  posterior  part  of  the 
canal ;  the  other  from  the  vidian  nerve,  at  the  front  of  the  canal. 

On  the  piece  of  bone  that  has  been  cut  off,  the  dissector  may  prepare 
very  readily  the  tympanum  with  its  membrane  and  chain  of  bones,  and 
the  chorda  tympani  nerve. 

The  internal  carotid  artery  (fig.  25,  d)  springs  from  the  bifurcation  of 
the  common  carotid  trunk.  It  extends  from  the  upper  border  of  the  thy- 
roid cartilage  to  the  base  of  the  skull ;  then  through  the  petrous  portion  of 
the  temporal  bone ;  and  lastly  along  the  base  of  the  skull  to  the  anterior 
clinoid  process,  where  it  ends  in  branches  for  the  brain.  This  \vinding 
course  of  the  artery  may  be  divided  into  three  parts  :  one  in  the  neck,  an- 
other in  the  temporal  bone,  and  a  third  in  the  cranium. 

Cervical  part.  In  the  neck  the  artery  ascends  almost  vertically  from 
its  origin  to  the  carotid  canal,  and  is  in  contact  with  the  pharynx  on  the 
inner  side.  The  line  of  the  common  carotid  artery  would  mark  its  posi- 
tion in  the  neck.  Its  depth  from  tlie  surface  varies  like  that  of  the  ex- 
ternal carotid ;  and  the  digastric  muscle  may  be  taken  as  the  index  of  this 
difference.  Thus,  below  that  muscle,  the  internal  carotid  is  overlapped 
by  the  sterno-mastoid  and  covered  by  the  common  teguments,  fascia,  and 
the  platysma,  and  is  on  the  same  level  as  the  external  carotid,  though 
farther  back.  But,  above  that  muscle,  the  vessel  is  placed  deeply  beneath 
the  external  carotid  artery  and  the  parotid  gland,  and  is  crossed  by  the 
styloid  process  and  the  stylo-pharyngeus  muscle.  Whilst  in  the  neck  tlie 
internal  carotid  lies  on  the  rectus  capitis  anticus  major  muscle,  which 
separates  it  from  the  vertebrae. 

Vein.  The  internal  jugular  vein  accompanies  the  artery,  being  con- 
tained in  a  sheath  witli  it,  and  placed  on  the  outer  side. 

Small  vessels.  Below  the  digastric  muscle  the  occipital  artery  is 
directed  back  over  the  carotid  ;  and  the  offset  from  it  to  the  sterno-mastoi- 
deus  may  run  down  on  the  carotid  trunk.  Above  the  digastric  the  poste- 
rior auricular  vessels  cross  the  carotid. 

Nerves.  The  pneumogastric  is  contained  in  the  sheath  between  the 
artery  and  vein,  being  parallel  to  them  ;  and  tlie  sympathetic,  also  run- 
ning longitudinally,  lies  behind  the  sheath  of  the  vessels.  Crossing  the 
artery  superficially,  from  below  up,  is  the  hypoglossal,  whicli  sends  the 


108 


DISSECTION    OF    THE    NECK. 


descendens  noni  along  it ;  next  the  small  pharyngeal  branch  of  the  vagus ; 
and  lastly  the  glosso-pharyngeal.  Dii-ected  inwards  beneath  tlie  carotid 
is  the  superior  laryngeal  nerve,  furnishing  the  external  laryngeal  branch  ; 
together  with  pharyngeal  offsets  of  the  upper  ganglion  of  the  sympathetic. 

Fig.  25. 


Deep  Vesskls  and  Nerves  op  the  Neck  (Illustrations  of  Dissections). 


Arteries:   a.  Subclaviau  trunk. 

b.  Common  carotid. 

c.  External  carotid,  cut. 

d.  Internal  carotid. 

/'.  Inferior  palatine  branch  of  the  facial. 
y.  Ascending  pharyngeal. 
Nerves:   1.  Glosso-pharyngeal. 

2.  Spinal  accessory. 

3.  Pneumo-gastric  or  vagus. 


4.  Hypoglossil. 

5.  Pharyngeal  branch  of  the  vagus. 

6.  Upper  laryngeal  branch  of  the  vagus. 

7.  External  laryngeal  branch  of  tlie  last. 

8.  Thyro-hyoid  branch  of  the  liyi)oglossal. 

9.  Descendens  noni  of  hypoglossal,  cut. 

10.  Phrenic  nerve  of  cervical  plexus. 

11.  Brachial  plexus.     Recurrent   of  the    vagus, 

winds  round  the  subclavian  artery,  a. 


Close  to  the  skull  the  cranial  nerves  of  the  neck  are  interposed  between 
the  artery  and  the  vein.  Around  the  carotid  entwine  branches  of  the 
sympathetic,  and  offsets  of  the  glosso-[)iiaryngeal  nerve. 

The  cervical  part  of  the  artery  remains  much  the  same  in  size  to  the 


ASCENDING    PHARYNGEAL    VESSELS.  109 

end,  though  it  is  sometimes  very  tortuous;  and  it  usually  does  not  furnish 
any  branch. 

Part  in  the  temporal  bone.  In  tlie  carotid  canal  the  winding  course  of 
the  vessel  commences.  The  artery  first  ascends  in  front  of  the  inner  ear 
(cochlea  and  tympanum)  ;  next  it  is  directed  forwards  almost  horizontally; 
and  lastly  it  turns  upwards  into  the  cranium  opposite  the  foramen  lacerum 
(basis  cranii).  Branches  of  the  sympathetic  nerve  surround  the  carotid 
in  the  bone. 

Whilst  in  the  canal  the  artery  supplies  a  small  branch  to  the  cavity  of 
the  typanum. 

The  cranial  part  of  the  artery  is  described  with  the  base  of  the  skull 
(p.  33). 

The  INTERNAL  JUGULAR  VEIN  is  continuous  with  the  lateral  sinus  of 
the  skull,  and  extends  from  the  foramen  jugulare  nearly  to  the  first  rib. 
At  the  lower  part  of  the  neck  it  joins  the  subclavian  to  form  the  innomi- 
nate vein  (p.  79). 

As  far  as  the  thyroid  cartilage  the  vein  accompanies  the  internal  carotid, 
but  below  that  point  it  is  the  companion  to  the  common  carotid  artery ; 
and  it  lies  on  the  outer  side  of  each.  Its  contiguity  to  the  artery  is  not 
equally  close  throughout,  for  near  the  skull  there  is  a  small  interval  be- 
tween them,  containing  the  cranial  nerves;  and  at  the  lower  part  of  the 
neck  there  is  a  still  larger  intervening  space,  in  which  the  pneumogastric 
nerve  with  its  cardiac  branch  is  found. 

The  size  of  the  upper  part  of  the  vein  remains  much  the  same  till  near 
the  OS  hyoides,  where  it  is  suddenly  increased  by  the  addition  of  those 
branches  of  the  head  and  neck,  corresponding  with  branches  of  the  exter- 
nal carotid  artery,  wliich  do  not  join  the  external  jugular  vein.^  Its  lower 
dilatation  and  its  valves  have  been  referred  to  (p.  82). 

The  following  branches  open  into  the  internal  jugular,  viz.,  the  facial, 
lingual,  thyroid  (superior),  occipital,  and  pharyngeal;  and  at  the  lower 
part  of  the  neck  it  receives  the  middle  thyroid  vein. 

The  ascending  pharyngeal  artery  (fig.  2i)^  g)  is  a  long  slender  branch  of 
the  external  carotid,  which  arises  near  the  commencement  of  that  vessel. 
Directed  upwards  on  the  spinal  column  between  the  internal  carotid  and 
the  pharynx,  the  artery  becomes  tortuous  near  the  skull,  and  enters  the 
pharynx  above  the  upper  constrictor  to  end  in  the  soft  palate.  In  the 
neck  the  artery  gives  some  small  offsets  to  the  surrounding  parts,  viz.,  the 
muscles  on  the  vertebree,  the  nerves,  and  the  lymphatic  glands. 

A  meningeal  branch  enters  the  cranium  through  the  foramen  lacerum 
(basis  cranii),  and  is  distributed  in  the  dura  mater  of  the  middle  fossa  of 
the  skull ;  this  is  seldom  seen  in  the  cranium,  because  it  is  but  rarely 
injected. 

The  palatine  branchy  which  is  larger  than  the  preceding,  divides  in 
the  pharynx  into  two  main  pieces,  which  are  directed  across  the  fore 
part  of  the  palate  beneath  the  mucous  membrane,  and  form  arches  with 
like  branches  of  the  opposite  side  ;  one  of  these  is  near  the  upper,  and 
the  other  near  the  lower  edge  of  the  soft  palate. ■'  The  size  of  the  pala- 
tine artery  depends  upon  that  of  the  inferior  palatine  branch  of  the  facial 
artery. 

'  Sometimes  the  term  internal  cephalic  is  applied  to  the  vein  between  the  skull 
and  the  hyoid  bone  ;  and  the  name  internal  jugular,  to  the  part  below  that  bone 
and  the  junction  of  its  large  branches. 

2  The  Anatomy  of  the  Arteries.     By  R.  Quain,  F.R.S.,  p.  110. 


110  DISSECTION    OF    THE    NECK. 

Pharyngeal  branches.  Other  small  arteries  ramify  in  the  upper  con- 
strictor, the  Eustachian  tube,  the  back  of  the  soft  palate,  and  the  tonsil. 

The  vein  accompanying  the  pharyngeal  artery  receives  branches  from  the 
cranium,  the  palate,  and  the  pharynx,  and  ends  in  the  internal  jugular  vein. 

Dissection  of  the  cranial  nerves  in  the  neck.  By  the  time  tliis  stage  of 
the  dissection  has  been  arrived  at,  the  condition  of  the  parts  will  not  per- 
mit the  tracing  of  th.e  very  minute  filaments  of  the  cranial  nerves  in  the 
loramen  jugulare  of  the  skull ;  and  all  the  paragraplis  marked  with  an 
asterisk  are  therefore  to  be  omitted  for  the  present.  Afterwards,  if  a  fresh 
piece  of  the  skull  can  be  obtained,  in  which  the  bone  has  been  softened  by 
acid,  and  the  nerves  hardened  in  spirit,  the  examination  of  the  branches 
now  passed  over  may  be  made. 

*  In  the  foramen  lacerum  (fig.  26).  Supposing  the  dissection  of  the 
internal  carotid  to  be  carried  out  as  is  described  at  page  107,  let  tlie  stu- 
dent cut  across  with  care  the  jugular  vein  near  the  skull.  Let  him  then 
remove  bit  by  bit  with  the  bone  forceps,  or  with  a  scalpel  if  the  part  has 
been  softened,  the  ring  of  bone  which  bounds  externally  the  jugular  fora- 
men, proceeding  as  far  forwards  as  the  osseous  crest  between  that  foramen 
and  the  carotid  canal.  Between  the  bone  and  the  coat  of  the  jugular  vein, 
the  small  auricjilar  branch  of  the  pneumogastric  nerve  is  to  be  found;  it  is 
directed  backwards  to  an  aperture  near  the  styloid  process. 

*  Trace,  then,  the  spinal  accessory  and  pneumogastric  nerves  through 
the  aperture,  by  opening  the  fibrous  slieath  around  them.  Two  parts, 
large  and  small,  of  the  spinal  accessory  nerve  should  be  defined  ;  the 
latter  is  to  be  shown  joining  a  ganglion  on  the  vagus,  and  applying  itself 
to  the  trunk  of  that  nerve.  A  communication  between  the  two  parts  of 
the  spinal  accessory  is  to  be  found.  On  the  pneumogastric  is  a  small  well- 
marked  ganglion,  from  which  the  auricular  branch  before  referred  to  takes 
origin  ;  and  from  the  ganglion  filaments  are  to  be  sought  passing  to  the 
smaller  portion  of  the  spinal  accessory  nerve,  and  to  the  ascenaing  branch 
of  the  upper  cervical  ganglion  of  the  sympathetic. 

*  Next  follow  the  glosso-pharyngeal  nerve  through  the  fore  part  of  the 
foramen,  and  take  away  any  bone  that  overhangs  it.  This  nerve  presents 
two  ganglia  as  it  passes  from  the  skull  (fig.  26):  one  (jugular),  which  is 
scarcely  to  be  perceived,  near  the  upper  part  of  the  tube  of  membrane 
containing  it;  the  other,  much  larger  (petrous),  is  situate  at  the  lower 
border  of  the  petrous  portion  of  the  temporal  bone.  From  the  lower  one, 
seek  the  small  nerve  of  Jacobson,  which  enters  an  aperture  in  the  crest  of 
bone  between  the  jugular  foramen  and  the  carotid  canal ;  and  another 
filament  of  communication  with  the  ganglion  of  the  sympathetic.  Some- 
times the  dissector  will  be  able  to  find  a  filament  from  the  lower  ganglion 
to  join  the  auricular  branch  of  the  pneumogastric  ;  and  anotlier  to  end  in 
the  upper  ganglion  of  the  jjueumogastric  nerve. 

Below  the  foramen  of  exit  from  the  skull  the  cranial  nerves  have  been 
greatly  denuded  by  the  dissection  of  the  internal  carotid  (fig.  25) ;  but 
the  intercommunications  of  the  vagus,  hypoglossal,  sympathetic,  and  first 
two  spinal  nerves  near  the  skull,  are  to  be  traced  out  more  completely. 

The  larger  part  of  the  spjnal  accessory  has  been  sufficiently  laid  bare 
already ;  but  its  small  piece  is  to  be  traced  to  the  vagus,  close  to  the  skull, 
and  onwards  by  the  side  of  that  trunk. 

The  chief  part  of  the  glosso-pharyngeal  has  been  also  dissected  ;  but  the 
offsets  on  the  carotid,  and  others  to  join  the  pharyngeal  branch  of  the 
vagus  and  the  pharyngeal  plexus  are  to  be  disphiyed. 


GLOSSO-PHARYNGEAL    NERVE.  Ill 

On  the  pneiimogastric  trunk  the  student  should  define  an  enlargement 
close  to  the  skull  (ganglion  of  the  trunk)  to  which  the  hypoglossal  nerve 
is  intimately  united.  From  the  ganglion  proceed  two  branches  (pharyn- 
geal and  laryngeal),  which  are  to  be  traced  to  the  parts  indicated  by  their 
names,  especially  the  first  which  enters  the  pharyngeal  plexus.  The  task 
of  disentangling  the  ramifications  of  the  branch  of  the  vagus,  and  those  of 
the  glosso-pharyngeal  and  sympathetic  in  the  plexus,  is  by  no  means  easy, 
in  consequence  of  the  dense  tissue  in  which  they  are  contained.  Two  or 
more  cardiac  offsets  of  the  vagus,  one  at  the  upper  and  another  at  the  lower 
part  of  the  neck,  may  be  recognized  readily.  Lastly  the  dissector  may 
prepare  more  fully  the  recurrent  branch  coursing  up  beneatli  the  lower 
part  of  the  common  carotid  :  by  removing  the  fat  around  it,  offsets  will  be 
seen  entering  the  chest  and  the  windpipe. 

Only  the  first,  or  the  deep  part  of  the  hypoglossal  nerve  remains  to  be 
made  ready  for  learning  ;  its  communications  with  the  vagus,  sympathetic, 
and  the  spinal  nerves  are  to  be  demonstrated. 

A  dissection  for  the  sympathetic  will  be  given  further  on  (p.  110);  but 
its  large  ganglion  near  the  skull  (upper  cervical)  should  be  defined,  and 
the  small  branches  from  it  to  the  pharyngeal  plexus  should  be  pursued 
beneath  the  carotid  artery. 

The  three  cranial  nerves^  glosso-pharyngeal,  pneumogastric,  and  spinal 
accessory,  which  constitute  the  eighth  nerve  of  Willis,  leave  the  cranium 
by  the  foramen  jugulare  (p.  32).  Outside  the  skull  the  nerves  take  dif- 
ferent directions  according  to  their  destination  ;  thus  the  glosso-pharyngeal 
is  inclined  inwards  to  the  tongue  and  pharynx  ;  the  spinal  accessory  back- 
wards to  the  sterno-mastoid  and  trapezius  muscles  ;  and  the  pneumogastric 
nerve  descends  to  the  viscera  of  the  thorax  and  abdomen. 

The  GLOSSO-PHARYNGEAL  NERVE  (fig.  26,  ')  is  the  Smallest  of  the  three 
trunks.  In  the  jugular  foramen  it  is  placed  somewhat  in  front  of  the  other 
two,  and  lies  in  a  groove  in  the  lower  border  of  the  petrous  part  of  the  tem- 
poral bone.  In  the  aperture  of  exit  the  nerve  is  marked  by  two  ganglionic 
swellings,  the  upper  one  being  the  jugular,  and  the  lower  the  petrous  ganglion. 

*  Ganglia.  Tha  jugular  ganglion,  *,  (ganglion  superius)  is  very  small, 
and  is  situate  at  the  upper  part  of  the  osseous  groove  containing  the  nerve. 
It  is  placed  on  the  outer  surface  of  the  glosso-pharyngeal  trunk,  and  in- 
cludes only  some  fibrils  of  the  nerve.  The  petrosal  ganglion,  ^,  (gang, 
inferius)  is  much  larger  than  the  preceding,  and  incloses  all  the  fibrils  of 
the  nerve.  Ovalish  in  form,  it  is  placed  in  a  hollow  in  the  lower  border 
of  the  temporal  bone  ;  and  from  it  spring  the  branches  that  unite  the  glosso- 
pharyngeal with  other  nerves-. 

After  the  nerve  has  quitted  the  foramen  it  comes  forwards  between  the 
jugular  vein  and  the  carotid  artery  (fig.  25,  ^),  and  crossing  inwards  over 
the  artery,  reaches  the  lower  border  of  the  stylo-pharyngeus  muscle.  At 
this  spot  the  nerve  becomes  almost  transverse  in  direction  in  its  course  to 
the  pharynx;  it  crosses  over  the  stylo-pharyngeus,  and  forms  an  arch 
across  the  side  of  the  neck  above  the  superior  laryngeal  nerve.  Finally 
it  passes  beneath  the  hyo-glossus  muscle,  and  ends  in  branches  to  the 
pharynx,  the  tonsil,  and  the  tongue. 

The  branches  of  the  glosso-pharyngeal  may  be  classed  into  those  con- 
necting it  with  other  nerves  at  the  base  of  the  skull,  and  those  distributed 
in  the  neck. 

*  Connecting  branches  arise  chiefly  from  the  petrosal  ganglion ;  and  in 
this  set  is  the  tympanic  nerve. 


112 


DISSECTION    OF    THE    NECK. 


*  K  filament  ascends  from  the  sympathetic  nerve  in  the  neck  to  join  the 
petrosal  ganglion.  Sometimes  there  is  an  offset  from  the  ganglion  to  the 
auricular  branch  of  the  vagus,  as  well  as  to  the  upper  ganglion  of  this 
nerve. 

*  The  tympanic  branch  (fig.  26,  *)  (nerve  of  Jaoobson)  enters  the 
aperture  in  the  ridge  of  bone  between  the  jugular  and  the  carotid  foramen, 
and  ascends  by  a  special  canal  to  the  inner  wall  of  the  tympanum,  where 
it  ends  in  branches :  its  distribution  is  given  with  the  tympanum  of  the 
ear. 

a.  Banches  for  Distribution.  In  the  neck  the  branches  are  furnished 
chiefly  to  the  pharynx  and  the  tongue. 

b.  Carotid  branches  surround  the  internal  artery  of  that  name,  and 
communicate  with  the  pharyngeal  branch  of  the  vagus,  and  the  sympa- 
thetic nerve. 

c.  Some  muscular  branches  enter  the  stylo-pharyngeus,  whilst  the  nerve 
is  in  contact  with  it. 

d.  Branches  to  the  pharynx  form  the  pharyngeal  plexus  by  uniting  with 
nerves  from  the  sympathetic  and  vagus. 

e.  The  tonsillitic  branches  supply  the  tonsil  and  the  arches  of  the  soft 
palate.     On  the  former  they  end  in  a  kind  of  plexus — circulus  tonsillaris. 

/.  Lingual  branches.  The  terminal  branches  of  the  nerve  supply  the 
root  and  posterior  part  of  the  tongue,  as  well  as  the  lateral  surface.  The 
distribution  of  these  is  described  with  the  tongue  (Section  15). 

Tiie  PNEUMOGASTRic  NERVE  (fig.  2G,  ^)  (vagus  nerve)  is  the  largest  of 
the  cranial  nerves  in  the  neck,  and  escapes  through  the  jugular  foramen 


Fig.  26. 


Glosso-pharyngeul  trunk. 

Vagus. 

Spinal  accessory. 

Jugular  ganglion. 

Petrosal  ganglion. 

Jacobson's  nerve. 

Auricular  branch. 

Kooc  ganglion  of  vagus. 

Trunk  ganglion  of  vagus. 

Branch  joining  the  petrosal  and  upper 

ganglion  of  the  vagus. 
Small  part  of  spinal  accessory. 
Chief  part  of  spinal  accessory. 
Pharyngeal  branch  of  vagus. 
Superior  laryngeal  branch  of  vagus. 


Diagram  of  the  Eighth  Nerve 


in  the  same  sheath  of  dura  mater  as  tlie  spinal  accessory.  In  tlie  aperture 
of  exit  it  has  a  distinct  ganglion  (gang,  of  the  root),  to  which  the  smaller 
part  of  the  spinal  accessory  nerve  is  connected. 


PNEUMOGASTRIC    NERVE.  113 

When  the  nerve  has  left  the  foramen,  it  receives  the  small  part  of  the 
spinal  accessory,  and  swells  into  a  ganglion  nearly  an  inch  long  (gang,  of 
the  trunk).  Here  the  nerve  lies  between  the  internal  carotid  artery  and 
jugular  vein,  and  communicates  with  several  nerves.  To  reach  the  thorax, 
the  vagus  descends  almost  vertically  (fig.  25, ')  between  the  internal  jugu- 
lar vein  and  the  internal  and  common  carotid  arteries;  and  enters  that 
cavity,  on  the  right  side,  by  crossing  over  the  subclavian  artery,  but 
beneath  the  innominate  vein. 

*  Ganglia.  The  ganglion  of  the  root  (gang,  superius),  (fig.  26,  ^)  is  of 
a  grayish  color,  and  in  texture  is  like  the  ganglion  on  the  large  root  of  the 
fifth  nerve.  Small  branches  in  the  foramen  jugulare  come  from  this  gan- 
glion. The  ganglion  of  the  trunk  (gang,  inferius),  (^)  is  cylindrical  in 
form,  is  reddish  in  color,  and  is  nearly  an  inch  in  length;  it  communicates 
with  the  hypoglossal,  spinal,  and  sympathetic  nerves.  All  the  intrinsic 
fibres  of  the  trunk  of  the  nerve  are  surrounded  by  the  ganglionic  substance, 
but  those  derived  from  the  spinal  accessory  nerve  (")  pass  over  the  gan- 
glion without  being  inclosed  in  it. 

The  branches  of  the  pneumogastric  nerve  may  be  arranged  into  those 
uniting  it  with  other  nerves,  and  those  distributed  to  parts  around. 

*  Connecting  branches  (fig.  26)  arise  from  the  ganglion  of  the  root  and 
the  ganglion  of  the  trunk  of  the  vagus. 

*  From  the  ganglion  of  the  root.  The  auricular  branch  (J)  is  the  chief 
offset,  and  crosses  the  jugular  fossa  to  enter  an  aperture  near  the  root  of 
the  styloid  process  ;  it  traverses  the  substance  of  the  temporal  bone,  and 
reaches  the  outer  ear,  on  which  it  is  distributed.  Its  farther  course  will 
be  described  with  the  anatomy  of  the  ear. 

*  One  or  two  short  filaments  unite  this  ganglion  with  the  spinal  acces- 
sory nerve ;  and  a  branch  of  the  sympathetic  nerve  in  the  neck  enters  it. 
Occasionally  there  is  an  offset  (^")  to  join  the  lower  (petrosal)  ganglion  of 
the  glosso-pharyngeal  nerve. 

From  the  ganglion  of  the  trunk.  Communicating  filaments  connect  it 
with  the  hypoglossal  nerve.  Other  branches  pass  between  it  and  the 
upper  ganglion  of  the  sympathetic,  and  between  it  and  the  loop  of  the  first 
two  cervical  nerves. 

Branches  for  Distribution  (fig.  25).  The  cervical  branches  arise  from 
the  inner  side  of  the  nerve,  and  are  directed  inwards,  to  supply  the 
pharynx,  the  larynx,  and  the  heart. 

a.  Tlie  pharyngeal  branch  (fig.  26,  ^')  is  an  offset  from  the  upper  part 
of  the  ganglion  of  the  trunk,  and  terminates  in  the  pharynx.  The  nerve 
is  directed  inwards  over  the  internal  carotid  artery  (fig.  25,  *),  and  joins 
the  branches  of  the  glosso-pharyngeal  nerve  on  that  vessel.  Finally  it 
courses  to  the  side  of  the  middle  constrictor  muscle,  and  communicates 
with  branches  of  the  glosso-pharyngeal,  superior  laryngeal,  and  sympa- 
thetic nerves,  to  form  the  pharyngeal  plexus.  From  the  plexus  branches 
are  furnished  to  the  constrictors  and  palato-glossus  and  pharyngeus,  and 
to  the  pharyngeal  mucous  membrane  between  the  tongue  and  the  hyoid 
bone. 

b.  The  superior  laryngeal  nerve  (fig.  26,^*)  is  much  larger  than  the 
preceding  branch,  and  comes  from  the  middle  of  the  ganglion  of  the  trunk. 
From  this  point  it  inclines  obliquely  inwards  beneath  tlie  internal  carotid 
artery  (fig.  25,  ^),  and  reaches  the  larynx  opposite  the  interval  between 
the  hyoid  bone  and  the  thyroid  cartilage.  Tlie  nerve  then  perforates  the 
thyro-hyoid   membrane,  and  is  distributed  to  the  mucous  lining  of  the 

8 


114  DISSECTION    OF    THE    NECK. 

larynx.  (See  *'  Larynx.")  In  the  neck  it  furnishes  branches  to  the 
thyroid  body,  and  the  following  off'set  to  one  laryngeal  muscle  and  the 
pharynx : — 

The  external  laryngeal  branch  (fig.  25,  ')  arises  beneath  the  internal 
carotid  artery,  and  runs  below  the  superior  laryngeal  nerve  to  the  side  of 
the  larynx.  Here  it  gives  offsets  to  the  pharyngeal  plexus,  and  it  is  con- 
tinued beneath  the  sterno-thyroideus  to  the  crico-thyroid  muscle  and  the 
inferior  constrictor.  Near  its  origin  this  branch  communicates  with  the 
superficial  cardiac  branch  of  the  sympathetic  nerve. 

c.  Cardiac  branches.  Some  small  cardiac  nerves  spring  from  the 
pneumo-gastric  at  the  upper  part  of  the  neck,  and  join  cardiac  branches 
of  the  sympathetic.  At  the  lower  part  of  the  neck,  on  each  side,  there  is 
a  single  cardiac  nerve  :  the  right  one  enters  the  chest  and  joins  the  deep 
nerves  to  the  heart  from  the  sympathetic  ;  and  the  left  nerve  terminates 
in  the  superficial  cardiac  plexus  of  the  thorax. 

d.  The  inferior  laryngeal  or  recurrent  nerve  (fig.  25)  leaves  the  pneumo- 
gastric  trunk  on  the  right  side  opposite  the  subclavian  artery,  and  winding 
round  that  vessel,  takes  an  upward  course  in  the  neck  to  the  larynx, 
ascending  beneath  the  common  carotid  and  inferior  thyroid  arteries,  and 
between  the  trachea  and  the  oesophagus.  At  the  larynx  it  enters  beneath 
the  ala  of  the  thyroid  cartilage,  where  it  will  be  afterwards  traced.  The 
following  branches  arise  from  it ; — 

Some  cardiac  branches  leave  the  nerve  as  it  turns  round  the  subclavian 
artery  ;  these  enter  the  thorax,  and  join  the  cardiac  nerves  of  the  sym- 
pathetic. 

Muscular  branches  spring  from  it  whilst  it  lies  between  the  trachea  and 
the  esophagus,  and  are  distributed  to  both  those  tubes.  Near  the  larynx 
some  filaments  are  furnished  to  the  inferior  constrictor  muscle. 

On  the  left  side  the  recurrent  nerve  arises  in  the  thorax,  opposite  the 
arch  of  the  aorta,  but  lies  between  the  trachea  and  oesophagus  in  the 
neck,  as  on  the  right  side. 

The  SPINAL  ACCESSORY  NERVE  (fig.  26,  ^^)  courscs  through  the  foramen 
jugulare  with  the  pneumo-gastric,  but  is  not  marked  by  any  ganglion. 
The  nerve  is  constructed  of  two  parts,  viz.,  accessory  to  the  vagus,  and 
spinal,  which  have  a  different  origin  and  distribution.  (Origin  of  the 
cranial  nerves.) 

The  part  accessory  to  the  vagus  (")  is  the  smaller  of  the  two,  and  finally 
blends  with  the  pneumo-gastric  beyond  the  skull.  In  the  foramen  of  exit 
it  lies  close  to  the  vagus,  and  joins  the  upper  ganglion  of  tliat  nerve  by 
one  or  two  filaments.  Below  the  foramen  it  is  continued  over  the  lower 
ganglion  of  the  nerve,  and  blends  with  the  trunk  beyond  the  ganglion. 
It  gives  offsets  to  join  the  pharyngeal  and  upper  laryngeal  branches  of  tlie 
pneumo-gastric,  and  according  to  Bendz,  to  many  other  branches  of  that 
nerve. 

The  spinal  part  (fig.  2G,  ^^)  is  much  larger,  is  round  and  cord-like,  and 
is  connected  with  tlie  smaller  piece  whilst  it  is  passing  through  the  fora- 
men jugulare.  Beyond  the  foramen  the  nerve  (fig.  25,  ^)  takes  a  back- 
ward course  through  the  sterno-mastoid  muscle,  and  across  the  side  of  tlie 
neck  to  end  in  the  trapezius  muscle :  at  first  it  is  concealed  by  the  jugular 
vein,  but  it  then  passes  either  over  or  under  that  vessel.  The  connections 
of  the  nerve  beyond  the  sterno-mastoideus  have  been  already  examined 
(p.  66). 


SUB-OCCIPITAL    NERVE.  115 

The  nerve  furnishes  muscular  offsets  to  the  sterno-mastoideus  and  the 
trapezius. 

The  HYPOGLOSSAL  NERVE  (ninth  of  Willis),  issuing  from  the  cranium 
by  the  anterior  condyloid  foramen,  lies  deeply  between  the  internal  carotid 
artery  and  the  jugular  vein  (fig.  25,  *).  It  next  comes  forwards  between 
the  vein  and  artery,  turning  round  the  outer  side  of  the  vagus  to  which  it 
is  united.  The  nerve  now  descends  in  the  neck,  and  becomes  superficial 
below"  the  digastric  muscle  in  the  anterior  triangular  space ;  from  this  spot 
it  is  directed  inwards  to  the  tongue  and  its  muscles. 

*  Connecting  branches.  Near  the  skull  the  hypo-glossal  is  united  by 
branches  with  the  vagus  nerve,  the  two  being  almost  inseparably  joined. 

*  Rather  lower  down  the  nerve  is  connected  by  offsets  with  the  sympa- 
thetic, and  with  the  loop  of  the  first  two  spinal  nerves. 

The  branches  for  distribution  have  been  met  with  in  the  foregoing  dis- 
sections. Thus  in  the  neck  it  supplies,  in  union  with  the  spinal  nerves, 
the  depressors  of  the  hyoid  bone.  In  the  submaxillary  region  it  furnishes 
branches  to  one  elevator  (genio-hyoid)  of  the  os  hyoides ;  to  the  extrinsic 
muscles  of  the  tongue  except  the  palato  and  pharyngeo-glossus ;  and  to  all 
the  intrinsic  of  the  tongue. 

Dissection.  The  small  rectus  capitis  lateralis  muscle,  between  the 
transversa  process  of  the  atlas  and  the  base  of  the  skull,  is  now  to  be  cleaned 
and  learnt.  At  its  inner  border  the  anterior  branch  of  the  first  cervical 
nerve,  which  forms  part  of  a  loop  on  the  atlas,  is  to  be  found. 

The  RECTUS  CAPITIS  LATERALIS  (fig.  25)  is  Small  and  thin,  and  repre- 
sents an  intertransverse  muscle.  It  arises  from  the  anterior  transverse 
process,  and  the  tip  of  the  united  transverse  processes  of  the  atlas ;  and  is 
inserted  into  the  jugular  eminence  of  the  occipital  bone. 

On  the  anterior  surface  rests  the  jugular  vein  ;  and  in  contact  with  the 
posterior  is  the  vertebral  artery.  To  the  inner  side  lies  the  anterior  pri- 
mary branch  of  the  first  cervical  nerve. 

Action.  It  assists  the  muscles  attached  to  the  mastoid  process  in  in- 
clining the  head  laterally. 

Dissection.  For  the  purpose  of  tracing  backwards  the  anterior  branch 
of  the  first  cervical  nerve  divide  the  rectus  lateralis  muscle,  and  observe 
the  offset  to  it ;  then  cut  off  the  end  of  the  lateral  mass  of  the  atlas,  and 
remove  the  vertebral  artery,  so  as  to  bring  into  view  the  nerve  as  it  lies 
on  the  first  vertebra. 

The  anterior  primary  branch  of  the  first  or  sub-occipital  nerve  is  slen- 
der in  size,  and  arises  from  the  common  trunk  on  the  neural  arch  of  the 
atlas.  From  that  origin  it  is  directed  forwards  on  the  arch,  beneath  the 
vertebral  artery,  to  the  inner  side  of  the  rectus  lateralis :  here  it  bends 
down  in  front  of  the  lateral  mass  of  the  bone,  and  forms  a  loop  by  uniting 
with  the  second  cervical  nerve.  As  the  nerve  passes  forwards  it  supplies 
the  rectus  lateralis  muscle,  and  branches  connect  the  loop  with  the  vagus, 
hypoglossal,  and  sympathetic  nerves. 

Sympathetic  Nerve.  In  the  neck  the  sympathetic  nerve  consists, 
on  each  side,  of  a  gangliated  cord,  which  lies  close  to  the  vertebral  column, 
and  is  continued  into  the  thorax.  On  this  part  of  the  nerve  are  three 
ganglia : — One  near  the  skull,  another  on  the  neck  of  the  first  rib,  and  a 
third  somewhere  between  the  two  ;  these  are  named  respectively  superior, 
inferior,  and  middle  ganglion.  From  the  ganglia  proceed  connecting 
branches  with  the  spinal  and  most  of  the  cervical  cranial  nerves;  and 
branches  for  distribution  to  viscera  and  bloodvessels. 


116  DISSECTION    OF    THE    NECK. 

Besides  the  ganglia  above  mentioned,  there  are  other  ganglia  in  the 
head  and  neck  in  connection  with  tlie  three  trunks  of  the  fifth  nerve. 

Dissection.  To  display  the  brandies  of  the  sympathetic  nerve  requires 
greater  care  than  is  necessary  in  tracing  the  white  fibred  nerves,  for  they 
are  softer,  more  easily  torn,  and  generally  of  smaller  size.  In  the  neck 
the  ganglia  and  their  branches  have  been  partly  prepared,  and  only  the 
following  additional  dissection  will  be  required  to  bring  them  into  view  : — 
The  jugular  vein  having  been  cut  through,  the  upper  ganglion  will  be 
seen  by  raising  the  carotid  artery,  and  the  trunks  of  the  vagus  and  hypo- 
glossal nerves,  and  by  cutting  through  the  branches  that  unite  these  two 
to  the  loop  of  the  first  and  second  spinal  nerves.  The  several  branches  of 
the  ganglion  are  to  be  traced  upwards  on  the  carotid  artery,  inwards  to 
the  pharynx,  down  along  tlie  neck,  and  outwards  to  other  nerves. 

The  dissector  has  already  seen  the  middle  ganglion  on  or  near  the  infe- 
rior thyroid  artery,  and  its  branches  to  spinal  nerves,  and  along  the  neck, 
are  now  to  be  traced. 

To  obtain  a  view  of  the  inferior  ganglion  the  greater  part  of  the  first 
rib  is  to  be  taken  away,  and  the  subclavian  artery  is  to  be  cut  through, 
inside  the  scalenus,  and  drawn  aside,  without  however  destroying  the  fine 
nerves  that  pass  over  it.  The  clavicle  is  supposed  not  to  be  in  position. 
The  ganglion  is  placed  on  the  neck  of  the  first  rib  ;  its  branches  are  large, 
and  are  easily  followed  outwards  to  the  vertebral  artery  and  the  spinal 
nerves,  and  downwards  to  the  thorax. 

The  SUPERIOR  CERVICAL  GANGLION  is  the  largest  of  the  three,  and  is 
of  a  reddish -gray  color.  Of  a  fusiform  shape,  it  is  as  long  as  the  second 
and  third  cervical  vertebrae,  and  is  placed  on  the  rectus  capitis  anticus 
major  muscle,  beneath  the  internal  carotid  artery  and  the  contiguous  cra- 
nial nerves.  Branches  connect  tlie  ganglion  with  other  nerves  ;  and  some 
are  distributed  to  the  bloodvessels,  the  pharynx,  and  the  heart. 

*  Connecting  branches  unite  the  sympathetic  with  both  the  spinal  and 
the  cranial  nerves. 

*  With  the  sj)inal  nerves.  The  four  highest  spinal  nerves  have  branches 
of  communication  with  the  upper  ganglion  of  the  sympathetic ;  but  the 
offset  to  the  fourth  nerve  may  come  from  the  cord  connecting  the  upper 
to  the  next  ganglion. 

*  With  the  cranial  nerves.  Near  the  skull  the  trunks  of  the  vagus  (its 
lower  ganglion)  and  hypoglossal  nerves  are  joined  by  branches  of  the 
sympathetic.  In  the  foramen  jugulare  also,  both  the  petrosal  ganglion 
of  the  glosso-pharyngeal  and  the  ganglion  of  the  root  of  the  vagus  receive 
small  filaments,  one  to  each,  from  an  ascending  offset  of  the  ganglion. 

Communications  are  formed  witli  several  other  cranial  nerves  by  means 
of  an  offset  from  the  ganglion  into  the  carotid  canal  (p.  33). 

Branches  for  Distribution.  This  set  of  branches  is  more  numerous 
than  the  preceding,  and  the  nerves  are  larger  in  size. 

Branches  for  bloodvessels  (nervi  molles).  These  nerves  surround  the 
external  carotid  artery,  and  ramify  on  its  branches  so  as  to  form  plexuses 
on  the  arteries  witli  tlie  same  names  as  the  vessels :  some  small  ganglia 
are  occasionally  found  on  these  ramifying  nerves.  By  means  of  the  plexus 
on  the  facial  artery  the  submaxillary  ganglion  communicates  with  the  sym- 
pathetic ;  and  through  the  plexus  on  the  internal  maxillary  artery  the  otic 
ganglion  obtains  a  similar  communication. 

Another  offset  from  the  upper  part  of  the  ganglion  accompanies  the 
internal  carotid  artery  and  its  branches.     Near  the  skull  it  divides  into 


CERVICAL    GANGLIA    OF    SYMPATHETIC.  117 

two  pieces,  which  enter  the  canal  for  the  carotid,  one  on  each  side  of  that 
vessel :  and  are  continued  to  the  eyeball  and  tlie  pia  mater  of  the  brain, 
forming  secondary  plexuses  on  the  ophthalmic  and  cerebral  arteries.  In 
the  carotid  canal  communications  are  formed  with  the  tympanic  nerve  (p. 
Ill)  and  with  the  spheno-palatine  ganglion  (p.  141)  ;  with  the  former  near 
the  lower,  and  with  the  latter  near  the  upper  opening  of  the  canal.  The 
communications  and  plexuses  which  these  nerves  form  in  their  course  to 
the  base  of  the  brain  are  described  at  p.  33. 

The  pharyngeal  nerves  pass  inwards  to  the  side  of  the  pharynx,  where 
they  join  with  other  branches  of  the  cranial  nerves  in  the  pharyngeal 
plexus  (p.  113). 

Cardiac  nerves  enter  the  thorax  to  join  in  the  plexuses  of  the  heart. 
There  are  tliree  cardiac  nerves  on  each  side,  viz.,  superior,  middle,  and 
inferior,  each  taking  its  name  from  the  ganglion  of  which  it  is  an  offset. 

The  superior  cardiac  nerve  (superficial)  of  the  right  side  courses  behind 
the  sheath  of  the  carotid  vessels,  and  enters  the  thorax  beneath  the  sub- 
clavian artery.  In  the  neck  the  nerve  is  connected  with  the  cardiac 
branch  of  the  vagus,  with  the  external  laryngeal,  and  with  the  recurrent 
nerv^e.     In  some  bodies  it  ends  by  joining  one  of  the  other  cardiac  nerves. 

The  MIDDLE  CERVICAL  GANGLION  (gang,  tliyroidcum)  is  of  small  size, 
and  is  situate  opposite  the  fifth  cervical  vertebra,  usually  on  or  near  the 
inferior  thyroid  artery.  It  has  a  roundish  shape,  and  lies  beneath  the 
great  vessels.     Its  branches  are  the  following : — 

*  Connecting  branches  with  the  spinal  nerves  sink  between  the  borders 
of  the  longus  colli  and  anterior  scalenus,  to  join  the  fifth  and  sixth  cervi- 
cal nerves. 

Branches  for  Distribution.  These  consist  of  nerves  to  the  thyroid 
body,  together  with  the  middle  cardiac  nerve. 

The  thyroid  branches  ramify  around  the  inferior  thyroid  artery,  and 
end  in  the  thyroid  body ;  they  join  the  external  and  recurrent  laryngeal 
nerves. 

The  middle  or  great  cardiac  nerve  descends  to  the  thorax  across  the 
subclavian  artery ;  its  termination  in  the  cardiac  plexus  will  be  learnt  in 
the  chest.  In  the  neck  it  communicates  with  the  upper  cardiac  and  re- 
current laryngeal  nerves. 

The  INFERIOR  CERVICAL  GANGLION  is  of  large  size  but  irregular  in 
shape,  and  occupies  the  interval  between  the  first  rib  and  the  lateral  mass 
of  the  last  cervical  vertebra,  its  position  being  internal  to  the  superior 
intercostal  artery.  Oftentimes  it  extends  in  front  of  the  neck  of  the  rib, 
and  joins  the  first  swelling  of  the  knotted  cord  in  the  thorax.  Its  branches 
are  similar  to  those  of  the  other  two  ganglia. 

One  or  two  branches  surround  the  trunk  of  the  subclavian  artery,  and 
supply  filaments  to  that  bloodvessel. 

*  Connecting  branches  join  the  last  two  cervical  nerves.  Other  nerves 
accompany  the  vertebral  artery,  forming  a  plexus — vertebral,  around  it, 
and  communicate  with  the  spinal  nerves  as  high  as  the  fourth. 

Only  one  branch  for  distribution,  the  inferior  cardiac  nerve,  issues  from 
the  lower  ganglion.  It  lies  beneath  the  subclavian  artery,  joining  in  that 
position  the  recurrent  laryngeal  nerve,  and  enters  the  thorax  to  terminate 
in  the  deep  cardiac  plexus  behind  the  arch  of  the  aorta. 

Directions.  The  student  now  proceeds  to  dissect  the  left  side  of  the 
neck,  but  the  remains  of  the  right  half  should  be  carefully  preserved  during 
the  time  occupied  in  the  examination  of  the  left  half. 


118  DISSECTION    OF    THE    NECK. 

Section  X. 

DISSECTION  OF  THE  LEFT  SIDE  OF  THE  NECK. 

Directions.  In  the  dissection  of  the  left  half  of  the  neck,  the  differences 
observable  between  it  and  the  right  side  are  specially  to  be  studied. 
When  the  description  of  the  right  side  will  suffice,  reference  will  be  made 
to  it. 

After  the  neck  has  been  made  tense  over  a  narrow  block,  the  anterior 
part  of  it  is  to  be  prepared  as  on  the  opposite  side.  The  description  of  the 
right  side  (p.  67  to  73)  is  to  be  used  for  the  anterior  triangular  space,  the 
sterno-mastoideus,  and  the  depressor  muscles  of  the  hyoid  bone. 

Next  the  scaleni  muscles  and  the  subclavian  vessels  are  to  be  learnt. 
The  dissection  and  description  of  the  muscles  on  the  right  side  (p.  73  to 
75),  will  serve  for  those  on  the  left,  except  that  the  student  will  meet  on 
the  left  side  with  the  thoracic  duct. 

The  thoracic  duct  is  contiguous  to  the  part  of  the  subclavian  artery  in- 
side the  scalenus  muscle.  If  it  is  uninjected  it  looks  like  a  vein,  rather 
smaller  than  a  crow-quill;  and  it  will  be  found  by  separating  the  jugular 
vein  from  the  carotid  artery,  about  half  an  inch  above  the  clavicle,  cours- 
ing from  beneath  the  artery  to  end  in  the  subclavian  vein. 

On  this  side  the  clavicle  may  remain  articulated,  in  order  that  the  joint 
may  be  learnt. 

The  LEFT  SUBCLAVIAN  ARTERY  ariscs  from  the  arch  of  the  aorta,  in- 
stead of  from  an  innominate  trunk,  and  ascends  thence  over  the  Urst  rib 
in  its  course  to  the  upper  limb.  With  this  difference  on  the  two  sides  in 
the  origin  of  the  subclavian — the  one  vessel  beginning  opposite  the  sterno- 
clavicular articulation,  the  other  in  the  thorax — it  is  evident  that  the 
length  and  connections  of  the  part  of  the  artery  on  the  inner  side  of  the 
scalenus  must  vary  much  on  opposite  sides. 

First  part.  The  part  of  the  artery  internal  to  the  anterior  scalenus  is 
much  longer  on  the  left  than  tlie  right  side,  and  is  almost  vertical  in  direc- 
tion, instead  of  being  horizontal  like  its  fellow.  After  leaving  the  chest 
it  is  deeply  placed  in  the  neck,  near  the  spine  and  the  oesophagus,  and 
does  not  rise  usually  so  high  above  the  first  rib  as  the  right  subclavian. 

Between  the  artery  and  the  surface  are  structures  like  those  on  the 
right  side,  viz.,  the  common  teguments  with  the  platysma  and  deep  fascia, 
and  the  sterno-mastoid,  hyoid,  and  thyroid  muscles.  Behind  the  vessel  is 
the  longus  colli  muscle.  To  the  inner  side  are  the  oesophagus  and  the 
thoracic  duct;  and  the  pleura  is  in  contact  with  the  outer  and  anterior 
parts.  Its  connections  lower  in  the  chest  are  described  in  the  dissection 
of  the  thorax. 

Veins.  The  internal  jugular  vein  is  superficial  to  the  artery  and  paral- 
lel to  it. 

Nerves.  The  pneumo-gastric  nerve  lies  parallel  to  the  vessel  instead 
of  across  it  as  on  the  right  side;  and  the  phrenic  nerve  crosses  over  it 
close  to  the  scalenus.  Accomi)aiiying  the  artery  are  the  cardiac  branches 
of  the  sympathetic,  which  course  along  its  inner  side  to  the  chest;  and 
beneath  it  is  the  inferior  cervical  ganglion. 

The  second  and  third  parts  of  the   artery,  viz.,  beneath  and   beyond 


ENDING    OF    THORACIC    DUCT.  119 

the  scalenus,  are  nearly  the  same  as  on  the  right  side  (p.  76);  but  the 
student  must  note  for  himself  the  variations  that  may  exist  in  the  connec- 
tions. 

The  branches  of  this  artery  resemble  so  closely  those  of  the  right  trunk, 
that  one  description  will  serve  for  both  (p.  76  to  78).  It  may  be  re- 
marked, that  the  superior  intercostal  of  the  left  side  is  usually  internal  to, 
instead  of  beneath  the  scalenus  as  on  the  right  side;  in  other  words,  this 
branch  arises  sooner. 

Tlie  thoracic  duct  (fig.  27,  ^)  conveys  the  chyle  and  lymph  of  the 
greater  part  of  the  body  into  the  venous  circulation.  Escaping  from  the 
thorax  on  the  oesophagus,  the  duct  ascends  in  the  neck  as  high  as  the 
seventh  or  sixth  cervical  vertebra.  At  the  spot  mentioned  it  issues  from 
beneath  the  carotid  trunk,  and  arches  outwards  above  or  over  the  subcla- 
vian artery,  and  in  front  of  the  scalenus  muscle  and  the  phrenic  nerve,  to 
open  into  the  subclavian  close  to  the  union  with  the  internal  jugular  vein. 
Double  valves,  like  those  of  the  veins,  are  present  in  the  interior  of  the 
tube  ;  and  a  pair  guards  the  opening  into  the  posterior  part  of  the  vein, 
to  prevent  the  passage  of  the  blood  into  it.  Frequently  the  upper  part  of 
tlie  duct  is  divided;  and  there  maybe  separate  openings  into  the  large 
vein,  corresponding  with  those  divisions. 

Fig.  27. 


Diagram  of  the  Ending  of  the  Ltmph  Duct  and  the  Thoracic  Duct  in  the  Veins. 

1.  Upper  veua  cava.  8.  Thoracic  duct. 

2.  Right,  and  3,  left  innominate  vein.  9.  A  lymphatic  vessel  joining  the  right  lym- 
4.  Left,  and  5,  right  internal  jugular.  phatic  duct,  as  this  is  about  to  end  in 
6.  Left,  and  7,  right  subclavian  vein.  the  subclavian  vein. 

Large  lymphatic  vessels  from  the  left  side  of  the  head  and  neck,  and 
from  the  left  upper  limb,  open  into  the  upper  part  of  the  duct,  and  some- 
times separately  into  the  vein  Q^). 

Structure,  This  tube  is  formed  of  three  coats  like  the  bloodvessels, 
viz.,  inner,  middle,  and  outer.  The  inner  is  an  elastic  layer  of  longitudi- 
nal fibres  covered  by  flattened  epitlielium;  the  middle  is  muscuhir  and 
elastic  with  transverse  fibres;  and  the  outer  is  constructed  chiefly  of  flbrous 
tissues  arranged  longitudinally  and  obliquely. 

Examine  next  the  brachial  and  cervical  plexuses,  using  the  description 
of  the  right  side  (p.  79  to  81). 


120  DISSECTION    OF    THE    NECK. 

Common  carotids.  On  opposite  sides  tliese  vessels  have  differences 
like  those  between  tlie  right  and  left  subclavian  arteries;  for  the  left  ves- 
sel arises  from  the  arcli  of  the  aorta,  and  is  therefore  deep  in  the  chest, 
and  longer  than  the  right.  The  description  of  the  artery  between  its 
origin  and  the  top  of  the  sternum  will  be  included  in  the  dissection  of  the 
thorax. 

Beyond  the  sterno-clavicular  articulation  the  vessels,  on  both  sides,  so 
nearly  resemble  one  another  that  the  same  description  may  serve  for  the 
two  (p.  81).  On  the  left  side,  however,  the  jugular  vein  and  the  pneumo- 
gastric  nerve  are  much  nearer  to  the  carotid  than  on  the  right  side,  and 
are  placed  over  the  artery  in  the  lower  third  of  the  neck.* 

Parts  in  the  upper  aperture  of  the  thorax.  The  relative  po- 
sition of  the  several  parts  entering  or  leaving  the  thorax  by  the  upper 
opening  may  be  now  observed. 

In  the  middle  line  lie  the  remains  of  the  thymus  gland,  and  the  trachea 
and  oesophagus.  In  front  of  the  trachea  are  the  lower  ends  of  the  sterno- 
hyoid and  sterno-thyroid  muscles  with  layers  of  the  cervical  fascia,  and  the 
inferior  thyroid  veins ;  and  behind  the  gullet  and  windpipe  is  the  longus 
colli  muscle.  Between  the  two  tubes  is  the  recurrent  nerve  on  the  left 
side. 

On  each  side  the  bag  of  the  pleura  and  the  apex  of  the  lung  project  into 
the  neck ;  and  in  the  interval  between  the  pleura  and  the  trachea  and 
oesophagus,  are  placed  the  vessels  and  nerves  passing  between  the  thorax 
and  the  neck.  Most  anteriorly  on  both  sides  lie  the  innominate  vein,  the 
phrenic  nerve,  and  the  internal  mammary  artery ;  but  the  vessels  and 
nerves  next  met  with  are  different  on  the  two  sides.  On  the  right  side 
come  the  innominate  artery,  with  the  vagus,  the  cardiac  nerves,  and  the 
right  lymphatic  duct ;  but  on  the  left  side  are  tlie  left  vagus,  the  left  com- 
mon carotid  artery,  the  thoracic  duct,  and  the  left  subclavian  artery  with 
the  cardiac  nerves.  Lastly,  altogether  behind  on  each  side  are  part  of  the 
first  intercostal  nerve,  the  cord  of  the  sympathetic,  and  the  superior  inter- 
costal artery. 

The  thyroid  body  is  a  soft  reddish  mass,  which  is  situate  opposite  the 
upper  part  of  the  trachea.  It  consists  of  two  lobes,  one  on  each  side, 
which  are  united  by  a  narrow  piece  across  the  front  of  the  windpipe.  The 
connecting  piece,  about  half  an  inch  in  depth,  is  named  the  isthmus,  and 
is  placed  opposite  the  second  and  third  rings  of  the  air  tube. 

Each  lobe  is  somewhat  conical  in  shape,  with  the  smaller  end  upwards, 
and  is  about  two  inches  in  length.  It  is  interposed  between  the  windpipe 
and  the  sheath  of  the  common  carotid  artery,  and  is  covered  by  the  sterno- 
thyroid, sterno-hyoid,  and  omo-hyoid  muscles.  The  extent  of  the  lobe 
varies ;  but  usually  it  reaches  as  high  as  the  middle  of  the  thyroid  cartilage, 
and  as  low  as  the  sixth  ring  of  the  tracliea. 

From  the  upper  part  of  the  thyroid  body,  and  most  commonly  from  the 
left  lobe,  a  conical  piece — pyramid,  ascends  towards  the  hyoid  bone,  to 
which  it  is  connected  by  a  fibrous  band.  Sometimes  this  part  is  attached 
to  the  OS  hyoides  by  a  slip  of  muscle,  the  levator  glandulce  thyroidece  of 
Scemmering. 

This  body  is  of  a  brownish  red  or  purple  hue,  is  granular  in  texture, 
and  weighs  from  one  to  two  ounces.     Its  size  is  larger  in  the  woman  than 

'  Occasionally  these  differences  will  be  reversed — the  vein  and  nerve  being  over 
the  artery  on  the  right  side,  and  away  from  it  on  the  left. 


THYROID    BODY.  121 

ill  the  man.     On  cutting  into  the  gland  a  viscid  yellowish  fluid  escapes. 
It  has  not  any  excretory  tube  or  duct. 

Structure.  The  thyroid  body  is  not  provided  with  a  distinct  capsule  ; 
but  it  is  surrounded  by  areolar  and  fine  elastic  tissues,  which  project  into 
the  substance  and  divide  it  into  masses. 

The  substance  of  the  gland  consists  of  spherical  or  elongated  vesicles, 
which  vary  in  size,  some  being  as  large  as  the  head  of  a  small  pin,  and 
others  only  ^|o^^^  ^^  ^^^  inch.  These  vesicles  are  simple  sacs,  distinct  from 
one  another,  and  contain  a  yellowish  fluid  with  corpuscles.  The  wall  of 
the  vesicles  consists  of  a  thin  proper  membrane  with  a  nucleated  epithelial 
lining.  Fine  vessels  and  areolar  tissue  unite  together  the  vesicles  into 
small  irregular  masses  or  lobules  of  the  size  of  the  little  finger  nail. 

The  arteries  of  the  thyroid  body  are  two  on  each  side — superior  and 
inferior  thyroid.  The  branches  of  the  external  carotids  (superior  thyroid) 
ramify  chiefly  on  the  anterior  aspect ;  w^hile  those  from  the  subclavians 
(inferior  thyroid)  pierce  the  under  surface  of  the  body.  A  very  free  com- 
munication is  established  between  all  the  vessels  ;  and  in  the  substance  of 
the  thyroid  body  the  arteries  form  a  capillary  network  around  the  vesicles. 
Occasionally  there  is  a  third  thyroid  branch  {art.  thyroid,  ima)  which 
arises  from  the  innominate  artery  into  the  thorax,  and  ascending  in  front 
of  the  trachea  assists  in  supplying  the  thyroid  body. 

The  veins  are  large  and  numerous ;  they  are  superior,  middle,  and  infe- 
rior thyroid  on  each  side.  The  first  two  enter  the  internal  jugular  vein 
(p.  82).  The  inferior  thyroid  vein  issues  from  the  lower  part  of  the  thy- 
roid body,  and  descends  on  the  trachea — the  two  forming  a  plexuse  on 
that  tube  beneath  the  sterno-thyroid  muscles  ;  it  enters  finally  the  innomi- 
nate vein  of  its  own  side. 

The  TRACHEA,  or  air  tube,  is  continued  from  the  larynx  to  the  thorax, 
and  ends  by  dividing  into  two  tubes  (bronchi)  one  for  each  lung.  It  occu- 
pies the  middle  line  of  the  body,  and  extends  commonly  from  the  fifth 
cervical  to  the  fourth  dorsal  vertebra,  measuring  about  four  inches  and  a 
half  in  length,  and  nearly  one  in  breadth.  The  front  of  the  trachea  is 
rounded  in  consequence  of  the  existence  of  firm  cartilaginous  bands  in  the 
anterior  wall,  but  at  the  posterior  aspect  the  cartilages  are  absent,  and  the 
tube  is  flat  and  muscular. 

The  cervical  part  of  the  trachea  is  very  movable,  and  has  the  following 
relative  position  to  the  surrounding  parts.  Covering  it  in  front  are  the 
small  muscles  reaching  from  the  sternum  to  the  hyoid  bone,  with  the  deep 
cervical  fascia :  beneath  those  muscles  is  the  inferior  thyroid  plexus  of 
veins  ;  and  near  the  larynx  is  the  isthmus  of  the  thyroid  body.  Behind 
the  tube  is  the  oesophagus,  with  the  recurrent  nerves.  On  each  side  are 
the  common  carotid  artery  and  the  thyroid  body. 

The  structure  of  the  trachea  is  described  in  Section  XYII. 
The  (ESOPHAGUS,  or  gullet,  reaches  from  the  pharynx  to  the  stomach. 
It  commences,  like  the  trachea,  opposite  the  fifth  cervical  vertebra,  and^ 
ends  opposite  the  tenth  dorsal  vertebra.  The  tube  reaches  through  part  of 
the  neck,  and  through  the  whole  of  the  thorax  ;  and  occupies  the  middle 
line  of  the  body.     In  length  it  measures  about  nine  inches. 

In  the  neck  its  position  is  behind  the  trachea  till  near  the  thorax,  where 
it  projects  to  the  left  side  of  tlie  air  tube,  and  touches  the  thyroid  body 
and  the  thoracic  duct.  Behind  the  oesophagus  is  the  longus  colli  muscle. 
On  each  side  is  the  common  carotid  artery,  the  proximity  of  the  left  being 
greatest  because  of  the  projection  of  the  oesophagus  towards  the  same  side. 


122  DISSECTION    OF    THE    PHARYNX. 

The  structure  of  the  oesophagus  will  be  examined  in  the  dissection  of 
the  thorax. 

Directions.  The  dissector  may  learn  next  the  digastric  and  stylo-hyoid 
muscles,  Avith  the  hypoglossal  nerve  (p.  82).  Afterwards  he  may  take 
the  trunk  of  the  external  carotid,  with  the  following  branches — superior 
thyroid,  facial,  occipital,  posterior  auricular,  and  superficial  temporal  (p. 
83  to  87). 

The  dissector  is  not  to  examine  now  the  pterygo-maxillary  or  sub- 
maxillary regions  on  the  left  side,  because  such  a  proceeding  would  inter- 
fere with  the  subsequent  dissections.  Before  learning  the  pharynx  he 
should  lay  bare,  on  this  side,  the  middle  and  inferior  ganglia  of  the  sym- 
pathetic with  their  branches. 

Dissection.  For  tlie  display  of  the  two  low^er  ganglia  of  the  sympathetic 
and  their  branches,  it  will  be  necessary  to  take  away  the  great  bloodvessels 
by  cutting  them  across  at  the  lower  part  of  the  neck,  and  near  the  digastric 
muscle.  In  removing  the  vessels,  care  must  be  taken  of  the  sympathetic 
beneath  them. 

The  middle  ganglion  must  be  sought  in  the  fat  and  areolar  tissue  near 
the  inferior  thyroid  artery ;  and  the  inferior  one  will  be  seen  on  the  neck 
of  the  first  rib,  after  the  subclavian  artery  has  been  divided.  The  upper 
cardiac  nerve  may  be  found  descending  beneath  tlie  carotid  sheath. 

The  upper  end  of  the  sternum  witli  its  attached  clavicle  is  to  be  taken 
away  next,  by  cutting  through  the  middle  of  the  first  rib  ;  and  the  piece 
of  bone  is  to  be  put  aside  for  the  subsequent  examination  of  the  sterno- 
clavicular articulation. 

The  middle  and  inferior  cervical  ganglia  of  the  sympathetic  nerve  are 
so  similar  to  the  corresponding  ganglia  of  the  right  side,  that  the  same 
description  will  suffice  (p.  117). 

The  cardiac  nerves  are  three  in  number  on  the  left  as  on  the  right  side, 
viz.,  superior,  middle,  and  inferior,  but  they  present  some  differences. 

The  s^iperior  cardiac  nerve  has  a  similar  course  in  the  neck  on  both 
sides ;  but  the  left  in  entering  the  chest  lies  between  and  parallel  to  the 
carotid  and  subclavian  arteries. 

The  middle  cardiac  nerve  unites  frequently  with  the  next,  and  passes 
beneath  tlie  subclavian  artery  to  the  deep  cardiac  plexus. 

The  inferior  cardiac  nerve  is  generally  a  small  branch,  wliich  enters 
the  thorax  conjoined  with  the  preceding,  to  end  in  the  cardiac  plexus. 


Section  XI. 

DISSECTION  OF  THE  PHARYNX. 


The  pharynx,  or  the  commencement  of  the  alimentary  passage,  can  be 
examined  only  when  it  has  been  separated  from  the  rest  of  the  head  ;  and 
it  will  therefore  be  necessary  to  cut  througli  the  base  of  the  skull  in  the 
manner  mentioned  below,  so  as  to  have  the  anterior  half,  with  the  pharynx 
connected  to  it,  detaclied  from  the  posterior  half. 

Dissection.  The  block  being  removed  from  beneatli  the  neck,  the  head 
is  to  be  ))laced  downwards,  so  that  it  may  stand  on  the  cut  edge  of  the 
skull.     Next  the  trachea  and  oesophagus,  togetlier  with   the  vagus  and 


PREPARATION    OF    PHARYNX.  123 

sympathetic  nerves,  are  to  be  cut  near  the  first  rib,  and  all  are  to  be  sepa- 
rated from  the  spine  as  high  as  the  basilar  process  of  the  occipital  bone  ; 
and  without  injuring,  on  the  left  side,  the  vessels  and  nerves  near  the 
skull. 

For  the  division  of  the  skull  turn  upwards  the  inner  surface  of  the  base, 
and  make  the  following  incisions  in  the  posterior  fossa.  On  the  right  side 
a  cut,  with  the  chisel,  is  to  be  carried  along  the  line  of  union  of  the 
petrous  part  of  the  temporal  with  the  occipital  bone.  On  the  left  side  an- 
other cut  with  the  chisel  is  to  be  made  in  the  same  direction,  but  through 
the  occipital  bone  internal  to  the  foramen  jugulare  and  the  inferior  petrosal 
sinus  :  this  is  to  begin  rather  behind  that  foramen,  and  to  end  opposite  the 
one  on  the  other  side.  The  skull  is  to  be  sawn  through  vertically  on  the 
left  side  close  behind  the  mastoid  part  of  the  temporal  bone,  so  that  the 
incision  shall  meet  tlie  outer  end  of  the  cut  made  with  the  chisel. 

Finally  placing  the  skull  again  upside  down,  let  the  student  chisel 
through  the  basilar  process  of  the  occipital  bone  between  the  attachments 
of  the  pharynx  and  the  muscles  of  the  spinal  column,  the  instrument  being 
directed  backwards.  The  base  of  the  skull  is  now  divided  into  two  parts 
(one  having  the  pharynx  attached  to  it,  the  other  articulating  with  the 
spine),  which  can  be  readily  separated  with  a  scalpel. 

The  spinal  column  with  the  piece  of  the  occipital  bone  connected  with 
it  should  be  set  aside,  and  kept  for  after  examination. 

Dissection  of  the  -pharynx  (fig.  28).  Let  the  student  take  the  anterior 
part  of  the  divided  skull,  and,  after  moderately  filling  the  pharynx  with 
tow,  fasten  it  with  hooks  on  a  block,  so  that  the  oesophagus  may  be  pen- 
dent and  towards  him. 

On  the  left  side  of  the  pharynx  a  different  view  from  that  of  the  right 
side  may  be  obtained  of  the  cranial  and  sympathetic  nerves  near  the  skull 
(p.  112),  when  some  loose  areolar  tissue,  and  the  styloid  process  with  its 
muscles,  have  been  removed :  if  the  lower  ends  of  the  nerves  are  fixed 
with  pieces  of  thread,  a  more  satisfactory  examination  can  be  made  of 
them. 

Afterwards  the  dissector  may  proceed  to  remove  the  fascia  from  the 
constrictor  muscles  of  the  right  side  (fig.  28),  in  the  direction  of  the  fibres 
— these  radiating  from  the  side  to  the  middle  line.  The  margins  of  the 
two  lower  constrictor  muscles  (middle  and  inferior)  are  to  be  defined. 
Beneath  the  lower  one  near  the  larynx,  will  be  found  the  recurrent  nerve 
with  vessels ;  whilst  intervening  between  the  middle  and  superior,  are  the 
stylo-pharyngeus  muscle  and  the  glosso-pharyngeal  nerve. 

To  see  the  attachment  of  the  superior  constrictor  to  the  lower  jaw  and 
the  ptery go-maxillary  ligament,  it  will  be  necessary  to  cut  through  the  in- 
ternal pterygoid  muscle  of  the  right  side.  Above  the  upper  fibres  of  this 
constrictor,  and  near  the  base  of  the  skull,  are  two  small  muscles  of  the 
palate  (F  and  H)  entering  the  pharynx  :  one — tensor  palati,  lies  between 
the  internal  pterygoid  plate  and  muscle ;  and  the  other — levator  palati,  is 
farther  in,  and  larger. 

The  PHARYNX  is  situated  behind  the  nose,  mouth,  and  larynx.  Its 
extent  is  from  the  base  of  the  skull  to  the  cricoid  cartilage  of  the  larynx, 
where  it  ends  in  the  oesophagus.  In  form  it  is  somewhat  conical,  with  the 
dilated  part  upwards  ;  and  in  length  it  measures  from  five  to  six  inches. 

The  tube  of  the  pharynx  is  incomplete  in  front,  where  it  communicates 
with  the  cavities  above  mentioned,  but  is  quite  closed  behind.  On  each 
side  of  it  are  placed  the  trunks  of  the  carotid  arteries,  wdth  the  internal 


124  DISSECTION    OF    THE    PHARYNX. 

jugular  vein  and  the  accompanying  cranial  and  sympathetic  nerves.  Behind 
it  is  the  spinal  column,  covered  by  muscles,  viz.,  longus  colli  and  rectus 
capitis  anticus  major. 

In  front  the  pharynx  is  united  to  the  larynx,  the  hyoid  bone  and  the 
tongue,  and  to  the  bony  framework  of  the  nasal  cavity  ;  but  behind  it  is 
unattached,  and  is  formed  chiefly  of  thin,  fleshy  strata.  In  the  posterior 
wall  are  contained  elevator  and  constrictor  muscles ;  and  at  the  u|)per  part 
the  bag  is  further  completed  by  an  aponeurotic  expansion  which  fixes  it  to 
the  base  of  the  skull.     The  whole  is  lined  by  mucous  membrane. 

The  aponeurosis  of  attachment  is  seen  at  the  upper  part  of  the  pharynx, 
where  the  muscular  fibres  are  absent,  to  connect  the  tube  to  tlie  base  of  the 
skull,  and  to  complete  the  posterior  boundary.  Superiorly  it  is  fixed  to 
the  basilar  process  of  the  occipital,  and  the  petrous  pai-t  of  the  temporal 
bone,  as  well  as  to  the  cartilage  between  the  two ;  but  inferiorly  it  becomes 
thin,  and  extends  between  the  muscular  and  mucous  strata.  On  this  mem- 
brane some  of  the  fibres  of  the  constrictor  muscles  terminate. 

The  CONSTRICTORS  are  three  thin  muscles,  which  are  arranged  like 
scales,  the  lower  partly  overlaying  the  middle,  and  the  middle  the  upper. 

The  inferior  constrictor  (fig.  28,  ^),  the  most  superficial  and  lowest, 
arises  from  the  side  of  the  cricoid  cartilage  ;  from  the  oblique  line  and 
upper  and  lower  borders  of  the  thyroid  cartilage,  and  from  the  part  of  the 
latter  which  is  behind  the  oblique  line.  The  origin  is  small  when  com- 
pared with  the  insertion,  for  the  fibres  are  directed  backwards,  radiating, 
and  are  inserted  into  a  raphe  along  the  middle  line,  where  it  meets  the 
corresponding  muscle  of  the  opposite  side. 

The  outer  surface  of  the  muscle  is  in  contact  with  the  sheath  of  the 
carotid  artery,  and  with  the  muscles  covering  the  spinal  column.  The 
lower  border  is  straight,  and  is  continuous  with  the  fibres  of  the  oesopha- 
gus ;  whilst  the  upper  border  overlaps  the  fibres  of  the  middle  constrictor 
(b).     The  recurrent  nerve  and  vessels  (^)  enter  beneath  the  lower  border. 

The  middle  constrictor  (fig.  28  ^)  has  nearly  the  same  shape  as  the  pre- 
ceding, that  is  to  say,  it  is  narrowed  in  front  and  expanded  behind.  Its 
fibres  arise  from  the  great  cornu  of  the  os  hyoides,  from  the  small  cornu 
of  the  same  bone,  and  from  the  stylo-hyoid  ligament.  From  this  origin 
the  fibres  radiate,  and  are  blended  along  the  middle  line  with  the  other 
muscles. 

The  surfaces  have  connections  similar  to  those  of  the  preceding  con- 
strictor. The  upper  border  is  separated  from  the  superior  constrictor  by 
the  stylo-pharyngeus  muscle  d,  and  ends  on  the  ajjoneurosis  of  the  pharynx, 
about  an  inch  from  the  base  of  the  skull.  The  lower  border  descends 
beneath  the  inferior  constrictor ;  and  opposite  the  interval  between  the  two 
is  the  up[)er  laryngeal  nerve  (^). 

The  superior  constrictor  (fig.  28  ^)  is  the  least  strong  of  the  three 
muscles,  and  wants  the  usual  conical  form.  Its  origin  is  extensive,  and 
is  connected  successively,  from  above  down,  with  the  inner  surface  of  the 
internal  pterygoid  plate  (the  lower  third  or  less),  witli  the  pterygo-maxil- 
lary  ligament,  with  tlie  posterior  part  of  the  mylo-hyoid  ridge  of  the  lower 
jaw,  and  with  the  mucous  membrane  of  the  mouth  and  the  side  of  the 
tongue.  The  fleshy  fibres  pass  backwards,  and  are  inserted  on  the  aponeu- 
rosis of  the  pharynx,  as  well  as  into  tlie  raphe  along  the  middle  line. 

The  parts  in  contact  externally  with  this  muscle  are,  the  deep  vessels 
and  nerves  of  the  neck ;  and  internally  it  is  lined  by  the  aponeurosis  and 
the  mucous  membrane.     The  upper  border  consists  of  arclied  fibres  which 


CONSTRICTOR    MUSCLES. 


125 


are  directed  backwards  from  tlie  pterygoid  plate;  and  above  it  the  levator 
palati  muscle  f  is  seen.  The  lower  border  is  overlaid  by  the  middle  con- 
strictor muscle.  The  attachment  to  the  pterygo-maxillary  ligament  cor- 
responds with  the  origin  of  the  buccinator  muscle  i. 

Fisr.  28. 


Muscles  : 

A.  Inferior  constrictor. 

B.  Middle  constrictor, 
c.  Upper  constrictor. 
D.  Stylo-pharyngeus. 
F.  Levator  palati. 

H.  Tensor  palati. 
I.  Buccinator. 
K.  Hyo-glossus. 

Nerves : 

1.  Glosso-pharyngeal. 

2.  Hypo-glossal. 

3.  Superior  laryu^eal. 

4.  External  laryngeal. 

5.  Recurrent  laryngeal. 

6.  Gustatory  nerve. 


Ekternai,  View  of  the  Pharynx  (Illustrations  of  Dissections) 


contracting  will 


Action  of  constrictors.  The  muscles  of  both  sides 
diminish  the  size  of  the  pharynx ;  and  as  the  anterior  attachments  of  the 
lower  muscles  are  nearer  together  than  those  of  the  upper,  the  tube  will 
be  contracted  more  behind  the  larynx  than  near  the  head. 

In  swallowing  the  morsel  is  seized  first  by  the  middle  constrictor,  and 
is  delivered  over  to  the  inferior,  by  which  it  is  conveyed  to  the  oesopha- 
gus :  both  muscles  act  involuntarily.  By  the  contraction  of  the  upper 
muscle  the  space  above  the  moutli  will  be  narrowed,  so  that  the  soft  palate 
being  raised,  the  upper  portion  of  the  pharyngeal  space  can  be  shut  off 
from  the  lower. 


126  DISSECTION    OF    THE    PHARYNX. 

Dissection  (fig.  29).  Open  the  pharynx  by  an  incision  along  its  mid- 
dle, and,  after  removing  the  tow  from  the  interior,  keep  it  open  with 
hooks:  a  better  view  of  the  cavity  will  be  obtained  by  partly  dividing  the 
occipital  attachment  on  each  side.  The  mucons  membrane  is  to  be  care- 
fully removed  below  the  dilated  extremity  of  tlie  Eustachian  tube  on  the 
right  side,  for  the  purpose  of  finding  some  pale  muscular  fibres,  salpingo- 
pharyngeus  C,  which  descend  from  it. 

The  ELEVATORS  of  the  pharynx  are  two  in  number  on  each  side — an 
external  (stylo-pharyngeus),  and  an  internal  (salpingo-pharyngeus). 

The  stylo-pharyngeiis  (external  elevator)  may  be  read  again  with  the 
pharynx.     Its  description  is  given  in  p.  106. 

Salpingo-pharyngeus,  C  (internal  elevator).  This  little  band  is  fixed 
by  tendon  to  the  lower  border  of  the  cartilage  of  tlie  Eustachian  tube  near 
the  orifice.  Its  fieshy  fibres  end  below  by  joining  those  of  the  palato- 
pharyngeus  Q.  If  the  part  is  not  tolerably  fresh  the  muscle  may  not  be 
visible. 

Action.  This  thin  muscle  elevates  the  upper  and  lateral  part  of  the 
pharynx  above  the  spot  where  the  large  external  elevator  enters  the  wall; 
but  it  is  probably  used  chiefly  in  opening  the  Eustachian  tube  in  swal- 
lowing. 

The  interior  of  the  pharynx  (fig.  29)  is  wider  from  side  to  side  tlian 
from  before  back,  and  its  greatest  width  is  opposite  the  hyoid  bone;  from 
that  spot  it  diminishes  both  upwards  and  downwards,  but  much  more 
rapidly  in  the  latter  than  in  the  former  direction.  Tlirough  the  part  of 
the  passage  above  the  mouth  the  air  moves  in  respiration ;  wliilst  through 
that  below  the  mouth  both  air  and  food  are  transmitted — the  air  passing 
to  the  aperture  of  the  windpipe,  and  the  food  to  the  oesophagus.  In  it 
the  following  objects  are  to  be  noticed : — 

At  the  top  are  situate  the  posterior  apertures,  G,  of  the  nasal  cavity, 
which  are  separated  by  the  septum  nasi;  and  below  them  hangs  the  soft 
palate,  partly  closing  the  cavity  of  the  mouth.  By  tlie  side  of  each  nasal 
aperture  is  the  trumpet-shaped  end  of  the  Eustachian  tube,  F. 

Below  the  soft  palate,  the  opening  into  the  mouth — isthmus  faucium, 
H,  is  to  be  recognized;  and  on  each  side  of  this  is  the  tonsil,  k,  which  is 
placed  in  a  hollow  between  two  prominences  named  pillars  of  the  soft 
palate — the  one,  i,  proceeding  from  the  soft  palate  to  the  side  of  the 
tongue,  and  the  other,  l,  from  the  same  part  to  the  side  of  the  pharynx. 

Next  in  order,  below  the  mouth,  comes  the  aperture  of  the  larynx,  n; 
and  close  in  front  of  it  is  the  epiglottis,  or  the  valve  which  assists  to  close 
that  opening  during  deglutition.  Lowest  of  all  is  the  opening,  o,  from 
the  pharynx  into  the  oesophagus. 

The  apertures  into  the  pharynx  are  seven  in  number,  and  have  the 
following  position  and  boundaries : — 

The  posterior  openings  of  the  ?iasal  fossce,  G,  are  oval  in  form,  and 
measure  about  an  inch  from  above  down,  but  only  half  an  inch  across. 
Each  is  constructed  in  the  dried  skull  by  tlie  sphenoid  and  palate  bones 
above,  and  by  the  palate  below ;  by  the  vomer  inside,  and  the  internal 
pterygoid  plate  outside;  and  it  is  lined  by  mucous  membrane. 

The  Eustachian  tube,  F,  is  a  canal,  partly  osseous,  partly  cartilaginous, 
by  which  the  tympanic  cavity  of  the  ear  communicates  with  the  exter- 
nal air. 

If  the  mucous  membrane  be  removed  from  the  tube  on  the  right  side, 
the  cartilaginous  part  appears   to  be  nearly  an  inch  long.     It  is  narrow 


OPENINGS    OF    PHARYNX. 


12T 


superiorly,  where  it  is  fixed  to  the  margins  of  a  groove  between  the  petrous 
part  of  the  temporal  and  the  sphenoid  bone ;  but  it  increases  in  width  as 
it  is  directed  downwards  to  the  pharynx,  and  ends  by  a  wide  aperture 
inside  the  internal  pterygoid  plate,  on  a  level  with  the  inferior  meatus. 
Its  opening  in  the  pharynx  is  oval  in  form;  and  the  inner  side,  which  is 
larger  than  the  outer,  projects  forwards,  giving  rise  to  a  trumpet-shaped 
mouth. 

Fig.  29. 


A.  Levator  palati. 

B.  Tensor  palati. 

c.  Salpingo-pharyngeus. 

D.  Azygos  uvulae. 

B.  Internal  pterygoid  muscle. 

F.  End  of  the  Eustachian  tube. 

G.  Posterior  uaris. 
H.  Mouth  cavity. 

I.   Anterior  pillar  of  the  fauces. 
K.  Apertures  of  the  tonsil. 
L.  Posterior  pillar  of  the  fauces. 
N.  Opening  of  the  larynx. 
o.  Opening  of  the  oesophagus. 
p.  Uvula. 

Q.   Superficial    part   of    Palato-pharya- 
geus. 


Internal  View  of  the  Pharnyx  (Illustrations  of  Dissections).    Muscles  of  the  Palate,  and 

NAMED  Parts. 


This  part  of  the  tube  is  constructed  by  a  triangular  piece  of  cartilage, 
whose  margins  are  bent  downwards  so  as  to  inclose  a  narrow  space;  but 
at  the  under  aspect  the  cartilage  is  deficient,  and  the  wall  is  formed  by 
fibrous  membrane.  Closely  united  to  the  pterygoid  plate,  the  tube  is 
covered  by  the  mucous  membrane;  and  through  it  the  mucous  lining  of 
the  cavity  of  the  tympanum  is  continuous  with  tliat  of  the  pharynx. 

The  space  included  between  the  root  of  the  tongue  and  tlie  arches  of 
the  soft  palate  on  opposite  sides  is  called  the  fauces.  It  is  wider  below 
than  above;  and  on  each  side  lies  the  tonsil. 


128  DISSECTION    OF    THE    PHARYNX. 

The  isthmus  faucium^  h,  is  the  narrowed  aperture  of  communication 
between  tlie  mouth  and  the  fauces,  whose  size  is  altered  by  the  elevated 
or  pendent  position  of  the  soft  palate.  Laterally  it  is  bounded  by  the 
anterior  arches  of  the  soft  palate,  which  are  named  jo?7/rtrs  of  the  fauces. 

The  aperture  of  the  larynx^  N,  is  wide  in  front,  where  it  is  bounded  by 
the  epiglottis,  and  pointed  behind  between  the  arytasnoid  cartilages.  The 
sides  are  sloped  from  before  back,  and  are  formed  by  folds  of  the  mucous 
membrane  extending  between  the  aryt^enoid  cartilages  and  the  epiglottis. 
Posteriorly  it  is  limited  by  the  cornicula  laryngis,  and  by  the  arytienoid 
muscle  covered  by  mucous  membrane.  During  respiration  this  aperture  is 
unobstructed,  but  in  the  act  of  deglutition  it  is  closed  by  the  epiglottis. 

The  opening  into  the  cesophagus,  o,  is  the  narrowest  part  of  the  pha- 
rynx, and  is  opposite  the  cricoid  cartilage  and  the  fifth  cervical  vertebra. 
Internally  the  mucous  membrane  in  the  oesophagus  is  paler  than  that  in 
the  pharynx  :  and  externally  the  point  at  which  the  pharynx  ends  is 
marked  by  a  slight  contraction,  and  by  a  change  in  the  direction  of  the 
muscular  fibres. 

The  SOFT  PALATE,  Q  (velum  pendulum  palati),  is  a  movable  structure 
between  the  mouth  and  the  pharynx,  which  can  either  close  the  opening 
of  the  mouth,  or  cut  off  the  passage  to  the  nose,  according  as  it  is  de- 
pressed or  elevated.  In  the  usual  position  of  the  soft  palate  (the  state  of 
relaxation)  the  anterior  surface  is  somewhat  curved,  and  is  continuous 
with  the  roof  of  the  mouth,  whilst  the  opposite  surface  is  convex  and 
turned  to  the  pharynx.  The  upper  border  is  fixed  to  the  posterior  margin 
of  the  hard  palate ;  and  each  lateral  part  joins  the  pharynx.  The  lower 
border  is  free,  and  presents  in  the  centre  a  conical  pendulous  part — the 
uvula^  p.  Along  its  middle  is  a  slight  ridge,  indicative  of  the  original 
separation  into  two  halves. 

Springing  from  the  lower  part  of  the  soft  palate,  near  the  uvula,  are  two 
folds  on  each  sides,  containing  muscular  fibres,  which  are  directed  down- 
wards on  the  sides  of  the  fauces.  These  are  named  arches  ov pillars  of  the 
palate,  and  are  distinguished  from  one  another  by  their  relative  position. 
The  anterior,  i,  readies  from  the  fore  part  to  the  side  of  the  tongue  near 
the  middle  ;  and  the  posterior,  l,  longer  than  the  other,  is  continued  from 
the  lower  border  to  the  side  of  the  pharynx.  As  they  diverge  from  their 
origin  to  their  termination,  they  limit  a  triangular  space  in  which  the  ton- 
sil lies. 

The  velum  consists  of  an  aponeurosis,  with  muscles,  vessels,  nerves,  and 
mucous  glands  ;  and  the  whole  is  enveloped  by  the  mucous  membrane. 

Dissection Some   of  the  muscles  of  the  palate  are  readily  displayed, 

but  others  require  care  in  their  dissection. 

On  the  right  side  the  two  principal  muscles  of  the  soft  palate — the  ele- 
vator and  tensor,  are  very  plain.  These  have  been  partly  dissected  on  the 
right  side  ;  but  to  follow  them  to  their  termination,  let  the  upper  attach- 
ment of  the  pharynx  on  the  same  side,  and  the  part  of  the  superior  con- 
strictor wliich  arises  from  the  internal  pterygoid  plate,  be  cut  through. 
The  levator  will  be  fully  laid  bare  by  the  removal  of  the  mucous  mem- 
brane, and  a  few  muscular  fibres  covering  its  lower  part.  The  tendon  of 
the  tensor  palati  should  be  followed  round  the  hamular  process  of  the 
pterygoid  plate ;  and  its  situation  in  the  palate  beneath  the  levator  should 
be  made  evident.  The  position  of  the  Eustachian  tube  with  respect  to 
those  muscles  should  be  ascertained. 


MUSCLES    OF    PALATE.  129 

On  the  left  side,  the  mucous  membrane  is  to  be  raised  with  great  care 
from  the  posterior  surface  of  the  palate,  to  obtain  a  view  of  the  superficial 
muscular  fibres.  Immediately  beneath  the  mucous  covering  are  some 
fine  transverse  fibres  of  the  palato-pharyngeus  muscle;  and  beneath  tliom, 
in  the  middle  line,  are  the  longitudinal  fibres  of  the  azygos  uvuhe.  A 
deeper  set  of  fibres  of  the  palato-pharyngeus  is  to  be  followed,  on  the  right 
side,  beneath  the  levator  and  iizygos  muscles. 

The  student  should  remove  next  the  mucous  membrane  from  tlie  mus- 
cular fibres  contained  in  the  arches  of  the  palate,  and  shoidd  follow  these 
upwards  and  downwards.  In  order  to  see  them  in  the  anterior  fold,  it 
will  be  necessary  to  take  the  membrane  from  the  anterior  surface  of  the 
palate.  If  the  part  is  not  tolerably  fresh,  some  of  the  paler  fibres  may 
not  be  visible. 

Aponeurosis  of  the  soft  palate.  Giving  strength  to  the  velum  is  a  thin 
but  firm  aponeurosis,  which  is  attached  to  the  hard  palate.  This  mem- 
brane becomes  thinner  as  it  descends  in  the  velum;  and  it  is  joined  by 
the  tendon  of  the  tensor  palati  muscle. 

The  MUSCLES  of  the  soft  palate  are  four  on  each  side, — an  elevator  and 
tensor;  with  the  palato-glossus  and  palato-pharyngeus,  which  act  as  de- 
pressors.    In  addition  there  is  a  small  median  azygos  muscle. 

The  LEVATOR  PALATI  (fig.  29,  ^)  is  a  thick,  roundish  muscle,  which  is 
partly  situate  outside  the  pharynx.  It  arises  from  the  under  surface  of 
the  apex  of  the  petrous  portion  of  the  temporal  bone  (fig.  30,  ^),  and  from 
the  inner  and  hinder  part  of  the  cartilage  of  the  Eustachian  tube.  The 
fibres  enter  the  pharynx  above  the  superior  constrictor,  and  then  spread 
out  in  the  soft  palate,  where  they  join  along  the  middle  line  with  those 
of  the  muscles  of  the  opposite  side. 

Outside  the  pharynx  this  muscle  rests  against  the  Eustachian  tube.  In 
the  palate  it  forms  a  stratum  that  reaches  the  whole  depth  of  that  struc- 
ture, an,d  is  embraced  by  two  planes  of  fibres  of  the  palato-pharyngeus  (*). 

Action.  It  tilts  backwards  the  free  edge  of  the  soft  palate  towards  the 
pharynx  so  as  to  enlarge  the  isthmus  faucium,  and  to  shut  off  with  the 
contracted  pharynx  the  nose  openings.  In  swallowing  the  palate  is  raised, 
and  is  arched  over  the  bolus  passing  from  the  mouth  to  the  pharynx.  For 
its  action  on  the  Eustachian  tube,  see  Tensor  palati. 

The  TENSOR  vel  circumflexus  palati  (fig.  29,  ^)  arises  like  the 
preceding  outside  the  pharynx,  and  is  a  thin  riband-like  band,  situate 
between  the  internal  pterygoid  plate  and  muscle.  About  one  inch  and  a 
half  wide  at  its  origin,  it  is  attached  to  the  slight  depression  (scaphoid 
fossa)  at  the  root  of  the  internal  pterygoid  plate,  to  the  outer  and  forepart 
of  the  Eustachian  tube,  and  still  further  out  to  the  spinous  process  of  the 
sphenoid,  and  the  vaginal  (tympanic)  process  of  the  temporal  bone.  In- 
feriorly  the  fleshy  fibres  end  in  a  tendon  which,  entering  the  pharynx 
between  the  attachments  of  the  buccinator  muscle,  is  reflected  round  the 
hamular  process  (fig.  30,  ^),  and  is  inserted  into  about  one-third  of  an  inch 
of  the  posterior  border  of  the  palate,  viz.,  from  the  central  spine  to  a  pro- 
jecting point;  and  inferiorly  into  the  aponeurosis  of  the  velum. 

As  the  tendon  winds  round  the  bone,  it  is  thrown  into  folds;  and  be- 
tween the  two  is  a  bursa.  In  the  soft  palate  it  lies  beneath  the  levator 
muscle.  The  Eustachian  tube  is  directed  inwards  between  this  muscle 
and  the  preceding. 

Action.  Acting  from  the  skull  the  muscle  will  fix  and  make  tense  the 
9 


130 


DISSECTION    OF    THE    PHARYNX 


latenil  part  of  the  soft  palate;  but  its  movements  will  be  very  limited, 
seeing  that  the  tendon  is  inserted  partly  into  the  palate  bone. 


Fiff.  30. 


1.  Azygos  uvulae. 

2.  Tensor  palati. 

3.  Levator  palati. 

4.  Palato-pharyngeus — upper  end. 
6.  External  pterygoid. 


If  the  soft  palate  is  fixed  by  the  depressor  muscles,  the  levator  and 
tensor,  and  the  salpingo-pharyngeus,  taking  their  fixed  points  below,  open 
the  Eustachian  tube  in  swallowing. 

The  PALATO-GLOSSUS  MUSCLE  (coustrictor  isthmi  faucium)  is  a  small, 
pale  band  of  fibres,  which  is  contained  in  the  anterior  arch,  i,  of  the  soft 
palate.  It  is  connected  inferiorly  with  the  lateral  surface  and  the  dorsum 
of  the  tongue ;  from  this  spot  the  fibres  ascend  beibre  the  tonsil  to  the 
anterior  aspect  of  the  soft  palate,  where  they  form  a  thin  muscular  stratum, 
and  join  those  of  the  fellow  muscle  along  the  middle  line. 

At  its  origin  the  muscle  is  blended  with  the  glossal  muscles,  and  at  its 
insertion  it  is  placed  before  the  tensor  palati. 

Action.  The  palato-glossus  narrows  the  isthmus  of  the  fauces ;  the  mus- 
cles of  opposite  sides  moving  inwards  towards  each  other,  and  separating 
from  the  mouth  the  morsel  to  be  swallowed. 

When  the  tongue  is  fixed  the  muscle  will  render  tense  and  draw  down 
the  soft  palate. 

The  PALATO-PHARYNGEUS  is  much  larger  in  size  than  the  preceding, 
and  gives  rise  to  the  eminence  of  the  posterior  pillar,  l,  of  the  soi"t  palate. 
Tlie  muscle  is  attached  below  to  the  posterior  border  of  the  thyroid  carti- 
lage, some  fibres  blending  witli  the  contiguous  portion  of  the  pharynx ; 
and  it  decussates  across  the  middle  line  with  corresponding  fibres  of  the 
muscle  of  the  opposite  side  (Merkel).^  Ascending  thence  behind  the 
tonsil,  the  fibres  enter  the  side  of  the  palate,  and  separate  into  two  layers 
(fig.  30,  *).  The  posterior,  thin  and  in  contact  with  the  mucous  mem- 
brane, joins  at  the  middle  line  a  like  offset  of  its  fellow.  Tiie  deeper  or 
anterior  stratum,  much  the  strongest,  enters  the  substance  of  the  palate 
between  the  levator  and  tensor,  and  joins  at  the  middle  line  the  corre- 
spcmding  part  of  the  opposite  muscle,  whilst  some  of  the  upper  fibres  end 
on  the  aponeurosis  of  tlie  palate. 

'  Di:.  Morkel,  in  the  work  before  referred  to,  states  tliat  tliis  muscle  has  no  firm 
fixed  attachment  below,  and  that  it  ends  altogether  in  the  wall  of  the  pharynx, 
decussating  with  the  muscle  of  the  opposite  side.  This  assertion  does  not  accord 
with  my  experience. 


THE    TONSIL.  131 

In  the  palate  the  muscle  incloses  the  levator  palati  and  azygos  uvulae 
between  its  two  strata. 

Action.  Taking  its  fixed  point  at  the  tliyroid  cartilage  the  muscle  de- 
presses and  makes  tense  the  soft  palate. 

During  the  act  of  swallowing  both  muscles  move  back  the  lower  edge 
of  the  soft  palate  towards  the  pliarynx;  and  approaching  each  other,  form 
an  oblique  plane  for  the  downward  direction  of  the  food  ;  in  that  state  the 
uvula  lies  in  the  interval  between  the  two. 

The  AZYGOS  uvuLiE  (fig.  29,  ^)  is  situate  along  the  middle  line  of  the 
velum  near  the  posterior  surface.  The  muscle  consists  of  two  narrow 
slips  of  pale  fibres,  which  arise  from  the  spine  at  tlie  posterior  border  of 
the  hard  palate,  or  from  the  contiguous  aponeurosis,  and  end  inferiorly  in 
tlie  tip  of  the  uvula.  Behind  this  muscle,  separating  it  from  the  mucous 
membrane,  is  the  thin  stratum  of  the  palato-pharyngeus. 

Action.  Its  fibres  elevate  the  uvula,  shortening  the  mid  part  of  the 
soft  palate,  and  direct  that  process  backwards. 

Tlie  tonsil,  k,  is  a  collection  of  follicular  capsules  resembling  those  on 
the  dorsum  linguop,  which  is  placed  close  above  the  base  of  the  tongue, 
and  between  the  arches  of  the  soft  palate.  Each  is  roundish  in  shape,  but 
variable  in  size  ;  and  apertures  are  apparent  on  its  surface.  Externally 
the  tonsil  is  situate  opposite  the  superior  constrictor  muscle  and  the  angle 
of  the  lower  jaw^ ;  and  when  enlarged  it  may  press  against  the  internal 
carotid  bloodvessel. 

The  apertures  on  the  surface  lead  to  rounded  terminal  recesses  or  hol- 
lows w^hich  are  lined  by  mucous  membrane.  Around  each  recess  is  a 
layer  of  small  closed  capsules,  which  are  seated  in  the  tissue  beneath  the 
mucous  membrane,  i\nd  are  filled  with  a  grayish  substance  containing 
cells  and  nuclear-looking  bodies.  No  openings  from  the  capsules  are  to  be 
recognized  in  the  recesses. 

Its  arteries  are  numerous  and  are  derived  from  the  facial,  lingual,  as- 
cending pharyngeal,  and  internal  maxillary  branches  of  the  external 
carotid.  Its  i'>eins  have  a  plexiform  arrangement  on  the  outer  side. 
Nerves  are  furnished  to  it  from  the  fifth  and  glosso-pharyngeal  nerves. 

The  mucous  membrane  of  the  pharynx  is  continuous  anteriorly  with  the 
lining  of  the  mouth,  nose,  and  larynx.  Covering  the  soft  palate  and  its 
numerous  small  glands  (palatine),  the  membrane  is  continued  to  the  ton- 
sils on  each  side,  and  is  prolonged  by  the  Eustachian  tube  to  the  tym- 
panum. In  front  of  each  aryta^noid  cartilage  it  incloses  a  mass  of  muci- 
])arous  glands  (arytnenoid).  Inferiorly,  it  is  continued  by  the  oesophagus 
to  the  stomach. 

The  mucous  membrane  is  provided  with  more  glands  in  the  upper,  than 
in  the  lower  part  of  the  pharynx  ;  and  its  character,  near  the  diflferent 
ai)ertures,  resembles  that  of  the  membrane  lining  the  cavities  communi- 
cating wMth  the  pharynx.  Its  epithelium  is  scaly  below  the  nares  (llenle)  ; 
but  is  columnar  and  ciliated  above  that  spot,  where  only  the  air  is  trans- 
mitted. 

Beginning  of  the  oesophagus.  Tiiis  tube  is  much  smaller  than  the  pha- 
rynx, and  the  walls  are  flaccid.  For  the  commencement,  and  its  connec- 
tions in  the  neck,  see  p.  121. 

The  gullet  consists  of  two  layers  of  muscular  fibres,  with  a  lining  of 
mucous  membrane.  The  external  layer  is  formed  of  longitudinal  fibres, 
which  begin  opposite  the  cricoid  cartilage  by  three  bundles,  anterior  and 
two  lateral ;  the  former  is  attached  to  the  ridge  at  the  back  of  the  carti- 


132  CAVITY  OF  THE  MOUTH. 

lage,  and  the  others  join  the  inferior  constrictor.  The  internal  layer^  on 
the  other  hand,  is  formed  of  circular  libres,  which  are  continuous  with 
those  of  the  inferior  constrictor.  The  structure  of  the  oesophagus  is  de- 
scribed more  fully  in  the  dissection  of  the  thorax. 


Section  XII. 

CAVITY  OF  THE  MOUTH. 


The  cheeks,  the  lips,  and  the  teeth  are  to  be  examined  with  the  mouth, 
as  all  may  be  considered  accessory  parts. 

The  Mouth.  The  cavity  of  the  mouth  is  situate  below  that  of  the 
nose,  and  extends  from  the  lips  in  front  to  the  isthmus  of  the  fauces  be- 
hind. Its  boundaries  are  partly  osseous  and  partly  muscular,  and  its  size 
depends  upon  the  position  of  the  lower  jaw  bone.  When  the  lower  jaw 
is  moderately  removed  from  the  upper,  the  mouth  is  an  oval  cavity  with 
the  following  boundaries.  The  roo}\  concave,  is  constituted  by  the  hard 
and  soft  palate,  and  is  limited  anteriorly  by  the  arch  of  the  teeth.  In  the 
Hoor  is  the  tongue,  bounded  by  the  arch  of  the  lower  teeth  ;  and  beneath 
the  tip  of  that  body  is  the  fraenum  linguae,  with  the  sublingual  gland  on 
each  side.  Each  lateral  boundary  consists  of  the  cheek  and  the  ramus  of 
the  lower  jaw  ;  and  in  it,  near  the  second  molar  tooth  in  the  upper  jaw, 
is  the  opening  of  the  parotid  duct.  The  anterior  opening  of  the  mouth  is 
bounded  by  the  lips ;  and  the  posterior  corresponds  with  the  anterior  pil- 
lars of  the  soft  palate. 

The  mucous  membrane  is  less  sensitive  on  the  hard  than  the  soft  parts 
bounding  the  mouth  ;  it  lines  the  interior  of  the  cavity,  and  is  reflected 
over  the  tongue.  Anteriorly  it  is  continuous  with  the  tegument,  and  pos- 
teriorly with  the  lining  of  the  pharynx.  The  epithelium  covering  the 
membrane  is  of  the  scaly  variety. 

Between  each  lip  and  the  front  of  the  coiTesponding  jaw  the  membrane 
forms  a  small  fold — fraenulum.  On  the  bony  part  of  the  roof  it  blends 
with  the  dense  tissue  (gums)  covering  the  vessels  and  nerves.  On  the 
soft  palate  it  is  smooth  and  thinner,  and  along  the  middle  of  the  palate  is 
a  ridge  which  ends  in  front  in  a  small  papilla.  In  the  floor  of  the  mouth 
the  membrane  forms  the  fra'num  linguae  beneath  the  tip  of  the  tongue,  and 
sends  tubes  into  the  openings  of  the  Whartonian  and  sublingual  ducts  ; 
whilst  on  each  side  of  the  fnenum  it  is  raised  into  a  ridge  by  the  subjacent 
sublingual  gland.  On  the  interior  of  the  cheek  and  lips  the  mucous  lining 
is  smooth,  and  is  separated  from  the  muscles  by  small  buccal  and  labial 
glands. 

Over  the  whole  cavity,  but  especially  on  the  lips,  are  papilla?  for  the 
pur})Ose  of  touch. 

The  CHEEK  extends  from  the  commissure  of  the  lips  to  the  ramus  of  the 
lower  jaw,  and  is  attached  above  and  below  to  the  alveolar  process  of  the 
jaw  on  the  outer  aspect.  The  chief  constituent  of  the  cheek  is  the  fleshy 
part  of  the  buccinator  muscle  ;  on  the  inner  surface  of  this  is  the  mucous 
membrane ;  and  on  the  outer  the  integuments,  with  some  muscles,  vessels, 
and  nerves.  Tiie  parotid  duct  perforates  the  cheek  near  the  second  molar 
tooth  of  the  upper  jaw. 


CAVITY    OF    THE    NOSE.  133 

The  LIPS  surround  the  opening  of  the  mouth  ;  they  consist  chiefly  of  the 
fleshy  part  of  the  orbicularis  oris  muscle,  covered  externally  by  integu- 
-ment,  and  internally  by  mucous  membrane.  The  lower  lip  is  the  larger 
and  more  movable  of  the  two.  Between  the  muscular  structure  and  the 
mucous  covering  lie  the  labial  glands ;  and  in  the  substance  of  each  lip, 
nearer  the  inner  than  the  outer  surface,  and  at  the  line  of  junction  of  the 
two  parts  of  the  orbicularis,  is  placed  the  arch  of  the  coronary  artery. 

Teeth.  In  the  adult  there  are  sixteen  teeth  in  each  jaw,  which  are 
set  in  the  alveolar  borders  in  the  form  of  an  arch,  and  are  surrounded  by 
the  gums.  Each  dental  arch  has  its  convexity  turned  forwards  ;  and, 
commonly,  the  arch  in  the  maxilla  overhangs  that  in  the  mandible  when 
the  jaws  are  in  contact.  The  teeth  are  similar  in  the  half  of  each  jaw, 
and  have  received  the  following  names  :  the  most  anterior  two  are  incisors, 
and  the  one  next  behind  is  the  canine  tooth  ;  two,  still  farther  back,  are 
the  bicuspids ;  and  the  last  three  are  molar  teeth.  Moreover,  the  last 
molar  tooth  has  been  called  also  "  dens  sapientije,"  from  the  late  period  of 
its  appearance.  The  names  applied  to  the  teeth  indicate  very  nearly  the 
part  they  perform  in  mastication  ;  thus  the  incisor  and  canine  teeth  act  as 
dividers  of  the  food,  wiiilst  the  bicuspid  and  molar  teeth  serve  to  grind 
the  aliment. 

The  several  parts  of  the  teeth,  viz.,  the  crown,  fang,  and  neck  ;  the 
general  and  special  characters  of  those  parts  in  the  diiferent  groups  of 
teeth  ;  and  the  structure  of  the  different  components  of  a  tooth,  must  be 
referred  to  in  some  general  treatise  on  anatomy. 


Section  XIII. 

DISSECTION  OF  THE  NOSE. 


To  obtain  a  view  of  the  interior  of  the  nose,  it  will  be  necessary  to  make 
a  longitudinal  section  through  the  base  of  the  skull.  Whilst  the  student 
is  examining  the  boundaries  of  the  nose  he  will  derive  advantage  from  the 
use  of  a  vertical  section  of  a  dried  nasal  cavity. 

Dissection.  Before  sawing  the  bone,  the  loose  part  of  the  lower  jaw 
on  the  right  side  should  be  taken  away ;  further,  the  tongue,  hyoid  bone, 
and  larynx,  all  united,  may  be  detached  from  the  opposite  half  of  the  lower 
jaw,  and  laid  aside  till  the  dissector  is  ready  to  use  them. 

On  the  right  side  of  the  middle  line  saw  through  the  frontal  and  nasal 
bones,  the  cribriform  plate  of  the  ethmoid,  and  part  of  the  body  of  the 
sphenoid  bone,  without  letting  the  saw  descend  into  the  nasal  cavity. 

Next  the  roof  of  the  mouth  is  to  be  turned  upwards,  and  the  soft  parts 
are  to  be  divided  on  the  right  of  the  median  line  opposite  the  cut  in  the 
roof  of  the  nose.  The  saw  is  then  to  be  carried  through  the  floor  of  the 
nose  and  the  body  of  the  sphenoid  bone  in  such  a  direction  as  to  come 
into  the  incision  above. 

The  piece  of  the  skull  is  now  separated  into  two  parts,  right  and  left; 
the  right  half  will  serve  for  the  examination  of  the  meatuses,  and  the  left 
wnll  show  the  septum  nasi,  after  the  mucous  membrane  has  been  removed. 

The  CAVITY  OF  THE  NOSE  is  placed  in  the  centre  of  the  bones  of  the 
face,  being  situate  above  the  mouth,  below  the  cranium,  and  between  the 


134  DISSECTION    OF    THE    NASAL    CAVITY. 

orbits.  This  space  is  divided  into  two  parts — nasal  fossae — by  a  vertical 
partition. 

Each  fossa  is  larger  below  tlian  above  ;  and  is  flattened  in  form,  so  that 
the  measurement  from  before  back  or  Jibove  down  exceeds  much  that  from 
within  out.  It  communicates  with  both  the  face  and  tlie  pharynx  by 
apertures  named  nares,  and  lias  also  apertures  of  communication  with  the 
sinuses  in  the  surrounding  bones,  viz.,  frontal,  ethmoid,  sphenoid,  and 
superior  maxillary.  The  student  has  to  examine  in  each  fossa  a  roof  and 
floor,  an  inner  and  outer  wall,  and  an  anterior  and  posterior  0[)ening. 

The  roof  is  somewhat  arched,  and  is  formed  by  the  cribriform  plate  of 
the  ethmoid  bone  in  tlie  centre  ;  by  the  frontal  and  nasal  bones,  and  the 
cartilages  in  front ;  and  by  tlie  body  of  the  sphenoid,  the  sphenoidal  spongy 
bone,  and  the  os  palati,  at  the  posterior  part.  In  the  dried  skull  many 
apertures  exist  in  it ;  most  are  in  the  ethmoid  bone  for  the  branches  of  the 
olfactory  nerve  with  vessels,  and  one  for  the  nasal  nerve  and  vessels ;  in 
the  front  of  the  body  of  the  sphenoid  is  the  opening  of  its  sinus. 

The  floor  is  slightly  hollowed  from  side  to  side,  and  in  it  are  the 
palate  and  superior  maxillary  bones — their  palate  processes.  Near  the 
front  in  the  dry  skull  is  the  incisor  foramen  leading  to  the  anterior  pala- 
tine fossa. 

Tlie  inner  boundary  (septum  nasi)  is  partly  osseous  and  partly  carti- 
laginous. The  osseous  part  is  constructed  by  the  vomer,  by  the  per|)en- 
dicular  plate  of  the  ethmoid  bone,  and  by  those  parts  of  the  frontal  and 
nasal  with  which  this  last  bone  articulates.  The  irregular  s[)ace  in  front 
in  the  prepared  skull  is  filled  in  the  recent  state  by  the  triangular  carti- 
lage of  the  septum,  which  forms  part  of  the  partition  between  the  nostrils, 
and  supports  the  cartilages  of  the  anterior  aperture.  Fixed  between  the 
vomer,  the  ethmoid  plate,  and  the  nasal  bones,  this  cartilage  rests  ante- 
riorly on  the  median  ridge  between  the  suj)erior  maxillie,  and  projects 
even  between  the  cartilages  of  each  nostril.  The  septum  nasi  is  commonly 
bent  to  one  side. 

The  outer  boundary  has  the  greatest  extent  and  the  most  irregular  sur- 
face. Six  bones  enter  into  its  formation,  and  they  come  in  the  following 
order  from  before  backwards  :  the  nasal  and  superior  maxillary  ;  tlie  small 
OS  unguis  with  the  lateral  mass  of  the  ethmoid  bone  ;  and  posteriorly  the 
ascending  part  of  the  palate  bone,  with  the  internal  pterygoid  platen  of  the 
sphenoid  bone  :  of  these,  the  nasal,  ungual,  and  ethmoidal  reach  only  about 
half  way  from  the  roof  to  floor,  whilst  the  others  extend  the  whole  depth. 
Altogether  in  front  of  the  bones,  the  lateral  cartilages  may  be  said  to  con- 
struct part  of  this  boundary. 

On  this  wall  are  three  convoluted  osseous  pieces,  named  spongy  or  tur- 
binate bones,  (fig.  31),  wliich  project  into  the  cavity  : — the  two  upper  (') 
and  (^),  are  processes  of  the  ethmoid,  but  the  lower  one  (^),  is  a  separate 
bone — the  inferior  spongy.  The  spongy  bones  are  confined  to  a  certain 
y)ortion  of  the  outer  wall,  and  their  extent  would  be  limited  by  a  line  con- 
tinued nearly  vertically  u[)wards  to  the  roof  of  the  cavity  from  both  the 
front  and  back  of  the  hard  j)alate.  Between  each  turbinate  bone  and  the 
wall  of  the  nose  is  a  longitudinal  hollow  or  meatus  ;  and  into  these  hollows 
the  nasal  duct  and  the  sinuses  of  the  surrounding  bones  open. 

The  meatuses  are  the  spaces  arched  over  by  the  spongy  bones  ;  and  as 
the  bones  are  limited  to  a  certain  part  of  the  outer  wall,  so  are  the  spaces 
beneath  them. 

The  upper  one  (fig.  31,  *)  is  the  smallest  and  straightest  of  the  three 


SPONGY    BONES    AND    MEATUSES 


135 


meatuses,  and  occupies  the  posterior  half  of  the  space  inchided  by  the  ver- 
tical lines  before  mentioned.  Into  it  the  posterior  ethmoidal  sinuses  open 
at  the  front ;  and  at  its  posterior  part,  in  the  dried  bone,  is  the  spheno- 
pahitine  foramen  by  which  the  nerves  and  vessels  enter  the  nose. 

The  middle  meatus  (fig.  31,  ^)  is  longer  than  the  preceding;  it  is 
curved  upwards  in  front,  and  reaches  all  across  the  space  referred  to  on 
the  outer  wall.  Anteriorly  it  communicates  by  a  funnel-shaped  passage 
(infundibulum)  with  the  frontal  sinus  and  the  anterior  ethmoidal  cells  ; 
and  near  its  middle  is  a  small  aperture,  which  leads  into  tlie  cavity  of  the 
upper  jaw. 

The  inferior  meatus  (fig.  31,*)  is  straighter  than  the  middle  one,  and 
rather  exceeds  the  width  of  the  included  space  on  the  outer  wall ;  and 

Fiff.  31. 


1.  Upper  spongy  bone. 

2.  Middle  spongy  bone. 

3.  Inferior  spongy  bone. 

4.  Square  part  of  the  ethmoid  bone. 

6.  Upper  meatus. 

7.  Middle  meatus. 

8.  Lower  meatus. 

9.  Rudimentary  fourth  meatus. 
10.  Vestibule  of  the  nasal  cavity. 

The  woodcut  shows  also  the  aper- 
tures of  the  glands  of  the  nose. 


Spongy  Bones  and  Meatuses  of  the  Nasal  Cavity. 


when  the  bone  is  clothed  by  the  mucous  membrane  it  extends  still  further 
forwards.     In  its  front  is  the  opening  of  the  ductus  ad  nasum. 

Occasionally  there  is  a  small  fourth  or  rudimentary  meatus  above  the 
rest  (fig.  31,  '),  which  communicates  with  a  posterior  ethmoidal  cell. 

The  naves.  In  the  recent  condition  of  the  nose  each  fossa  has  a  dis- 
tinct anterior  opening  in  the  face,  and  another  in  the  pharynx  ;  but  in  the 
skeleton  there  is  only  one  common  opening  in  front  for  both  sides.  These 
apertures,  and  the  parts  bounding  them,  have  been  before  described  (pp. 
42  and  126). 

The  mucous  membrane  lining  the  nasal  fossa  is  called  the  pituitary  or 
Schneiderian  membrane  ;  and  from  its  blending  with  the  periosteum  it 
acquires  much  strength.  It  is  continuous  with  the  integument  at  the  nos- 
tril, and  with  the  membrane  lining  the  pharynx  through  the  posterior 
opening :  moreover,  it  is  also  continuous  with  the  mucous  membrane  of 
the  eyeball,  and  with  that  of  the  different  sinuses,  viz.,  frontal,  ethmoidal, 
sphenoidal,  and  maxillary. 

The  foramina  in  the  dry  bones,  which  transmit  nerves  and  vessels,  are 
entirely  closed  by  the  membrane,  viz.,  the  incisor,  spheno-palatine,  the 
holes  in  the  cribriform  plate,  and  the  foramen  for   the  nasal  nerve  and 


136 


DISSECTION    OF    THE    NASAL    CAVITY, 


vessels  ;  but  the  apertures  that  lead  to  the  sinuses  and  the  orbit  are  only 
somewhat  diminished  by  the  lining  they  receive.  The  membrane  is 
stretched  over  the  opening  of  the  ductus  ad  nasum,  forming  a  flap  or  valve 
to  close  the  aperture. 

The  characters  of  the  membrane  in  the  lower  or  respiratory  part  of  the 
nose  differ  greatly  from  those  of  the  same  layer  in  the  olfactorial  region 
near  the  roof. 

In  the  lower  region  of  the  nose,  through  which  the  air  passes  to  the 
lungs,  the  membrane  is  thick,  and  closely  united  to  the  subjacent  perios- 
teum and  pericliondrium ;  and  on  the  margins  of  the  two  inferior  spongy 
bones  it  is  projected  somewhat  by  the  large  submucous  vessels,  so  as  to 
increase  the  extent  of  surface.  In  the  canals  and  sinuses  it  is  very  thin. 
Near  the  nostril  it  is  furnished  with  papillae,  and  small  hairs  (vibrissae). 

The  surface  is  covered  by  the  apertures  of  branched  mucous  glands, 
which  are  in  greatest  abundance,  and  of  largest  size,  about  the  middle  and 
posterior  parts  of  the  nasal  fossa.  In  the  lower  part  of  the  nose,  and  in 
the  sinuses,  the  epithelium  is  of  the  columnar  ciliated  kind;  but  it  becomes 
laminated  or  scaly  in  the  dilatation  or  vestibule  inside  the  nostril  (fig. 
31,  ^0). 

Fig.  32. 


A.  1.  Columnar  epithelium  at  the  free  surface. 

2.  Granular  or  middle  layer  of  the  same. 

3.  Deepest  layer  of  elouj,'ated  cells  placed  vertically. 

4.  Secreting  tubular  glands. 

B.  a.  Pieces  of  the  columnar  epithelium  greatly  en- 

larged. 
6.  Olfactorial  cells  amongst  the  epithelium  parti- 
cles. 


Magnified  Vertical  Section  of  the  Mucous  Membrane  of  the  Nose  (altered  from  Henle). 


The  olfactory  region  (fig.  32)  is  situate  at  the  top  of  the  nasal  cavity, 
and  is  confined  to  the  surface  of  the  roof  formed  by  the  cribriform  plate  of 
the  ethmoid;  to  a  portion  of  the  outer  wall  constructed  by  the  lateral 
mass  of  the  ethmoid  bone:  and  to  a  corresponding  extent  of  the  septum, 
viz.,  about  one-tliird. 

Tlie  mucous  membrane  in  the  olfactory  region  receives  the  olfactory 
nerve,  and  is  tlierefore  tiie  seat  of  the  sense  of  smell.  It  differs  much 
from  that  in  the  lower  portion  of  the  nose,  for  it  is  less  strong  and  vascu- 
lar; and  is  of  a  yellowish  color,  wliich  is  due  to  pigment  in  tiie  epithelium 
and  the  glands. 

Tlie  epithelium  (fig.  32  a)  is  thicker  but  softer  here  than  lower  in  the 
cavity,  and  it  is  columnar  on  the  surface,  but  not  ciliated.     Beneath  the 


OLFACTORY    NERVE, 


137 


surface  layer  are  strata  of  granules  and  ovalish  cells  (^),  amongst  which 
sink  the  pointed  or  attached  ends  of  the  pieces  of  epithelium. 

Around  the  pieces  of  the  columnar  epithelium  stand  numerous  bodies 
named  olfactorial  cells  by  Schultze  (fig.  32  b.  *).  They  consist  of  small 
spindle-shaped  nucleated  cells,  with  a  rounded  filament  prolonged  from 
each  end  towards  the  attached  and  free  surfaces  of  the  mucous  membrane : 
that  to  the  free  surface,  the  larger,  ends  on  a  level  with  the  pieces  of  the 
columnar  epithelium.  But  the  connections  of  the  deeper  threads  or  pro- 
cesses are  unknown ;  they  have  been  supposed  to  unite  with  the  olfactory 
nerve. 

The  glands  in  the  olfactory  region  are  simple  lengthened  tubes  (fig. 
32  A.  *)  like  those  in  the  stomach,  but  are  slightly  wavy,  and  end  in  the 
submucous  tissue  by  closed  extremities.  A  flattened  epithelium,  with 
colored  granular  contents,  lines  the  tubes (Henle.) 

Dissection.  At  this  stage  of  the  dissection,  little  will  be  seen  of  the 
distribution  of  the  olfactory  nerve.  If  the  septum  nasi  be  removed,  so  as 
to  leave  entire  the  membrane  covering  it  on  the  opposite  side  (the  left), 
the  filaments  of  the  nerve  will  appear  on  the  surface,  near  the  cribriform 
plate.  In  the  membrane,  too,  near  the  front  of  the  septum,  is  an  offset  of 
the  nasal  nerve. 

The  naso-palatine  nerve  and  artery  (fig.  33,  ^)  are  to  be  sought  lower 
down,  as  they  are  directed  from  behind  forwards,  towards  the  anterior 

Fijr.  33. 


Nerves  op  the  Septum  of  the  Nose. 

1.  Olfactory  bulb  and  its  ramifications  on  the        3.  Naso-palatine  nerve  from  Meckel's  ganglion 

septum.  (too  lar^e  in  the  cut.) 

2.  Nasal  nerve  of  the  ophthalmic  trunk. 


palatine  fossa;  the  artery  is  rejidily  seen,  especially  if  it  is  injected,  but 
the  fine  nerve,  which  is  about  as  large  as  a  coarse  liair,  is  imbedded  in  the 
membrane  and  will  be  found  by  scraping  with  the  point  of  the  scalpel. 

By  cutting  through  the  fore  and  upper  jmrt  of  the  membrane  that  has 
been  detached  from  the  septum  nasi,  other  branches  of  the  olfactory  nerve 
may  be  traced  on  the  outer  wall  of  tlie  nasal  fossa. 


138  DISSECTION    OF    THE    HEAD. 

The  OLFACTORY  NERVE  (fig.  33,  ^)  fomis  a  bulb  on  the  cribriform  plate 
of  the  ethmoid  bone,  and  send8  branches  to  the  olfactory  region  of  the 
nose  througl)  the  apertures  in  the  roof.  These  branches  are  about  twenty 
in  number,  and  are  divisible  into  three  sets.  An  inner  set,  the  largest, 
descend  in  the  grooves  on  the  septum  nasi,  and  branching,  extend  over 
the  upper  third.  A  middle  set  is  confined  to  the  roof  of  the  nose.  And 
an  external  set  is  distributed  on  the  upper  spongy  bone,  on  the  anterior 
square  surface  of  the  os  ethmoides,  and  on  the  fore  part  of  the  middle 
spongy  bone. 

As  the  branches  of  the  olfactory  nerve  leave  the  skull,  they  receive 
tubes  from  the  dura  mater  and  pia  mater,  which  are  lost  in  the  tissue  to 
which  the  nerves  are  distributed.  The  nerves  ramify  in  the  pituitary 
membrane  in  tufts  of  filaments  which  communicate  freely  with  the  con- 
tiguous twigs,  forming  a  network,  but  their  mode  of  termination  in  the 
tissue  is  unknown.  It  has  been  suggested  by  Schulze  that  they  join  the 
deep  processes  or  ends  of  the  so-called  olfactorial  cells ;  but  this  union  has 
not  been  seen. 

The  olfactory  nerve  differs  in  structure  from  the  other  cranial  nerves ; 
for  its  branches  are  deficient  in  the  white  substance  of  Schwann,  are  not 
divisible  into  fibrillar,  and  are  nucleated  and  granular  in  texture.  They 
resemble  the  ganglionic  fibres:  and  seem  to  consist  of  an  extension  of  the 
nerve  substance  of  the  olfactory  bulb. 

The  other  nerves  in  the  nose  will  be  described  in  the  following  section. 

Bloodvessels.  Foi*  a  statement  of  the  different  vessels  of  the  nose,  see  p. 
141.  The  arteries  form  a  network  in  the  pituitary  membrane,  and  a 
large  submucous  plexus  on  the  edge  of  each  of  the  two  lower  spongy  bones, 
especially  on  the  inferior.  The  veins  have  a  plexiform  disposition  like 
the  arteries,  and  this  is  largest  on  the  lower  spongy  bone  and  the  septum 
nasi. 


Section  XIV. 


SPHENO-PALATINE  AND  OTIC  GANGLIA,  FACIAL  AND  NASAL  NERVES, 
AND  BRANCHES  OF  THE  INTERNAL  MAXILLARY  ARTERY. 

The  preparation  of  Meckel's  ganglion  and  its  branches  (fig.  34),  and  of 
the  terminal  branches  of  the  internal  maxillary  artery,  is  a  somewhat  ditti- 
cult  task  in  consequence  of  the  nerves  and  vessels  being  contained  in 
osseous  canals  which  require  to  be  opened.  As  is  the  case  witii  other 
dissections,  the  student  seeks  first  the  branches,  and  traces  these  to  the 
ganglion  and  main  trunk. 

Dissection.  The  left  half  of  the  head  is  to  be  used  for  the  display  of  the 
ganglion  and  its  branches;  but  the  student  may  previously  acquire  some 
skill  by  attempting  the  dissection  on  the  remains  of  the  right  side. 

To  lay  bare  the  branches  of  the  palate,  detach  the  soft  parts  in  the  roof 
of  the  mouth  from  the  bone,  until  tlie  nerves  and  vessels  escaping  from  the 
posterior  y)alatine  foramina  are  arrived  at.  Cut  off,  with  a  bone  forceps, 
the  j)OSterior  part  of  the  hard  i)alate  to  a  level  with  the  vessels  and  nerves  ; 
and  cleaning  these,  trace  offsets  behind  into  the  soft  palate,  and  follow  the 
main  pieces  forwards  to  the  front  of  the  mouth. 

Take  away  without  injury  to  the  naso-palatine  nerve  and  vessels  (already 


SPHENO-PALATINE    GANGLION.  139 

found),  the  hinder  part  of  the  loose  piece  of  mucous  membrane  before  de- 
tached from  the  septum  nasi,  and  separate  the  mucous  membrane  from 
the  outer  wall  of  the  nasal  fossa,  behind  the  spongy  bones,  as  high  as  the 
spheno-palatine  foramen.  In  reflecting  forwards  the  membrane  many 
branches  of  vessels  and  nerves  will  be  seen  entering  it  through  the  fora- 
men ;  but  these  may  be  left  for  the  present,  as  directions  for  their  dissec- 
tion will  be  subsequently  given.  When  the  lining  membrane  of  the  nose 
has  been  removed  behind  the  spongy  bones,  palatine  nerves  and  vessels 
will  appear  through  the  thin  translucent  palate  bone,  and  will  be  readily 
reached  by  breaking  carefully  through  it  w^ith  a  chisel.  Afterwards  the 
tube  of  membrane  containing  the  palatine  vessels  and  nerves  being  opened, 
these  are  to  be  followed  down  to  the  soft  palate  and  the  roof  of  the  mouth, 
and  upwards  to  the  ganglion  which  is  close  to  the  body  of  the  sphenoid 
bone. 

To  bring  the  ganglion  fully  into  view,  it  will  be  necessary  to  saw  through 
the  overhanging  part  of  the  sphenoid  bone,  to  cut  away  pieces  of  the  bones 
surrounding  the  hollow  in  which  it  lies,  and  to  remove  with  care  tlie 
enveloping  fat  and  the  periosteum.  The  ganglion  then  appears  as  a  flat- 
tened reddish-looking  body,  from  which  the  vidian  and  pharyngeal  nerves 
pass  backwards.  Besides  the  branches  referred  to,  the  student  should 
seek  two  large  nerves  from  the  upper  part  of  the  ganglion  to  join  the 
upper  maxillary,  and  smaller  offsets  to  the  floor  of  the  orbit. 

To  trace  backwards  the  vidian  branch  to  tlie  carotid  plexus  and  the 
facial  nerve,  the  student  must  lay  open  the  canal  which  contains  it  and 
its  artery  in  the  root  of  the  pterygoid  process;  and  in  doing  this  he  must 
define  the  small  pharyngeal  brandies  of  nerve  and  artery  which  are  super- 
ficial to  tlie  vidian,  and  lie  in  the  pterygo-palatine  canal.  At  the  back  of 
the  pterygoid  canal,  a  small  branch  from  the  vidian  to  the  plexus  on  the 
internal  carotid  artery  is  to  be  looked  for.  Lastly,  the  vidian  nerve  is  to 
be  followed  into  the  skull  through  the  cartilage  in  the  foramen  lacerum 
(basis  cranii),  after  cutting  away  the  point  of  the  petrous  portion  of  the 
temporal  bone,  and  dividing  the  internal  carotid  artery;  and  it  is  to  be 
pursued  on  the  surface  of  the  temporal  bone,  beneath  the  ganglion  of  the 
fifth  nerve,  to  the  hiatus  Fallopii :  its  junction  with  the  facial  nerve  will 
be  seen  with  the  dissection  of  that  nerve. 

The  branches  of  the  ganglion  to  the  nose  will  be  found  entering  the 
outer  surface  of  the  detached  mucous  membrane  opposite  the  spheno-pala- 
tine foramen,  with  corresponding  arteries.  One  of  these  nerves  (naso- 
palatine), before  dissected  in  the  membrane  of  the  septum,  is  to  be  isolated, 
and  to  be  followed  forwards  to  where  it  enters  the  floor  of  the  nose.  The 
branches  of  the  internal  maxillary  artery  with  the  nerves  are  to  be  cleaned 
at  tiie  same  time. 

The  SPHENO-PALATINE  GANGLION  (fig.  34,  ')  (ganglion  of  Meckel) 
occupies  the  spheno-maxillary  fossa,  close  to  the  spheno-palatine  foramen, 
and  is  connected  with  the  branches  of  the  superior  maxillary  nerve  to  the 
palate.  The  ganglionic  mass  is  somewhat  triangular  in  form,  and  of  a 
reddish-gray  color.  It  is  situate  for  the  most  part,  behind  the  branches 
(spheno-palatine)  of  the  superior  maxillary  nerve  to  the  palate,  so  as  to  sur- 
round only  part  of  their  fibres  ;  and  it  is  prolonged  posteriorly  into  the 
vidian  nerve.  Meckel's  ganglion  resembles  the  other  ganglia  in  connec- 
tion with  the  fifth  nerve  in  having  sensory,  motor,  and  sympathetic  offsets 
or  roots  connected  with  it. 

The  Branches  of  the  ganglion  are  distributed  for  the  most  part  to  the 


140 


DISSECTION    OF    THE    HEAD. 


nose  and  palate,  but  small  offsets  are  given  to  the  pharynx  and  the  orbit. 
Other  offsets  connect  it  with  surrounding  nerves. 

Branches  of  the  nose.  The  nasal  branches,  from  three  to  five  in  num- 
ber, are  for  the  most  part  very  small  and  soft,  and  pass  inwards  through 
the  spheno-palatine  foramen  :  their  distribution  is  given  below  : — 

The  superior  nasal  branches  (f  t)  are  distributed  in  the  mucous  mem- 
brane on  the  two  upper  spongy  bones,  and  a  few  filaments  reach  the  back 
part  of  the  septum  nasi. 

The  naso-palatine  nerve  (nerve  of  Cotunnius)  (fig.  33,  ^)  crosses  the 
roof  of  the  nasal  fossa  to  reach  the  septum  nasi,  and  descends  on  that  par- 
tition to  near  the  front.  In  the  floor  of  the  nose  it  enters  a  special  canal 
by  the  side  of  the  septum,  the  left  being  anterior  to  the  other,  and  is  con- 
veyed to  the  roof  of  the  mouth,  where  it  lies  in  the  centre  of  the  anterior 
palatine  fossa.  Finally,  the  nerves  of  opposite  sides  are  united  in  the 
mouth,  and  are  distributed  in  the  mucous  membrane  behind  the  incisor 
teeth.  On  the  septum  nasi  filaments  are  supplied  by  the  naso-palatine 
nerve  to  the  mucous  membrane.  To  follow  the  nerve  to  its  termination, 
the  canal  in  the  roof  of  the  mouth  must  be  opened. 


Fiff.  34. 


Nerves  op  the  Nose  and  Palate. 


1.  Olfactory  nerve. 

2.  Olfactory  bulb  giving  branches  to  the  nose. 

3.  Third  nerve. 
4    Fourth  nerve. 
.0.  Fifth  nerve. 

6.  Nasal  nerve  of  the  ophthalmic  trunk. 


7.  Meckel's  ganglion. 

S.  Vidian  nerve. 

9.  Larger  palatino  nerve. 
10.  Smaller  palatine  nerve, 
ft  Nasal  nerve. 


Branches  of  the  palate.  The  nerves  of  the  palate,  though  connected  in 
part  with  tlie  ganglionic  mass,  are  the  continuation  of  the  spheno-palatine 
branches  of  tjje  su])erior  maxillary  nerve  (p.  104).  Below  the  ganglion 
they  are  divided  into  three — large,  small,  and  external. 

The  larffe  palatine  nerve  (anterior)  (fig.  34,  ^)  reaches  the  roof  of  the 
mouth  through  the  largest  palatine  canal,  and  courses  forwards  nearly  to 
tlie  incisor  teeth,  where  it  joins  the  naso-palatine  nerve.  Whilst  in  the 
canal,  the  nerve  furnishes  two  or  more  filaments  {inferior  nasal  t)  to  the 


SPHENO-PALATINE    GANGLION.  141 

membrane  on  the  middle  and  lower  spongy  bones  ;  in  the  roof  of  the 
mouth  it  supplies  the  mucous  membrane  and  glands,  and  gives  an  offset  to 
the  soft  palate. 

The  small  jmlatiiie  nerve,  10  (posterior),  lies  in  the  smaller  canal,  and 
ends  inferiorly  in  the  soft  pahite,  and  the  levator  j^alati  and  azygos  uvulje 
muscles  ;  it  supplies  the  uvula  and  tonsil. 

The  external  palatine  nerve  is  smaller  than  the  other  two,  and  de- 
scends in  the  canal  of  the  same  name.  Leaving  the  canal,  the  nerve  is 
distributed  to  the  velum  palati  and  the  tonsil. 

The  pharyngeal  branch  is  very  small,  and  is  directed  through  the 
pterygo-palatine  canal  to  the  mucous  membrane  of  the  pharynx  near  the 
Eustachian  tube,  in  which  it  ends. 

Branches  to  the  orbit.  Two  or  three  in  number,  these  ascend  through 
the  spheno-maxillary  fissure,  and  end  in  the  fleshy  layer  of  the  musculus 
orbitalis  (p.  GO).  It  will  be  necessary  to  cut  throngh  the  sphenoid  bone 
to  follow  these  nerves  to  their  termination. 

Connecting  branches.  The  ganglion  is  united,  as  before  said,  with  the 
spheno-palatine  branches  of  the  fiftli  nerve  (fig.  24,  ^),  receiving  sensory 
nerve  fibres  through  them  ;  and  through  the  medium  of  the  vidian,  which 
is  described  below,  it  communicates  with  a  motor  nerve  (facial)  and  with 
the  sympathetic  nerve. 

The  vidian  nerve  (^)  passes  backwards  through  the  vidian  canal,  and 
sends  some  small  filaments,  through  the  bone,  to  the  membrane  of  the  back 
of  the  roof  of  the  nose  {upper posterior  nasal  branches).  At  its  exit  from 
the  canal,  the  nerve  receives  a  soft  reddish  offset  {carotid  branch)  from 
the  sympathetic  on  the  outer  side  of  the  carotid  artery.  The  continuation 
of  the  nerve  enters  the  cranium  through  the  cartilaginous  substance  in  the 
foramen  lacerum  (basis  cranii),  and  is  directed  backwards  in  a  groove  on 
the  surface  of  the  })etrous  part  of  the  temporal  bone,  where  it  takes  the 
name  of  large  superficial  petrosal  nerve  (fig.  35,  ^).  Lastly  it  is  continued 
through  the  hiatus  Fallopii,  to  join  the  gangliform  enlargement  on  the 
facial  nerve.  AVhilst  in  the  temporal  bone,  the  vidian  receives  a  twig 
from  the  tympjuiic  nerve. 

The  vidian  nerve  is  supposed  to  consist  of  motor  and  sympathetic  fibres 
in  the  same  sheath,  as  in  the  connecting  branches  between  the  sympa- 
thetic and  spinal  nerve. 

Directions.  The  student  may  now  give  his  attention  to  the  remaining 
nerves  in  the  nasal  cavity. 

Dissectioti.  The  nasal  nerve  is  to  be  sought  in  the  nose  beiiind  the 
nasal  bone  (fig.  34),  by  gently  detaching  the  lining  membrane,  after 
having  cut  olf  the  projecting  bone.  A  branch  is  given  from  the  nerve  to 
the  septum  nasi,  but  probably  this,  and  the  trunk  of  the  nerve,  will  be 
seen  but  imperfectly  in  the  present  condition  of  the  part. 

The  terminal  branches  of  the  internal  maxillary  artery  in  the  spheno- 
maxillary fossa  have  been  laid  bare  in  the  dissection  of  Meckel's  ganglion, 
but  they  may  be  now  completely  traced  out. 

The  nasal  nerve  (of  the  ophthalmic)  (fig.  34,  ^)  has  been  already  seen 
in  the  skull  and  orbit.  Entering  the  nasal  fossa  by  an  a})erture  at  the 
front  of  the  ethmoid  bone,  the  nerve  gives  a  branch  to  the  membrane  of 
the  septum,  and  is  continued  in  a  groove  behind  the  os  nasi  to  the  lower 
margin  of  this  Ijone  where  it  escapes  to  the  surface  of  the  nose  in  the 
face  (fig.  9,  '). 


142  DISSECTION    OF    THE    HEAD. 

Branches.  Tlie  branch  to  the  septum  (fig.  33)  divides  into  fibiments 
that  ramify  on  the  anterior  part  of  tliat  partition,  and  reach  nearly  to  the 
lower  border. 

One  or  two  jilaments  are  likewise  furnished  by  the  nerve  to  the  mueous 
membrane  on  the  outer  wall  of  the  nasal  fossa ;  these  extend  as  low  as  the 
inferior  spongy  bone. 

Terminal  branches  of  the  internal  maxillary  artery.  The 
branches  of  the  artery  in  the  spheno-maxillary  fossq,,  which  have  not  been 
examined,  are  the  superior  palatine,  naso-palatine,  pterygo-palatine,  and 
vidian. 

The  superior  or  descending  palatine  is  the  largest  branch,  and  accom- 
panies the  large  palatine  nerve  through  the  canal,  and  along  the  roof  of 
the  mouth  ;  it  anastomoses  beiiind  the  incisor  teeth  wdth  its  fellow,  and 
with  a  branch  through  the  incisor  foramen.  This  artery  supplies  offsets 
to  the  soft  palate  and  tonsil  tlirough  the  other  palatine  canals,  and  some 
twigs  are  furnished  to  the  lining  membrane  of  the  nose.  In  the  roof  of 
the  mouth  the  mucous  membrane,  glands,  and  gums,  receive  their  vessels 
from  it. 

The  nasal  Qv  spheno -palatine  artery  enters  the  nose  through  the  spheno- 
palatine foramen,  and  divides  into  branches  :  Some  of  these  are  distributed 
on  the  spongy  bones,  and  the  outer  wall  of  tlie  nasal  fossa,  and  supply  oif- 
sets  to  tlie  posterior  ethmoidal  cells.  One  long  branch,  artery  of  the  sep- 
tum {art.  naso.  palatino?)  runs  on  the  partition  between  the  nasal  fossne  to 
the  incisor  foramen,  through  which  it  anastomoses  with  the  superior  pala- 
tine in  the  roof  of  the  mouth  ;  this  branch  accompanies  the  naso-palatine 
nerve,  and  covers  the  septum  with  numerous  ramifications. 

'YXxe  pterygo-palatine  is  a  very  small  branch  which,  passing  backwards 
through  the  canal  of  the  same  name,  is  distributed  to  the  lining  membrane 
of  the  pharynx. 

The  vidian  or  pterygoid  branch  is  contained  in  the  vidian  canal  with 
the  nerve  of  the  same  name,  and  ends  on  the  mucous  membrane  of  the 
Eustachian  tube  and  the  upper  part  of  the  pharynx. 

Some  small  nasal  arteries  are  furnished  to  the  roof  of  the  nasal  fossa 
by  the  posterior  ethmoidal  branch  of  the  ophthalmic  (p.  56).  Also  the 
anterior  ethmoidal  (internal  nasal,  p.  57),  enters  the  cavity  with  the  nasal 
nerve,  and  ramifies  in  the  lining  membrane  of  the  fore  part  of  the  nasal 
chamber  as  low  as  the  vestibule  ;  a  branch  passes  to  the  face  between  the 
OS  nasi  and  the  cartilage,  with  its  nerve.  Other  offsets  from  the  facial 
artery  supply  the  part  near  the  nostril. 

Veins.  Tlie  veins  accompanying  the  terminal  branches  of  the  internal 
maxillary  artery  unite  in  the  spheno-maxillary  fossa  in  the  cdveolar 
plexus.  Into  this  plexus  offsets  are  received  from  the  pterygoid  plexus 
and  the  infraorbital  vein  ;  and  from  the  plexus  a  large  trunk  (anterior  in- 
ternal maxillary)  is  directed  forwards  below  the  malar  bone  to  join  the 
facial  vein  (p.  40).  Beneath  the  mucous  membrane  of  the  nose  the  veins 
have  a  {)lexiform  arrangement,  as  before  said. 

Facial  nerve  in  the  temporal  bone  (fig.  35).  This  nerve  winds 
through  the  petrous  part  of  the  temporal  bone  ;  and  it  is  followed  with 
difficulty  in  consequence  of  the  extreme  density  of  the  bone,  and  the  ab- 
sence of  marks  on  the  surface  to  indicate  its  position.  To  render  this 
dissection  easier,  the  student  should  be  provided  with  a  temporal  bone,  in 
which  the  course  of  the  facial  nerve  and  the  cavity  of  the  tympanum  are 
displayed. 


FACIAL    NERVE    IN    THE    BONE, 


143 


Dissection.  The  examination  of  the  nerve  is  to  be  begun  at  the  stylo- 
mastoid foramen,  and  to  be  carried  forwards  from  that  point.  With  this 
view,  the  side  of  the  skull  should  be  sawn  through  vertically  between  the 
meatus  externus  and  tlie  anterior  border  of  tlie  mastoid  process,  so  as  to 
open  the  ])Osterior  part  of  the  aqueduct  of  Fallopius.  The  nerve  will  be 
then  seen  entering  deeply  into  the  substance  of  the  temporal  bone  ;  and  it 
can  be  followed  by  cutting  away  with  the  bone  forceps  all  the  bone  pro- 
jecting above  it.  In  this  last  step  the  cavity  of  the  tympanum  will  be 
more  or  less  opened,  and  the  chain  of  bones  in  it  laid  bare. 

The  nerve  is  to  be  traced  onwards  along  tlie  inner  side  of  the  tympa- 
num, till  it  becomes  enlarged,  and  bends  suddenly  inwards  to  the  meatus 
auditorious  internus.  Tlie  surrounding  bone  is  to  be  removed  from  that 
enlargement  so  as  to  allow  of  the  petrosal  nerves  being  traced  to  it  ;  and 
the  meatus  auditorious  is  to  be  laid  open,  to  see  the  facial  and  auditory 
nerves  in  that  hollow. 

The  course  of  the  chorda  tympani  nerve  (branch  of  the  facial)  across 
the  tympanum  will  be  brought  into  sight  by  the  removal  of  the  central  ear 
bone,  the  incus.     This  nerve  may  be 
also   followed  to   the  facial   througii 
the  wall  of  the  cavity  behind,  as  well 
as  out  of  the  cavity  in  front. 

The  remaining  branches  of  the 
facial  nerve  in  the  bone  are  very 
minute,  and  are  not  to  be  seen  ex- 
cept on  a  fresh  piece  of  the  skull 
which  has  been  softened  in  acid.  The 
student  may  therefore  omit  the  para- 
graphs marked  with  an  asterisk,  till 
he  is  able  to  obtain  a  part  on  which 
a  careful  examination  can  be  made. 

The  facial  nerve  (fig.  35,  ^)  is  re- 
ceived into  the  internal  auditory  mea- 
tus, and  entering  the  aqueduct  of 
Fallopius  at  the  bottom  of  that  hol- 
low, is  conducted  through  the  tem- 
poral bone  to  the  stylo-mastoid  fora- 
men and  the  face  (p.  48).  In  its 
serpentine  course  tlirough  the  bone, 
the  nerve  is  first  directed  outwards 
to  the  inner  wall  of  the  tympanum  : 
at  that  S[)Ot  it  bends  backwards,  and 
is  marked  by  a  ganglifbrm  swelling 
(in  tu  muscen  tia  gangliformis),  to 
which  several  small  nerves  are  united. 
From  this  swelling  the  nerve  is  con- 
tinued through  the  arched  aqueduct,  to  the  aperture  of  exit  from  the 
bone. 

The  branches  of  the  nerve  in  the  bone  serve  for  the  most  part  to  con- 
nect it  with  otlier  nerves  ;  but  one  supplies  the  tongue,  and  another  the 
stapedius  muscle. 

*  Connecting  branches  communicate  with  the  auditory  and  glosso- 
pharyngeal nerves  ;  and  with  two  trunks  (superior  and  inferior  maxillary) 
of  the  fifth  nerve. 


Nerves  joining  the  ENLAROhMENT  of  thk 
Facial  Nerve. 

1.  Facial  nerve. 

2.  Large  superficial  petrosal. 

3.  Small  superficial  petrosal  from  Jacobson's 

nerve. 
i.  External  superficial  petrosal. 
5.  Chorda  tympaui  of  the  facial. 


144  DISSECTION    OF    THE    HEAD. 

*  Union  with  the  auditory  nerve.  In  the  bottom  of  the  meatus  the 
facial  and  auditory  nerves  are  connected  by  one  or  two  minute  fihiments. 

*  Connecting  branches  of  the  gangliform.  enlargement.  The  swelling 
of  the  facial  nerve  receives  three  small  twigs.  One  in  front  is  the  large 
superficial  petrosal  nerve^  (vidian)  ;  another  is  the  small  superficial  petro- 
sal^ of  the  tympanic  nerve  ;  and  the  third  is  the  external  superficial 
petrosal,  *,  which  is  derived  from  the  sympathetic  on  the  middle  menin- 
geal artery. 

*  The  branch  of  the  stapedius  muscle  arises  at  the  back  of  the  tympa- 
num, and  reaches  its  muscle  by  a  special  canal. 

Chorda  tympani.  This  long  but  slender  branch  of  the  facial  nerve 
crosses  the  tympanum,  and  ends  in  the  tongue.  Arising  about  a  quarter 
of  an  inch  from  the  stylo-mastoid  foramen  (fig.  35,  ^),  it  enters  the  tym- 
panum below  tlie  pyramid.  In  the  cavity  the  nerve  is  directed  forwards 
across  the  handle  of  the  malleus  and  tlie  membrana  tympani  to  the  Glase- 
rian  fissure,  or  to  an  aperture  on  the  inner  side,  through  which  it  leaves 
the  tympanum.  As  it  issues  from  the  cavity  it  emits  a  small  branch  to 
the  laxator  tympani  muscle  (?). 

Outside  the  skull  the  chorda  tympani  joins  the  gustatory  nerve,  and 
continues  along  it  to  the  submaxillary  ganglion  and  the  tongue  (p.  102). 

The  AUDITORY  NERVE  will  be  learnt  with  the  ear.  Entering  the  audi- 
tory meatus  with  the  facial  it  divides  into  two  parts,  of  whicli  one  belongs 
to  the  cochlea,  and  the  other  to  the  vestibule. 

Otic  ganglion  (fig.  36).  At  this  stage  of  the  dissection  there  is  little 
to  be  seen  of  the  ganglion,  but  the  student  should  remember  that  it  is  one 
of  the  things  to  be  examined  in  a  fresh  part.  Its  situation  is  on  the 
inner  aspect  of  the  inferior  maxillary  nerve,  close  to  the  base  of  the  skull, 
and  it  must  therefore  be  arrived  at  from  the  inner  side. 

Dissection.  Putting  the  part  in  the  same  position  as  for  the  examina- 
tion of  Meckel's  ganglion,  the  dissector  should  define  the  Eustachian  tube 
and  the  muscles  of  the  palate,  and  then  take  away  the  levator  palati  and 
that  tube,  using  much  care  in  removing  the  last.  When  some  loose 
areolar  tissue  has  been  cleared  away  the  internal  pterygoid  muscle  (6) 
comes  into  view,  with  the  trunk  of  the  inferior  maxillary  nerve  above  it ; 
and  a  branch  (internal  pterygoid,  *)  descending  from  that  nerve  to  the 
muscle.  If  the  nerve  to  the  pterygoid  be  taken  as  a  guide,  it  will  lead  to 
the  ganglion. 

To  comjjlete  the  dissection,  saAv  vertically  through  the  petrous  part  of 
the  tem[)oral  bone,  near  the  inner  wall  of  the  tympanum,  the  bone  being 
supported  whilst  it  is  divided.  Taking  off  some  membrane  which  covers 
the  ganglion,  the  student  may  follow  backwards  a  small  branch  to  the 
tensor  tympani  muscle  ;  but  he  must  open  the  small  tube  that  contains  the 
muscle,  by  entering  it  below  tlirough  tlie  carotid  canal.  Above  this  small 
branch  there  is  said  to  be  another  minute  nerve  (small  superficial  petrosal), 
which  issues  from  the  skull,  and  joins  the  back  of  the  ganglion.  A  small 
twig  is  to  be  sought  from  the  front  of  the  ganglion  to  the  tensor  palati 
muscle  ;  and  one,  near  the  same  spot,  to  join  the  sympathetic  nerve  on 
the  middle  meningeal  artery. 

The  otic  ganglion  (gang,  auriculare,  Arnold)  (fig.  3G)  is  a  small 
reddish  body,  which  is  situate  on  the  inner  surface  of  the  inferior  maxil- 
lary nerve  close  to  the  skull,  and  surrounds  the  origin  of  the  nerve  to  the 
internal  ))terygoid  muscle.  By  its  inner  surface  the  ganglion  is  in  contact 
with  the  Eustachian  tube,  and  at  a  little  distance,  behind,  lies  the  middle 


OTIC    GANGLION. 


145 


meningeal  artery.  In  this  ganglion,  as  in  the  others  connected  with  the 
fifth  nerve,  filaments  from  motor,  sensory,  and  sympathetic  nerves  are 
blended.     Some  twigs  are  furnished  by  it  to  muscles. 

Connecting  branches — roots.  The  ganglion  is  joined  by  a  fasciculus  from 
the  motor  part  of  the  inferior  maxillary  nerve,  and  is  closely  united  with 


n.  Tensor  tympani  muscle. 

b.  Internal   pterygoid  muscle   with    its 

nerve  entering  it. 

c.  External  carotid  artery  with  the  sym- 

pathetic on  it. 

1.  Otic  ganglion. 

2.  Branch  of  Jacobson's  nerve. 
8.  Nerve  to  tensor  tympani. 

4.  Chorda  tympani  joining  gustatory. 

5.  Nerve  to  pterygoideus  internus. 

6.  Nerve  of  tensor  palati. 

7.  Auriculo-temporal  nerve. 


Inner  View  of  the  Otic  Ganglion. 

the  branch  of  that  nerve  to  the  internal  pterygoid  muscle,  thus  receiving 
two  of  its  roots,  motor  and  sensory,  from  the  fifth  nerve.  Its  connection 
with  the  sympathetic  is  established  by  a  twig  from  the  plexus  on  the 
middle  meningeal  artery.^ 

Branches  to  muscles.  Two  muscles  receive  their  nerves  from  the  otic 
ganglion,  viz.,  tensor  tympani  and  circumfiexus  palati.  The  nerve  to  the 
tensor  tympani^  '',  is  directed  backwards,  and  enters  the  bony  canal  con- 
taining that  muscle.  The  branch  for  the  circumjiexus,  ^  arising  from  the 
front  of  the  ganglion,  may  be  supposed  to  be  derived  from  the  internal 
pterygoid  nerve. 

The  nerve  of  the  internal  pterygoid  mnscle,  ^,  arises  from  the  inner  side 
of  the  inferior  maxillary  nerve  near  the  skull  and  penetrates  the  deep 
surface  of  the  muscle.  This  branch  is  joined  by  a  fasciculus  from  thcT 
motor  root  of  the  fifth  nerve. 

Directions.  The  remainder  of  the  pterygo-maxillary  region  of  the  left 
side  may  be  noAv  examined. 

I  Further,  the  ganglion  is  said  to  be  connected  with  the  tympanic  nerve  (of  the 
glosso-pliarjngeal)  by  means  of  the  small  superficial  petrosal  nerve,  2,  joining  the 
posterior  part. 


10 


146  DISSECTION    OF    THE    TONGUE, 


Section  XV. 

DISSECTION  OF  THE  TONGUE. 

Directions.  The  tongue  and  larynx  are  to  remain  connected  with  each 
other  whilst  the  student  learns  the  general  form  and  structure  of  the 
tongue. 

Dissection.  The  ends  of  the  extrinsic  lingual  muscles  that  have  been 
detached  on  the  right  side  may  be  shortened,  but  enough  of  each  should 
be  left  to  trace  it  afterwards  into  the  substance  of  the  tongue. 

The  TONGUE  occupies  the  floor  of  the  mouth,  and  is  rather  flattened, 
with  the  larger  end  turned  backwards.  It  is  free  over  the  greater  part  of 
the  surface;  but  at  the  hinder  part,  and  at  the  posterior  two-thirds  of  the 
under  surface,  it  gives  attachment  to  the  muscles  and  the  mucous  mem- 
brane which  fix  it  to  the  parts  around. 

The  tip  of  the  tongue  (apex)  touches  the  incisor  teeth ;  and  the  base, 
which  looks  towards  the  pharynx,  is  attached  to  the  hyoid  bone,  and  is 
connected  likewise  with  the  epiglottis  by  three  folds  of  mucous  membrane 
— a  central  and  two  lateral. 

The  upper  surface  of  dorsum  is  somewhat  convex,  and  is  received  into 
the  hollow  of  the  roof  of  the  mouth ;  along  the  anterior  two-thirds  it  is 
divided  into  two  equal  parts  by  a  median  groove,  whicli  ends  behind  in  a 
hollow  named  foramen  ciecum.  Tliis  surface  is  covered  with  papilhe  over 
the  anterior  two-thirds;  but  is  smoother  at  the  posterior  third,  though 
even  here  the  surface  is  irregular  in  consequence  of  projecting  mucous 
glands  and  follicles.  The  under  surface,  free  only  in  part,  gives  attach- 
ment to  the  mucous  membrane,  and  to  the  different  lingual  muscles  con- 
nected with  the  hyoid  bone  and  the  jaw ;  and  in  front  of  those  muscles  is 
a  fold  of  the  mucous  membrane  named  fra^num  linguae. 

The  borders  of  the  tongue  are  thick  and  round  at  the  base  of  the  organ, 
where  they  are  marked  by  vertical  ridges  and  furrows ;  but  gradually  be- 
come thinner  near  the  tip. 

Papillce.  On  the  dorsum  of  the  tongue  are  the  following  kinds  of  pa- 
pillae; the  conical  and  filiform,  the  fungiform,  and  tlie  circumvallate. 

The  cojiical  and  filiform  pajHllae  are  the  numerous  small  jn-ojections, 
like  the  villi  on  the  mucous  membrane  of  the  small  intestine,  wliich  cover 
the  anterior  two-thirds  of  the  dorsum  of  the  tongue.  Some  of  the  papilla? 
(conical)  are  wider  at  their  attached  than  at  their  free  ends,  and  these  are 
most  developed  over  the  central  part  of  the  tongue.  Others  become  longer 
(filiform),  especially  towards  the  sides  of  the  tongue.  These  ])apilla3  are 
furnished  with  minuter  papilla;,  and  are  provided  at  the  tip  with  hair-like 
processes  of  the  epithelium.  Towards  their  limit  behind,  as  well  as  on  the 
side  of  the  tongue,  they  have  a  linear  arrangement. 

T\\G  fungiform  j)apilla.'  are  less  numerous  but  larger  than  the  preceding 
set,  amongst  which  tliey  are  scattered.  They  are  wider  at  the  free  end 
than  at  the  part  fixed  to  the  tongue,  and  project  beyond  the  other  set ; 
they  are  situate  mostly  at  the  tip  and  sides  of  the  tongue.  They  are 
covered  witli  small  simple  papilhi). 

The  circumvallate  or  caliciform  are  fewer  in  number  and  larger  tlian 
the  others,  and  are  placed  at  the  junction  of  the   two  anterior  with  the 


STRUCTURE  OF  THE  TONGUE.  147 

posterior  third  of  the  tongue  :  tlieir  number  varies  from  eight  to  ten 
These  papillae  extend  across  the  tongue  in  a  line  resembling  the  letter  V 
with  the  point  turned  backwards.  Each  papilla  consists  of  a  central 
truncated  part  of  a  conical  form,  which  is  surrounded  by  a  fold  of  the 
mucous  membrane  ;  its  wider  part  or  base  projects  above  the  surface, 
whilst  the  apex  is  attached  to  tlie  tongue.  Both  the  papilla  and  the  sur- 
rounding fold  are  furnished  with  smaller  secondary  papillae. 

Minute  simple  papilhe  exist  behind  the  c^lciform  kind,  and  on  the  under 
surface  of  the  free  portion  of  the  tongue ;  but  they  are  not  observed  till 
the  epithelium  is  removed. 

Taste  buds.  Around  the  circum vallate  papilla?  is  a  circle  of  small 
peculiar  bodies,  which  are  covered  by  the  epithelium  :  they  are  like  a 
small  carafe  in  shape,  the  base  resting  on  the  corium.  They  are  formed 
of  elongated  epithelium-like  cells,  of  which  the  central,  resembling  olfac- 
torial  cells,  are  supposed  to  be  connected  with  the  nerve  of  taste. 

A  small  collection  of  similar  bodies  occupies  tlie  back  of  the  tongue,  on 
each  side,  just  in  front  of  the  anterior  pillar  of  the  fauces. 

Structure  of  the  PapillcB.  The  simple  papillte  are  constructed  like 
those  of  the  skin,  viz.  of  a  projecting  cone  of  membrane,  which  is  covered 
by  epithelium,  and  filled  with  a  loop  of  capillaries,  and  a  nerve. 

The  other  compound  forms  of  the  papillae  may  be  said  to  be  produced 
by  outgrowths  from  the  simple  kind.  Thus  smaller  papillary  eminences 
spring  from  the  common  cone  of  limiting  membrane  ;  and  each  has  its 
separate  investment  of  epithelium,  by  which  the  brush-like  appearance  on 
the  surface  is  pi-oduced.  From  the  plexus  of  capillary  vessels  in  the  in- 
terior of  the  papilla  a  looped  offset  is  furnished  to  each  smaller  papillary 
projection.  The  entering  nerve  sends  offsets  to  the  different  subdivisions 
of  the  papilla,  on  some  of  which  end-bulbs  may  be  recognized. 

Structure.  The  tongue  consists  of  two  symmetrical  halves  separated 
by  a  fibrous  layer  in  the  middle  line.  Each  half  is  made  up  of  muscular 
fibres  with  interspersed  fat ;  and  entering  it  are  the  lingual  vessels  and 
nerves.  The  whole  tongue  is  enveloped  by  the  mucous  membrane  ;  and  a 
special  fibrous  membrane  attaches  it  to  the  hyoid  bone. 

Dissection.  To  define  the  septum,  and  the  membrane  attaching  the 
tongue  to  the  hyoid  bone,  the  tongue  is  to  be  placed  on  its  dorsum  ;  and, 
the  remains  of  the  right  mylo-  and  genio-hyoideus  having  been  removed, 
the  genio-hyo-glossi  muscles  are  to  be  cleaned,  and  drawn  from  one  another 
along  the  middle  line.  After  separating  those  muscles,  except  for  an  inch 
in  front,  and  cutting  across  tlieir  intercommunicating  fibres,  the  edge  of 
the  septum  will  appear.  By  tracing  the  hinder  fibres  of  the  genio-hyo- 
glossus  muscle  towards  the  os  hyoides,  the  hyo-glossal  membrane  will  be 
arrived  at. 

Outside  this  triangular  muscle  in  the  middle  line,  is  the  longitudinal 
bundle  of  the  inferior  lingualis,  which  will  be  better  seen  subsequently. 

Fibrous  tissue.  Along  the  middle  line  of  the  tongue  is  placed  a  thin 
lamina  of  this  tissue,  forming  a  septum :  its  root  is  attached  by  another 
fibrous  structure,  the  hyo-glossal  membrane  ;  and  covering  the  greatiir  part 
of  the  organ  is  a  submucous  layer  of  the  same  tissue. 

Septum.  This  structure  forms  a  vertical  partition  between  the  two 
halves  of  the  tongue  (fig.  37,  ^),  and  extends  from  the  base  to  the  apex. 
It  is  thicker  posteriorly  than  anteriorly,  and  is  connected  behind  with  the 
hyo-glossal  membrane.  To  each  side  the  transverse  muscle  is  connected. 
Its  disposition  may  be  better  seen  subsequently  on  a  vertical  section.     In 


148  DISSECTION    OF    THE    TONGUE. 

some  instances  a  small  fibro-cartilage,  about  a  quarter  of  an  inch  deep  and 
lonjr,  exists  in  the  septum. 

The  hyo-glossal  membrane  is  a  thin  but  strong  fibrous  lamina,  which 
attaches  the  root  of  the  tongue  to  the  upper  border  of  the  body  of  the 
hyoid  bone.  On  its  under  or  anterior  surface  some  of  the  hinder  fibres  of 
the  genio-hyo-glossi  are  inserted,  as  if  this  was  their  aponeuroses  to  attach 
tliem  to  the  os  hyoides. 

The  submucous  Jibrous  or  aponeurotic  stratum  of  the  tongue  invests  the 
organ,  and  is  continued  into  the  sheaths  of  the  muscles.  Over  the  pos- 
terior third  of  the  dorsum  its  strength  is  greater  than  elsewhere;  and  in 
front  of  the  epiglottis  it  forms  bands  in  the  folds  of  the  mucous  membrane 
in  that  situation.  Into  it  are  inserted  the  muscular  fibres  which  end  on 
the  surface  of  the  tongue. 

Muscles.  Each  half  of  the  tongue  is  made  up  of  extrinsic  and  in- 
trinsic muscles.  The  former  or  external  are  distinguished  by  having  only 
their  termination  in  the  tongue  ;  and  the  latter  or  internal,  by  having  both 
origin  and  insertion  within  the  origin — that  is  to  say,  springing  from  one 
part  and  ending  in  another. 

The  extrinsic  muscles  (fig.  37)  are  the  following :  palato  and  stylo- 
glossus, hyo  and  genio-hyo-glossus,  and  pharyngeo-glossus.  Only  the 
lingual  endings  of  these  are  now  to  be  looked  to. 

Dissection.  After  the  tongue  has  been  firmly  fastened  on  its  left  side, 
the  extrinsic  muscles  may  be  dissected  on  the  right  half.  Three  of  these 
muscles,  viz.,  palato-,  d,  stylo-,  b,  and  hyo-glossus,  c,  come  together  to  the 
side  of  the  tongue,  at  the  junction  of  the  middle  and  posterior  third  ;  and,  to 
follow  their  radiating  fibres  forwards,  it  will  be  necessary  to  remove  from 
the  dorsum,  between  them  and  the  tip,  a  thin  layer  consisting  of  the  mu- 
cous membrane  and  fleshy  fibres  of  the  upper  lingualis.  Beneath  the  tip 
a  junction  between  the  stylo-glossus  muscles  of  opposite  sides  is  to  be 
traced. 

The  part  of  the  constrictor  muscle,  g,  which  is  attached  to  the  tongue, 
and  the  ending  of  the  genio-hyo-glossus,  will  come  into  view  on  the  divi- 
sion of  the  hyo-glossus. 

Only  the  two  parts  of  the  hyo-glossus  (basio-  and  cerato-glossus,  p.  99), 
which  arise  from  the  body  and  great  wing  of  the  hyoid  bone,  are  referred 
to  above.  To  lay  bare  the  third  part,  or  the  chondro-glossus,  f,  which  is 
a  small  muscular  slip  attached  to  the  small  cornu  of  tlie  os  hyoides,  turn 
upwards  the  dorsum  of  the  tongue,  and  feel  for  the  small  cornu  of  the 
hyoid  bone  through  the  mucous  membrane.  Then  remove  the  mucous 
membrane  in  front  of  the  cornu,  and  the  fibres  of  the  muscle  radiating 
forwards  will  be  exposed. 

The  palato  and  stylo-glossus  muscles,  D  and  b,  are  partly  combined  at 
their  attachment  to  the  lateral  part  of  the  tongue,  and  form,  together  with 
tiie  following  muscle,  an  expansion  over  the  anterior  two-thirds  of  the 
dorsum  beneath  the  superficial  lingualis.  In  this  stratum  tiie  fibres  radi- 
ate irom  the  point  of  contact  of  the  muscles  with  the  tongue — some  passing 
almost  horizontally  inwards  to  the  middle,  and  others  obliquely  forwards 
to  the  tip  of  the  organ. 

A'  great  portion  of  the  stylo-glossus  is  directed  along  the  side  of  the 
tongue ;  and  some  fibres  are  inclined  to  the  under  surface  in  front  of  the 
hyo-glossus,  to  join  those  of  tlie  opposite  muscle  beneath  the  tip. 

Hyo-glossvs.    The  two  superficial  parts  of  the  muscle  (basio  and  cerato- 


MUSCLES    OF    THE    TONGUE. 


149 


Fig: 


glossus,  c,  p.  99)  enter  the  under  surface  of  the  tongue,  between  the 
stylo-glossus  and  the  lingualis.  After  entering  that  surface  by  separate 
bundles,  they  are  bent  round  the  margin,  and 
form,  with  the  two  preceding  muscles,  a 
stratum  on  the  dorsum  of  the  tongue. 

The  third  part  of  the  muscle,  or  the  chondro- 
glossus,  F,  is  distinct  from  the  rest.  About 
two  or  three  lines  wide  at  its  origin  from  the 
root  of  the  small  cornu,  and  from  part  of  the 
body  of  the  os  hyoides,  tlie  muscle  entering 
beneath  the  upper  lingualis,  passes  obliquely 
inwards  over  the  posterior  third  of  the  dorsum, 
to  blend  with  the  hyo  glossus. 

Cortex  of  the  tongue.  The  muscles  above 
described,  together  with  the  superficial  lingua- 
lis, constitute  a  cortical  layer  of  oblique  and 
longitudinal  fibres,  which  covers  the  tongue, 
except  below  where  some  muscles  are  placed, 
and  resembles  "a  slipper  turned  upside 
down."  This  stratum  is  pierced  by  deeper 
fibres. 

The  genio-hyo-glossus  (fig.  38,  ^)  enters  the 
tongue  vertically  on  the  side  of  the  septum, 
and  perforates  the  cortical  covering  to  end  in 
the  submucous  tissue.  In  the  tongue  the 
fibres  spread  like  the  rays  of  a  fan  from  apex 
to  base,  and  are  collected  into  bundles  as  they 
pass  through  the  transversalis.  The  most  [)OS- 
terior  fibres  end  on  the  hyo-glossal  membrane 
and  the  hyoid  bone ;  and  a  slip  is  prolonged 
from  them,  beneath  the  hyo-glossus,  to  the  up- 
per constrictor  of  the  pharynx.  A  vertical  section  at  a  future  stage  will 
siiow  tlie  radiation  of  its  fibres. 

The  pharyngeo-glossiis  (glosso-pharyngaus),  or  the  part  of  the  upper 
constrictor   attaclied   to    the    side    of    the 
tongue,  passes  amongst  fibres  of  the  hyo- 
glossus,  and  is  continued  with  the  trans- 
verse muscle  to  the  septum. 

The  intrinsic  nmscles  (fig.  38)  are  three 
in  number  in  each  half  of  the  tongue,  viz., 
transversalis,  with  a  superior  and  an  infe- 
rior lingualis. 

Dissection.  To  complete  the  prepara- 
tion of  the  inferior  lingualis  on  the  right 
side,  the  fibres  of  the  stylo-glossus  covering 
it  in  front,  and  those  of  the  genio-hyo- 
glossus  over  it  behind,  are  to  be  cut 
through. 

The  superior  lingualis  (fig.  37,  ^)  may 
be  shown,  on  the  left  side,  by  taking  the 
thin  mucous  membrane  from  tlie  ui)per  surface  from  tip  to  base. 

The  transversalis   (fig.  38,  ^)    may  be  laid  bare  on  the  right  side,  by 
cutting  away  on  the  upper  surface  the  stratum  of  the  extrinsic  muscles 


Muscles  on  the  surface  of 

THE   ToXdUE. 

A.  Superficial  lingualis. 

B.  Stylo-glossus. 
c    Hyo-glossus. 
D.  Palato-glossus. 
F.  Chondro-glossus. 

o.  Phaiyngeo-glossus. 

H.  Septum  liuguaj  (Zaglas). 


Fig.  38. 


Intrinsic  Muscles  of  the  Tongue. 

A.  Geuio-hyo-glossu8. 

B.  Septum  linguffl. 
c.  Traasversalis. 

D.  Inferior  lingualis  (Zaglas). 


150  DlSSECTrON    OF    THE    TONGUE. 

already  seen  ;  and  by  removing  on  the  lower  surface,  the  inferior  lingualis 
and  the  genio-hyo-glossus. 

The  nerves  of  the  tongue  are  to  be  dissected  on  the  left  half  as  well  as 
the  part  will  admit ;  but  a  recent  specimen  would  be  required  to  follow 
them  satisfactorily. 

The  transversalis  muscle  (fig.  38,  ^)  forms  a  horizontal  layer  in  the 
substance  of  the  tongue  from  base  to  apex.  The  fibres  are  attached  in- 
ternally to  the  side  of  the  septum,  and  are  directed  thence  outwards,  the 
posterior  being  somewhat  curved,  to  their  insertion  into  the  side  of  the 
tongue. 

Its  fibres  are  collected  into  vertical  plates,  so  as  to  allow  the  passage 
between  them  of  the  ascending  fibres  of  the  genio-hyo-glossus. 

Action.  By  the  contraction  of  the  fibres  of  these  muscles  the  tongue  is 
made  narrower  and  rounder,  and  is  increased  in  length. 

The  superior  lingualis  (fig.  37,  ^,  noto-glossus  of  Zaglas)  is  a  very  thin 
layer  of  oblique  and  longitudinal  fibres  close  beneath  the  submucous  tissue 
on  the  dorsum  of  the  tongue.  Its  fibres  arise  from  the  fraenum  ej)iglotti- 
dis,  and  from  the  fascia  along  the  middle  line  ;  from  this  attachment  they 
are  directed  obliquely  outwards,  the  anterior  becoming  longitudinal,  to  the 
margin  of  the  tongue,  at  which  they  end  in  the  fascia. 

Action.  Both  muscles  tend  to  shorten  the  tongue ;  and  they  will  bend 
the  point  back  and  up. 

The  inferior  lingualis  (fig.  38,  ^)  is  much  stronger  than  the  preceding, 
and  is  placed  under  the  tongue,  between  the  hyo  and  genio-hyo-glossus. 
The  muscle  arises  posteriorly  from  the  fascia  at  the  root  of  the  tongue ; 
and  the  fibres  are  collected  into  a  roundish  bundle:  from  its  attached  sur- 
face fasciculi  are  continued  vertically  through  the  transverse  fibres  up- 
wards to  the  dorsum;  and  at  the  anterior  tliird  of  the  tongue,  where  the 
muscle  is  overlaid  by  the  stylo-glossus,  some  of  the  fibres  are  applied  to 
that  muscle  and  distributed  with  it. 

Action.  Like  the  upper  lingualis  this  muscle  shortens  the  tongue,  and 
bends  the  point  down  and  back. 

The  mucous  membrane  is  a  continuation  of  that  lining  the  mouth,  and 
is  provided  with  a  laminar  epithelium.  It  partly  invests  the  tongue,  and 
is  reflected  off  at  different  points  in  the  form  of  folds  (p.  1.46).  At  the 
epiglottis  are  three  small  glosso-epiglottid  folds,  connecting  tiiis  body  to 
the  root  of  the  tongue ;  the  central  one  of  these  is  called  the  fra^num  of  the 
epiglottis.  Like  the  membrane  of  the  moutli,  it  is  furnished  with  numerous 
glands,  and  some  follicles. 

The  follicles  are  depressions  of  the  mucous  membrane,  which  are  sur- 
rounded by  closed  capsules  in  the  submucous  tissue,  like  the  arrangement 
in  the  tonsil:  they  occupy  the  dorsum  of  the  tongue  between  the  papillne 
circumvallaia3  and  the  epiglottis,  where  they  form  a  stratum,  close  beneath 
the  mucous  membrane. 

The  glands  (lingual)  are  racemose  or  compound  in  structure,  similar  to 
those  of  tlie  lips  and  cheek,  and  are  placed  beneath  tlie  mucous  membrane 
on  the  dorsum  of  the  tongue  behind  the  papilhe  vallatie.  A  few  are  found 
in  front  of  the  circumvallate  papillae,  where  they  project  into  the  muscular 
substance.  Some  of  their  ducts  open  on  the  surface;  others  into  the  hol- 
lows around  the  large  [)apill*!,  or  into  the  foramen  Ciccum  and  the  depres- 
sions of  the  follicles. 

Opposite  the  papilhe  vallatae,  at  the  margin  of  the  tongue,  is  a  small 
cluster  of  submucous  glands.     Under  the  tip  of  the  tongue,  on  each  side 


EXTERNAL    LARYNGEAL    MUSCLES.  151 

of  the  fi'cTinum,  is  another  elongated  collection  of  the  same  kind  of  glands 
imbedded  in  the  muscular  fibres,  from  which  several  ducts  issue. 

Nerves.  There  are  three  nerves  on  the  under  part  of  each  half  of  the 
tongue,  viz.,  the  gustatory,  the  hypoglossal,  and  the  glosso- pharyngeal 
(fig.  23). 

The  gustatory  nerve  gives  upwards  filaments  to  the  muscular  substance, 
and  to  the  two  smallest  sets  of  papilla?,  conical  and  fungiform ;  it  joins 
also  the  hypoglossal  nerve. 

The  hypoglossal  nerve  is  spent  in  long  slender  offsets  to  the  muscular 
substance  of  the  tongue. 

The  glosso-pharyngeal  nerve  divides  under  the  hyo-glossus  into  two 
branches: — One  turns  to  the  dorsum,  and  ramifies  in  the  mucous  mem- 
brane behind  the  foramen  cjecum.  The  other  passes  beneath  the  side  of 
the  tongue,  and  ends  in  branches  for  the  muscular  substance;  it  supplies 
the  papillae  circumvallatse,  as  well  as  the  mucous  membrane  covering  the 
lateral  part  of  the  tongue. 

Vessels.  The  arteries  are  derived  chiefly  from  the  lingual  of  each 
side;  these,  together  w^ith  the  veins,  have  been  examined  (p.  101.) 


Section  XVI. 

DISSECTION  OP  THE  LARYNX. 


The  larynx  is  the  upper  dilated  part  of  the  air  tube,  in  which  the  voice 
is  produced.  It  is  constructed  of  several  cartilages  united  together  by 
ligamentous  bands ;  of  muscles  for  the  movement  of  the  cartilages ;  and  of 
vessels  and  nerves.     The  whole  is  lined  by  mucous  membrane. 

Dissection.  The  tongue  may  be  removed  from  the  larynx  by  cutting 
through  its  root,  but  this  is  to  be  done  without  injuring  the  epiglottis. 

If  the  student  learns  the  laryngeal  cartilages  before  he  begins  the  dis- 
section of  the  larynx,  he  will  obtain  more  knowledge  from  the  study  of  this 
Section. 

Occupying  the  middle  line  of  the  neck,  the  larynx  is  placed  in  front  of 
the  pharynx,  and  between  the  carotid  vessels.  It  is  pyramidal  in  form. 
The  base  is  turned  upwards,  and  is  attached  to  the  hyoid  bone ;  and  the 
apex  is  continuous  with  the  trachea. 

In  length  it  measures  about  one  inch  and  a  half;  in  width  at  the  top 
one  inch  and  a  quarter,  and  at  the  lower  end  one  inch. 

The  front  is  prominent  along  the  middle  line  of  the  neck;  and  the  pos- 
terior surface  is  covered  by  the  mucous  membrane  of  the  pharynx.  The 
larynx  is  very  movable,  and  during  deglutition  is  elevated  and  depressed 
by  the  different  extrinsic  muscles. 

Muscles.  Commonly  five  pair  and  one  single  muscle  are  described  in 
the  larynx.  Three  are  outside  the  cartilages,  and  three  are  more  or  less 
concealed  by  the  thyroid  cartilage. 

Directions.  On  one  side  of  the  larynx,  say  the  right,  the  muscles  may 
be  dissected,  and  on  the  opposite  side  the  nerves  and  vessels ;  and  those 
superficial  muscles  are  to  be  first  learnt,  which  do  not  require  the  carti- 
lages to  be  cut. 

Dissection.  The  larynx  being  extended  and  fastened  with  pins,  the 
dissector  may  clear  away  from  tlie  os  hyoides  and  the  thyroid  cartilage  the 


152 


DISSECTION    OF    THE    LARYNX 


following  extrinsic  muscles,  viz.,  constrictor,  sterno-liyoid,  sterno-thyroid, 
and  thyro-hyoid. 

In  front,  between  the  thyroid  and  cricoid  cartilages,  one  of  the  three 
small  external  muscles — crico-thyroid  (fig.  39),  will  be  recognized. 

The  other  two  external  muscles  (fig.  40)  are  situate  at  the  posterior 
aspect  of  the  larynx:  to  denude  them  it  will  be  necessary  to  turn  over  the 
larynx,  and  to  remove  the  mucous  membrane  covering  it.  On  the  back 
of  the  circoid  cartilage  the  dissector  will  find  the  crico-arytajnoideus  posti- 
cus muscle;  and  above  it,  on  the  posterior  part  of  the  arytaenoid cartilages, 
the  arytaenoid  muscle  will  appear. 

The  CRico-THYROiDEL'S  MUSCLE  (fig.  39,  ^)  is  triangular  in  form,  and 
is  separated  by  an  interval  from  the  one  on  the  opposite  side.  It  arises 
from  the  front  and  the  lateral  part  of  the  cricoid  cartilage  ;  and  its  fibres 


Fig.  39. 


Fiff.  40. 


Front  View  of  the  Larynx. 

1.  Crico-thyroid  muscle 

2.  Thyroid  cartilai(e. 

3.  Cricoid  cartilage. 


Hinder  View  of  the  Lartn.x. 

A.  Superficial  part  of  the  arytsenoideus muscle. 

B.  Deep  part  of  the  arytacnoideus. 
0.  Crico-arytseuoideus  posticus. 


ascend  to  be  inserted  into  the  lower  cornu,  and  the  low'er  border  of  the 
thyroid  cartilage  as  far  forwards  as  a  quarter  of  an  inch  from  the  middle 
line  ;  also,  for  a  short  distance  (a  line),  into  the  inner  surface  of  that  carti- 
lage. The  muscle  rests  on  the  crico-thyroid  membrane,  and  is  concealed 
by  the  sterno-thyroid  muscle. 

Action.  It  approaches  the  thyroid  to  the  cricoid  cartilage,  making 
longer  the  distance  between  the  thyroid  and  the  arytaenoid  cartilages,  and 
tightens  indirectly  the  vocal  cords. 

The  CKico-ARYTiENOiDEUS  POSTICUS  MUSCLE  (fig.  40,  ^)  lics  on  the 
posterior  part  of  the  cricoid  cartilage.  Its  origin  is  from  the  depression  on 
the  side  of  the  vertical  ridge  at  the  back  of  that  cartilage.  From  this 
origin  the  fibres  are  directed  outwards,  and  are  inserted  into  a  projection 
at  tlie  outer  part  of  the  base  at  the  arytaiuoid  cartilage. 


INTERNAL    LARYNGEAL    MUSCLES.  153 

Action.  It  rotates  the  aiyta^noid  cartilage,  turning  out  the  lateral  pro- 
jection at  the  base,  and  enlarges  the  interval  between  the  cartilages.  At 
the  same  time  the  upper  orifice  of  the  larynx  is  widened  by  the  separation 
from  each  other  of  its  lateral  boundaries. 

Musciilus  kerato-cricoideus  (Merkel).  This  is  a  small  fleshy  slip  which 
is  occasionally  seen  below  and  close  to  the  precedingmuscle  ;  it  arises  from 
the  cricoid  cartilage,  and  is  inserted  into  the  back  part  of  the  lower  cornu 
of  the  thyroid  cartilage. 

The  ARYT^NOiDEUS  is  a  single  muscle  in  the  middle  line  (fig.  40,  ^), 
and  is  placed  on  the  posterior  surface  of  the  aryt^enoid  cartilages :  it  pos- 
sesses two  sets  of  fibres,  superficial  and  deep,  with  different  directions. 
The  deep  fibres,  b,  are  transverse,  and  are  inserted  into  the  outer  border 
and  the  posterior  surface  of  each  cartilage  ;  they  close  the  interval  between 
the  cartilages.  The  superficial  fibres,  a,  consist  of  two  oblique  fasciculi, 
which  cross  like  the  parts  of  the  letter  X,  each  passing  from  the  base  of 
one  cartilage  to  the  apex  of  the  other  :  a  few  of  these  fibres  are  continued 
beyond  the  cartilage  to  join  the  thyro-arytajnoid  muscle,  and  the  depressor 
of  the  epiglottis. 

Action,  The  muscle  causes  the  arytainoid  cartilages  to  glide  towards 
one  another,  and  diminishes  much,  or  closes  the  rima  glottidis. 

Acting  with  the  depressors  of  the  epiglottis  it  will  assist  in  closing  the 
upper  orifice  of  the  larynx. 

Dissection.  The  remaining  muscles  and  the  vocal  apparatus  would  be 
learnt  better  on  a  fresh  larynx,  if  this  can  be  obtained.  To  bring  into 
view  the  muscles,  which  are  concealed  by  the  thyroid  cartilage  (fig.  41) 
it  will  be  necessary  to  remove  the  right  half  of  the  cartilage,  by  cutting 
through  it  a  (piarter  of  an  inch  from  the  middle  line,  after  its  lower  cornu 
has  been  detached  from  the  cricoid.  By  dividing  next  the  crico-thyroid 
membrane  attached  to  the  lower  edge,  and  the  thyro-hyoid  ligament  con- 
nected with  the  upper  margin,  the  loose  piece  will  come  away  on  separat- 
ing it  from  the  subjacent  areolar  tissue. 

By  the  removal  of  some  areolar  tissue,  the  dissector  will  define  inferiorly 
the  crico-arytjcnoid  muscle ;  above  it,  the  thyro-arytienoideus  muscle ;  and 
still  higher,  the  thin  muscular  fibres  (depressor  of  the  epiglottis)  in  the  fold 
of  mucous  membrane  between  the  epiglottis  and  the  aryta^noid  cartilage. 
On  cleaning  the  fibres  of  the  thyro-arytjenoideus  near  the  front  of  the 
larynx,  the  top  of  the  sacculus  laryngis  with  its  small  glands  will  appear 
above  the  fleshy-fibres. 

The  CRico  AKYT.ENOiDEUS  LATERALIS  (fig.  41,^)  is  a  Small  lengthened 
band,  which  arises  from  the  upper  border  of  the  cricoid  cartilage  at  the 
lateral  part  ;  its  fibres  are  directed  backwards  to  be  inserted  into  a  })rojec- 
tion  on  the  outer  side  of  the  base  of  the  arytaenoid  cartilage,  and  into  the 
contiguous  part  of  the  outer  surface. 

This  muscle  is  concealed  by  the  crico-thyroideus,  and  its  upper  border 
is  contiguous  to  the  succeeding  muscle. 

Action.  Rotating  the  aryta^noid  cartilage  by  moving  inwards  the  pro- 
jection on  the  outer  part  of  the  base,  it  replaces  the  cartilage  after  tliis  has 
been  everted  by  the  crico-aryta^noideus  posticus.  It  may  also  approach  the 
one  vocal  cord  to  tlie  other,  and  so  narrow  the  glottis. 

The  THYRO-ARYTyENOiDEUs  MUSCLE  (fig.  41)  extends  from  the  thyroid 
to  the  arytcBnoid  cartilage  ;  it  is  thick  below,  but  thin  and  expanded  above. 
The  muscle  arises  from  the  thyroid  cartilage  near  the  middle  line,  for 
about  the  lower  half  of  the  deptli,  and  from  the  crico-thyroid  ligament.  The 
fibres  are  directed  backwards  with  different  inclinations  : — The  external,  *, 


154 


DISSECTION    OF    THE    LARYNX 


Fig.  41.  ascend  somewhat,  and  are  inserted  in- 

to the  u{)per  part  of"  the  outer  surface 
of  the  arytaenoid  cartilage,  and  blend 
with  the  depressor  of  the  epiglottis. 
The  internal  and  lower  fibres,  ^,  are 
transverse,  and  form  a  thick  bundle, 
which  is  inserted  into  the  fore  part  of 
the  base  of  that  cartilage,  and  into  the 
outer  surface. 

By  its  outer  surface  the  muscle  is  in 
contact  with  the  thyroid  cartilage  ;  and 
the  inner  surface  rests  on  the  vocal 
cords,  and  on  the  ventricle  of  the 
larynx  and  the  pouch. 

Action.  It  moves  forwards  the  ary- 
taenoid cartilage  towards  the  thyroid, 
and  relaxes  the  vocal  cord.  By  a  thin 
band  of  fibres  along  the  upper  edge  the 
rima  glottidis  can  be  narrowed,  and  the 
cord  put  into  the  vocalizing  position. 

The  DEPRESSOR  OB'  THE  EPIGLOT- 
TIS (fig.  41,  ^)  (thyro-arytseno-epiglot- 
tideus)  is  a  thin  muscular  layer  by  the 
side  of  the  upper  opening  of  the  larynx. 
Its  fibres  arise  posteriorly  from  the 
front  of  the  arytaenoid  cartilage,  some 
being  continuous  below  with  fibres  of 
the  arytiianoid  and  thyro-aryta^noid 
muscles  ;  and  anteriorly  by  a  narrow 
slip  from  the  thyroid  cartilage  near  the 
middle  line.  From  those  attachments 
the  fibres  turn  upAvards  with  very  dif- 
ferent directions,  and  are  inserted  into 
the  border  of  the  epiglottis  on  the  same 
side.  The  strengtii  of  the  muscle  va- 
ries much  in  diflferent  bodies. 

Some  of  the  lower  fibres  of  the 
muscle,  which  cover  the  top  of  the 
laryngeal  pouch,  have  been  described  by  Mr.  Hilton  as  a  separate  muscle 
with  the  name  arytceno-epiglottideus  inferior. 

Action.  By  the  contraction  of  the  fibres,  the  tip  of  the  arytaenoid  car- 
tilage will  be  moved  forwards  and  inwards,  and  the  eppiglottis  will  be 
lowered  over  the  orifice  of  the  larynx. 

The  fibres  of  the  muscle  which  are  s})read  over  the  sacculus  will  compress 
it,  and  assist  in  the  expulsion  of  the  contents. 

Parts  inside  the  larynx.  The  |)arts  more  immediately  concerned 
in  the  production  of  the  voice  are,  the  vocal  cords,  the  glottis,  and  the 
ventricle  of  the  larynx  and  its  pouch  :  these  are  placed  within,  and  are 
protected  by  the  laryngeal  cartilages. 

Dissection.  For  the  purpose  of  displaying  the  vocal  apparatus,  let  the 
tube  of  the  larynx  be  divided  along  the  posterior  i)ai't,  as  in  fig.  42  ;  and 
in  cutting  through  the  arytitnoid  muscle,  let  the  incision  be  rather  to  the 
right  of  the  middle  line,  so  as  to  avoid  the  nerves  entering  it. 

On  looking  into  the  larynx  a  hollow  (ventricle)  will  appear  on  each 


View  op  the  Internal  Mpsci-es  of  the 
Larynx. 

1.  Crico-thyroidens  detached. 

2.  Crico-arytierioideiis  p  )8ticu8. 

3.  Crico  arytaeaoideus  lateralis. 

4.  Thyro-arytsenoideus,  superficial  part. 
a.  Depressor  of  tlie  epiglottis. 

6.  Thyro-hyoideus,  cut 
8.  Deep  or  transverse  part  of  thyro-arytae 
noideus. 


GLOTTIS    AND    LARYNGEAL    POUCH.  155 

side ;  and  bounding  the  ventricle  above  and  below  are  the  whitisli  bands 
of  the  vocal  cords. 

If  a  probe  be  passed  into  that  hollow,  it  will  enter  a  small  pouch  (sac- 
culus  laryngis)  by  an  aperture  in  the  anterior  and  upper  part.  The  dis- 
sector should  fill  the  sacculus  on  the  left  side  by  introducing  a  small  piece 
of  cotton  wool  into  it. 

The  laryngeal  space  reaches  from  the  epiglottis  to  the  lower  border  of 
the  cricoid  cartilage.  It  opens  above  into  the  pharynx,  and  below  into 
the  trachea ;  and  in  the  intermediate  portion  are  lodged  the  parts  pro- 
ducing voice. 

The  upper  orifice  of  the  larynx  (fig.  29,  ^)  will  be  evident  on  placing 
in  contact  the  cut  surfaces.  It  is  triangular  in  shape,  with  the  base  in  front 
and  the  apex  behind,  and  its  sides  are  sloped  obliquely  downwards  in  the 
antero-posterior  direction.  Its  boundaries  are, — the  epiglottis  in  front, 
the  aryta3noid  muscle  and  cartilages  behind,  and  the  arytieno-epiglottidean 
fold  of  mucous  membrane  on  each  side.  This  aperture  is  closed  by  the 
epiglottis  during  deglutition. 

The  lower  opening^  limited  by  the  inferior  edge  of  the  cricoid  cartilage, 
is  circular  in  form,  and  is  of  the  same  size  as  that  cartilage. 

The  laryngeal  cavity  is  much  reduced  in  size  within  the  thyroid  car- 
tilage by  the  vocal  cords,  and  is  dilated  above  and  below  them  for  the  pur- 
pose of  allowing  their  free  vibration.  The  lower  dilatation  may  be  seen 
to  be  as  large  as  the  ring  of  the  cricoid  ;  and  the  upper,  much  smaller, 
corresponds  with  the  ventricle  of  the  larynx.  Above  the  upper  bulge  the 
wall  of  the  larynx  slants  up  to  the  epiglottis. 

The  glottis  or  rima.  glottidis^  is  the  interval  between  the  lower  vocal 
cords  (fig.  44)  ;  it  is  })laced  on  a  level  with  the  base  of  the  arytsenoid  car- 
tilages, and  is  the  narrowest  part  of  the  laryngeal  cavity. 

Its  sides  are  constructed  partly  of  ligament  and  partly  of  cartilage  : — 
thus,  for  about  the  two  anterior  thirds  is  the  elastic  vocal  cord  (fig.  42,  ^), 
whilst  at  the  posterior  third  is  the  smooth  inner  surface  of  the  arytasnoid 
cartilage,  e.  Behind  it  is  bounded  by  the  arytnsnoid  muscle  ;  and  in  front 
by  the  thyroid  cartilage  and  the  attachments  of  the  vocal  cords. 

The  size  of  the  interval  differs  in  the  two  sexes.  In  the  male  it  mea- 
sures from  before  back  nearly  an  inch  (less  a  line),  and  across  at  the  base, 
when  dilated,  about  a  third  of  the  other  measurement.  In  the  female  the 
dimensions  will  be  less  by  two  or  three  lines. 

Alterations  in  the  size  and  form  affect  the  interval  where  it  is  bounded 
by  the  cartilages,  as  well  as  where  it  is  limited  by  the  ligaments.  In  the 
former  part,  the  clianges  are  occasioned  by  the  movements  of  the  arytas- 
noid cartilages  ;  but  in  the  latter  they  are  due  to  the  lengthening  and 
shortening  of  the  bands. 

In  the  state  of  rest  it  is  a  narrow  fissure  which  is  enlarged  a  little  behind 
and  rounded;  but  when  dilated  it  is  triangular  in  form,  like  the  upper  orifice, 
though  its  wider  part  is  turned  backwards  to  the  aryta^ioid  muscle.  In  the 
living  body  the  fissure  is  larger  in  inspiration  than  in  exi)iration.  The  mus- 
cles too  are  constantly  producing  alterations  in  the  fissure,  some  acting  more 
immediately  on  the  cartilages  as  dilators  and  contractors  of  the  base;  and 
others  altering  the  state  of  the  ligaments,  by  elongating  and  shortening 
the  sides. 

The  base  is  enlarged,  and  the  interval  rendered  triangular  by  the  poste- 
rior crico-arytienoid  ;  and  is  diminished  by  the  arytienoid,  and  the  lateral 
crico-aryta3noid.  And  the  ligamentous  sides  are  elongated  and  made  tense 
by  the  crico-thyroidei,  but  are  shortened  by  the  thyro-arytienoidei. 


156 


DISSECTION    OF    THE    LARYNX 


The  ventricle  of  the  larynx  (fig.  42,  ^)  is  best  seen  on  the  left  side.  It 
is  the  oval  hollow  between  the  vocal  cords,  whose  upper  margin  is  semi- 
lunar, and  the  lower  straight.  It  is  lined  by  the  mucous  membrane,  and 
on  the  outer  surface  are  the  fibres  of  the  thyro-aryt:enoid  muscle.  In  the 
anterior  part  is  the  aperture  into  the  laryngeal  pouch. 

The  laryngeal  pouch  (sacculus  laryngis)  (fig.  42,^),  has  been  laid  bare 
in  part  on  the  right  side  by  the  removal  of  the  half  of  the  thyroid  cartilage 
(p.  153),  but  it  will  be  seen  again  in  the  subsequent  dissection  for  the 
vocal  cords. 

It  is  a  small  membranous  sac,  half  an  inch  deep  and  cylindrical  in  form, 
which   projects  upwards   between   the  upper  vocal  cord  and  the  thyroid 

slip  of  the  depressor  of  the  epiglottis, 
and  reaches  sometimes  as  high  as  the 
upper  border  of  the  thyroid  cartilage. 
Its  cavity  communicates  with  the 
front  of  the  ventricle  by  a  somewhat 
narrow  aperture.  On  the  outer  sur- 
face are  numerous  small  glands, 
whose  ducts  are  transmitted  through 
tile  coats  of  the  sac  to  the  inside. 
Numerous  nerves  are  distributed  over 
the  top.  Its  upper  part  is  covered  by 
the  muscular  slip  before  referred  to. 

Dissection.  The  general  shape  and 
position  of  the  vocal  cords  are  evi- 
dent on  tlie  left  half  of  the  laryngeal 
tube,  but  to  show  more  fully  the  na- 
ture of  the  lower  cord,  put  the  cut 
surfaces  in  contact,  and  detach  on  the 
right  side  the  crico-arytajnoideus  lat- 
eralis from  its  cartilages.  Remove 
in  like  manner  the  thyro-arytognoi- 
deus,  raising  it  from  beibre  back.  By 
the  removal  of  the  last  muscle,  a 
fibrous  membrane,  crico-thyroid  (fig. 
44,  ^),  comes  into  view,  and  its  up- 
per free  edge  will  be  perceived  to 
constitute  the  inferior  or  true  vocal 
cord.  Whilst  taking  away  the  thyro- 
arytienoideus,  the  ventricle  and  the 
sacculus  laryngis,  which  are  formed 
chiefiy  by  mucous  membrane,  will 
disappear. 

The  vocal  cords  or  the  thyro-ary- 
tcenoid  ligaments  (fig.   42),  are  two 
bands  on  each    side,  which  are  ex- 
tended from  the  angle  of  the  thyroid 
to  the  aryti«noid  cartilage — one  ibrm- 
ing  the    u|)per,  the  other  the  lower 
margin  of  the  ventricle. 
The  upper  ligament  (false  vocal  cord  (fig.  42,  ^)  is  semilunar  in  form, 
and  is  much  weaker  than   the  other.     It  is  fixed  in  front  to  the  angle  of 
the  thyroid  cartilage,  near  the  attachment  of  the  epiglottis  ;  and  behind  to 


Vocal  Apparatus,  o\  a  Vertical  Section 
OF  THE  Larynx. 

A.  Ventricle  of  the  larynx. 

B.  True  vocal  cord, 
c.  False  vocal  cord. 
D.  Sacculus  laryugif. 

E    Arytaenoid  cartilage. 

F.  Cricoid  cartilage. 

G,  Thyroid  cartilage. 
H.  Epiglottis. 

K.  Crico-thynnd  ligament. 
L.  Thyro-hyoid  ligament. 


GLOTTIS    AND    LARYNGEAL    POUCH.  157 

the  outer  surface  of  the  aryta^noid  cartilage.  This  ligament  consists  chiefly 
of  white  fibrous  tissue,  whicli  is  continuous  with  that  in  the  arytteno-epi- 
glottidean  fold  of  mucous  membrane. 

The  inferior  ligament  (chorda  vocalis,  fig.  42,  ^)  is  attached  in  front  to 
the  angle  of  the  thyroid  cartilage,  about  half-way  down  below  the  notch  ; 
the  ligament  is  directed  backwards,  and  is  inserted  into  the  anterior  promi- 
nence at  the  base  of  the  arytienoid  cartilage.  It  is  about  seven  lines  long 
in  man,  and  two  less  in  the  woman.  Internally  this  band  is  covered  by 
thin  mucous  membrane,  and  projects  towards  its  fellow  into  the  cavity  of 
the  larynx,  the  interval  between  it  and  the  opposite  one  being  the  glottis. 
Externally  it  is  connected  with  the  thyro-aryttenoid  muscle  And  infe- 
riorly  it  is  continuous  with  the  crico-thyroid  ligament,  k.  The  edge  that 
bounds  the  ventricle  is  straight  and  well  defined,  and  vibrates  to  produce 
sounds.     The  ligament  is  composed  of  fine  elastic  tissue. 

The  mucous  membrane  of  the  larynx  is  continued  from  that  investing 
the  pharynx,  and  is  prolonged  to  the  lungs  through  the  trachea.  When 
entering  the  larynx  it  is  stretched  between  the  epiglottis  and  the  tip  of 
the  arytenoid  cartilage,  forming  the  arytaeno-epiglottid  fold  on  each  side  of 
the  laryngeal  orifice:  at  this  spot  it  is  very  loose,  and  the  submucous  tissue 
abundant.  In  the  larynx  the  membrane  lines  closely  the  cavity,  sinks 
into  the  ventricle,  and  is  prolonged  into  the  laryngeal  pouch.  On  the 
thyro-arytenoid  ligaments  it  is  very  thin  and  adherent,  allowing  these  to 
be  visible  through  it. 

In  the  small  part  of  the  larynx  above  the  vocal  cords,  the  epithelium  is 
of  the  laminar  kind,  and  free  from  cilia.  But  a  columnar  ciliated  epithe- 
lium covers  the  surface  below  the  level  of  the  superior  cords,  though  it 
becomes  flattened  without  cilia  on  the  cords  :  on  the  epiglottis  it  is  ciliated 
in  the  lower  half. 

Numerous  branched  glands  are  connected  with  the  mucous  membrane 
of  the  larynx,  and  the  orifices  will  be  seen  on  the  surface,  especially  at 
the  posterior  aspect  of  the  epiglottis.  In  the  edge  of  the  arytieno-epiglot- 
tidean  fold  there  is  a  little  swelling  occasioned  by  a  mass  of  subjacent 
glands  (arytJEUoid)  ;  and  along  the  upper  vocal  cord  lies  another  set. 
None  exist  over  the  vocal  cords,  but  close  to  those  bands  is  the  collection 
of  the  sacculus  laryngis,  which  lubricates  the  ventricle  and  the  lower  vocal 
cord. 

Dissection  of  nerves  and  vessels.  The  termination  of  the  laryngeal 
nerves  may  be  dissected  on  the  untouched  side  of  the  larynx.  For  this 
purpose  the  other  half  of  the  thyroid  is  to  be  disarticulated  from  the  cri- 
coid cartilage,  care  being  taken  of  the  recurrent  nerve,  which  lies  near 
the  joint  between  the  two.  The  trachea  and  larynx  should  be  fastened 
down  next  with  pins;  and  after  the  thyroid  has  been  drawn  away  from 
the  cricoid  cartilage,  the  inferior  laryngeal  nerve  can  be  traced  over  the 
side  of  the  latter  cartilage  to  the  muscles  of  the  larynx,  and  mucous  mem- 
brane of  the  pharynx. 

Afterwards  the  superior  laryngeal  is  to  be  found  as  it  pierces  the  thyro- 
hyoid membrane,  and  branches  of  it  are  to  be  followed  to  the  mucous 
membrane  of  the  larynx  and  pharynx.  Two  communications  are  to  be 
looked  for  between  the  laryngeal  nerves  ;  one  is  b(meath  the  thyroid  car- 
tilage, the  other  in  the  mucous  membrane  of  the  pharynx. 

An  artery  accompanies  each  nerve,  and  its  offsets  are  to  be  dissected  at 
the  same  time  as  the  nerve. 


158  DISSECTION    OF    THE    LARYNX. 

Nerves.  The  nerves  of  the  larynx  are  the  superior  and  inferior  hiryn- 
geal  branches  of  the  pneumo-gastric  (p.  113);  the  former  is  distributed 
to  the  mucous  membrane,  and  tlie  latter  cliiefly  to  the  muscles. 

The  inferior  laryngeal  nerve  (recurrent),  when  about  to  enter  the 
larynx,  furnishes  backwards  an  offset  to  the  mucous  membrane  of  the 
pharynx  ;  this  joins  filaments  of  the  upper  laryngeal.  The  nerve  then 
passes  beneath  the  ala  of  the  thyroid  cartilage,  and  ends  in  branches  for 
all  the  special  muscles  of  the  larynx  except  the  crico-thyroideus.  Its 
small  muscular  branches  are  superficial,  but  that  to  the  aryta^noid  muscle 
passes  beneath  the  crico-arytfenoideus  posticus.  Beneath  the  thyroid  car- 
tilage the  inferior  is  joined  by  a  long  offset  of  the  upper  laryngeal  nerve. 

The  superior  laryngeal  nerve  pierces  the  thyro-hyoid  ligament,  and 
gives  offsets  to  the  mucous  membrane  of  the  pharynx  ;  it  furnishes  also  a 
long  branch  beneath  the  ala  of  the  thyroid  cartilage  to  communicate  with 
the  recurrent  nerve.  The  trunk  then  terminates  in  many  branches  for  the 
supply  of  the  mucous  membrane  : — Some  of  these  ascend  in  the  aryta3no- 
epiglottid  fold  to  the  epiglottis,  and  the  root  of  the  tongue.  The  others, 
which  are  the  largest,  descend  on  the  inner  side  of  the  ventricular  pouch, 
and  supply  the  lining  membrane  of  the  larynx  as  low  as  the  vocal  cords. 
One  nerve  of  this  set  pierces  the  arytsenoid  muscle,  and  ends  in  the  mucous 
membrane. 

Vessels.  The  arteries  of  the  larynx  are  furnished  from  the  superior 
and  in  erior  thyroid  branches  (p.  85  and  78). 

The  laryngeal  branch  of  the  superior  thyroid  artery  enters  the  larynx 
with  the  superior  laryngeal  nerve,  and  divides  into  ascending  and  descend- 
ing branches ;  some  of  these  enter  tlie  muscles,  but  the  rest  supply  the 
epiglottis,  and  the  mucous  membrane  from  the  root  of  the  tongue  to  the 
chorda  vocalis.  Like  the  nerves,  it  unites  with  the  following  artery  both 
beneath  the  ala  of  the  thyroid  cartilage,  and  in  the  mucous  membrane  of 
the  pharynx. 

The  laryngeal  branch  of  the  inferior  thyroid  artery  ascends  on  the 
back  of  the  cricoid  cartilage,  and  ends  in  the  mucous  membrane  of  the 
pharynx  and  the  postei-ior  muscles  of  the  larynx. 

Some  other  twigs  from  the  superior  thyroid  artery  perforate  the  crico- 
thyroid membrane,  and  ramify  in  the  mucous  lining  of  the  interior  of  the 
larynx  at  the  lower  part. 

Laryngeal  veins.  The  vein  accompanying  the  branch  of  the  superior 
thyroid  artery,  joins  the  internal  jugular  or  the  superior  thyroid  vein  ; 
and  the  vein  with  the  artery  from  the  inferior  thyroid  opens  into  the 
plexus  of  the  inferior  thyroid  veins  (p.  85  and  78). 


Section  XVII. 


HYOID  BONE,  CARTILAGES  AND  LIGAMENTS  OF  THE  LARYNX,  AND 
STRUCTURE  OF  THE  TRACHEA. 

Dissection.  All  the  muscles  and  the  mucous  membrane  are  to  be 
taken  away  so  as  to  denude  the  hyoid  bone,  the  cartilages  of  tlie  larynx, 
and  the  epiglottis ;  but  the  piece  of  membrane  that  joins  the  hyoid  bone 


CARTILAGES    OF    LARYNX.  159 

to  the  thyroid  cartilage,  and  the  ligaments  uniting  one  cartilage  to  another 
on  the  left  side,  should  not  be  destroyed. 

In  the  arytieno-epiglottidean  fold  of  mucous  membrane,  a  small  carti- 
laginous body  (cuneiform)  may  be  recognized ;  an  oblique  whitish  pro- 
jection indicates  its  position. 

The  hyoid  bone  (os  hyoides)  (fig.  43)  ^'s  situate  between  the  larynx  and 
the  root  of  the  tongue.  Resembling  the  letter  U,  placed  horizontally  and 
with  the  legs  turned  backwards,  it  offers  for  examination  a  central  part  or 
body,  and  two  lateral  pieces  or  cornua  on  each  side. 

The  body,  c,  is  thin  and  flattened,  and  measures  most  in  the  transverse 
direction.  Convex  in  front,  where  it  is  marked  by  a  tubercle,  it  presents 
an  uneven  surface  for  the  attachment  of  muscles ;  whilst  on  the  opposite 
aspect  it  is  concave.  To  the  upper  border  the  fibrous  membrane  (hyo- 
glossal) fixing  the  tongue  is  attached. 

The  cornua  are  two  in  number  on  each  side  (large  and  small).  The 
large  cornu,  h,  continues  the  bone  backwards,  and  is  joined  to  the  body 
by  an  intervening  piece  of  cartilage.  The  surfaces  of  this  cornu  look 
somewhat  upwards  and  downwards  ;  and  the  size  decreases  from  before 
backwards.  It  ends  posteriorly  in  a  tubercle.  The  small  cornu,  or  ap- 
pendix, J,  is  dissected  upwards  from  the  point  of  union  of  the  great  cornu 
with  the  body,  and  is  joined  by  the  stylo-hyoid  ligament :  it  is  seldom 
wholly  ossified. 

Cartilages  of  the  Larynx  (fig.  43).  There  are  four  large  carti- 
lages in  the  larynx,  which  are  concerned  in  the  production  of  the  voice, 
viz.,  the  thyroid,  the  cricoid,  and  the  two  arytasnoid.  In  addition  there 
are  some  yellow  fibro-cartilaginous  structures,  viz.,  the  epiglottis,  a  capitu- 
lum  to  each  aryttenoid  cartilage,  and  a  small  ovalish  piece  (cuneiform)  in 
each  arytoeno-epiglottidean  fold  of  mucous  membrane. 

The  thyroid  cartilage.,  B,  is  the  largest  of  all :  it  forms  the  front  of  the 
larynx,  and  protects  the  vocal  apparatus  as  with  a  shield.  The  upper 
part  of  the  cartilage  is  considerably  wider  than  the  lower,  and  in  conse- 
quence of  this  form  the  larynx  is  somewhat  funnel-shaped.  The  anterior 
surface  is  prominent  in  the  middle  line,  forming  the  subcutaneous  swelling 
named  pomiim  Adami ;  but  the  cartilage  is  concave  behind  at  the  same 
spot,  and  gives  attachment  to  the  epiglottis  and  the  thyro-arytaenoid  mus- 
cles and  ligaments.     The  upper  border  is  notched  in  the  centre. 

The  cartilage  consists  of  two  square  halves,  which  are  united  in  the 
middle  line.  Posteriorly  each  half  of  the  cartilage  has  a  thick  border, 
which  terminates  upwards  and  downwards  in  a  rounded  process  or  cornu 
(e  and  f).  Both  cornua  are  bent  slightly  inwards:  of  the  two,  the  upper, 
E,  is  the  longest ;  but  the  lower  one,  f,  is  tliicker  than  the  other,  and 
articulates  with  the  cricoid  cartilage.  The  inner  surface  of  each  half  is 
smooth  ;  but  the  outer  is  marked  by  an  oblique  line  for  the  attachment  of 
muscles,  which  extends  from  a  tubercle  near  the  root  of  the  upi)er  cornu, 
almost  to  the  middle  of  the  lower  border. 

The  cricoid  cartilage,  D,  is  stronger  though  smaller  than  the  thyroid, 
and  encircles  the  cavity  of  the  larynx  ;  it  is  partly  concealed  by  the  shield- 
like cartilage,  below  which  it  is  placed.  It  is  very  unequal  in  depth  be- 
fore and  behind, — the  posterior  part  being  three  times  deeper  than  the 
anterior,  something  like  a  signet  ring.  Its  hollow  is  about  as  large  as  the 
fore  finger. 

The  outer  surface  is  rough,  and  gives  attachment  to  muscles.  At  the 
back  of  the  cartilage  there  is  a  flat  and   rather  square   portion,  which  is 


160 


DISSECTION    OF    THE    LARYNX. 


Fig.  43. 


marked  by  a  median  ridge  between  two  contiguous  muscular  depressions. 
On  eacli  side,  immediately  in  front  of  the  square  part,  is  a  shallow  articu- 
lar mark,  whicli  receives  the  lower  cornu  of  the  thyroid  cartilage.  The 
inner  surface  is  smooth,  and  is  covered  by  mucous  membrane. 

The  lower  border  is  undulating,  and  is  united  to  the  trachea  by  fibVous 
membrane.     The  upper  border  is  nearly  straight  posteriorly,  opposite  the 

deep  part  of  the  ring;  and  this  portion 
is  limited  on  each  side  by  an  articular 
mark  for  the  arytcenoid  cartilage.  In 
front  of  that  spot  the  border  is  sloped 
obliquely  downwards  to  the  middle  line. 
At  the  middle  line  behind  there  is  a 
sliglit  excavation  in  each  border. 

The  two  arytcenoid  cartilages,  c,  are 
placed  one  on  each  side  at  the  back  of 
the  larynx,  on  the  upper  border  of  the 
cricoid  cartilage.  Each  is  pyramidal  in 
shape,  is  about  half  an  inch  in  depth, 
and  offers  for  examination  a  base  and 
apex,  and  three  surfaces. 

The  base  has  a  slightly  hollowed  sur- 
face behind  for  articulation  w^ith  the 
cricoid  cartilage,  and  is  elongated  in 
front  into  a  process  which  gives  attach- 
ment to  tlie  vocal  cord.  The  apex  is 
directed  backwards  and  somewhat  in- 
wards, and  is  surmounted  by  the  carti- 
lage of  Santorini. 

The  inner  surface  is  narrow,  especially 
above,  and  flat.  The  outer  is  wide  and 
irregular,  and  on  it  is  a  small  projection 
at  the  base,  wdiich  receives  the  insertion 
of  some  of  the  muscles.  At  the  pos- 
terior aspect  tlie  cartilage  is  concave  and 
smooth. 

Cartilages  of  Santorini.  Attached 
to  the  apex  of  each  arytienoid  cartilage 
is  the  small,  conical  fibro-cartilage  of 
Santorini  (corniculum  ca[)itulum),  which 
is  bent  inwards  towards  the  one  of  the 
opposite  side.  The  arytoeno-epiglottidean 
fold  is  connected  with  it. 

Cuneiform  cartilages.  Two  other 
small  fibro-cartilaginous  bodies,  one  on 
each  side,  which  are  contained  in  the  arytoeno-epiglottid  folds,  have 
received  tliis  name.  Each  is  somewhat  elongated  and  rounded  in  form, 
like  a  grain  of  rice;  it  is  situate  obliquely  in  front  of  tiie  capitulum  of  the 
arytamoid  cartilage,  and  its  place  in  the  fold  of  the  mucous  membrane  is 
marked  by  a  sliglit  whitish  projection. 

The  epiglottis  (fig.  43,  ^)  is  single,  and  is  the  largest  of  the  pieces  of 
yellow  fibro-cartilage.  In  form  it  is  cordate,  and  it  resembles  a  leaf, 
with  the  stalk  below  and  the  lamina  or  expanded  part  above.  Its  position 
is  behind  the  tongue,  and  in  front  of  the  orifice  of  the  larynx.      During 


HyoiD  Bonk  and  the  Laryw«eal 

Cartilages. 
a.  Body  of  the  hyoid  bone. 
H.  Large  cornu. 
J.  Small  cornu. 

A.  Epiglottis. 

B.  Thyroid  cartilage, 
c.  Arytenoid  cartilage. 

D.  Cricoid  cartilasje. 

E.  Upper  cornu,  and 

F.  Lower  cornu  of   the  thyroid  carti- 

lage. 


LIGAMENTS    OF    LARYNX 


161 


Fisr.  44. 


respiration  it  is  placed  vertically,  but  during  deglutition  it  takes  a  hori- 
zontal direction  so  as  to  close  tlie  opening  of  the  larynx. 

The  anterior  sui-face  is  bent  forwards  to  the  tongue,  to  which  it  is  con- 
nected by  three  folds  of  mucous  membrane ;  and  the  posterior  surface, 
hollowed  laterally,  is  convex  from  above  down.  To  its  sides  the  arytseno- 
epiglottid  folds  of  mucous  membrane  are  united.  After  the  mucous  mem- 
brane has  been  removed  from  tlie  epiglottis  its  substance  will  be  seen  to 
be  perforated  by  numerous  spaces,  which  lodge  mucous  glands. 

Between  the  epiglottis  and  the  hyoid  bone  is  a  mass  of  yellowish  fat 
with  some  glands;  this  has  been  sometimes  called  the  epiglottidean  gland. 

Ligaments  of  the  Larynx.  The  larynx  is  connected  by  extrinsic 
ligaments  with  the  hyoid  bone  above  and  the  trachea  below.  Other  liga- 
ments join  together  the  cartilages,  forming  joints  in  some  cases. 

Union  of  the  larynx  with  the  hyoid  bone  and  the  trachea.  A  thin  loose 
elastic  membrane  (thyro-hyoid)  passes  from  the  thyroid  cartilage  to  the 
hyoid  bone;  and  a  second  membrane  connects 
the  cricoid  cartilage  with  the  trachea. 

The  thyro-hyoid  ligament  (fig.  42,  l)  is  at- 
tached on  the  one  part  to  the  upper  border  of  the 
thyroid  cartilage;  and  on  the  other,  to  the  upper 
border  of  the  hyoid  bone,  at  the  posterior  aspect. 
Of  some  thickness  in  the  centre,  it  gradually  be- 
comes thinner  towards  the  sides ;  and  it  ends 
laterally  in  a  rounded  elastic  cord,  which  inter- 
venes between  the  extremity  of  the  hyoid  bone 
and  the  upper  co]"nu  of  the  thyroid  cartilage. 

The  superior  laryngeal  nerve  and  vessels  per- 
forate the  ligament,  and  a  synovial  membrane  is 
placed  between  it  and  the  posterior  surface  of  the 
hyoid  bone.  In  the  elastic  lateral  part  of  the 
ligament  will  be  found  occasionally  a  small  ossific 
nodule  (cartilago  triticea). 

The  membrane  joining  the  lower  border  of  the 
cricoid  cartilage  to  the  ilrst  ring  of  the  trachea 
— crico-tracheal  ligament,  resembles  the  band 
joining  the  rings  of  the  trachea  to  each  other. 

Union  of  the  cricoid  and  thyroid  cartilages. 
These  cartilages  are  joined  in  the  middle  line  in 
front  by  ligament ;  and  on  the  side,  by  a  joint 
with  the  small  cornu  ot  the  thyroid  cartilage. 

The  crico-thyroid  ligament  or  membrane  (fig. 
44,  ^)  closes  the  space  between  the  thyroid,  cri- 
coid, and  arytaenoid  cartilages,  and  the  right  half 
is   now   visible.     It   is  yellow   in   color,  and  is 
formed  mostly  of  elastic  tissue.     At  the  centre  it 
is  thick  and  strong,  but  is  thinner  on  each  side 
as  it  is  continued  backwards.      By  the  lower  bor- 
der it  is  fixed  to  the  upper  edge  of  the  cricoid  as 
far  back  on  each  side  as  the  joint  with  the  aryttenoid  cartilage.     Its  upper 
border,  free  and  rounded,  is  covered  by  mucous  membrane,  and  forms  the 
lower  vocal  cord.     In  front  it  is  united  to  the  thyroid  cartilage;  and  be- 
hind to  the  base  of  the  arytaenoid. 
11 


View  of  the  Vocal  Cords 
ANP  Crico-thyroid  Liua- 

MENTS. 

1.  True  vocal  cord. 

2.  Post,  crico-arytaen    niascle. 

3.  Cricoid  cartilage. 

4.  Aryifpnoid  cartilage. 

5.  Sacculus  laryngis. 

6.  Crico-thyroid  membrane. 


162  DISSECTION    OF    THE    LARYNX. 

The  ligament  is  partly  concealed  by  the  crico-thyroid  muscle,  and  some 
small  apertures  exist  in  it  for  the  passage  of  fine  arteries  into  the  larynx. 

The  strong  forepart  of  the  ligament  serves  the  purpose  of  uniting  the 
two  large  laryngeal  cartilages;  and  the  lateral  piece,  closing  the  larynx, 
ends  above  in  the  vocal  cord. 

A  capsular  ligament  surrounds  the  articular  surfaces  between  the  side 
of  the  cricoid  and  the  lower  cornu  of  the  thyroid  cartilage.  Its  fibres  are 
strongest  behind.     A  synovial  membrane  lines  the  capsule. 

This  joint  admits  forward  and  backward  movements  of  the  thyroid  car- 
tilage, by  which  the  condition  of  the  vocal  cords  is  altered.  If  that  carti- 
lage is  moved  forwards  the  cords  are  stretched,  and  if  backwards  the  cords 
are  relaxed. 

Articulation  of  the  cricoid  and  arytcenoid  cartilages.  The  articular 
surfaces  of  the  cartilages  are  retained  by  a  loose  capsule,  and  possess  a 
synovial  sac. 

The  capsular  ligament  is  fixed  to  each  cartilage  around  its  articular 
surface ;  and  one  part — posterior  ligament,  is  strongest  on  the  inner  and 
posterior  aspects.  A  loose  synovial  meinhrane  is  present  in  the  articu- 
lation. 

The  arytienoid  cartilage  glides  freely  forwards  and  backwards,  inwards 
and  outwards;  but  if  its  horizontal  movements  are  controlled  by  muscular 
action,  it  can  be  rotated  around  a  vertical  axis,  the  anterior  spur  being 
moved  inwards  and  outwards.  Obviously  the  state  of  the  vocal  cords  will 
be  changed  by  the  movements  of  the  cartilages.  When  the  arytsenoids 
glide  in  and  out  the  cords  will  be  approximated  and  separated;  when 
backwards  and  forwards,  the  cords  will  be  tightened  and  relaxed ;  and  in 
rotation  the  cords  will  be  moved  away  from,  and  brought  towards  each 
other. 

A  kind  of  capsule,  formed  of  thin  scattered  fibres,  with  a  synovial  sac, 
unites  the  apex  of  the  arytcenoid  cartilage  with  the  hollowed  base  of  the 
capitulum  of  Santorini.     Sometimes  these  cartilages  are  blended  together. 

Fibrous  bands  (thyro-arytaenoid)  join  the  thyroid  with  the  arytcenoid 
cartilages,  and  have  been  examined  as  the  vocal  cords  (p.  156). 

Ligaments  of  the  epiglottis.  A  band,  thyro-epiglottidean,  connects  the 
lower  part  of  the  epiglottis  to  the  thyroid  cartilage,  close  to  the  excavation 
in  the  upper  border  of  the  latter  (fig.  42).  Some  fibrous  and  ela.stic  tis- 
sues— hyo-epiglottid  ligament,  connect  likewise  the  front  of  the  epiglottis 
to  the  hyoid  bone. 

Structure  of  the  Trachea.  The  air  tube  consists  of  a  series  of 
pieces  of  cartilage  (segments  of  rings)  (fig.  40),  which  are  connected 
together  by  fibrous  tissue.  The  interval  between  the  cartilages  at  the  back 
of  the  tube  is  closed  by  fibrous  membrane,  and  by  muscular  fibres  and 
mucous  glands.  The  trachea  is  lined  by  mucous  membrane  with  subja- 
cent elastic  tissue. 

Cartilages.  The  pieces  of  cartilage  vary  in  number  from  sixteen  to 
twenty.  Each  forms  an  incomplete  ring,  which  extends  about  three- 
fourths  of  a  circle  ;  and  each  is  convex  forwards,  forming  the  front  and 
sides  of  the  air  tube.  Botli  above  and  below,  the  cartilaginous  pieces  are 
less  constant  in  size  and  form  :  for  towards  the  larynx  they  increase  in 
dei)th,  whilst  in  the  op])osite  direction  they  may  be  slit  at  their  ends  or 
blended  together ;  and  the  lowest  j)iece  of  cartilage  is  shaped  like  the 
letter  V. 

A  fibrous  tissue  is  continued  from  one  to  another  on  both  aspects,  though 


LOXGUS    COLLI    MUSCLE.  163 

in  greatest  quantity  externally,  so  as  to  incase  and  unite  them  ;  and  it  is 
extended  across  the  posterior  part  of  the  air  tube. 

Dissection.  On  removing  for  about  two  inches  the  fibrous  membrane 
and  the  mucous  glands  from  the  interval  between  the  cartilages  at  the  back 
of  the  trachea,  the  muscular  fibres  will  appear. 

After  the  muscular  fibres  have  been  examined  the  membranous  part  of 
the  tube  may  be  slit  down,  to  see  the  elastic  tissue  and  the  mucous  mem- 
brane. 

Muscular  fibres.  Between  the  ends  of  the  cartilages  is  a  continuous 
layer  of  transverse  bundles  of  unstriated  muscle,  which  is  attached  to  the 
truncated  ends  and  the  inner  surface  of  the  cartilages.  By  the  one  sur- 
face the  fleshy  fibres  are  in  contact  with  the  membrane  and  glands,  and 
by  the  other  with  the  elastic  tissue.  Some  longitudinal  fibres  are  super- 
ficial to  the  transverse  ;  they  are  arranged  in  scattered  bundles,  and  are 
attached  to  the  fibrous  tissue. 

The  elastic  tissue  forms  a  complete  lining  to  the  tracheal  tube  beneath 
the  mucous  membrane  ;  and  at  the  posterior  part,  where  the  cartilages  are 
deficient,  it  is  gathered  into  strong  longitudinal  folds.  This  layer  is  closely 
connected  with  the  mucous  membrane  covering  it. 

Tlie  mucous  membrane  of  the  trachea  lines  the  tube,  and  resembles  that 
of  the  larynx  in  being  furnislied  with  a  columnar  ciliated  epithelium. 

Connected  with  this  membrane  are  numerous  branched  mucous  glands 
of  variable  size.  The  largest  are  found  at  the  back  of  the  trachea,  in  the 
interval  between  the  cartilages,  where  some  are  placed  beneath  the  fibrous 
membrane  with  the  muscular  fibres,  and  others  outside  that  layer. 

Other  smaller  glands  occupy  the  front  and  sides  of  the  trachea,  being 
situate  on  and  in  the  fibrous  tissue  connectins:  the  cartilasfinous  rinjrs. 


Section  XVIII. 

PREVERTEBRAL  MUSCLES  AND  VERTEBRAL  VESSELS. 

Directions.  On  the  part  of  the  spinal  column  that  was  laid  aside  after 
the  separation  of  the  pharynx  from  it,  the  student  is  to  learn  the  deep 
muscles  on  the  front  of  the  vertebn^. 

Dissection.  The  prevertebral  muscles  will  be  prepared  by  removing 
the  fascia  and  areolar  tiss'ue.  The  muscles  are  three  in  number  on  each 
side  (fig.  45),  and  are  easily  distinguished.  Nearest  the  middle  line  lies 
the  longus  colli — this  is  the  longest ;  the  muscle  external  to  it,  which 
reaches  to  the  head,  is  the  rectus  capitis  anticus  major  ;  and  the  small 
muscle  close  to  the  skull,  which  is  external  to  the  last  and  partly  concealed 
by  it,  is  the  rectus  capitis  anticus  minor.  The  smaller  rectus  muscle  is 
often  injured  in  cutting  through  the  basilar  process  of  the  occipital  bone. 

The  LONGUS  COLLI  muscle  (fig.  45,  ^)  is  situate  on  the  bodies  of  tlie 
cervical  and  upper  dorsal  vertebra3,  and  is  pointed  above,  but  larger  below. 
It  consists  of  two  parts — internal  and  external,  the  former  being  vertical, 
and  the  latter  oblique  in  direction,  as  on  the  right  side  of  the  figure. 

The  internal  part  arises  by  fleshy  and  tendinous  processes  from  the 
bodies  of  the  two  upper  dorsal  and  two  lower  cervical  vertebrae ;  and  the 
external  piece  takes  origin  from  the  anterior  transverse  processes  of  four 


164 


DISSECTION    OF    THE    NECK. 


cervical  vertebrae  (sixth,  fifth,  fourth,  and  tliird)  Both  parts  of  the  mus- 
cle are  blended  above,  and  the  whole  is  inserted  by  four  slips  into  the  bodies 
of  the  four  upper  cervical  vertebra). 

Some  of  the  lowest  fibres  of  the  muscle  are  attached  separately  by  ten- 
don to  the  anterior  transverse  process  of  one  or  two  of  the  lower  cervical 
vertebrae. 

Fig.  45. 


A.  Longus  medius. 

B.  Rectus  capitis  auticus  major, 
c.  Scalenus  auticus. 

D.  Scalenus  medius. 

F.  Scalenus  posticus. 

G.  Rectus  capitis  anticus  minor. 


Deep  Muscles  of  the  Frokt  of  the  Neck  and  the  Scaleni  Muscles, 


In  contact  with  the  anterior  surface  of  the  muscle  is  the  pharynx.  The 
inner  border  is  at  some  distance  inferiorly  from  the  muscle  of  tlie  opposite 
side,  but  superiorly  only  the  pointed  anterior  common  ligament  of  the  ver- 
tebrae separates  the  two.  The  outer  border  is  contiguous  to  the  scalenus, 
to  the  vertebral  vessels,  and  to  the  rectus  capitis  anticus  major  muscle. 

Action.  Botli  muscles  bend  forwards  the  neck ;  and  the  upper  oblique 
fibres  of  one  will  turn  the  neck  and  head  to  the  same  side,  by  the  attach- 
ment to  the  atlas. 

The  RECTUS  CAPITIS  ANTICUS  MAJOR  (fig.  45,  ^)  is  external  to  the 
preceding  muscle,  and  is  largest  at  the  upper  end.  Its  origin  is  by  pointed 
tendinous  slips,  with  the  longus  colli,  from  the  summits  of  the  anterior 
transverse  processes  of  four  cervical  vertebrae  (sixth,  fifth,  fourth,  and 
third) ;  and  the  fibres  ascend  to  be  inserted  into  the  basilar  process  of  the 
occipital  bone,  in  front  of  the  foramen  magnum. 

The  anterior  surface  of  the  muscle  is  covered  by  the  pharynx,  and  by 
the  carotid  artery  and  the  numerous  nerves  near  the  base  of  the  skull. 
The  muscle  j)artly  conceals  the  following  one.  At  its  insertion  the  rectus 
is  fleshy,  an<l  reaches  from  the  middle  line  to  the  temporal  bone. 

Action.  Both  muscles  incline  forwards  the  head;  and  one  will  bring 
the  face  to  the  same  side  by  rotating  the  head. 


INTERTRANSVERSE    MUSCLES.  165 

The  RECTUS  CAPITIS  ANTicus  MINOR  (fig.  45,  ^),  is  a  small  flat 
muscle,  which  arises  from  the  anterior  transverse  process  and  body  of  the 
atlas;  and  is  inserted  into  the  basilar  process  of  the  occipital  bone  between 
the  foramen  magnum  and  the  rectus  major,  and  half  an  inch  from  its 
fellow. 

The  anterior  primary  branch  of  the  suboccipital  nerve  lies  between  the 
borders  of  this  niuscle  and  the  rectus  capitis  lateralis. 

Action.  Its  power  is  very  slight,  but  it  will  help  in  moving  forwards 
the  head. 

Dissection.  The  small  intertransversales  muscles  will  come  into  view 
when  the  other  muscles  have  been  removed  from  the  front  and  back  of  the 
transverse  processes.  By  tracing  towards  the  spine  the  anterior  primary 
branches  of  tlie  cervical  nerves,  the  intertransversales  will  be  readily  seen 
on  their  sides. 

After  the  muscles  and  nerves  have  been  examined,  the  tips  of  the 
conjoined  transverse  processes  may  be  cut  off  to  lay  bare  the  vertebral 
artery. 

The  INTERTRANSVERSE  MUSCLES  are  slender  fleshy  slips  in  the  inter- 
vals between  the  transverse  processes.  In  the  neck  there  are  seven  pairs 
— the  first  being  between  the  atlas  and  axis,  and  the  last  between  the 
lowest  cervical  and  the  first  dorsal  vertebra.  One  set  is  attached  to  the 
anterior,  and  the  other  to  the  posterior  tubercles  on  the  tips  of  the  con- 
joined transverse  processes. 

Between  the  muscles,  except  in  the  first  two  spaces,  is  the  anterior  pri- 
mary branch  of  a  cervical  nerve ;  and  beneath  the  posterior  muscle  is  the 
other  primary  branch  of  the  same  nerve.  In  the  upper  space  the  posterior 
muscle  is  often  wanting;  and  in  the  lowest  space,  the  muscle  of  the  ante- 
rior set  is  smaller  than  the  others,  or  it  may  be  absent. 

Action.  By  ap})roximating  the  transverse  processes  these  muscles  bend 
the  spinal  column  laterally. 

Cervical  nerves  at  their  exit  from  the  spinal  canal.  The  trunks  of  the 
cervical  nerves  issue  from  the  spinal  canal  through  the  intervertebral 
foramina,  except  the  first  two,  and  bifurcate  into  anterior  and  posterior 
branches. 

The  anterior  primary  branch  passes  outwards  between  the  intertrans- 
verse muscles,  and  joins  in  plexuses  with  its  fellows. 

The  posterior  primary  branch  turns  to  the  Back  beneath  the  posterior 
intertransverse  muscle,  and  the  other  muscles  attached  to  the  posterior 
transverse  processes ;  in  its  course  it  lies  close  to  the  bone  between  the 
articular  processes  of  the  vertebra. 

Peculiarities  in  the  first  two.  The  first  two  nerves  leave  the  spinal 
canal  above  the  neural  arches  of  the  atlas  and  axis,  and  divide  at  the  back 
of  the  neck  into  anterior  and  posterior  branches. 

The  anterior  primary  branch  of  the  first  or  suboccipital  nerve  has  been 
examined  (p.  115).  The  anterior  branch  of  the  second  nerve,  after  per- 
forating the  membrane  between  the  neural  arches  of  the  first  and  second 
vertebraB,  is  directed  forwards  outside  the  vertebral  artery,  and  beneath 
the  first  pair  of  intertransverse  muscles,  to  join  the  cervical  plexus. 

The  posterior  primary  branches  of  the  first  two  nerves  are  described  in 
the  dissection  of  the  Back. 

The  vertebral  artery  has  been  seen  at  its  origin  in  the  neck  (p.  77); 
and  its  termination  is  described  with  the  vessels  of  the  brain.  Entering 
usually  the  foramen  in  the  sixth  cervical  vertebra,  the  artery  ascends  ver- 


166  DISSECTION    OF    THE    NECK. 

tically  through  the  corresponding  foramina  in  the  other  vertebrae.  Beyond 
the  atlas,  the  vessel  turns  backwards  on  the  neural  arch  of*  that  bone,  and 
passing  beneath  the  ligament  joining  the  first  vertebra  with  the  os  occipi- 
tis,  enters  the  skull  through  the  foramen  magnum.  In  its  course  through 
the  foramina  the  artery  lies  in  front  of  the  anterior  trunks  of  the  cervical 
nerves,  except  those  of  the  first  and  second — the  former  of  which  crosses 
on  the  inner,  and  the  latter  on  the  outer  side.  The  vessel  is  accompanied 
by  a  vein,  and  by  a  {)lexus  of  nerves  of  the  same  name. 

In  the  neck  the  artery  furnishes  small  twigs  to  the  surrounding  muscles, 
the  spinal  canal,  and  the  spinal  cord. 

The  vertebral  vein  begins  by  small  radicles  in  the  occiput,  and  in  the 
muscles  of  the  back  of  the  neck,  and  enters  the  aperture  of  the  atlas,  where 
it  receives  sometimes  a  vein  from  the  skull  through  the  posterior  condyloid 
foramen  of  the  occipital  bone.  Accompanying  the  artery,  the  vein  tra- 
verses the  apertures  between  the  transverse  processes,  and  ends  in  the 
subclavian  vein. 

In  its  course  it  is  joined  by  branches  from  the  internal  and  external 
spinal  veins;  its  other  branches  are  described  at  p.  78. 

The  vertebral  plexus  of  nerves  is  derived  from  the  inferior  cervical 
ganglion  of  the  sympathetic  (p.  117).  It  surrounds  the  artery,  and  com- 
municates with  the  spinal  nerves  as  high  as  the  third  or  fourth. 


Section  XIX. 

LIGAMENTS  OF  THE  VERTEBRA  AND  CLAVICLE. 

Directions.  On  the  remaining  part  of  the  spine,  the  ligaments  connect- 
ing the  cervical  vertebrae  to  each  other  and  to  the  occipital  bone  are  to  be 
learnt. 

Dissection.  Disarticulate  the  last  cervical  from  the  first  dorsal  verte- 
bra. Then  remove  altogether  the  muscles,  vessels,  nerves,  and  areolar 
tissue  and  fat  from  the  cervical  vertebra?.  By  sawing  through  the  occipi- 
tal bone,  so  as  to  leave  only  an  osseous  ring  behind  the  foramen  magnum, 
the  ligaments  between  the  atlas  and  the  occipital  bone  can  be  more  easily 
cleaned. 

The  COMMON  LIGAMENTS  attaching  together  the  cervical  vertebra?  are 
similar  to  those  uniting  the  vertebrse  in  other  parts  of  the  S[)ine,  viz.,  an 
anterior  and  a  posterior  common  ligament;  bands  between  the  lamina?  and 
spines;  capsular  ligaments  and  synovial  membranes  for  the  articulating 
processes ;  and  an  intervertebral  ligament  between  the  bodies  of  the  bones. 

Directions.  The  common  ligaments  will  be  best  seen  on  the  dorsal  or 
lumbar  portions  of  the  spine  where  they  are  more  fully  developed ;  their 
})reparation  and  description  will  be  found  at  the  end  of  the  thorax,  with 
the  description  of  the  ligaments  of  the  spine.  Should  the  student  examine 
them  in  the  neck,  to  see  their  difference  in  this  region  of  the  spine,  he 
should  leave  uncut  the  neural  arches  of  the  three  highest  cervical  vertebrae, 
to  which  special  ligaments  are  attached. 

Special  ligaments  unite  the  first  two  cervical  vertebrae  to  each  other 
and  to  the  occipital  bone :  some  of  these  are  external  to,  and  others  within 
the  spinal  canal. 


LIGAMENTS  OF  ATLAS  AND  AXIS. 


167 


The  ligaments  outside  the  spinal  canal  are  thin  fibrous  membranes, 
which  connect  the  bodies  and  arches  of  the  first  two  vertebrae  in  front  and 
behind ;  and  join  the  atlas  with  the  occipital  bone  at  the  same  aspects. 

Fiff.  46. 


External  Ligaments  in  front  between  the  Atlas  and  Axis  and  the 
Occipital  Bone  (Bourgery). 

1.  Sawn  basilar  process.  3.  Anterior  atlo-axoid. 

2.  Anterior  occipito-atloid.  4.  Articulation  of  the  articular  processes  cut  open. 

Capsular  ligaments  surround  the  articular  surfaces  of  all  the  bones;  but 
these  will  be  examined  more  conveniently  after  the  spinal  canal  has  been 
opened. 

Union  of  the  atlas  with  the  axis.  The  posterior  ligament  (atlo-axoid) 
(fig.  47,  ^)  is  a  thin  loose  membrane,  which  is  attached  by  one  margin  to 
the  neural  arch  of  the  atlas,  and  by  the  other  to  the  corresponding  arch  of 
the  axis.  Below  the  superficial  part  are  some  deeper  and  stronger  fibres. 
The  posterior  primary  branch  of  the  second  nerve  pierces  it. 

Fig.  47. 


External  Ligaments  behind  between  the  Atlas  and  Axis  and  the  Occipital  Bone. 

1.  Posterior  occipito-atloid  ligament.  3.  Vertebral  artery  entering  beneath  the  oc- 

2.  Posterior  atlo-axoid.  cipito-atloid  ligament. 

The  anterior  ligament  (fig.  46,  ^)  unites  the  bodies  of  the  first  two  ver- 
tebnie  in  the  same  manner  as  the  preceding  ligament  connects  their  arches. 
It  is  thickest  in  the  middle. 


168  DISSECTION    OF    THE    NECK. 

Union  of  the  atlas  with  the  occipital  hone.  The  anterior  ligament  (oc- 
cipito-atloid)  (fig.  46,  '^)  is  thin  and  wide,  and  passes  from  the  basilar 
process  of  the  occipital  bone,  in  front  of  the  foramen  magnum,  to  the  body 
of  the  atlas.  The  middle  part  of  the  ligament,  which  is  fixed  to  the 
tubercle  on  the  front  of  the  atlas,  is  much  the  thickest. 

The  posterior  ligament  (fig.  47,  ^)  is  fixed  to  the  occipital  bone  behind 
tlie  foramen  magnum,  and  to  the  neural  arch  of  the  atlas.  It  is  thin ;  and 
at  its  attachment  to  the  atlas  the  vertebral  artery  (^),  and  the  posterior 
primary  branch  of  the  suboccipital  nerve,  pass  beneath  it. 

The  ligaments  inside  the  spinal  canal  are  peculiar  in  form,  and  assist 
in  retaining  the  skull  in  place  during  the  rotatory  and  nodding  movements 
of  the  head.     Between  the  occipital  bone  and  the  second  vertebra  are 

Fig.  48. 


Internal  Ligament  between  Occipital  Bonk  and  Axis  (Bourgery). 
1  and  2.  Attachments  of  the  occipito-axoidean  ligament. 

three  strong  ligaments — a  central,  and  two  lateral  or  check ;  and  the  odon- 
toid process  of  the  axis  is  fixed  against  the  body  of  the  atlas  by  a  strong 
transverse  band. 

Dissection.  Supposing  the  neural  arches  of  the  cervical  vertebra?  to  be 
removed  except  in  the  first  three,  the  arches  of  these  vertebrae  are  to  be 
sawn  through  close  to  the  articular  processes.  Nextly  the  ring  of  the 
occipital  bone  bounding  posteriorly  the  foramen  magnum  is  to  be  taken 
away.  Lastly,  the  student  should  detach  the  tube  of  dura  mater  from  the 
interior  of  the  spinal  canal ;  and,  on  raising  from  below  the  upper  part  of 
the  posterior  common  ligament  of  the  bodies  of  the  vertebrae,  the  liga- 
mentous band  between  the  occipital  bone  and  the  axis  (occipito-axoid) 
will  come  into  view. 

Union  of  the  occipital  hone  with  the  axis.  Tlie  central  ligament  (oc- 
cipito-axoidean) (fig.  48,  ^)  is  a  strong,  thick  layer  beneath  the  posterior 
common  ligament  of  the  bodies  of  the  vertebrae,  and  is  rather  triangular 
in  form  with  tlie  base  uppermost.  Above  it  is  attached  to  the  basilar 
process  (on  the  cranial  aspect)  near  the  margin  of  the  foramen  magnum, 
extending  as  far  on  each  side  as  the  insertion  of  the  ciieck  ligaments. 
From  that  spot  it  descends  over  the  odontoid  process,  and,  becoming  nar- 
rower, is  inserted  into  the  body  of  the  axis.  Occasionally  a  bursa  is  found 
between  it  and  the  transverse  ligament  of  the  atlas. 


LIGAMENTS    OF    ATLAS    AND    AXIS. 


169 


DisserAion  (fig.  49).  After  the  removal  of  the  occipito-axoidean  liga- 
ment, by  cutting  transversely  through  it  above,  and  reflecting  it,  the  stu- 
dent should  define  a  strong  band,  the  transverse  ligament  which  crosses 

Fig.  49. 


Intkrnal  Ligaments  between  the  Occipital  Bone  and  the  Atlas  and  Axis  (Bourgery). 

1.  The  left  cheek  ligament.  3.  Cut  end  of  the  occipito-axoidean  ligament. 

2.  The  transverse  ligament,  sending  offsets 

upwards  and  downwards. 

the  root  of  the  odontoid  process,  and  sends  upwards  and  downwards  a  slip 
to  the  occipital  bone  and  the  axis.  The  upper  offset  from  the  transverse 
ligament  may  be  cut  through  afterwards  for  the  purpose  of  seeing  the 
check  ligaments  which  diverge,  one  on  each  side,  from  the  odontoid 
process. 

The  lateral  odontoid  or  check  ligaments  (fig.  49,  ^)  are  two  strong  bun- 
dles of  fibres,  attached  by  one  end  to  the  side  of  the  head  of  the  odontoid 
process,  and  by  the  other  to  a  depression  on  the  inner  surface  of  the  con- 
dyle of  the  occipital  bone.  These  ligaments  are  covered  by  the  occipito- 
axoidean  band;  their  upper  fibres  are  short  and  almost  horizontal,  and 
the  lower  are  longer  and  oblique. 

Between  the  lateral  bands  is  a  central  odontoid  ligament j  which  connects 
the  tip  of  the  odontoid  process  to  the  margin  of  the  basilar  process  of  the 
occipital  bone. 

Union  of  the  atlas  with  the  axis.  The  transverse  ligament  of  the  atlas 
(fig.  49,  ^)  is  a  flat,  strong,  arched 
band  behind  tlie  odontoid  process, 
which  is  attached  on  each  side  to  a 
tubercle  below  the  inner  part  of  tlie 
articular  process.  This  ligament  is 
widest  in  the  centre;  and  at  this 
spot  it  has  a  band  of  longitudinal 
fibres  connected  with  the  upper  and 
lower  margins  (fig.  49),  so  as  to 
produce  a  cruciform  appearance: 
the  upper  piece  is  inserted  into  the 
basilar  process,  and  the  lower  into 
the  body  of  the  second  vertebra. 
Its  surface  towards  the  cord  is  con- 
cealed by  the  occipito-axoid  liga- 
ment. 


Fiff.  50. 


First  Vertebra  with  the  Odontoid  Process 
removkd  from  the  socket  formed  by  thb 
Bone  and  the  Transverse  Ligament. 

1.  Transverse  ligament  with  its  offsets  cut. 

2.  Sociiet  for  the  odontoid  process. 


170  DISSECTION    OF    THE    NECK. 

This  ligament  fixes  the  odontoid  process  of  the  second  vertebra  against 
the  body  of  the  atlas,  confining  it  in  a  ring  (fig.  50). 

Wlien  the  transverse  and  check  ligaments  have  been  cut  througli,  the 
tip  of  the  odontoid  process  will  be  seen  to  have  two  cartilaginous  surfaces ; 
one  in  front  where  it  touches  the  atlas,  the  other  at  the  opposite  aspect, 
where  it  is  in  contact  with  the  transverse  ligament.  Two  synovial  mem,- 
hranes  facilitate  the  movements  of  the  odontoid  process,  one  serving  for 
the  joint  between  this  piece  of  bone  and  the  atlas ;  and  the  other  for  the 
joint  between  it  and  the  transverse  ligament. 

Union  of  the  articular  surfaces.  The  articular  surfaces  of  the  occipital 
bone  and  atlas  are  surrounded  by  a  capsular  ligament  of  scattered  fibres, 
which  is  strongest  externally  and  in  front.  When  the  joint  is  opened,  the 
condyle  of  the  occipital  bone  Avill  be  seen  to  look  somewhat  outwards,  and 
the  hollowed  surface  of  the  atlas  inwards.  A  synovial  membrane  is  pre- 
sent on  each  side. 

The  articular  surfaces  of  the  first  two  vertebrae  are  inclosed  on  each  side 
by  a  capsule  (fig.  46,  *),  which  is  stronger  in  front  than  behind.  On 
opening  the  joint  the  surfaces  of  the  bones  may  be  perceived  to  be  almost 
horizontal.     On  each  side  there  is  a  separate  loose  synovial  memhrane. 

Movements  of  the  head.  The  head  can  be  bent  forwards  and  backwards; 
turned  from  side  to  side — rotation ;  and  inclined  towards  the  shoulder. 

Nodding  takes  place  in  the  joints  between  the  atlas  and  the  occipital 
bone,  the  condyles  gliding  forwards  and  backwards.  When  the  head  is 
moved  more  freely,  flexion  and  extension  of  the  cervical  vertebras  come 
into  play. 

Rotation  is  permitted  by  the  several  joints  between  the  atlas  and  axis. 
In  this  movement  the  axis  is  fixed,  and  the  atlas,  bound  to  it  by  the 
transverse  ligament,  moves  to  the  right  and  the  left,  carrying  the  weight 
of  the  head.  Too  great  a  movement  of  the  face  to  the  side  is  checked  by 
the  odontoid  ligament.  Only  part  of  the  whole  of  the  rotatory  movement 
to  one  side  is  obtained  between  the  atlas  and  axis,  the  rest  being  made  up 
by  the  neck. 

Approximation  of  the  head  to  the  shoulder  is  effected  by  the  neck  move- 
ment: perhaps  a  very  slight  degree  of  it  may  be  due  to  gliding  downwards 
of  the  occipital  condyle  of  the  same  side  on  the  articular  surface  of  the 
atlas. 

Sterno-clavicular  Articulation  (fig.  ol).  The  articular  surfaces 
are  somewhat  irregular  and  adapted  to  each  other,  with  an  intermediate 
fibro-cartilage ;  and  they  are  retained  in  contact  by  a  capsular  ligament; 
by  a  band  to  the  first  rib ;  and  by  anotlier  band  between  the  ends  of  the 
clavicles. 

Dissection.  For  the  examination  of  the  ligaments  of  the  sterno-clavicu- 
lar articulation,  take  the  piece  of  the  sternum  tliat  was  set  aside  for  the 
purpose  (p.  134).  If  the  ligaments  have  become  dry,  they  may  be  moist- 
ened for  a  short  time.  The  several  ligaments  will  a[)pear  in  the  situation 
indicated  by  their  names,  after  the  removal  of  some  fibrous  tissue. 

Capsular  ligament.  Tliis  is  a  thin  membranous  expansion  (fig.  51,  ^), 
which  incases  tlie  articular  ends  of  the  bones  and  the  fibro-cartilage.  It 
is  attached  near  the  articular  surface  of  each  bone,  and  is  thinner  before 
than  beliind.  Sometimes  the  stronger  fibres  in  front  and  at  the  back  are 
described  as  separate  ligaments. 

The  interclavicular  ligament  (fig.  51,  ^)  extends  above  the  sternum, 
between  the  ends  of  the  clavicles.     The  fibres  do  not  cross  in  a  straight 


STERNO-CLAVICULAR    JOINT. 


171 


line,  but  dip  into  the  hollow  between  the  collar  bones,  and  are  connected 
with  the  upper  piece  of  the  sternum. 

The  costo-clavicular  ligament  (fig.  51,  ^)  is  a  short  strong  band  of  ob- 
lique fibres  between  the  first  rib  and  the  clavicle.  Inferiorly  it  is  fixed  to 
the  upper  surface  of  the  cartilage  of  the  first  rib,  and  superiorly  to  a  tuber- 
cle on  the  under  surface  of  the  clavicle  near  the  sternal  end.  The  sub- 
clavius  muscle  is  in  front  of  the  ligament. 

Sometimes  the  clavicle  touches  the  rib,  and  is  provided  with  an  articular 
surface  and  a  synovial  membrane. 

The  inter  articular  fibro-cartilage  (fig.  51,  ^)  will  come  into  view  by 
cutting  the  ligaments  before  described,  and  raising  the  clavicle.  It  is 
ovalish  in  form  and  flattened,  but  is  thicker  at  the  circumference  than  the 
centre.  By  its  upper  margin  and  surface  the  cartilage  is  united  to  the 
head  of  the  clavicle  which  is  imbedded  in  it;  and  by  the  opposite  surface 
and  margin  it  is  inserted  into  the  cartilage  of  the  first  rib.  At  its  cir- 
cumference it  unites  with  the  capsule  of  the  joint.  Sometimes  there  is  an 
aperture  in  the  centre  of  the  fibro-cartilage. 

Two  synovial  sacs  are  present  in  the  articulation,  one  on  each  side  of 
the  fibro-cartilage.  The  sac  in  contact  with  the  sternum  is  looser  than 
that  touching  the  clavicle. 

Movement.  The  inner  end  of  the  clavicle  can  be  moved  up  and  down, 
and  forwards  and  backwards,  and  the  direction  it  takes  is  the  opposite  to 


LiGAMRNTS  OF  THE  INNER  EnD  OF  THE  CLAVICLE,  AND  OF  THE  CARTILAGE  OF  THE  SECOND  RiB. 

1.  Capsule.  4.  Ligaments  of  the  second  rib  with  the  sternum. 


2    Costo-clavicular  ligament. 
3.  Interclavicular  ligament. 


6.  Interarticular  fibro-cartilage  of  second  rib. 

7.  Interarticular  fibro-cartilage  of  the  clavicle. 


that  of  the  shoulder:  thus  when  the  limb  is  depressed  the  sternal  end  of 
the  clavicle  is  raised  ;  and  so  on  in  the  other  movements.  The  extent  of 
each  movement  is  but  limited,  though  those  forwards  and  upwards  are  the 
freest,  and  dislocation  may  ensue  in  any  direction  except  downwards, 
from  force  applied  to  the  limb. 


172  DISSECTION    OF    THE    BRAIN. 


CHAPTER  IL 

DISSECTION  OF  THE  BRAIN. 


Section  I. 

MEMBRANES  AND  VESSELS. 

During  the  examination  of  the  membranes,  vessels,  and  nerves,  the 
brain  is  to  be  placed  upside  down,  resting  in  the  coil  of  a  cloth  which  sup- 
ports it  evenly. 

Membranes  of  the  Brain.  Tlie  coverings  of  the  brain  (meninges) 
are  three  in  number,  viz.,  dura  mater,  pia  mater,  and  arachnoid  mem- 
brane. The  dura  mater  is  a  firm  fibrous  investment,  which  supports  part 
of  the  brain,  and  serves  as  an  endosteum  to  the  bones.  The  pia  mater  is 
the  most  internal  layer,  and  is  very  vascular.  And  the  arachnoid  is  a  thin 
serous  sac,  which  is  situate  between  tlie  other  two. 

Besides  enveloping  the  brain,  these  membranes  are  prolonged  on  the 
cord  into  the  spinal  canal.  Only  the  cranial  part  of  the  two  last  will  be 
now  noticed.  For  the  description  of  the  cranial  part  of  the  dura  mater,  see 
p.  24. 

The  ARACHNOID  is  a  thin  serous  membrane,  which  lines  the  inner  sur- 
face of  the  dura  mater,  and  is  reflected  over  the  pia  mater  and  the  brain. 
Around  the  vessels  and  nerves  that  intervene  between  the  skull  and  the 
brain,  the  membrane  forms  sheaths,  which  extend  a  short  distance  into 
the  several  apertures,  and  then  become  continuous  with  the  parietal  or 
cranial  portion.  Like  other  serous  membranes,  it  forms  a  sac  whicli  con- 
tains a  lubricating  moisture ;  and  it  consists  of  a  parietal  and  a  visceral 
part. 

The  parietal  part  is  inseparably  united  to  the  inner  surface  of  the  dura 
mater,  giving  this  a  smooth  and  polished  surface,  and  is  continued  over 
the  pieces  of  the  fibrous  membrane  projecting  between  portions  of  the 
brain. 

The  visceral  part  covers  the  encephalon  loosely,  especially  at  the  under 
surface  of  the  brain,  but  is  united  to  the  underlying  pia  mater  by  fibrous 
processes  ;  beneath  it  there  is  a  considerable  interval  (subarachnoid  space). 
On  the  upper  or  convex  surface  of  the  great  brain  the  membrane  passes 
from  one  convolution  to  another,  without  dipping  into  the  intervening  sulci ; 
though  it  lines  the  great  median  fissure  as  low  as  the  extent  of  the  falx. 
On  the  lower  surface  of  the  cerebrum  there  is  a  large  space  between  it  and 
the  centre  of  the  brain.  vStill  more  posteriorly,  Ixitween  the  hemispheres 
of  the  little  brain,  there  is  an  interval,  similar  to  that  at  the  under  part  of 
the  cerebrum. 

The  subarachnoid  space,  or  the  interval  between  the  arachnoid  mem- 
brane and  the  pia  mater,  is  larger  in  one  spot  than  anotlier ;  and  it  con- 


MEMBRANES    OF    THE    BRAIN.  173 

tains  more  or  less  fluid,  which  has  been  named  cerehro-spinal.  The  space 
is  largest  at  the  under  part  of  the  great  brain,  about  its  middle,  and  in  the 
fissure  between  the  hemispheres  of  it  and  the  cerebellum.  Under  the 
arachnoid,  in  the  fissure  between  the  halves  of  the  cerebellum,  is  the  aper- 
ture of  the  fourth  ventricle,  by  which  that  cavity  communicates  with  the 
subarachnoid  space. 

The  PiA  MATER  closely  invests  the  different  parts  of  the  brain,  and  dips 
into  the  fissures,  as  well  as  into  the  sulci  between  the  convolutions  and 
laminae.  Besides  covering  the  exterior  of  the  brain,  it  sends  processes 
into  the  interior  to  supply  vessels  to  the  walls  of  the  inclosed  space  :  thus, 
one  penetrates  into  the  cerebrum  below  the  corpus  callosum,  and  is  named 
velum  interpositum  ;  and  two  vascular  fringes,  which  project  into  the  fourth 
ventricle,  are  known  as  the  choroid  plexuses  of  that  cavity. 

This  membrane  is  a  network  of  vessels,  and  is  constructed  of  the  minute 
ramifications  of  the  arteries  and  veins  enterino:  into  or  issuing:  from  the 
cerebral  substance ;  whilst  the  intervals  between  the  vessels  are  closed  by 
fine  areolar  tissue,  so  as  to  form  a  continuous  thin  layer.  From  the  under 
surface  of  the  membrane  proceed  numerous  fine  vessels  for  the  nutrition  of 
the  brain. 

Vessels  and  nerves.  The  arachnoid  membrane  has  but  few  vessels, 
whilst  the  pia  mater  is  composed  almost  entirely  of  vessels.  The  pia 
mater  is  largely  suj)plied  by  oflf'sets  of  some  cranial  nerves,  and  by  branches 
of  the  sympathetic  which  accompany  the  vessels  at  the  base  of  the  brain 
(p.  33).  Bochdalek  has  described  branches  to  the  arachnoid  from  some 
cranial  nerves. 

Subdivisions  of  the  encephalon.  Before  the  description  of  the 
arteries  is  given,  the  chief  subdivisions  of  the  encephalon  will  be  shortly 
noticed. 

The  cranial  or  encephalic  mass  of  the  nervous  system  consists  of  cere- 
brum or  great  brain,  cerebellum  or  small  brain,  pons,  and  medulla  oblon- 
gata.    Each  of  these  parts  has  the  following  situation  and  subdivisions  : — 

The  medulla  oblongata,  or  the  upper  end  of  the  spinal  cord,  lies  in  the 
groove  between  the  halves  of  the  small  brain,  and  is  divided  into  two 
symmetrical  parts  by  a  median  fissure.  To  it  several  of  the  cranial  nerves 
are  united. 

The  pons  Varolii  is  situate  in  front  of  the  medulla  oblongata,  and  is 
marked  along  the  middle  by  a  groove,  which  indicates  its  separation  into 
halves.  Anterior  to  it  are  two  large  processes  (crura  cerebri)  connecting 
it  to  the  great  brain  ;  on  each  side  it  is  united  to  the  small  brain  by  a  sim- 
ilar white  mass  (crus  cerebelli)  ;  and  behind  it  is  the  enlarged  upper  part 
of  the  cord. 

The  cerebellum,  or  the  small  brain,  is  separated  into  two  by  a  median 
fissure,  and  each  half  will  be  subsequently  seen  to  consist  of  lobes. 

The  cerebrum,  or  the  large  brain,  is  divided  into  hemispheres  by  a 
longitudinal  fissure  in  the  middle  line  ;  and  each  half  is  further  subdivided 
into  two  by  a  transverse.sulcus — the  fissure  of  Sylvius.  In  the  centre  of 
the  cerebrum,  between  the  hemispheres  and  in  front  of  the  pons,  are  seve- 
ral small  bodies  that  will  be  afterwards  enumerated. 

Dissection,  To  follow  out  the  arteries,  let  the  brain  remain  upside 
down,  and  let  the  remains  of  any  arachnoid  membrane  be  removed.  Hav- 
ing displayed  the  trunks  of  the  vertebral  arteries  on  the  medulla  oblon- 
gata, and  those  of  the  carotid  in  front  near  the  median  fissure  of  the  large 
brain,  the  student  should  lay  bare  on  one  side  the  branches  to  the  large 


174 


DISSECTION    OF    THE    BRAIN 


brain.  Define  first  the  two  arteries  lying  in  I  lie  median  fissure  and  join- 
ing by  a  short  branch  ;  next,  an  artery  that  passes  outwards  transversely 
in  the  fissure  of  Sylvius,  and  pursue  it  to  the  outer  surface  of  the  hemis- 
phere. Look  tlien  for  a  much  smaller  vessel  (choroid),  which  enters  into 
the  brain  substance  on  the  outer  side  of  the  crus  cerebri.  By  gently 
raising  the  cerebellum  on  the  same  side,  the  last  artery  of  the  cerebrum 
may  be  traced  back  along  the  inner  aspect  of  the  hemisphere. 

Two  arteries  pass  out  to  the  small  brain.  One  on  the  u[)per  surface 
may  be  brought  into  view  on  raising  the  cerebellum  ;  and  care  is  to  be 
taken  of  the  slender  fourth  nerve  which  lies  by  its  side.  The  other  artery 
turns  inwards  to  the  median  hollow  of  the  cerebellum,  and  may  be  easily 
followed. 

Arteries  of  the  Brain  (fig.  52).  The  brain  is  supplied  with  blood 
by  the  vertebral  and  internal  carotid  arteries. 

The  vertebral  artery,  '^,  is  a  branch  of  the  subclavian  trunk  (p. 
77),  and  enters  the  trunk  through  the  foramen  magnum  ;  directed  upwards 
round  the  medulla  oblongata,  it  blends  with  its  fellow  in  a  common  trunk 
(basilar)  at  the  lower  border  of  the  pons.  As  the  vessel  winds  round  the 
upper  part  of  the  cord,  it  lies  between  the  roots  of  the  suboccipital  and 
hypoglossal  nerves ;  but  it  is  afterwards  internal  to  the  last. 

Fig.  52. 


1.  Internal  carotid  trunk. 

2.  Anterior  cerebral  branch. 

3.  Anterior  communicating. 

4.  Middle  cerebral  branch. 

5.  Choroidal  branch. 

6.  Posterior  communicating. 

7.  Posterior  cerebral  branch. 

8.  Upper  cerebellar  branch. 

9.  Internal  auditory  branch, 

10.  Interior  cerebellar  branch. 

11.  Basilar  artery, 

12.  Vertebral  artery. 

13.  Anterior  spinal  branch. 


Akteries  at  the  Base  of  the  Brain. 


Branches.  Between  its  entrance  into  the  spinal  canal  and  its  termina- 
tion, each  artery  furnishes  offsets  to  the  spinal  cord,  the  dura  mater,  and 
the  cerebellum. 

a.  The  posterior  spinal  branch  is  of  inconsiderable  size,  and  arises 
opposite  the  posterior  part  of  the  medulla :  it  descends  along  the  side  of 
the  cord,  behind  the  nerves,  and  anastomoses  with  its  fellow,  and  with 
branches  that  enter  by  the  intervertebral  foramina. 

b.  The  anterior  spinal  branch  ('^)  is  small  like  the  [)receding,  and 
springs  from  the  artery  oj)posite  the  front  of  the  spinal  cord.  It  joins  the 
corresponding  twig  on  tlie  opposite  side,  and  the  resulting  vessel  is  con- 
tinued along  the  middle  of  the  cord  on  the  anterior  aspect. 

c.  The  posterior  ineningeal  artery  leaves  the  vertebral  trunk  opposite 


ARTERIES  OF  THE  BRAIN.  175 

the  foramen  magnum,  and  ramifies  in  the  dura  mater  lining  the  fossa  of 
the  occipital  bone. 

d.  The  inferior  cerebellar  artery  (posterior)  Q^)  is  distributed  to  the 
under  surface  of  the  cerebellum.  Taking  origin  from  the  end  of  the 
vertebral,  this  branch  winds  backwards  round  the  medulla  between  the 
pneumogastric  and  spinal  accessory  nerves,  to  the  median  fissure  of  the 
cerebellum.  Directed  onwards  along  the  fissure  the  artery  reaches  the 
upper  surface  of  the  small  brain,  and  there  anastomoses  with  the  superior 
cerebellar  artery. 

An  offset  of  this  branch  ramifies  over  the  under  part  of  the  cerebellum, 
and  ends  externally  by  anastomosing  with  the  artery  of  the  upper  surface. 
As  the  vessel  lies  by  the  side  of  the  aperture  of  the  fourth  ventricle  it  gives 
a  small  choroid  offset  to  the  plexus  of  that  cavity. 

The  BASILAR  ARTERY  (^^),  formed  by  the  union  of  the  two  vertebrals, 
reaches  from  the  lower  to  the  upper  border  of  the  pons,  where  it  ends  by 
dividing  into  two  branches  (posterior  cerebral)  for  the  cerebrum.  The 
vessel  touches  the  basilar  process  of  the  occipital  bone,  from  that  circum- 
stance receiving  its  name,  and  lies  in  the  median  groove  of  the  pons.  On 
each  side  of,  and  almost  parallel  to  it,  is  the  sixth  nerve. 

Branches.  Besides  the  two  terminal  branches  mentioned  above,  the 
artery  supplies  transverse  offsets  to  the  pons  and  the  under  part  of  the 
cerebellum,  and  a  large  branch  to  the  upper  surface  of  the  cerebellum. 

a.  The  transverse  arteries  of  the  pons  are  four  or  six  small  twigs,  which 
are  named  from  their  direction,  and  are  distributed  to  the  substance  of  the 
pons.  One  of  them  (^)  gives  an  offset  (auditory)  to  the  internal  ear  along 
the  auditory  nerve. 

b.  Resembling  this  set  of  branches  is  the  following  artery,  the  inferior 
cerebellar  (anterior)  :  this  arises  from  the  basilar  trunk,  and  extends  to 
the  fore  part  of  the  under  surface  of  the  cerebellum,  on  which  it  is  dis- 
tributed. 

c.  The  superior  cerebellar  artery  i^)  is  derived  from  the  basilar  so  near 
the  termination  as  to  be  often  described  as  one  of  the  final  branches  of  that 
vessel.  Its  destination  is  to  the  upper  surface  of  the  small  brain,  to  which 
it  is  directed  backwards  over  the  third  nerve  and  the  crus  cerebri,  but 
parallel  with  the  fourth  nerve.  On  the  upper  surface  of  the  cerebellum 
the  artery  spreads  its  ramifications,  which  anastomose  with  the  vessel  of 
the  opposite  side,  and  with  the  inferior  cerebellar  artery. 

Some  twigs  of  this  vessel  enter  the  piece  of  the  pia  mater  (velum  inter- 
positum),  wiiich  projects  into  the  posterior  part  of  the  cerebrum. 

d.  The  posterior  cerebral  artery  (^)  takes  on  each  side  a  backward 
course,  similar  to  that  of  the  preceding  artery,  but  separated  from  it  by  the 
third  nerve.  The  vessel  is  then  applied  to  the  inner  surface  of  the  cere- 
brum, and  divides  into  many  branches  :  some  of  these  supply  the  under 
part,  whilst  others  turn  upwards  on  both  the  outer  and  inner  surfaces 
of  the  back  of  the  hemisphere,  and  anastomose  with  the  other  cerebral 
arteries. 

JS'ear  its  origin  it  is  joined  by  the  posterior  communicating  artery  of  the 
carotid ;  and  its  branches  to  the  brain  are  the  following : — 

Numerous  small  long  branches  leave  it  close  to  its  origin,  and  enter  the 
base  of  tlie  brain  between  the  crura  cerebri  (posterior  perforated  spot). 

A  small  choroid  artery  (posterior)  supplies  the  fold  of  pia  mater  that 
projects  into  the  cerebrum :  this  small  branch  is  transmitted  between  the 


176  DISSECTION    OF    THE    BRAIN. 

cms  and  hemisphere  of  the  cerebrum  to  the  vehim  interpositum  and  the 
choroid  plexus. 

From  the  foregoing  examination  of  tlie  offsets  of  the  vertebral  arteries 
and  the  basilar  trunk,  it  appears  that  about  half  the  encephalon — viz.,  the 
medulla  oblongata,  the  pons,  the  cerebellum,  and  the  posterior  third  of  the 
cerebrum — receives  its  blood  through  the  branches  of  the  subclavian 
arteries. 

The  INTERNAL  CAROTID  ARTERY  Q)  terminates  in  branches  for  the  re- 
maining part  of  the  cerebrum.  The  vessel  emerges  from  the  cavernous 
sinus  (p.  33)  inside  the  anterior  clinoid  process,  and  divides  at  tlie  inner 
end  of  the  fissure  of  Sylvius  into  cerebral  and  communicating  arteries.  At 
th3  base  of  the  brain  the  carotid  lies  between  the  second  and  third  nerves, 
but  nearest  the  former. 

Branches.  In  the  skull  the  carotid  gives  off  the  ophthalmic  offset,  before 
it  ceases  in  the  following  terminal  branches  to  the  cerebrum. 

a.  The  anterior  cerebral  artery  ('^)  supplies  the  inner  part  of  the  cerebral 
hemisphere.  It  is  directed  forwards  to  the  median  fissure  between  the 
halves  of  the  large  brain  ;  and  as  it  is  about  to  enter,  it  is  united  to  its  fel- 
low by  a  short  thick  branch — the  anterior  communicating  (^).  Then 
passing  into  the  fissure,  it  bends  round  the  anterior  part  of  the  corpus 
callosum,  so  as  to  be  placed  on  the  upper  aspect  in  the  natural  position  of 
the  brain,  and  is  continued  backwards  distributing  offsets  nearly  to  the 
posterior  extremity  of  the  hemisphere. 

It  gives  off  numerous  branches,  and  some  of  them  supply  the  base  of  the 
cerebrum,  thus  : — 

Near  the  commencement  it  furnishes  small  branches  to  the  part  of  the 
brain  (anterior  perforated  spot)  contiguous  to  the  inner  end  of  the  fissure 
of  Sylvius  :  and  it  distributes  some  branches  to  the  under  part  of  the 
frontal  lobe. 

b.  The  middle  cerebral  artery  (*)  is  the  largest  offset  of  the  carotid,  and 
ramifies  over  the  outer  side  of  the  hemisphere.  Entering  the  fissure  of 
Sylvius,  the  artery  divides  into  many  large  branches,  which  issue  at  the 
outer  end  of  that  groove,  and,  spreading  over  the  external  surface  of  the 
hemisphere,  inosculate  with  the  other  two  cerebral  arteries  at  tiie  front, 
the  back,  and  the  upper  part  of  the  brain.  Only  a  few  fine  offsets  require 
special  notice : 

A  set  of  small  branches  arise  at  the  inner  end  of  the  fissure  of  Sylvius, 
and  enter  the  cerebral  substance  through  the  substantia  perforata  antica. 

c.  The  posterior  communicating  artery  (°)  is  a  small  twig,  which  is 
directed  backwards  parallel  to,  and  on  the  inner  side  of  the  tliird  nerve,  to 
join  the  posterior  cerebral  artery  (of  the  basilar)  near  the  pons. 

d.  The  choroid,  artery  (anterior)  (^)  is  small  in  size,  and  arises  either 
from  tlie  trunk  of  the  carotid,  or  from  the  middle  cerebral  artery  :  it  passes 
backwards  on  the  other  side  of  the  preceding,  and  finds  its  way  between 
the  hemisphere  and  the  crus  cerebri  to  the  choroid  plexus  of  the  lateral 
ventricle. 

Circle  of  Willis.  The  arteries  at  the  under  part  of  the  brain  are  united 
freely  both  on  their  own  side  and  across  the  middle  line  in  an  arterial 
anastomosis, — the  circle  of  Willis.  On  each  side  this  circle  is  formed  by 
the  trunk  of  the  internal  carotid  giving  forwards  the  anterior  cerebral,  and 
backwards  the  posterior  communicating  artery.  In  front  it  is  constructed 
by   the   converging  anterior  cerebral,   and  the  anterior  communicating 


ORIGIN  OF  CRANIAL  NERVES.  177 

artery.  And  behind  is  the  bifurcation  of  the  basilar  trunk  into  the  poste- 
rior cerebrals.  In  the  area  of  the  circle  lie  several  parts  corresponding 
with  the  floor  of  the  third  ventricle. 

The  complete  inosculation  between  the  cranial  vessels  in  the  circle  of 
Willis  allows  at  all  times  a  free  circulation  of  blood  through  the  brain, 
even  though  a  large  vessel  on  one  side  of  the  neck  should  be  obstructed. 

The  VEINS  of  the  brain  enter  the  sinuses  of  the  dura  mater,  instead  of 
uniting  trunks  as  companions  to  the  arteries. 

Two  sets  of  veins  belong  to  the  cerebrum,  viz.,  superficial  or  external, 
and  deep  or  internal. 

The  external  veins  of  the  upper  surface  are  collected  into  the  superior 
longitudinal  sinus  (p.  29) ;  and  those  of  the  lateral  and  under  parts  enter 
the  sinuses  in  the  base  of  the  skull,  especially  the  lateral  sinus. 

The  deep  veins  of  the  interior  of  the  cerebrum  join  the  veins  of  Galen, 
and  reach  the  straight  sinus. 

The  veins  of  the  cerebellum  end  differently  above  and  below.  On  the 
upper  surface  they  are  received  by  the  veins  of  Galen  and  the  straight 
sinus;  and  on  the  lower  surface  they  terminate  in  the  occipital  and  lateral 
sinuses. 

Dissection.  The  pia  mater  and  the  vessels  are  now  to  be  stripped  from 
the  brain,  and  the  origin  of  the  cranial  nerves  is  to  be  defined.  Over  the 
greater  part  of  the  cerebrum,  the  pons,  and  the  medulla,  the  pia  mater  can 
be  detached  with  tolerable  facility  by  using  two  pairs  of  forceps  ;  but  on 
the  cerebellum  the  membrane  adheres  so  closely  as  to  require  some  care  in 
removing  it  without  tearing  the  substance  of  the  brain. 

In  clearing  out  the  fissure  between  the  halves  of  the  cerebellum  on  the 
under  surface,  the  membrane  bounding  the  opening  of  the  fourth  ventricle 
will  probably  be  taken  away  :  therefore  the  position,  size,  and  limits  of 
that  opening  between  the  back  of  the  medulla  oblongata  and  the  cerebel- 
lum should  be  now  noted. 

When  the  surface  has  been  cleaned,  the  brain  is  to  be  replaced  in  the 
spirit,  but  it  is  to  be  turned  over  occasionally,  so  that  all  the  parts  may  be 
hardened. 


Section  II. 

ORIGIN  OF  THE  CRANIAL  NERVES. 

The  cranial  nerves  take  origin  from  the  encephalon,  with  one  exception 
(spinal  accessory),  and  pass  from  it  through  apertures  in  the  skull. 

The  origin  of  a  nerve  is  not  determined  by  tlie  place  at  which  it  appears 
on  the  surface  of  the  brain,  for  fibres  or  roots  may  be  traced  deeply  into 
the  brain  substance.  Each  nerve  has  therefore  a  superficial  or  apparent, 
and  a  deep  or  real  origin  in  the  encephalon. 

With  respect  to  the  superficial  attachment  there  cannot  be  any  doubt ; 
but  there  is  much  difference  of  opinion  concerning  the  deep  origin,  in  con- 
sequence of  the  difficulty  of  tracing  the  roots.  When  the  roots  are  followed 
into  the  encephalon,  they  enter  masses  of  gray  substance,  which  are  looked 
upon  as  ganglia  of  origin. 
12 


178 


DISSECTION    OF    THE    BRAIN 


The  cranial  nerves  may  be  regarded  either  as  nine  or  twelve  pairs, 
according  to  the  mode  of  classifying  them.' 

The  several  nerves  may  be  designated  first,  second,  third,  and  so  forth  : 
this  numerical  mode  of  naming  applies  to  all,  and  is  the  one  generally  used. 

But  a  second  name  has  been  derived  for  some  of  the  nerves  from  the 
parts  to  which  they  are  supplied ;  as  instances  of  this  nomenclature  the 
terms  hypoglossal,  pneumogastric,  may  be  taken..  And  a  diiferent  ap- 
pellation is  given  to  others,  in  consequence  of  the  function  conferred  on 
the  part  to  which  they  are  distributed,  as  the  terms  auditory  and  olfactory 
express.  In  this  way  two  names  may  be  employed  in  referring  to  a  nerve: 
one  being  numerical,  the  other  local  or  functional,  as  is  exemplified  below. 

The  FIRST  OR  OLFACTORY  NERVE  (olfactory  process)  (fig.  o3,')  is  soft 

Fiff.  53. 


Olfactory. 

Optic. 

Motor  oculi. 

Trochlear. 

Trigeminal  with  small  and  large  root. 

AViductor  oculi. 

Facial  and  auditory, the  former  smaller 
and  internal. 

Eighth  nerve  consisting  of  three 
trunks  in  a  line  :  the  upper,  glosso- 
pharyngeal ;  the  middle,  pneumo- 
gastric ;  and  the  lowest  spinal  ac- 
cessory. 

Roots  of  attachment  of  the  hypoglossal 


Ori'jin  of  the  Cranial  Nerves. 

and  pulpy,  being  destitute  of  a  neurilemma ;  and  it  may  be  considered  an 
advanced  part  of  the  brain,  for  it  has  both  gray  substance  and  white  fibres 
in  its  composition,  like  the  cerebrum. 

The  olfactory  process  is  a  flat-looking  band,  wider  at  each  end  than  in 
the  middle,  which  is  lodged  in  a  sulcus  on  the  under  aspect  of  the  frontal 
lobe  of  the  cerebrum,  and  is  kept  in  position  by  the  reflection  of  the  arach- 
noid membrane  over  it.     When   the  so-called  nerve  is  raised  from  the 


•  Those  anatomists,  who  take  the  smaller  number  after  the  example  of  Willis, 
include  in  one  nerve  all  the  trunks  contained  in  the  same  aperture  of  the  skull : 
as  in  the  case  of  the  eighth  nerve,  which  consists  of  three  trunks  in  the  foramen 
jugulare.  But  those  who  are  disposed  with  Sommerring  to  enumerate  twelve 
nerves,  consider  each  of  the  three  trunks  of  the  eighth  nerve  before  mentioned, 
to  constitute  a  separate  cranial  nerve,  notwithstanding  that  it  may  be  combined 
with  others  in  the  foramen  of  exit. 


ORIGIN    OF    CRANIAL    NERVES.  179 

sulcus,  it  is  prismatic  in  form,  the  apex  of  the  prism  being  directed  down- 
wards (in  this  position). 

Anteriorly  the  nervous  substance  swells  into  the  olfactory  hulb^ — a  pyri- 
form  grayish  mass,  about  half  an  inch  in  length,  which  rests  on  the  ethmoid 
bone,  and  distributes  nerves  to  the  nose. 

Posteriorly  the  olfactory  process  is  connected  to  the  cerebrum  by  three 
roots,  external,  internal,  and  middle. 

The  external  or  long  root  is  a  slender  white  band,  which  is  directed 
backwards  along  the  outer  part  of  the  anterior  perforated  space,  and  across 
the  fissure  of  Sylvius,  and  sinks  into  the  substance  of  the  cerebrum. 

The  internal  or  short  root^  not  always  visible,  is  white  and  delicate,  and 
comes  from  the  inner  part  of  the  cerebrum. 

The  middle  or  gray  root  is  connected  with  the  gray  matter  on  the  sur- 
face of  the  brain  by  means  of  a  conical  elevation  at  the  back  of  the  sulcus 
which  lodges  the  nerve. 

Deep  origin.  The  external  root  is  said  to  be  traceable  to  one  of  the  convolutions 
of  the  island  of  Reil.  The  inner  root  joins  a  band  of  white  fibres  connected  with 
a  convolution  (gyrus  fornicatus)  to  be  afterwards  examined.  And  the  middle  root, 
continuous  With  the  gray  matter  of  the  convolutions,  contains  white  fibres  which 
enter  the  corpus  striatum. 

The  SECOND  or  optic  (^)  is  the  largest  of  the  cranial  nerves  except  the 
fifth,  and  appears  as  a  flat  band  on  the  crus  cerebri.  Anteriorly  the  nerves 
of  opposite  sides  are  united  in  a  commissure.  The  part  of  the  nerve  pos- 
terior to  the  commissure  is  named  optic  tract ;  but  the  part  beyond  the 
commissural  union,  which  is  round  and  firm,  is  called  optic  nerve.  The 
destination  of  the  nerve  is  to  the  eyeball. 

The  origin  of  the  nerve  will  be  afterwards  seen  to  come  from  the  optic 
thalamus  and  the  corpora  geniculata,  and  from  one  of  the  corpora  quadri- 
gemina  (nates). 

The  tract  is  the  flattened  part  of  the  optic  winding  round  the  peduncle 
of  the  cerebrum.  In  front  it  ends  in  the  commissure,  and  behind  it  splits 
into  two  pieces  by  which  it  is  fixed  to  the  brain.  As  the  tract  reaches 
forwards  it  crosses  the  crus  cerebri,  to  which  it  is  attached  by  its  outer  or 
anterior  edge ;  and  in  front  of  the  crus  it  is  placed  between  the  substantia 
perforata  antica  on  the  outside,  and  the  tuber  cinereum  on  the  inside,  but 
wiiether  it  receives  filaments  from  the  latter  is  uncertain. 

The  commissure  (chiasma)  of  the  nerves  measures  half  an  inch  across, 
and  lies  on  the  olivary  eminence  of  the  sphenoid  bone,  within  the  circle 
of  Willis.  It  is  placed  in  front  of  the  tuber  cinereum  ;  and  passing  be- 
neath it  (in  tliis  position  of  the  brain)  is  the  thin  lamina  cinerea. 

In  the  commissure  each  tract  is  resolved  into  three  sets  of  fibres  with 
the  following  arrangement : — the  outer  fibres,  few  in  number,  are  continued 
straight  to  the  eyeball  of  the  same  side.  The  middle,  the  largest,  decus- 
sate with  the  corresponding  bundle  of  the  other  tract, — those  of  the  riglit 
nerve  being  continued  to  the  left  side,  to  the  opposite  eye,  and  vice  versd. 
And  the  most  internal  are  continued  through  the  tract  of  the  other  side 
back  to  the  brain  without  entering  the  eye.  At  the  front  of  the  commis- 
sure are  placed  some  transverse  fibres,  which  are  prolonged  to  the  eyeballs 
through  the  part  of  each  nerve  in  front  of  the  commissure,  but  have  not 
any  connection  with  the  tracts  and  the  brain. 

The  part  called  nerve  extends  from  the  commissure  to  the  eyeball. 
Leaving  the  skull  by  the  optic  foramen,  it  receives  a  tube  of  dura  mater, 


180  DISSECTION    OF    BRAIN. 

and  its  course  in  the  orbit  is  described  in  p.  56.     In  the  eyeball  it  ends  in 
the  retina. 

The  THIRD  NERVE  ('),  motor  nerve  of  the  eyeball,  is  round  and  firm, 
and  is  attached  by  a  slanting  line  of  threads  to  the  inner  surface  of  the 
cerebral  peduncle,  near  the  locus  perforatus,  and  close  in  front  of  the  pons 
Varolii. 

Deep  origin.  The  deep  origin  is  uncertain.  According  to  Stilling, •  the  fibres  of 
the  nerve  pierce  the  peduncle,  passing  tlirough  the  locus  niger,  and  enter  a  nu- 
cleus of  gray  substance  near  the  floor  of  the  aqueduct  of  Sylvius. 

The  FOURTH  or  trochlear  nerve  (*)  cannot  be  followed  backwards 
at  present  to  its  origin.  It  is  the  smallest  of  the  cranial  nerves,  and  issues 
from  the  valve  of  Vieussens  over  the  fourth  ventricle  (fig.  G8,  *).  The 
nerve  appears  between  the  cerebrum  and  the  cerebellum,  on  the  side  of 
the  crus  cerebri ;  and  is  then  directed  forwards  to  enter  an  aperture  in  the 
free  edge  of  the  tentorium  cerebelli  near  the  posterior  clinoid  process. 

Deep  origin.  In  entering  the  valve  of  Vieussens,  filaments  of  the  nerves  of  oppo- 
site sides  cross  and  communicate.  Each  divides  into  two  parts  :  the  anterior  enters 
a  nucleus  of  gray  matter  on  the  side  of  the  aqueduct  of  Sylvius  ;  the  posterior 
joins  a  nucleus  (upper  trigeminal)  near  the  top  of  the  fourth  ventricle  (Stilling). 

The  fifth  or  trigeminal  is  the  largest  of  all  the  cranial  nerves,  and 
consists  of  two  roots,  ganglionic  or  sensory,  and  aganglionic  or  motor, 
which  are  partly  blended  in  one  trunk  beyond  the  ganglion. 

The  nerve  is  attached  to  the  side  of  the  pons  Varolii,  nearer  the  upper 
than  the  lower  border  (^).  The  small  or  aganglionic  root  is  highest,  and 
is  separated  from  the  large  one  by  two  or  three  of  the  transverse  fibres  of 
the  pons.  Both  roots  pass  outwards  through  an  aperture  in  the  dura 
mater,  above  the  petrous  part  of  the  temporal  bone,  and  are  blended  in  the 
peculiar  manner  stated  in  page  31. 

Both  roots  penetrate  the  fibres  of  the  pons,  and  are  connected  with  nu- 
clei in  the  floor  of  the  fourth  ventricle. 

Deep  origin.  The  large  root  divides  into  two  parts  near  the  mass  of  gray  matter 
called  locus  caeruleus  (p.  217).  One  piece  arises  from  the  gray  matter  near  tlie 
locus  creruleus  (upper  trigeminal  nucleus)  ;  and  the  other,  from  a  deeper  nucleus, 
lower  trigeminal,  opposite  the  lower  border  of  the  pons,  within  the  fasciculus  teres 
(Stilling). 

The  small  root  begins  with  the  fourth  nerve  in  the  upper  trigeminal  nucleus  near 
the  top  of  the  fourth  ventricle  (Stilling). 

The  SIXTH  NERVE  (^),  abduccnt  nerve  of  the  eyeball,  springs  from  the 
pyramidal  body  close  to  the  pons,  and  by  a  second  band  from  the  lower 
part  of  the  pons. 

Deep  origin.  The  fibres  of  the  nerve  bend  backwards,  through  the  medulla 
oblongata,  to  a  nucleus  in  the  floor  of  the  fourth  ventricle,  whose  position  is  on 
the  outer  part  of  the  fasciculus  teres,  and  behind  the  ant(;rior  fossa.  See  Anatomy 
of  the  Fourth  Ventricle  (p.  217). 

The  SEVENTH  CRANIAL  NERVE  (Willis)  (')  appears  at  the  lower  border 
of  the  pons  near  the  restifbrm  body.  It  consists  of  two  distinct  trunks, 
facial  and  auditory  ;  the  former  being  the  motor  nerve  of  the  face,  and  the 
latter  the  special  nerve  of  the  organ  of  hearing. 

The  Jacial  nerve  (portio  dura,  seventh  nerve,  Sommerring)  is  firm  and 

'    Unterauchungen  uber  den  Bau  des  Hirnknotens. 


ORIGIN    OF    CRANIAL    NERVES.  181 

round,  and  smaller  than  the  auditory,  internal  to  which  it  is  placed.  It 
issues  from  the  lateral  tract  of  the  medulla  at  the  upper  part,  and  is  con- 
nected by  a  slip  with  the  lower  border  of  the  pons. 

The  facial  nerve  receives  a  small  accessory  band  of  fibres  (intermediate 
portion  of  Wrisberg)  from  the  same  })art  of  the  medulla,  and  enters  the 
internal  meatus  with  the  auditory  trunk. 

The  auditory  nerve  (portio  mollis,  eighth  nerve,  Sommerring)  has  a 
surface  attachment  to  the  restiform  body  and  the  floor  of  tlie  fourth  ven- 
tricle. The  nerve  is  very  soft,  and  receives  one  of  its  names  from  that 
fact. 

Deep  origin.  The  facial  nerve  penetrates  to  the  floor  of  the  fourth  ventricle,  and 
arises  from  the  same  nucleus  as  the  sixth  nerve,  which  it  joins  (Clarke '). 

The  fasciculus  of  the  auditory  nerve  which  reaches  the  floor  of  the  fourth  ventri- 
cle, bends  backwards  over  the  restiform  body  to  the  auditory  nucleus  ;  and  some 
arciforra  fibres  out  of  the  median  sulcus  are  joined  with  this  part  of  the  root. 
The  other  fasciculus  pierces  the  restiform  body,  and  takes  origin  from  a  network 
connected  with  the  posterior  pyramid  (Clarke). 

The  EIGHTH  CRANIAL  NERVE  (Willis)  (^)  is  placed  along  the  side  of 
the  medulla  oblongata,  and  consists  of  three  distinct  trunks,  glosso- 
pharyngeal, pneumogastric,  and  spinal  accessory :  the  names  of  the  first 
two  indicate  their  destination  ;  and  the  last,  besides  being  accessory  to  the 
pneumogastric,  supplies  some  muscles. 

The  ghsso-pharyngeal  nerve  (ninth  nerve,  Sommerring)  is  the  smallest 
of  the  three,  and  is  situate  highest.  Its  apparent  origin  is  by  three  or 
more  fibrils,  which  penetrate  the  lateral  tract  of  the  medulla  close  to  the 
facial  nerve. 

The  pneumogastric  or  vagus  (tenth  nerve,  Sommerring)  is  connected 
with  the  lateral  tract  of  the  medulla,  below  the  glosso-pharyngeal  nerve, 
by  a  series  of  filaments,  which  are  collected  at  first  into  bundles,  but  are 
finally  gathered  into  one  flat  band. 

The  spinal  accessory  nerve  (eleventh  nerve,  Sommerring)  consists  of 
two  parts — accessory  to  the  vagus,  and  spinal. 

The  accessory  part  is  of  small  size,  and  arises  by  fine  filaments  in  a  line 
with  the  root  of  the  vagus,  as  low  as  the  first  cervical  nerve.  Finally  this 
fasciculus  throws  itself  into  the  pneumogastric  nerve  outside  tiie  skull. 
(Seep.  114.) 

The  spinal  part  is  firm  and  round,  like  the  third  or  the  sixth  nerve,  but 
only  a  small  piece  of  it  can  be  seen.  It  arises  by  a  number  of  fine  fila- 
ments from  the  lateral  column  of  the  spinal  cord  near  the  lateral  fissure, 
as  low  as  the  sixth  cervical  nerve.  As  the  nerve  ascends  along  the  side 
of  the  cord  it  lies  between  the  ligamentum  denticulatum  and  the  posterior 
roots  of  the  spinal  nerves,  with  the  upper  of  which  it  may  be  connected  ; 
and  it  finally  enters  the  skull  by  the  foramen  magnum. 

All  three  nerves  converge  below  the  cms  cerebelli,  and  rest  on  a  small 
lobe  of  the  cerebellum  (flocculus).  From  that  spot  they  are  directed  out- 
wards to  the  foramen  jugulare  (p.  32). 

The  fibrils  of  the  nerves  pierce  the  medulla  ;  and  each  nerve,  except  the 
spinal  part  of  the  last,  takes  origin  from  a  special  deposit  of  gray  matter  at 
the  back  of  the  medulla  oblongata,  and  near  the  lower  of  the  fourth  ven- 
tricle (p.  217). 

'  On  the  structure  of  the  Medulla  Oblongata,  by  J.  Lockhart  Clarke,  F.  R.  S.,  in 
the  Philosophical  Transactions  for  1858,  part  i. 


182  DISSECTION    OF    THE    BRAIN. 

Deep  origin.  The  glosso-pharyngeal  penetrates  as  far  as  the  vagus  nucleus,  where 
it  ends  in  fibres  which  enter  that  deposit. 

The  vagus  nerve  arises  in  a  special  nucleus  (p.  217)  ;  but  some  fibres  pass  through 
the  hypoglossal  nucleus. 

The  accessory  part  of  the  spinal  accessory  nerve  is  transmitted  to  a  special  nucleus 
below  that  of  the  vagus  ;  and  some  fibres  decussate  across  the  middle  line  with 
their  fellows. 

The  roots  of  the  spinal  part  of  the  nerve,  piercing  the  lateral  column  of  the  cord, 
pass  through  a  collection  of  cells  to  the  anterior  cornu  of  the  crescent  (Clarke). 

The  NINTH  or  hypoglossal  nerve  of  Willis  (twelfth  nerve,  Sbmmer- 
ring)  (*)  is  placed  on  the  front  of  the  medulla  oblongata,  and  arises  by  a 
series  of  filaments  from  the  sulcus  between  the  pyramidal  and  olivary 
bodies,  in  a  line  with  the  anterior  roots  of  the  spinal  nerves. 

The  filaments  of  origin  unite  into  two  bundles,  which  pierce  separately 
the  dura  mater,  and  do  not  blend  together  till  they  are  outside  the  cranial 
cavity. 

Deep  origin.  The  filaments  of  the  nerve  can  be  traced  through  the  corpus  olivare 
to  a  nucleus  below  the  level  of  the  fourth  ventricle,  and  in  front  of  the  canal  of 
the  cord  ;  but  some  bend  inwards  to  decussate  through  the  raphe  with  the  nerve  of 
the  opposite  side  (Clarke). 


Section  III. 

MEDULLA  OBLONGATA  AND  PONS  VAROLII. 

The  medulla  oblongata  and  the  pons  are  interposed  between  the  spinal 
cord  and  the  brain  proper. 

Directions.  On  a  single  brain  the  student  may  ascertain  nearly  all  the 
anatomy  of  the  parts  composing  the  medulla  and  the  pons  ;  but  if  he  can 
procure  one  hardened  specimen  of  the  medulla  and  the  pons  united,  and 
another  of  a  vertical  median  section  through  those  bodies,  he  will  compre- 
hend much  more  readily  the  following  description. 

Position.  The  brain  is  to  remain  in  the  same  position  as  for  the  exami- 
nation of  the  nerves  and  vessels. 

The  MEDULLA  oblongata  is  the  dilated  upper  part  of  the  spinal  cord 
which  is  contained  in  the  cranium  (fig.  54).  Its  limit  is  the  lower  border 
of  the  pons  in  one  direction,  and  the  upper  margin  of  the  atlas  in  the 
other.  This  part  of  the  cord  is  pyramidal  in  form,  and  measures  about 
one  inch  and  a  quarter  in  length  ;  half  an  inch  in  breadth  below,  and  about 
an  inch  at  its  widest  part. 

Its  base  joins  the  pons,  the  transverse  fibres  of  the  latter  marking  its 
limit;  and  its  apex  is  blended  with  the  spinal  cord.  The  anterior  surface 
is  irregularly  convex,  and  is  in  contact  with  the  hollowed  basilar  process 
of  the  occipital  bone.  The  opposite  surface  is  somewhat  excavated  supe- 
riorly, where  it  forms  the  floor  of  th '.  fourth  ventricle  ;  and  it  rests  in  the 
fissure  between  the  halves  of  the  cerebellum.  On  the  posterior  aspect  there 
are  not  any  cross  fibres  of  the  pons,  as  in  front,  to  mark  the  extent  of  the 
medulla. 

The  medulla  oblongata  is  divided  into  halves  by  a  median  fissure  in 
front  and  behind.  The  fissures  are  in  a  line  with  those  along  the  cord  : 
the  anterior  ceases  at  the  pons  in  a  dilated  part  (foramen  ca3cum),  but 


MEDULLA    OBLONGATA. 


183 


the  posterior  is  prolonged,  behind  the  pons,  into  the  floor  of  the  fourth 
ventricle. 

Each  half  of  the  medulla  is  constituted  of  pieces  continuous  with  those 
of  the  spinal  cord  (fig.  54);  and  slight  grooves  indicative  of  these  divi- 
sions are  to  be  seen  on  the  surface.  Thus  at  the  middle  line  in  front  is 
the  anterior  pyramid  (^)  corresponding  with  the  anterior  column  of  the 
cord ;  at  the  middle  line  behind  is  the  small  posterior  pyramid  (*)  con- 
tinuous with  the  posterior  median  column.  On  the  side  is  the  larger  pro- 
jecting restiform  body  C),  joining  below  the  posterior  column  of  the  cord; 
and  between  this  and  the  anterior  pyramid  is  the  lateral  tract  (^),  with  an 
oval  projecting  body  (corpus  olivare)  (^)  on  the  exterior,  which  blends 
below  with  the  lateral  column. 


Fig.  54. 


Fig.  55. 


Anterior  View  of  the  Medulla  Oblongata 
AND  Pons.. 

1.  Anterior  pyramid. 

2.  Lateral  tract. 

3.  Restiform  body. 

5.  Corpus  olivare. 

6.  The  decussation. 


Hinder  View  of  the  Medulla  Oblongata. 

1.  Floor  of  the  fourth  ventricle. 

2.  Eiiiiuentia  teres. 

3.  Restiform  body. 

4.  Posterior  pyramid. 


The  anterior  pyramid  (fig.  54,  ^)  is  the  most  internal  eminence  and 
receives  its  name  from  its  position  and  form.  vSituate  on  the  side  of 
the  median  fissure,  it  is  internal  to  the  olivary  body,  from  which  it  is  sepa- 
rated by  a  slight  groove.  Enlarging  as  it  ascends,  this  body  enters  the 
pons,  but  before  disappearing  beneath  the  transverse  fibres,  it  is  somewhat 
constricted  and  rounded. 

Lateral  tract  and  olivary  body.  The  lateral  tract  (funiculus  lateralis) 
(^)  fills  the  interval  between  the  anterior  pyramid  and  the  restiform  body. 
Its  surface  width  is  not  the  same  throughout :  opposite  the  lower  part  of 
the  medulla  oblongata  it  measures  as  much  as  the  pyramid  ;  but  near  the 
pons  it  is  concealed  by  the  olivary  body,  so  that  it  is  seen  only  in  the 
narrow  interval  between  the  outer  side  of  the  corpus  olivare  and  the  resti- 
form body. 

The  olivary  body  (corpus  olivare)  (^)  is  an  oval  projection,  about  half 


184 


DISSECTION    OF    THE    BRAIN, 


an  inch  long.  A  shallow  groove  separates  it  from  the  pyramid,  and  a 
deeper  and  wider  one  intervenes  between  it  and  the  restifbrm  body.  This 
eminence  is  shorter  than  tlie  pyramid,  and  does  not  reach  to  the  pons. 
Its  upper  end  is  most  prominent ;  and  arching  round  the  lower  end,  and 
over  the  surface,  are  some  white  fibres  (fibrte  arciformes). 

Restiform  body  (^).  The  restiform  body  (restis,  a  rope)  forms  the 
largest  prominence  on  the  half  of  the  medulla  oblongata,  and  cannot  be 
seen  satisfactorily  except  on  a  distinct  preparation.  It  is  [)osterior  to  the 
lateral  tract,  and  projects  on  the  side,  so  as  to  give  the  width  to  the  upper 
part  of  the  medulla  oblongata.  Behind,  the  restiform  bodies  diverge  above 
from  each  other,  and  between  them  is  the  space  of  the  fourth  ventricle. 

The  posterior  pyramid  (funic,  gracilis)  (fig.  55,  *)  lies  along  the  side  of 
the  posterior  median  fissure,  and  is  much  narrower  than  either  of  the  other 
component  pieces.  By  drawing  forwards  the  medulla  it  will  be  seen  to 
be  slightly  enlarged  (clava)  at  the  apex  of  the  fourth  ventricle,  and  then 
to  become  gradually  indistinct  along  the  inner  part  of  the  corpus  restiforme. 

Structure.  From  the  interposition  of  the  medulla  oblongata  between 
the  brain  and  the  spinal  cord,  it  is  continuous  with  both.  Below,  the  con- 
stituent pieces  of  the  half  join  directly  (as  before  said)  those  of  the  spinal 
cord ;  but,  above,  they  are  continued  chiefly  to  the  cerebrum,  only  one 
piece  (restiform)  entering  the  cerebellum. 

Dissection  (fig.  56).  The  student  has  now  to  show  the  continuity  of  the 
constructing  parts  of  one-half  of  the  medulla  oblongata  with  those  of  the 

Fig.  56. 


a.  Anterior  pyramid. 

b.  Decussation  of  the  medulla  oblon- 

gata   (decussation    of    the  pyra- 
mids). 
e.  Fibres  of  the  pyramid  in  the  pons. 

d.  Fibres  of  the  pyramids  in  the  crus 

cerebri. 

e.  Superficial  fibres  of  the   pons,  cut 

through  and  reflected. 
/.  Superficial   fibres   of    the   pons,   in 
place. 


Fibres  of  the  Medulla.  Pons  and  Ckus  Cerebri. 


gpinal  cord.  Let  him  trace  out  first  the  fibres  of  the  pyramid  on  the  right 
side :  in  it  two  sets  of  fibres  have  to  be  shown — one  from  the  same,  and 
one  from  the  opposite  side  of  the  cord.  The  fibres  from  the  of)posite  half 
of  the  cord  will  appear  in  the  median  fi.ssure,  when  the  pyramids  are  gently 
drawn  from  one  another,  where  they  are  named  the  decussating  fibres  ; 
and  to  lay  these  bare  more  completely,   the  small  part  of  the  anterior 


FIBRES  OF  OBLONG  MEDULLA 


185 


column  of  the  cord  on  the  opposite  side,  which  remains  below  the  cross 
fibres  (for  the  cord  has  been  cut  through  near  these),  may  be  forcibly  turned 
outwards. 

The  anterior  pyramid  (fig.  bQ),  a)  receives  fibres  inferiorly  from  tlie 
anterior  column  of  the  cord  of  its  own  side,  and  from  the  opposite  half  of 
the  cord.  The  inner  set  of  fibres,  b,  deep  at  their  origin,  become  super- 
ficial, and  are  directed  upwards,  close  to  the  median  fissure,  joining  the 
fibres  continued  from  the  anterior  column  of  the  cord  ;  and  as  the  inner 
fibres  of  each  pyramid  are  derived  from  the  opposite  side,  they  cross  each 
other  in  the  median  line — forming  thus  the  decussation  of  the  medulla  ob- 
longata. 

The  fibres  of  the  pyramid  are  white  and  longitudinal,  and  are  collected 
into  a  bundle  of  a  prismatic  form.  Superiorly  they  enter  the  pons  (fig. 
56),  to  reach  the  cerebrum. 

Dissection.  For  the  purpose  of  seeing  the  arrangement  of  the  fibres  of 
the  lateral  tract,  the  anterior  pyramid  is  to  be  cut  across  on  the  right  side, 
between  its  decussation  and  the  olivary  body  (fig.  57),  and  to  be  raised 
towards  the  pons. 

The  lateral  tract  of  the  medulla  is  prolonged  inferiorly  into  the  portion 
of  the  spinal  cord  between  the  anterior  and  posterior  roots  of  the  nerves. 
The  continuation  of  the  tract  (fig.  57)  ascends  beneath  the  olivary  body, 
and  leaving  the  surface  of  the  medulla  enters  the  pons. 

The  olivary  body,  and  its  fillet  (fig.  57,  c).  The  olivary  mass  consists 
of  three  parts,  viz.,  a  gray  incasing  layer,  a  nucleus,  and  a  band  prolonged 
from  it — the  fillet. 

Fig.  57. 


a.  Anterior  pyramid  fibres,  cut 
through,  and  raised  as  far 
as  the  optic  thalamus. 

6.  Lateral  tract  of  the  medulla 
oblongata. 

c.  Olivary  body,  and  fillet  of  the 

olivary  body  issuing  at  the 
upper  end. 

d.  Fibres  of  the  lateral  tract  in 

the  pons  and  crus  cerebri. 

e.  Superficial,  and 

f.  Depp  transverse  fibres  of  the 

pons,  cut  through, and  turn- 
ed outwards. 

g.  Locus  niger  in  the  crus  cere- 

bri, between  the  fibres  of  the 
lateral  tract  and  pyramid. 


Fibres  of  the  Lateral  Tract  and  of  the  Olivary  Body. 


"When  the  olivary  body  has  been  sliced  obliquely,  a  very  thin  wavy 
layer  of  gray  substance  surrounding  a  nucleus  of  whitish  matter  will  be 
apparent:  this  is  the  corpus  dentatum  (fig.  58,/).  It  forms  a  thin  cap- 
sule or  bag,  having  a  zigzag  outline  in  a  section,  with  the  dilated  part 


186  DISSECTION    OF    THE    BRAIN. 

towards  the  surfuce,  and  tlie  narrowed  part  or  neck  open  and  directed 
backwards  near  the  middle  line.  It  consists  of  small,  nucleated,  and  rami- 
tied  nerve  cells.  ^ 

The  nucleus  is  the  yellowish  white  substance  filling  the  capsule ;  and 
from  it  and  the  capsule  issue  transverse  fibres,  which  unite  the  olivary 
bodies  across  the  middle  line  (fig.  58,  g)  :  this  uniting  band  is  close  below 
the  anterior  median  fissure. 

The  fillet  is  a  narrow  band  of  fibres,  which  ascends  from  the  olivary 
body  to  the  cerebrum  (fig.  57).  It  is  formed  in  part  by  longitudinal  fibres 
of  tjie  lateral  tract  which  diverge  to  inclose  the  corpus  olivare,  and  in  part 
by  fibres  derived  from  the  sac. 

The  restiform  body  (fig.  54,  ')  is  continuous  inferiorly  with  the  poste- 
rior column  of  the  cord.  Superiorly  it  bends  outwards  to  the  cerebellum 
without  entering  the  pons. 

The  posterior  pyramid  runs  below  into  the  posterior  median  column  of 
the  cord,  and  is  directed  above  along  the  floor  of  the  fourth  ventricle, 
joining  the  fibres  of  the  lateral  tract  of  the  same  side. 

The  decussation  of  the  medulla  oblongata  (pyramids)  (fig.  56^  b)  occu- 
pies the  anterior  groove  of  the  oblong  medulla,  at  the  distance  of  three- 
quarters  of  an  inch  from  the  pons.  It  is  about  a  quarter  of  an  inch  in 
length,  and  is  constructed  by  the  crossing  of  three  or  four  bundles  of  fibres 
from  each  side. 

In  this  intercommunication  the  fibres  are  derived,  according  to  Mr. 
Clarke,  from  all  the  constituent  parts  of  the  half  of  the  spinal  cord  of  the 
opposite  side  except  from  the  anterior  column  ;  but  the  fibres  from  the 
lateral  column  of  that  side,  blended  with  offsets  from  the  contiguous  gray 
substance,  form  the  chief  yiortion  of  the  decussation.     . 

Arched  or  commissural  fibres  of  the  medulla.  In  each  half  of  the  me- 
dulla oblongata  are  fine  transverse  fibres,  both  on  the  exterior  and  in  its 
substance.  At  the  middle  line  the  fibres  of  opposite  sides  unite,  and  give 
rise  to  a  commissure  between  the  halves  (raphe). 

The  superficial  transverse  fibres  (fig.  58,  s,  and  fig.  54),  more  marked 
in  some  bodies,  issue  from  the  nucleus  in  the  restiform  body  (Clarke),  and 
advance  over  the  surface  of  the  olivary  and  pyramidal  bodies  to  the  ante- 
rior fissure,  where  they  enter  the  half  of  the  medulla  of  the  same,  and  of 
the  opposite  side.  Below  the  olivary  body  they  form  oftentimes  a  distinct 
band,  the  fibrce  arciformes  (fig.  54). 

The  deep  transverse  fibres  (fig.  58,  h)  are  to  be  seen  with  the  micro- 
scope on  thin  hardened  transverse  sections  ;  thi^y  begin  behind  in  nuclei 
of  the  posterior  pyramid  and  restiform  body  (Clarke),  and  penetrate  be- 
tween the  longitudinal  fibres,  and  througli  the  corpus  olivare,  as  they  reach 
forwards  to  enter  the  raphe  in  the  middle  line. 

The  raphe  (fig.  58,  h  and  y),  in  which  the  arched  fibres  meet,  occupies 
the  middle  line  of  the  medulla  above  the  decussation  of  the  pyramids,  and 
serves  as  the  commissure  between  the  halves  of  the  medulla  and  the  oli- 
vary bodies. 

Gray  matter  of  the  medulla  oblongata.  In  the  medulla  oblongata  there 
are  the  remains  of  the  gray  matter  of  the  spinal  cord ;  and  some  special 
deposits.  Cross  sections  of  tlie  part  when  hardened  would  be  required  to 
see  them. 

'  TJie  arrangement  of  the  fibres  in  the  sac  is  most  complicated,  and  a  fuller 
account  may  ])e  obtained  bj  consulting  Mr.  Clarke's  Paper  in  the  Philosophical 
Transactions  for  1858. 


GRAY  SUBSTANCE  OF  MEDULLA. 


187 


Remains  of  gray  matter  of  the  spinal  cord.  At  the  lower  part  of  the 
medulla  the  central  gray  matter  resembles  that  in  the  spinal  cord  (see  fig. 
126),  but  it  undergoes  the  following  changes:^  The  posterior  cornu  in- 
creases in  bulk,  and  extends  towards  the  side  of  the  cord,  where  it  appears 
on  the  surface,  in  front  of  the  restiform  body,  as  the  gray  tubercle  of  Ro- 
lando (tuberculo  cinero)  (fig.  58,  t).  Higher  in  the  medulla  it  becomes 
the  chief  nucleus  of  the  sensory  root  of  the  fifth  nerve. 

The  piece  of  the  gray  commissure  behind  the  central  canal  of  the  cord 
joins,  above,  the  nucleus  of  the  vagus  nerve,  and  contributes  to  the  audi- 
tory nucleus :  and  the  piece  in  front  of  the  canal  is  laid  bare  in  the  floor 


Transverse  Section  op  the  Medulla  Oblongata  above  the  Middle  of  the  Olivary  Boot 

(Clarke). 


a.  Anterior  pyramid. 

b  and  c.  Lateral  column. 

d.  Restiform  body. 

e.  Posterior  pyramid. 

/.  Corpus  olivarewitli  roots  of  tbe  ninth  nerve 

piercing  it. 
g.  Olivary  commissure 
h.    Deep  transverse  or   commissural  fibres   of 

the  medulla  meeting  in  the  raph6  (a  few 

more  are  added  in  this  cut  from  a  second 

drawing). 


Accessory  olivary  nucleus. 

other  gray  deposits  inside  the  olivary  body. 

Floor  of  the  fourth  ventricle  covered  by 
epithelium. 

Nnclei  of  the  ninth  nerve. 

Nuclei  of  the  vagus  and  glosso-pharyngeal 
nerves. 

Nucleus  of  the  auditory  nerve. 

Superficial  transverse  fibres. 

Remains  of  the  gelatinous  substance  (tuber- 
culo cinereo). 


of  the  fourth  ventricle  by  the  inclination  outwards  of  the  restiform  bodies ; 
it  disappears  above  the  fasciculi  teretes. 

Special  deposits  of  gray  matter.  Other  masses  of  gray  substances  are 
deposited  in  the  medulla,  both  in  front  and  behind  :  those  behind  are  near 
the  floor  of  the  fourth  ventricle,  and  serve  as  nuclei  of  origin  for  certain 
nerves  ;  whilst  those  in  front  are  interspersed  amongst  the  fibres  continued 
from  the  lateral  columns  of  the  cord. 

Nuclei  at  the  hack  of  the  medulla.  A  nucleus  for  the  hypoglossal  nerve 
is  deposited  in  front  of  the  central  canal,  and  extends  upwards  into  the 
floor  of  the  fourth  ventricle  close  to  the  median  sulcus  (fig.  58,  o). 

The  nucleus  of  the  accessory  part  of  the  spinal  accessory  nerve  is  placed 
opposite  that  of  the  hypoglossal,  behind  the  central  canal. 

The  nucleus  of  the  vagus  begins  on  a  level  with  the  fourth  ventricle 

'  The  description  of  the  arrangement  of  the  gray  matter  in  the  meduHa  oblon- 
gata is  a  summary  of  the  facts  contained  in  Mr.  Clarke's  paper  in  the  "Transac- 
tions of  the  Royal  Society  for  1858." 


188  DISSECTION    OF    THE    BRAIN. 

(fig.  58,  p),  and  is  continuous  below  with  tliat  of  the  accessory  nerve. 
On  the  surface  it  forms  a  pyriform  swelling  along  the  inner  side  of  the 
posterior  pyramid,  and  limits  laterally  the  calamus  scriptorius. 

Above,  this  sinks  under  the  auditory  nucleus,  and  joins  a  nucleus  for 
the  glosso-pharyngeal  nerve  in  a  line  with  it. 

Above  the  last  two  nerves  is  another  collection  of  cells  serving  as  a 
nucleus  for  the  auditory  nerve.  This  projects  on  the  lateral  part  of  the 
medulla  (fig.  58,  r). 

At  the  front  of  the  medulla.  Outside  the  pyramid  is  the  gray  layer  of 
the  olivary  body  (fig.  58,/')  already  described  (p.  185).  Behind  this  is 
another  separate,  elongated,  and  flattened  yellowish  streak,  the  accessory 
olivary  nucleus  (fig.  43,  ^•) ;  while  at  the  inner  part  of  the  olive,  near  the 
raphe^  is  a  second  collection  (fig.  58,  /),  which  is  broken  up  into  pieces. 
Both  of  the  last  deposits  Mr.  Clarke  considers  to  be  but  parts  of  the  cut 
folds  of  the  corpus  dentatum. 

PONS    VAROLII. 

The  PONS,  or  annular  protuberance  (pons  Varolii,  nodus  encephali) 
(fig.  54),  is  situate  above  the  medulla  oblongata,  and  between  the  hemi- 
spheres of  the  cerebellum.  In  its  natural  position  in  the  skull  it  lies  below 
the  opening  in  the  tentorium  cerebelli.  It  is  nearly  of  a  square  shape, 
though  it  is  rather  widest  from  side  to  side,  and  measures  two  inches  in 
the  last  direction. 

The  anterior  surface  is  grooved  along  the  middle  line,  and  is  received 
into  the  basilar  hollow  in  the  base  of  the  skull.  By  the  opposite  surface 
the  pons  forms  part  of  the  floor  of  the  fourtli  ventricle. 

The  upper  border  is  longest  and  most  curved,  and  arches  over  the  cere- 
bral peduncles  ;  and  the  lower  border  overlays  the  medulla  oblongata.  On 
each  side  is  the  crus  cerebelli,  whose  fibres  radiate  over  the  surface. 

Structure.  In  the  pons  are  alternating  strata  of  transverse  and  longi- 
tudinal fibres  (fig.  56)  : — The  transverse  set  are  continuous  with  tlie  fibres 
of  the  crus  cerebelli,  much  gray  matter  being  interspersed:  and  the  longi- 
tudinal are  prolonged  from  the  medulla  oblongata. 

Dissection.  Tlie  transverse  superficial  fibres  of  the  pons  being  divided 
along  the  line  of  the  pyramidal  body  of  the  right  side  (fig.  ^^Q))^  may  be 
turned  outwards  so  as  to  denude  the  longitudinal  fibres  (c)  of  the  pyramid ; 
and  this  first  set  of  longitudinal  fibres,  having  been  cut  across  already  in 
the  medulla  oblongata,  may  be  raised  as  far  as  the  upper  border  of  the 
pons.  Beneath  them  will  appear  the  second  or  deep  set  of  transverse  fibres 
of  the  pons  (fig.  57,/). 

The  deep  transverse  fibres  may  be  cut  through  outside  the  pyramidal 
(fig.  57) ;  then  the  deep  longitudinal  fibres  from  the  lateral  column  and 
the  posterior  pyramid  (c?)  will  appear.  Amongst  this  last  set  of  longitu- 
dinal fibres  is  the  fillet  of  the  corpus  olivare,  which  the  dissector  should 
trace  upwards  from  that  body. 

The  superficial  fibres  of  the  pons  can  be  seen  on  the  side  that  is  un- 
touched. 

The  transverse  fibres  of  the  annular  protuberance  (fig.  5G),  are  collected 
chiefly  into  two  strata — a  superficial  and  deej),  wliicli  are  united  in  tiie 
middle  line  :  they  are  commissural  fibres  of  the  cerebellum,  and  are  de- 
rived from  the  crus  or  middle  {)eduncle  of  that  body.  There  are  a  few 
other  transverse,  which  serve  also  as  a  commissure. 


CRURA    OF    THE    CEREBRUM.  189 

The  superficial  set  (fig.  56,  /)  are  mostly  horizontal,  but  some  from  the 
upper  margin  of  the  pons  descend  obliquely  over  the  others. 

The  deep  layer  (fig.  57,/)  is  thickened,  and  contains  much  gray  matter 
between  its  fibres. 

The  longitudinal  fibres  consist  of  two  sets,  viz.,  one  from  the  anterior 
pyramidal  body ;  and  another  from  the  lateral  tract  and  the  posterior 
pyramid,  to  which  a  slip  is  added  from  the  corpus  olivare.  The  fibres  are 
not  continued  simply  through  the  pons,  but  are  increased  in  number  by 
the  addition  of  others  (peduncular)  which,  beginning  in  the  upper  two- 
thirds  of  the  pons,  join  them  on  the  outer  side. 

The  fibres  of  the  anterior  pyramid  (fig.  b^^  c)  pass  through  the  pons 
between  the  two  sets  of  transverse  fibres,  but  not  as  one  mass,  for  they 
are  divided  into  a  number  of  small  bundles  in  their  progress.  Much  in- 
creased in  number,  the  fibres  enter  the  crus  cerebri  at  the  upper  border  of 
the  pons,  and  construct  that  fasciculated  surface  of  the  peduncle  {d),  which 
is  now  uppermost. 

The  fibres  of  the  lateral  column  and  posterior  pyramid  are  altogether 
deeper  than  the  transverse  fibres  of  the  pons  (fig.  57,  d),  and  are  mixed 
up  with  gray  matter ;  they  are  also  more  numerous  than  the  preceding 
set.  They  project  close  to  the  middle  line,  in  the  floor  of  tlie  fourth  ven- 
tricle, and  form  the  eminence  of  the  fasciculus  teres  (fig.  55,  ^)  ;  from  that 
spot  they  are  continued  upwards  to  the  crus  cerebri,  of  which  they  form 
the  deeper  or  cerebral  part  (fig.  57,  d).  In  the  pons  a  band  from  the 
olivary  fasciculus  is  added  to  these  fibres. 

The  olivary  fasciculus  (fillet,  fig.  57)  divides  into  two  slips  the  pons. 
One  passes  backwards  to  the  upper  (in  this  position  deeper)  part  of  the 
crus  cerebri,  and  ends  in  and  beneath  the  corpora  quadrigemina  (p.  208). 
The  other  is  continued  to  the  crus  cerebri  with  the  fibres  of  the  lateral 
column. 

Commissure  of  the  pons.  At  the  back  of  the  pons  there  is  a  commissure 
between  the  halves,  opposite  the  deep  longitudinal  fibres.  It  consists, 
like  that  of  the  medulla  oblongata,  of  fine  anterior-posterior  and  trans- 
verse fibres. 


Section  IV. 

DISSECTION  OF  THE  CEREBRUM. 


The  cerebrum,  or  the  great  brain,  is  the  largest  of  the  subdivisions  of 
the  encephalon,  and  weighs  on  an  average  49  oz.  in  the  male,  and  44  oz. 
in  the  female.  It  fills  the  upper  part  of  the  cavity  of  the  skull ;  and  its 
under  surface  would  correspond  with  an  oblique  line  on  the  head  from  the 
eyebrow  to  the  articulation  of  the  jaw  ;  and  from  this  point  to  the  occipi- 
tal protuberance. 

Taking  the  general  form  of  the  cranium,  the  cerebrum  is  convex  on  the 
upper  aspect,  and  uneven  on  the  lower.  It  consists  of  two  hemispheres, 
which  are  placed  side  by  side,  and  are  partly  separated  by  a  median  or 
longitudinal  fissure.  Across  the  middle  line  the  halves  are  united  by  cer- 
tain interior  parts  (commissures),  as  well  as  by  several  connecting  struc- 
tures at  the  under  surface.     Superiorly  the  surface  of  the  hemisphere  is 


190 


DISSECTION    OF    THE    BRAIN 


without  any  large  cleft ;  but  inferiorly  it  is  divided  into  two  by  a  trans- 
verse fissure — that  of  Sylvius. 

Under  Surface  or  Base  of  the  Cerebrum  (fig.  59).  At  its  under 
part  the  cerebrum  is  very  irregular,  in  consequence  of  its  fitting  into  in- 
equalities in  the  base  of  the  skull ;  and  on  this  aspect  the  separation  into 
hemispheres  is  not  so  complete  as  on  the  upper,  for  the  median  fissure 
exists  only  at  the  front  and  back.  The  following  objects  are  to  be  recog- 
nized at  the  base  of  the  brain  alone:  the  middle  line. 


59. 


IlNnER  Surface  of  the  Brain 
b.  Cereb'^llum.  i. 

r.  Temporo-sphenoidal  lobe  of  the  cerebrum.         I. 
p.  Frontal  lobe  of  the  cerebrum:  the  great  fig-        m 
sure  between  the  two  lobes,  is  the  Sylvian.       n 
a.  Medulla  oblongata. 

d.  Pons  Varolii. 
/.  Crus  cerebri. 
g.  Locus  perforatns  posticus. 

e.  Corpus  albic;in8. 
h.  Tuber  ciuereum. 


Commissure  of  the  optic  nerves. 

Locus  perforatus  amicus. 

Lamina  cinerea. 

Lower  end  (rostrum)  of  the  corpus  callosnm 
in  the  great  median  fissure;  the  point  in 
front  where  it  bends  is  named  genu.  On 
each  side  of  the  lamina  ciuerea  a  narrow 
white  band  is  continued  fi'om  the  end  of 
the  corpus  callosum  :  this  is  the  fillet  of 
the  corpus  callosum. 


Immediately  in  front  of  the  pons  {d)  are  two  large  white  masses,  the 
peduncles  of  the  cerebrum  (crura  cerebri,/),  one  belonging  to  each  hem- 
isphere ;  and  between  is  a  space  perforated  by  vessels,  which  is  named 
locus  perforatus  posticus  {g).  Outside  the  peduncle  is  the  optic  tract  (/) ; 
and  between  it  and  the  inner  part  of  the  hemisphere  is  a  fissure  leading 
into  the  lateral  ventricle. 

In  front  of  the  peduncles  are  placed  two  white  bodies  like  peas,  the 


BASE    OF    THE    BRAIN.  191 

corpora  albicantia  (e) ;  and  anterior  to  these  a  grayish  mass,  called  tuber 
cinereum  (//).  From  the  tuber  cinereum  a  conical  reddish  tube,  the  in- 
fundibulum,  descends  to  the  pituitary  body  in  the  sella  Turcica  of  the 
sphenoid  bone. 

Anterior  to  the  tuber  cinereum  are  the  converging  optic  tracts  with 
their  commissure  (/).  Beneath  the  commissure  lies  a  thin  grayish  layer 
(lamina  cinerea,  m)  ;  and  still  further  forwards  is  the  great  longitudinal 
fissure  between  the  hemispheres,  with  the  white  corpus  callosum  {n)  in 
the  bottom  of  it. 

At  the  inner  end  of  the  transverse  fissure  (Sylvian)  across  the  hemi- 
sphere, is  another  spot,  perforated  by  vessels,  and  distinguished  by  the 
name  substantia  perforata,  or  locus  perforatus  anticus  (/). 

Peduncle  of  the  cerebrum  (crus  cerebri,/).  This  is  a  large,  white, 
stalk-like  piece,  which  reaches  from  the  upper  border  of  the  pons  to  the 
under  part  of  the  cerebral  hemisphere  of  the  same  side,  near  the  inner 
margin.  In  the  natural  position  the  two  peduncles  fill  the  opening  in  the 
tentorium  cerebelli.  Each  is  about  three-quarters  of  an  inch  long,  and 
widens  as  it  approaches  the  cerebrum.  Crossing  its  outer  surface  is  the 
optic  tract ;  and  between  the  crura  of  opposite  sides  is  the  interpeduncular 
space,  which  contains  the  locus  perforatus,  the  corpora  albicantia,  and  the 
tuber  cinereum. 

Structure.  The  peduncle  consists  of  longitudinal  fibres,  continuous  with 
the  longitudinal  fibres  of  the  pons,  which  inclose  here  a  mass  of  gray  mat- 
ter between  them. 

Dissection.  For  the  purpose  of  showing  the  structure  of  the  crus,  on 
the  right  side  (fig.  57),  the  optic  tract  should  be  divided,  and  the  fibres 
continuous  vvitli  tlie  anterior  pyramid  of  the  medulla  oblongata  should  be 
raised  as  far  into  the  crus  as  the  optic  thalamus.  In  this  proceeding 
the  mass  of  gray  matter  (locus  niger)  will  appear,  and  beneath  it  will  be 
seen  a  second  or  deeper  set  of  longitudinal  fibres. 

The  superficial  fibres,  which  form  the  under  or  free  part  of  the  crus, 
are  continued  from  the  anterior  pyramidal  body  (fig.  06,  c).  They  are 
longitudinal  in  direction,  and  coarse  in  texture,  and  are  directed  upwards 
radiating  to  the  cerebrum.  The  suH'ace  of  the  peduncle,  which  is  com- 
posed of  these  fibres,  is  called  iha  fasciculated  portion,  or  the  crust. 

The  deeper  fibres  are  also  prolonged  to  the  cerebrum.  They  are  derived 
chiefly  from  the  lateral  tract  and  posterior  pyramid  of  the  medulla  oblon- 
gata, with  a  slip  from  the  olivary  fasciculus  (fig.  57,  d).  Others  come 
from  the  cerebellum,  and  mix  with  the  former :  some  of  these  decussate 
across  the  middle  line^  (p.  215).  The  fibres  obtained  from  these  four 
sources  are  situate  beneath  (as  now  seen)  the  gray  matter :  besides  being 
deejjer  they  are  finer  than  the  superficial  set,  and  inclose  much  gray  sub- 
stance :  the  part  of  the  crus  formed  by  tliem  is  named  tegmentum. 

The  gray  matter  (locus  niger)  of  the  crus  (fig.  57,  y)  forms  a  thin  layer, 
which  reaches  nearer  the  inner  than  the  outer  margin  of  that  body  ;  it  is 
convex  towards  the  free  surface,  but  concave  in  the  opposite  direction. 

The  posterior  perforated  spot  (pons  Tarini,  g)  is  situate  between  the 
peduncles  of  the  cerebrum  ;  in  the  area  of  the  space  is  a  layer  of  grayish 

'  M.  Foville  describes  a  median  commissure  for  the  medulla  oblongata,  pons, 
and  cerebral  peduncles,  which  is  composed  of  the  interweaving  of  fibres  of  oppo- 
site sides.  See  the  work  of  M.  Foville,  entitled  :  Traits  complet  de  VAnatomie,  af-c, 
du  Syst^me  Nerveux  cerebrospinal,  p.  323,  1844. 


192  DISSECTION    OF    THE    BRAIN. 

matter,  and  numerous  vessels  penetrate  it.  This  structure  forms  tlie 
hinder  part  of  the  floor  of  the  third  ventricle. 

The  corpora  albicantia  (cor[).  mamillaria,  e)  are  two  small,  white 
bodies,  about  the  size  of  peas,  which  are  constructed  in  greater  part  by 
the  crura  of  the  fornix.  If  one,  say  the  right,  is  cut  across,  it  will  be 
seen  to  contain  gray  matter.  In  front  of  them  is  the  gray  mass  of  tlie 
tuber  cinereum. 

The  median  eminence  of  the  tuher  cinereum  (h)  forms  part  of  the  third 
ventricle,  and  is  continuous  with  the  gray  substance  in  that  cavity.  In 
front  of  it  are  the  optic  tracts  and  commissure,  and  from  its  centre  projects 
the  following. 

The  infundihuhim  (funnel)  is  a  conically-shaped  tube  which  reaches 
from  the  tuber  cinereum  to  the  upper  part  of  the  posterior  lobe  of  the 
pituitary  body.  It  consists  of  a  layer  of  gray  matter,  surrounded  by  the 
pia  mater ;  and  it  is  lined  by  the  ependyma  of  the  third  ventricle,  as  far 
as  it  is  pervious.  In  the  foetus  this  tube  is  open  between  the  third  ven- 
tricle and  the  pituitary  body,  but  in  the  adult  it  is  closed  inferiorly. 

T\\Q  pituitary  body  will  be  very  imperfectly  seen  when  it  has  been  dis- 
lodged from  its  resting-place :  therefore  it  should  be  sometimes  examined 
in  the  base  of  the  skull  by  removing  the  surrounding  bone.  Its  use  is 
unknown. 

It  is  situate  in  the  hollow  (sella  Turcica)  on  the  sphenoid  bone,  and 
consists  of  two  lobes,  anterior  and  posterior.  The  anterior  is  the  largest, 
and  is  hollowed  out  behind,  where  it  receives  the  round  posterior  lobe.  In 
the  adult  this  body  is  solid,  and  firm  in  texture  ;  but  in  the  fa3tus  it  is  hol- 
low, and  opens  into  the  third  ventricle  through  the  infundibulum. 

Structure.  It  is  firm  and  reddish  externally,  but  softer  and  yellowish 
internally.  In  it  are  nucleated  cells,  mixed  with  a  granular  semi-fluid 
substance;  and  the  whole  is  contained  in  roundish  spaces,  which  are  con- 
structed by  a  stroma  of  areolar  tissue  with  bloodvessels  (Sharpey). 

Dissection.  To  see  the  lamina  cinerea  and  the  anterior  termination  of 
the  corpus  callosum,  the  hemispheres  are  to  be  gently  separated  from  each 
other  at  the  fore  part. 

The  lamina  cinerea  (m)  is  a  thin  concave  layer  of  gray  substance, 
which  gradually  tapers  forwards  from  the  tuber  cinereum  to  the  anterior 
termination  of  the  corpus  callosum.  This  stratum  closes  the  anterior  part 
of  the  third  ventricle,  and  is  continuous  laterally  with  the  anterior  perfo- 
rated spot.  In  consequence  of  its  great  thinness,  this  structure  is  often 
broken  through  in  removing  the  brain. 

The  corpus  callosum  (n),  bent  in  front,  is  continued  horizontally  back- 
wards in  the  longitudinal  fissure  to  the  lamina  cinerea,  and  ends  in  two 
white  narrow  bands,  the  fillets  or  peduncles  of  the  corpus  callosum :  each 
band  is  continued  onwards  by  the  side  of  the  lamina  cinerea  to  the  anterior 
perforated  spot.  To  the  anterior  bend  of  the  corpus  callosum  the  term 
knee  (genu)  is  applied,  and  to  the  prolonged  central  part  the  appellation 
rostrum  has  been  given.  Laterally  the  corpus  callosum  reaches  into  the 
frontal  lobe,  and  forms  part  of  the  floor  of  tlie  lateral  ventricle. 

Anterior  perforated  spot  (substantia  perforata  antica,  /)  is  a  space  near 
the  inner  end  of  the  fissure  of  Sylvius,  which  is  situate  between  the  frontal 
and  temporo-sphenoidal  lobes  of  the  cerebrum,  and  external  to  the  optic 
tract.  On  the  inner  side  it  is -continuous  with  the  lamina  cinerea;  and 
crossing  it,  from  within  outwards,  is  the  fillet  of  the  corpus  callosum. 
This  space  is  gray  on  tlie  surface ;  it  corresponds  with  the  corpus  striatum 


FrSSL'RES    OF    THE    HEMISPHERES.  193 

in  the  interior  of  the  brain,  and  is  perforated  by  numerous  vessels  for  that 
body. 

Position  of  the  part.  Now  the  base  of  the  cerebrum  has  been  dissected, 
the  brain  should  be  turned  over  for  the  examination  of  the  upper  part. 
Something  should  then  be  placed  beneath  the  front,  in  order  that  it  may 
be  raised  to  the  same  level  as  the  back ;  and  a  rolled-up  cloth  should 
loosely  encircle  tlie  whole,  to  support  the  hemispheres. 

Upper  Surface  of  the  Cerebrum.  On  the  upper  surface  the  cere- 
brum, taken  as  a  whole,  is  oval  in  form,  and  is  convex  in  its  outline,  in 
accordance  with  the  shape  of  the  skull. 

A  median  hngitudi7ial  fissure  (\.\\\dki^  i\w,  Q.^Ye\)vum  incompletely  into 
two  halves.  At  the  front  and  back  the  hemispheres  are  quite  separated 
by  it;  but  at  the  middle  and  under  parts  they  are  united  by  connecting 
pieces,  the  largest  of  which  is  the  white  corpus  callosum.  In  it  the  falx 
cerebri  is  lodged. 

Each  hemisphere  is  larger  in  front  than  behind.  Its  outer  surface  is 
convex;  but  the  inner  is  flat,  and  in  contact  in  front  with  the  opposite 
half.  On  the  upper  aspect  tlie  surface  of  the  hemisphere  is  divided  by 
fissures  into  lobes,  and  on  the  under  aspect  it  is  cleft  into  two  large  pieces 
by  the  fissure  of  Sylvius.  The  superficies  of  the  hemisphere  is  marked 
by  tortuous  eminences,  the  projections  on  it  being  named  convolutions  or 
gyri,  and  the  intervening  depressions,  sulci  or  anfractuosities.^ 

Fissures  of  the  Hemisphere.  The  larger  fissures  separate  the 
lobes,  and  the  smaller  sulci  mark  the  extent  of  particular  convolutions. 
Tlie  fissures  dividing  the  hemisphere  into  lobes  are  the  three  following: — 

The  fissure  of  Sylvius  {S,  fig.  60)  begins  below  at  the  anterior  perfo- 
rated spot,  and  directed  out  between  the  frontal  and  temporo-sphenoidal 
lobes,  divides  into  two  parts,  anterior  and  posterior. 

The  anterior  limb,  '>S,  ascends  for  a  short  distance  into  the  frontal 
lobe. 

The  posterior,  limb,  the  continuation  of  the  fissure,  is  directed  obliquely 
U])wards  and  backwards  to  about  the  middle  of  the  outer  face  of  the  hemi- 
sphere.    At  its  extremity  it  is  sometimes  divided  into  smaller  sulci. 

Fissure  of  Rolando  (i?,  fig.  GO).  Beginning  above,  about  half  way 
along  the  hemisphere,  in  or  near  the  longitudinal  fissure  of  the  cerebrum, 
it  is  prolonged  outwards  between  the  frontal  and  parietal  lobes  nearly  to 
the  j)Osterior  part  of  the  Sylvian  fissure, — about  the  middle  of  that  limb. 

The  external  parieto-occipital  fissure  (opposite  P  0,  fig.  60)  begins 
in  the  median  longitudinal  fissure  half  way  between  the  preceding  and  the 
hinder  end  of  the  hemisphere.  It  is  very  variable  in.  extent,  being  some- 
times an  inch  long,  and  at  others  only  a  slight  indentation  ;  but  it  may  be 
always  recognized  by  its  continuity  with  the  perpendicular  f  ssure  on  the 
inner  face  of  the  hemisphere  (fig.  62). 

Lobes  of  the  Hemisphere.  Each  hemisphere  is  divided  into  five 
lobes,  which  have  the  following  names  and  limits  : — 

The  fi'ontal  lobe  (Pr,  fig,  60)  forms  the  anterior  half  of  the  hemisphere. 
It  is  limited  below  by  the  fissure  of  Sylvius,  S,  and  behind  by  tlie  fissure 

'  In  the  following  description  of  the  surface  anatomy  of  the  cerebrum  I  have 
followed  chiefly  the  arrangement  of  Professor  Turner  in  liis  paper  "On  the  Con- 
volutions OF  THE  Human  Cerebrum;"  and  to  hi»i  I  am  indebted  for  permission  to 
copy  the  wood-cuts  employed  in  illustration  of  his  publication. 
13 


194 


DISSECTION    OF    THE    BRAIN, 


of  Rolando,^  7?.     Its  under  part,  which  rests  on  the  orbital  plate,  has  been 
called  the  orbital  lobule. 

The  parietal  lobe  {Par,  fig.  GO)  is  placed  behind  the  preceding,  and 
reaches  down  to  the  Sylvian  fissure.  It  is  about  half  as  long  as  the  fron- 
tal. In  front  it  is  bounded  by  the  fissure  of  Rolando,  R,  and  behind  by 
the  parieto-occipital  {P  0).  Tlie  upper  and  hinder  part,  close  to  the 
median  fissure,  is  named  the  parietal  lobule  (5^). 


Lobes  op  the  Hemisphere,  and  Convolutions 
Fr.  Frontal  lobe. 
Par.  Parietal  lobe. 
Oc.  Occipital  lobe. 
T  S.  Teinporo-sphenoidal  lobe. 
E.  Fissure  of  Rolando. 
8.  Posterior. 

'8.  Ascending  limb  of  the  Sylvian  fissure. 
P  0.  Place  of  the  external  parieto-occipital 
fissure  "which  is  not  visible  in  a  side 
view. 
IP.  Intra-parietal  sulcus.  A. 

P.   Parallel  sulcus — 

1,  inferior; 

2,  middle ;  and 

3,  superior  frontal  gyrus; 


AND  Fissures  of  the  Outer  Surface. 

4,  ascending  frontal ;  and 

5,  ascending  parietal  gyrus  ; 
5',  parietal  lobule; 

6,  angular  gyrus ; 

7,  superior ; 

8,  middle ;  and 

9,  inferior  teniporo-sphenoidal  gyrus  ; 

10,  superior ; 

11,  middle  ;  and 

12,  inferior  occipital  convolution. 
Supra- marginal  convolution — 

a,  first; 
6, second  ; 

c,  third ;  and 

d,  fourth,  annectant  gyrus. 


The  occipital  lobe  {Oc,  fig.  CO)  constitutes  the  pointed  end  of  the  hemi- 
sphere, and  measures  about  a  fifth  of  the  whole.  In  front  it  is  separated 
from  the  parietal  lobe  by  the  parieto-occipital  fissure  {P  0),  but  below  it 
blends  with  the  following  lobe.  It  rests  on  the  tentorium.  On  the  inner 
surface  is  a  triangular  piece,  the  occipital  lobule  {^^,  fig.  62). 

The  temporo-sphenoidal  lobe  (T  S,  fig.  GO)  projects  into  the  middle 
fossa  of  the  base  of  the  skull.  It  is  situate  behind  the  fissure  of  Sylvius, 
and  below  the  parietal  and  occipital  lobes.  The  outer  sniface  is  in  contact 
with  the  cranium,  and  the  opposite  is  supported  mainly  on  the  tentorium. 

The  central  lobe  or  the  island  of  Reil  {C,  fig.  Gl)  lies  in  tlie  sylvian  fis- 
sure, and  is  concealed  by  the  overlapping  of  tlie  frontal  and  temporo-sphe- 
noidal lobes.     On  separating  those  lobes  it  will  be  seen  to  be  bounded  in 


•  By  some  the  anterior  limb  of  the  fissure  'S  is  made  the  hinder  bound  of  the 
lobe  ;  but  this  is  not  so  good  an  anangement  as  that  in  the  text. 


OUTER  CEREBRAL  CONVOLUTIONS.  195 

front  and  behind  by  the  limbs  of  the  Sylvian  fissure,  and  externally  by  a 
deep  groove  separating  it  from  the  frontal  and  parietal  lobes.  It  is  of  a 
triangular  form  with  the  apex  down. 

Convolutions  of  the  Cerebrum.  In  different  brains  the  convolu- 
tions vary  slightly  in  form,  and  even  in  the  two  liemispheres  of  the  same 
cerebrum  they  are  not  exactly  alike  :  but  there  is  always  similarity 
enough  for  the  recognition  of  the  chief  eminences.  Each  lobe  possesses 
convolutions,  but  these  run  into  each  other  by  means  of  smaller  gyri, 
either  on  the  surface  of  the  brain  or  at  the  bottom  of  tlie  sulci ;  and  the 
student  may  experience  some  difficulty  at  first  in  defining  the  limits  of 
each.     It  is  in  the  smaller  gyri  that  the  greatest  variation  will  be  found. 

A.  Convolutions  of  the  Obter  Surface.  About  the  middle  of  the 
hemisphere  are  two  straight  vertical  convolutions,  one  on  each  side  of  the 
fissure  of  Rolando,  i?,  which  will  serve  as  a  starting  point.  In  front  of 
tliose  two  the  convolutions  are  longitudinal ;  and  behind  they  take  an 
oblique  direction  to  the  back  of  the  brain. 

a.  The  frontal  convolutions  (fig.  60)  form  two  sets,  one  on  the  outer, 
the  other  on  the  under  surface  of  the  frontal  lobe  :  those  on  the  outer 
aspect  are  four,  viz.,  one  vertical  or  posterior,  and  three  longitudinal  or 
anterior,  as  follows  : — 

The  ascending  frontal  (*)  is  the  vertical,  straight  convolution,  which 
bounds  in  front  the  Rolando  fissure.  It  reaches  down  from  the  median  to 
the  sylvian  fissure  (posterior  limb).  Along  the  anterior  border  it  is  joined 
by  the  three  frontal  convolutions  ;  and  below  it  unites  with  the  most  ante- 
rior convolution  of  the  parietal  lobe  round  the  lower  end  of  the  fissure  of 
Rolando,  R. 

The  three  longitudinal  frontal  convolutions  are  much  subdivided  and 
blended,  and  are  separated  by  two  intervening  sulci.  They  are  named 
superior  (^),  middle  Q)^  and  inferior  (})  :  they  communicate  behind  by 
secondary  gyri  with  the  ascending  frontal  (*),  the  highest  having  often  two 
processes ;  and  are  directed  forwards  one  outside  another  to  the  anterior 
extremity  of  the  hemisphere. 

The  under  or  orbital  surface  of  the  frontal  lobe,  concave,  is  represented 
in  fig.  01.  Near  the  inner  margin  is  a  sulcus,  the  olfactory,  lodging  the 
olfactory  nerve  ;  and  internal  to  it  is  the  lower  end  of  the  marginal  convo- 
lution ('7).  External  to  the  sulcus  lies  a  convolution,  which  is  pointed 
behind,  but  widened  and  subdivided  in  front,  and  incloses  smaller  gyri 
and  sulci  within  its  coil :  this  has  been  subdivided  into  three  parts,  an 
inner  C^),  a  posterior  (^),and  an  external  (^). 

b.  The  parietal  convolutions  (fig.  60),  like  the  outer  frontal,  are  four  in 
number  ;  an  anterior,  or  ascending,  Avhich  is  vertical  along  the  fissure  of 
Rolando,  and  three  directed  back  from  it. 

The  ascending  parietal  (^),  narrow  and  straight,  limits  behind  the  fissure 
of  Rolando,  and  reaches  from  the  middle  line  to  the  hinder  limb  of  the 
Sylvian  fissure,  *S'.  Above,  it  runs  into  the  parietal  lobule,^' ;  and  below, 
it  joins  the  ascending  frontal  round  the  lower  end  of  the  fissure  of  Rolando. 
Behind  it  is  separated  from  the  other  gyri  of  the  parietal  lobe  by  a  suclus, 
IP} 

The  parietal  lohiile  (^')  appears  to  be  an  appendage  to  the  upper  end  of 

'  Tlie  intraparietal  sulcus  (IP,  fig.  60,  Turner), 'is  placed  between  the  ascending 
parietal  and  the  supra-marginal  convolution,  A.  Above,  it  is  directed  back  near 
the  upper  part  of  the  hemisphere,  separating  the  parietal  lobule  (5')  and  the 
supra-marginal  convolution,  A. 


196 


DISSECTION    OF    THE    BRAIN 


the  ascending  convolution,  and  is  continued  back  along  the  upper  margin 
of  tlie  hemisphere  as  far  as  the  parieto-occipital  fissure.  Subdivided  on  the 
surface  into  two  chief  parts  it  is  joined  behind  to  the  occipital  lobe  by  tiie 
small  annectant  gyrus  (a).  To  its  outer  side  lies  the  upper  part  of  the 
intraparietal  sulcus  ;  and  here  it  joins  usually  the  following  convolution,  A. 

The  supra-marginal  convolution  A,  lying  outside  and  below  the  preced- 
ing, is  interposed  between  the  intraparietal  sulcus,  /  P,  and  the  Sylvian 
fissure  (outer  end).  Variable  in  shape  it  joins,  below,  the  ascending 
parietal  convolution  (^)  ;  it  may  communicate  above  with  the  parietal 
lobule,  and  behind  with  the  following. 

The  angular  convolution  (*),  very  complicated  and  not  well  defined,  is 
placed  at  the  extremity  of  the  hinder  limb  of  the  Sylvian  fissure,  and  is 

composed  of  two  or   three  pieces 


Fig.  61. 


Above    it    is    the    parietal   lobule ; 
and  below,  the  temporo-sphenoidal 
j^^     ^--..  lobe  which  it  joins.     In  front  lies 

1/        \     \     ^.  the     supra-marginal     convolution ; 

'     •        i     '        \  r^nd  behind,  the  occipital  lobe,  with 

which  it  blends  by  the  small  annect- 
ant gyrus  (6). 

c.  The  occipital  convolutions  (fig. 
GO)  are  small  and  very  much  di- 
vided, so  that  their  outline  is  un- 
certain. They  are  three  in  number, 
lying  one  above  another,  and  sepa- 
rated by  sulci,  something  like  the 
frontal  gyri  at  the  opposite  end  of 
the  hemisphere. 

The  upper  (^°),  forming  part  of 
the  margin  of  the  longitudinal  fis- 
sure, receives  an  annectant  gyrus 
from  the  parietal  lobule. 

The  middle  (^^),  crossing  out- 
wards the  hemisphere,  has  two  an- 
nectant gyri  to  other  convolutions; 
one  (6)  joining  it  above  to  the  an- 
gular convolution,  and  another  (c) 
passing  to  the  middle  temporo- 
sphenoidal  convolution. 

The  inferior  ('^)  occupies  the  tip 
of  the  hemisphere  between  the  up- 
per and  under  surfaces.  At  the 
inner  end  it  is  continuous  witli  the 
upper  gyrus  ;  and  at  the  outer  end 
with  the  inferior  temporo-S{)henoi- 
dal  convolutioti  (")  by  an  annectant 
gyrus  {d). 
d.  The  temporo-sphenoidal  convolutions  (fig.  GO),  three  in  number,  run 
from  above  down,  and  are  separated  from  one  another  by  two  sulci. 

The  superior  {J)  bounds  posteriorly  the  horizontal  limb  of  the  Sylvian 
fissure.  At  the  upper  end  it  is  connected  by  a  gyrus  with  the  angular 
convolution. 

The  middle  {^)  is  separated  from   the  first  by  the  parallel   sulcus  (P). 


View  of  the  Orbital  Lobule  and  the 
Central  Lobe. 

C.  Island  of  Reil  or  median  lole. 

0.  Olfactory  salens. 

2.  Internal ;  and 

6.  External  orbital  convolution. 

posterior ; 
17.  Marginal  convolution  of  the  hemisphere 


INNER  CEREBRAL  CONVOLUTIONS.  197 

Above,  it  blends  commonly  with  the  angular  convolution,  and  is  connected 
to  the  middle  occipital  convolution  by  an  annectant  gyrus  (c). 

The  inferior  C),  less  well  marked  than  the  other  two,  forms  part  also 
of  the  inner  surface  of  the  temporo-sphenoidal  lobe.  By  the  upper  end 
it  is  united  to  the  third  occipital  convolution  by  an  annectant  gyrus  (d). 

The  parallel  sulcus  (/*,  iig.  60),  named  from  its  position  to  the  Sylvian 
fissure,  extends  from  the  lower  end  of  the  temporo-sphenoidal  lobe  to  the 
angular  convolution. 

e.  The  convolutions  of  the  central  lohe  (  O,  iSg.  61),  about  six  in  number, 
are  straight  for  the  most  part,  and  are  separated  by  shallow  sulci :  they 
are  directed  upwards  from  apex  to  base  of  the  lobe.  The  posterior  gyri 
are  the  longest  and  broadest,  and  the  anterior  joins  the  convolution  of  the 
under  surface  of  the  orbital  lobule. 

B.  The  CONVOLUTIONS  ON  THE  INNER  SURFACE  of  the  hemisphere 
(fig.  62)  are  generally  well  defined  ;  but  some  being  so  long  as  to  reach 
beyond  the  extent  of  a  lobe,  the  arrangement  of  them  in  lobes  cannot  be 
followed,  as  on  the  exterior. 

Dissecti07i.  Without  the  use  of  a  separate  hardened  hemisphere,  the 
parts  now  to  be  described  will  not  be  seen  satisfactorily.  If  the  student 
possesses  only  one  brain,  he  may  bring  into  view  much  of  the  inner  sur- 
face by  cutting  of  the  left  hemisphere  as  low  as  the  white  corpus  callosum 
in  the  median  fissure. 

Convolution  of  the  corpus  callosum^  gyrus  fornicatus  (^®),  is  long  and 
simple,  and  arches  round  the  body  from  which  it  takes  its  name.  Begin- 
ning at  the  base  of  the  brain  in  the  anterior  perforated  spot,  it  bends 
backwards  in  contact  with  the  corpus  callosum  {Cal),  and  below  the  back 
of  that  body  blends  by  a  narrowed  part  with  the  uncinate  convolution  Q^) 
of  the  temporo-sphenoidal  lobe.  Anteriorly  a  sulcus  separates  it  from  the 
following  convolution  ;  and  smaller  gyri  often  connect  the  two  across  that 
sulcus. 

The  marginal  convolutioti  (^^)  is  named  from  its  position  on  tKe  edge  of 
the  median  fissure.  Its  extent  is  rather  more  than  half  the  length  of  the 
hemisphere,  for  it  begins  in  front  at  the  anterior  perforated  spot,  and  ter- 
minates near  the  back  of  the  corpus  callosum,  just  behind  the  fissure  of 
Rolando.  It  is  much  subdivided  both  internally  and  externally;  and  on 
the  under  part  of  the  frontal  lobe  (fig.  61)  it  lies  internal  to  the  olfactory 
sulcus.  Between  it  and  the  preceding  convolution  is  situate  the  calloso- 
marginal  sulcus  (^)  which  marks  its  hinder  limit. 

The  calloso-inarginal  sulcus  (/,  Huxley),  designated  from  its  situation, 
begins  in  front  below  the  corpus  callosum,  and  ends  beliind,  near  the  back 
of  the  same  body,  by  ascending  to  the  edge  of  the  hemisphere.  Smaller 
gyri  uniting  the  two  bounding  convolutions,  frequently  interrupt  it,  and 
secondary  sulci  are  prolonged  from  it  into  the  same  convolutions. 

The  quadrilateral  lobule  Q^)  reaches  from  the  marginal  convolution  in 
front  to  the  parieto-occipital  fissure  behind.  It  is  much  divided  by  sulci, 
and  projects  above  to  the  edge  of  the  hemisphere  ;  it  joins  below  the  gyrus 
fornicatus. 

The  occipital  lobule  ('^*)  is  triangular  in  shape,  with  the  base  upwards, 
at  the  margin  of  the  hemisphere.  Measuring  about  an  inch  and  a  half 
in  depth,  it  lies  between  the  internal  parieto-occipital  fi.ssure,  PO,  and  the 
calcarine  sulcus  (/).  Sulci  running  from  apex  to  base  divide  it  into  four 
or  five  narrow  convolutions. 


198  DISSECTION    OF    THE    BRAIN. 

Internal  perpendicular  or  parieto-occipital  fissure  {PO,  fig.  02)  sepa- 
rates the  two  preceding  lobules.  Continuous  with  the  external  fissure  of 
the  same  name,  it  opens  below  into  the  following. 

The  calcarine  sulcus  /,  (Huxley)  is  directed  across  the  back  of  the 
hemisphere  below  the  level  of  the  corpus  callosum,  and  ends  in  front  at 
the  gyrus  fornicatus  ('®),  whose  hinder  limit  it  marks.     It  receives  above 

Fiff.  62. 


Convolutions  and  Fissures  on  the  Inner  Face  of  the  Hemisphere. 

P.  0.  Internal  parietooccipital  fissure.  18.  Convolution  of  corpus  callosum. 

Cal.   Corpus  callosum,  cut.  18'.  Quadrilateral  lobule. 

i.    Calioso-marginal  sulcus.  19.  Uncinate  gyrus. 

I.    Calcarine  sulcus.  19'.  Crotchet  or  hook  of  the  uncinate  gyrus, 

m.  Dentate  sulcus.  25.  Occipital  lobule. 

«.   Collateral  sulcus.  9.  Inferior  temporo-sphenoidal  gyrus  partly 

17.  Marginal  gyrus.  seen. 

the  internal  perpendicular  fissure;  and  it  sinks  into  the  posterior  cornu  of 
the  lateral  ventricle,  forming  the  eminence  of  the  hippocampus  minor. 

Internal  temporo-sphenoidal  convolutions  (fig.  62)  are  two  in  number, 
viz.,  the  uncinate  and  dentate,  and  occupy  the  tentorial  surface  of  the 
hemisphere. 

The  uncinate  or  hippocampal  convolution  (^')  is  prolonged  from  the 
posterior  end  of  the  hemisphere  nearly  to  the  tip  of  the  temporo-sphenoidal 
lobe.  It  is  somewhat  narrowed  in  the  middle,  where  the  gyrus  fornicatus 
blends  with  it ;  and  is  enlar<]jed  at  each  end,  especially  at  the  posterior 
where  it  is  subdivided  by  sulci.  Below  it  is  a  long  curved  sulcus,  the 
collateral  (n) ;  and  above  it  are  the  calcarine  (/),  and  the  dentate  sul- 
cus (m).  From  the  anterior  extremity  a  narrow  part  (^^',  uncus)  is  pro- 
longed back  for  half  an  inch  on  the  inner  side,  like  a  hook. 

Below  the  uncinate  convolution  is  part  of  the  inferior  temporo-sphe- 
noidal convolution  (^),  before  described,  which  forms  the  lower  edge  of 
the  temporo-sphenoidal  lobe,  appearing  more  largely  on  the  inner  than 
on  the  outer  face. 

The  collateral  sulcus  n,  (Huxley)  courses  along  tlie  lower  border  of  the 
uncinate  convolution  ;  it  projects  into  the  inferior  cornu  of  the  lateral 
ventricle,  and  gives  rise  to  the  prominence  of  the  eminentia  collateralis. 
Secondary  sulci  emanate  from   it,  and  it  is  often  interrupted  by  cross 

The  dentate  sulcus  m^  (Huxley)  is  the  deep  groove  at  the  upper  edge  of 
the  uncinate  convolution  ('^j,  and  corresponds  with  the  prominence  of  the 


CORPUS    CALLOSUM.  199 

hippocampus  major  in  the  descending  cornu  of  the  lateral  ventricle. 
Upwards  it  is  limited  by  the  corpus  callosum  {Cal)  and  downwards  it 
intervenes  between  the  hook  and  the  body  of  the  uncinate  convolution. 

In  the  dentate  sulcus  is  the  gray  substance  of  the  hemisphere,  which 
presents  a  notclied  border  at  the  inner  edge  of  the  temporo-sphenoidal 
lobe ;  this  has  been  called  the  dentate  convolution,  and  will  be  better  seen 
in  a  subsequent  stage  of  the  dissection  of  the  brain. 

Structure  of  the  convolutions.  Each  convolution  is  continuous  with  the 
interior  of  the  brain  on  the  one  side  (base)  ;  and  is  free  on  the  surface  of 
the  brain  on  the  other  side,  where  it  presents  a  summit  and  lateral  parts. 
On  a  cross  section  it  will  be  seen  to  consist  externally  of  gray  cerebral 
substance  as  a  cortical  layer,  which  is  continued  from  one  eminence  to 
another  over  the  surface  of  the  hemisphere ;  and  internally  it  is  composed 
of  white  brain  substance — the  medullary  part,  which  is  derived  from  the 
fibrous  mass  in  the  interior.  The  cortical  layer  is  composed  of  two,  or  in 
some  parts  of  three  strata,  which  are  separated  by  their  intervening  paler 
layers  ;  and  an  outer  white  stratum,  which  covers  the  surface,  is  most 
marked  over  the  internal  and  lower  portions  of  the  uncinate  convolution. 

IxTEiiiOR  OF  TfiE  Cerebrum.  The  cerebrum  consists  on  each  side  of 
a  dilated  part  or  hemisphere,  and  of  a  stalk  or  peduncle.  In  the  interior 
is  a  large  central  space,  which  is  subdivided  into  smaller  hollows  or  ven- 
tricles by  the  before-mentioned  connecting  pieces.  And  the  whole, 
except  the  peduncle,  is  surrounded  by  a  convoluted  crust. 

In  conducting  the  dissection  of  the  cerebrum,  the  student  will  learn  the 
form  and  situation  of  the  several  constituent  parts,  and  the  connections 
between  these  by  means  of  fibres. 

Dissection.  Supposing  both  hemispheres  entire,  the  left  is  to  be  cut  off 
to  the  level  of  the  convolution  of  the  corpus  callosum.  When  this  has 
been  done,  the  surface  displays  a  white  central  mass  of  an  oval  shape 
(centrum  ovale  minus),  which  sends  processes  into  the  several  convolu- 
tions. In  a  fresh  brain  this  surface  would  be  studded  with  drops  of  blood 
escaping  from  the  divided  vessels. 

Next,  the  convolution  of  the  corpus  callosum  is  to  be  divided  about  the 
middle,  and  the  two  pieces  are  to  be  thrown  backwards  and  forwards. 
Under  it  lies  a  thin  narrow  band,  the  covered  band  of  Reil,  which  bends 
down  before  and  behind  the  corpus  callosum. 

The  same  steps  of  the  dissection  are  to  be  taken  on  the  opposite  side  ; 
and  the  tops  of  the  hemispheres  being  removed  to  the  level  of  the  coqms 
callosum,  the  transverse  fibres  of  that  body  are  to  be  defined  as  they  radi- 
ate to  the  convolutions. 

Now  a  much  larger  white  surface  comes  into  view  (larger  ovan  centre), 
which  has  been  named  centrum  ovale,  Vieussens  ;  and  the  white  mass  in 
each  hemisphere  is  seen  to  be  continuous,  across  the  middle  line,  through 
the  corpus  callosum. 

Tiie  corpus  callosum  reaches  from  the  one-half  of  the  cerebrum  to  the 
other,  and  forms  the  roof  of  a  space  (lateral  ventricle)  in  each  hemisphere. 
Between  the  halves  of  the  brain,  where  it  occupies  the  longitudinal  fissure, 
it  is  of  small  extent,  being  about  four  inches  in  length,  and  somewhat 
arched  from  before  backwards.  It  is  narrower  in  front  tlian  behind,  and 
extends  nearer  to  the  anterior  than  the  posterior  part  of  the  cerebrum. 

In  front  the  corpus  callosum  is  bent  to  the  base  of  the  brain  (fig.  o9,  w), 
as  before  described  (p.  192);  and  behind  it  ends  in  a  thick  roll,  which  is 
connected  with  the  subjacent  fornix. 


200  DISSECTION    OF    THE    BRAIN. 

On  the  upper  surfjice  the  fibres  are  directed  from  the  hemispheres  to 
the  middle  line — the  middle  being  transverse,  but  those  from  the  anterior 
and  posterior  parts  oblique.  Along  the  centre  is  a  ridge  or  niphe,  and 
close  to  it  are  two  or  more  slight  longitudinal  white  lines  (nerves  of 
Lancisi).  Still  further  out  may  be  seen  other  longitudinal  lines  (covered 
band),  beneath  the  convolution  of  the  corpus  callosum,  if  all  of  them 
have  not  been  taken  away  in  the  removal  of  that  convolution.  The 
longitudinal  fibres  in  the  middle  line  are  continued  downwards  in  front, 
and  joining  the  covered  band  or  fillet  are  continued  to  the  anterior  per- 
forated spot. 

Dissection.  In  order  to  see  the  thickness  of  the  corpus  callosum,  and 
to  bring  into  view  the  parts  in  contact  with  its  under  surface,  a  cut  is  to 
be  made  through  it  on  the  right  side  about  half  an  inch  from  the  central 
ridge  :  and  this  is  to  be  extended  forwards  and  backwards,  as  far  as  the 
limits  of  the  underlying  ventricle.  Whilst  cutting  through  the  corpus  callo- 
sum, the  student  may  observe  that  a  thin  membranilbrm  structure  lines 
its  under  surface. 

The  corpus  callosum  is  thicker  at  each  end  than  at  the  centre,  in  con- 
sequence of  a  greater  number  of  fibres  being  collected  from  the  cerebrum  ; 
and  the  pt)sterior  part  is  the  thickest  of  all.  Connected  with  its  under 
surface  along  the  middle  is  the  septum  lucidum  or  partition  between  the 
ventricles  (fig.  G3,  h)^  and  still  posterior  to  that  is  the  fornix. 

This  body  is  the  chief  commissural  part  of  the  halves  of  the  brain,  and 
reaches  laterally  even  to  the  convolutions,  but  its  fibres  are  not  distinct 
far  in  the  hemisphere. 

Dissection.  The  left  lateral  ventricle  is  to  be  now  opened  in  the  same 
way  as  the  right ;  and  to  prepare  for  the  examination  of  the  cavity  on  the 
right  side,  as  much  of  the  corpus  callosum  as  forms  the  roof  of  the  space 
is  to  be  removed.  A  pai-t  of  the  ventricle  extends  down  in  the  temporo- 
sphenoidal  lobe  towards  the  base  of  the  brain  ;  and  to  open  it,  a  cut  is  to 
be  carried  outwards  and  downwards,  through  the  substance  of  the  hemi- 
sphere, along  the  course  of  the  hollow.     (See  fig.  63.) 

Ventricles  of  the  brain — The  ventricular  spaces  in  the  interior  of 
the  cerebrum  are  derived  from  the  subdivision  of  a  large  central  hollow, 
and  are  five  in  number.  One  (lateral)  is  contained  in  each  lu^misphere  ; 
and  these  constitute  the  first  and  second.  The  third  occupies  tlie  middle 
line  of  the  brain  near  the  under  surface ;  and  the  small  fiftli  is  included  in 
the  partition  between  the  lateral  ventricles.  The  fourth  is  situate  be- 
tween the  cerebellum  and  the  posterior  surface  of  the  medulla  oblongata 
and  pons. 

The  lateral  ventricles  (fig.  63)  are  two  in  number,  one  in  each  hemi- 
sphere ;  they  are  separated  incompletely  in  the  middle  line  by  a  septum, 
as  they  communicate  by  iui  ai)erture  below  that  partition.  The  interior 
is  lined  by  a  thin  stratum  of  areolar  tissue  covered  by  nucleated  epithelium 
(the  ependyma  ventriculorum),  with  cilia  at  some  spots. 

P^ach  is  a  narrow  interval,  which  rt^aches  into  the  anterior,  posterior, 
and  middle  regions  of  the  corresponding  hemisphere.  Its  central  part 
(body)  is  almost  straight,  but  the  extremities  (cornua)  are  curved.  Thus 
there  are  three  cornua  in  each,  which  have  the  following  disposition  : — 
The  anterior  is  directed  outwards  from  its  fellow  in  the  other  hemisphere. 
The  posterior  or  the  digital  cavity  is  much  smaller  in  size,  and  is  bent 
inwards  in  the  occipital  lobe  towards  the  one  on  the  opposite  side.  And 
the  inferior  coniu,  beginning  opposite  the  posterior  fold  of  the  corpus  cal- 


BOUNDS    OF    LATERAL    VENTRICLE 


201 


losum  (a),  descends  in  a  curved  direction  in  the  temporo-sphenoidal  lobe, 
with  the  concavity  of  tlie  bend  turned  inwards. 

For  the  purpose  of  examining  its  boundaries,  tlie  ventricle  may  be  di- 
vided into  an  upper  or  horizontal,  and  a  lower  or  descending  part. 

The  upper  or  iiorizontal  portion  reaches  from  the  frontal  to  the  occipital 
lobe,  and  is  shaped  like  the  italic  letter  /; 


View  of  the  Lateeal  Ventricles:   on    the  left  side  the   Descendi.vq  Corxc  is  laid 
OPEX.     (From  a  cast  ia  a  museum  of  University  College,  Loudon.) 

a.  Kemains  of  the  corpus  callosum.  g.  Optic  thalamus. 

6.  Septum  luciduni,  iuclosiug  the  small  space  /*.  Choroid  plexus. 

of  the  fifth  ventricle.                                 ^  i    Hippocampus  minor. 

c.  Fornix,  fc.  Eminentia  coUatfralis. 

d.  Posterior  crus  or  tajnia  of  the  fornix.  I.  Hippocampus  major. 

e.  Corpus  striatum.  o.  Digital  fossa. 
/.  Taenia  semicircalaris. 

The  roof  is  formed  by  the  corpus  callosum.  The  floor  is  irregular  in 
outline,  and  presents  from  before  backwards  the  following  objects  ; — first, 
a  small  piece  of  the  under  part  of  the  corpus  callosum  ;  next,  a  large,  gray 
body,  the  corpus  striatum  (<?)  ;  behind  this,  the  large  white  projection, 
named  optic  thalamus  {g)  ;  and  between  the  two  last  bodies  is  a  white 
band  (/),  tainia  semicircularis.  On  the  sui-face  of  the  optic  thalamus  is  a 
vascular  fold  of  the  pia  mater  (//) — the  plexus  choroides,  together  with 
the  thin  white  half  of  the  fornix  (c).  Close  behind  the  thalamus  is  the 
beginning  of  a  projection  (hippocampus  major)  (e),  in  the  floor  of  the  de- 
scending part  of  the  lateral  ventricle  ;  and  in  the  posterior  cornu  is  an 
elongated  eminence,  the  hippocampus  minor  (/). 


202  DISSECTION    OF    THE    BRAIN. 

The  inner  boundary  (septum  ventriculorum)  is  a  tliin  layer  which  is 
sometimes  named  septum  lucidum  (fig.  63,  b).  Its  extent  corresponds 
with  the  central  part  of  the  corpus  callosum.  Below  it  and  the  fornix, 
opposite  the  front  of  the  oi)tic  thalamus,  is  the  aperture  of  communication 
(foramen  of  Moin-o)  between  the  two  lateral  ventricles. 

The  lower  or  descending  part  of  the  ventricle  winds  beneath  the  optic 
thalamus,  and  forms  a  curve  like  the  half-bent  forefinger.  The  roof  is 
formed  by  the  optic  thalamus  and  the  contiguous  part  of  the  hemisphere. 
In  the  floor  is  a  large  curved,  convex  eminence,  somewhat  indented  at 
the  end — the  hippocampus  major  (/)  ;  and  along  its  concave  margin  is  a 
thin  white  band — toenia  (d),  which  is  prolonged  from  the  fornix.  Ex- 
ternal to  the  projection  of  the  hippocamjjus  is  another  white  eminence, 
the  eminentia  collateralis  (k),  whicli  tapers  from  above  down.  In  this 
part  of  the  ventricle  is  the  vascular  fringe  of  the  plexus  choroides. 

The  septum  lucidum  (fig.  G3,  h),  or  the  thin  structure  between  the 
lateral  ventricles,  is  translucent,  and  hangs  vertically  in  the  middle  line 
along  the  anterior  two-thirds  of  the  corpus  callosum.  It  is  somewhat 
triangular  in  form,  with  the  larger  part  turned  forwards,  and  the  pointed 
extremity  backwards.  Its  surfaces  look  to  the  lateral  ventricles.  The 
u])per  border  is  attached  altogether  to  the  under  surface  of  the  corpus  cal- 
losum ;  and  the  lower  border  is  joined  in  part  to  the  fornix  (c),  but  in 
front  of  that  body  it  is  inserted  into  the  under  or  prolonged  portion 
(rostrum)  of  the  corpus  callosum.  The  septum  consists  of  two  layers, 
which  inclose  a  space — the  fifth  ventricle ;  and  each  layer  is  formed  of 
white  substance,  with  an  external  coating  of  gray  matter. 

Dissection.  The  space  of  the  fifth  ventricle  will  come  into  view  by 
cutting  through  the  'part  of  the  corpus  callosum  which  remains  in  the 
middle  line,  and  by  detaching  the  anterior  half  from  the  septum  lucidum, 
and  raising  it.     (See  fig.  63.) 

The  ventricle  of  the  septum,  or  the  fifth  ventricle,  is  a  triangular  space 
in  the  fore  part  of  the  ventricular  partition,  where  the  depth  is  greatest. 
Like  the  septum  containing  it,  its  largest  part  is  in  front.  Its  surface  has 
an  epithelial  covering  like  that  in  the  lateral  ventricles.  In  the  adult  it 
is  closed ;  but  in  the  foetus  it  opens  inferiorly  into  the  third  ventricle  be- 
tween the  pillars  of  the  fornix. 

Dissection.  The  fornix  is  to  be  next  examined.  To  lay  bare  this 
body  the  posterior  part  of  the  corpus  callosum  should  be  detached  with 
care  from  it,  and  thrown  backwards^  and  the  septum  lucidum  should  also 
be  removed  from  its  upper  surface. 

The  fornix,  or  arch  (fig.  63,  c),  is  a  thin  white  horizontal  stratum  be- 
neath the  corpus  callosum,  which,  projecting  on  each  side  into  the  lateral 
ventricle,  forms  part  of  the  floor  of  that  cavity.  Its  central  part  or  body 
is  triangular  in  shape,  with  the  base  turned  backwards ;  and  it  is  continu- 
ous with  the  rest  of  the  brain  by  processes  or  crura  before  or  behind. 

To  the  upper  surface  of  the  body,  along  the  middle  line,  the  septum 
lucidum  is  attached.  Each  border  is  free  in  the  corresj)onding  lateral 
ventricle,  where  it  rests  on  the  op^ic  thalamus  ;  and  along  it  lies  the  cho- 
roid plexus.  At  its  posterior  part  it  joins  the  corpus  callosum  in  the 
middle  line,  whilst  on  each  side  it  sends  off  a  small  riband-like  band — 
tii^nia  hippocampi  (d),  along  the  concave  margin  of  the  hippocampus 
major.  At  the  anterior  part  it  is  arched  over  the  foramen  of  Monro, 
opposite  the  front  of  the  optic  thalamus,  and  ends  likewise  in  two  pro- 


FLOOR  OF  LATERAL  VENTRICLE.  203 

cesses  or  crura,  which  will  be  afterwards  followed  to  the  corpora  albicantia 
and  the  optic  thalami  (p.  208). 

If  the  formix  be  cut  across  near  its  front,  the  foramen  of  Monro  will  be 
opened,  and  the  descending  anterior  pillars  will  be  seen  (fig.  64).  When 
the  posterior  part  is  raised,  it  will  be  found  to  be  supported  on  a  process 
of  the  pia  mater,  named  velum  interpositum.  And  near  its  base  (on  the 
under  aspect)  between  the  two  offsets  of  the  toenias  hippocampi,  is  a  trian- 
gular sui-face,  which  is  marked  bj  transverse  lines  :  the  part  which  is  so 
defined  has  been  called  the  lyra  (fig.  64). 

The  fornix  may  be  described  as  consisting  of  two  bands,  right  and  left, 
whicli  are  united  for  a  certain  distance  in  the  central  part  or  body.  Ac- 
cording to  this  view  each  band,  commencing  in  the  optic  thalamus,  passes 
over  the  foramen  of  Monro,  and  after  forming  the  body  of  the  fornix,  is 
continued  as  a  distinct  piece  to  the  uncinate  convolution. 

The  foramen  of  Monro  is  the  interval  beneath  the  anterior  part  of  the 
fornix,  which  opens  on  each  side  by  a  slit  between  the  edge  of  the  fornix 
and  the  .optic  thalamus.  In  it  the  plexus  choroides  lies;  and  through  it 
the  lateral  ventricles  communicate  with  one  another  and  with  the  third 
ventricle. 

Floor  of  the  Lateral  Ventricle The  student  may  leave  un- 
touched, for  the  present,  the  membrane  on  which  the  fornix  rests ;  and 
proceed  to  examine,  on  the  right  side,  the  different  bodies  which  have 
been  enumerated  as  constituting  the  tloor  of  the  lateral  ventricle. 

The  corpus  striatum  (superior  ganglion  of  the  cerebrum)  (fig.  63,  e)  is 
the  large  gray  body  in  the  front  of  the  lateral  ventricle.  It  is  placed  op- 
posite the  island  of  Reil  in  the  fissure  of  Sylvius;  and  it  has  received  its 
name  from  the  striated  appearance  of  a  vertical  section. 

Dissection.  To  see  the  composition  of  the  corpus  striatum,  the  student 
should  slice  off  obliquely  the  upper  and  outer  part  until  certain  white 
fibres  crossing  it  obliquely  from  within  outwards  are  reached.  The  knife 
should  then  be  carried  through  this  layer  of  white  fibres  until  another 
mass  of  gray  substance,  similar  to  the  first,  is  arrived  at. 

The  striate  body  is  a  pyriform  mass  of  gray  matter  of  considerable 
thickness,  which  is  surrounded  by  the  white  substance  of  the  hemisphere, 
except  where  it  projects  into  the  lateral  ventricle.  Its  position  is  oblique 
with  respect  to  the  middle  line  of  the  brain,  for  the  anterior  part  is  near 
the  septum  of  the  ventricles,  whilst  the  posterior  is  external  to  the  optic 
thalamus.  By  means  of  the  incision  in  the  corpus  striatum,  white  fibres 
can  be  seen  to  be  directed  through  it  in  such  a  way  as  to  divide  the  gray 
matter  into  two  parts,  one  being  situate  in  the  ventricle  (intra-ventricular) 
a^ove  the  white  fibres,  and  the  other  outside  the  ventricular  space  (extra- 
ventricular),  below  these  fibres. 

The  intra-ventricular  piece  (nucleus  caudatus)  is  shaped  like  a  kite, 
and  projects  into  the  floor  of  the  ventricle.  The  end,  directed  forwards, 
is  large  and  rounded;  wliilst  the  opposite  end  is  thin  and  pointed,  and  is 
continued  backwards,  outside  the  optic  thalamus,  to  the  roof  of  the  de- 
scending cornu  of  the  lateral  ventricle.  Numerous  veins  cover  this  part 
of  the  corpus  striatum. 

The  extra-ventricular  part  (nucleus  lenticularis)  will  be  better  seen, 
afterwards,  by  sections  made  from  the  outer  side  or  from  below.  It  is 
oval  in  form,  but  does  not  reach  so  far  back  as  the  other,  and  is  bounded 
interiorly  by  a  white  capsule;  through  it  the  anterior  commissure  of  the 
brain  passes  very  obliquely,  as  a  subsequent  dissection  will  show. 


201  DISSECTION    OF    THE    BRAIN. 

The  taenia  semiclrcnlaris  (fig.  63,/)  is  a  thin  and  narrow  wliite  band 
of  longitudinal  fibres,  which  lies  between  the  corpus  striatum  and  the  optic 
thalamus.  In  front  this  band  becomes  broarler  and  joins  the  pillar  of  the 
fornix;  and  behind  it  is  continued,  along  with  the  pointed  end  of  the  cor- 
pus striatum,  into  the  white  substance  of  the  roof  of  the  descending  cornu 
of  the  lateral  ventricle.  Superficial  to  the  anterior  part  of  the  taenia  is  a 
yellowish  semi-transparent  layer  (lamina  cornea) ;  and  beneath  this  pass 
some  small  veins  from  the  corpus  striatum,  in  their  course  to  the  veins  of 
Galen. 

The  optic  thalamus  is  only  partly  laid  bare  in  this  stage  of  the  dissec- 
tion, and  its  examination  may  be  omitted  till  the  third  ventricle  has  been 
learnt. 

The  hippocampus  minor  (calcar  avis)  resembles  a  cock's  spur  (fig. 
G3,  ^),  as  it  lies  in  the  posterior  cornu  of  the  ventricle.  It  is  pointed  at 
its  posterior  extremity,  and  is  covered  on  the  free  surface  by  a  medullary 
layer  continuous  with  the  corpus  callosum.  When  it  is  cut  across  a  gray 
stratum  will  be  found  beneath  the  white;  and  the  eminence  itself  will  be 
seen  to  be  produced  by  the  extension  inwards  of  the  calcarine  sulcus  at 
the  inner  surface  of  the  hemisphere  (p.  1 98). 

The  hippocampus  major  (fig.  63,  /)  is  the  curved  projection  in  the 
floor  of  the  descending  cornu  of  the  lateral  ventricle.  Convex  on  the 
surface  that  looks  to  the  cavity,  this  body  is  curved  in  the  same  direction 
as  the  cornu,  and  has  its  concavity  turned  inwards.  The  anterior  ex- 
tremity is  the  largest,  and  presents  two  or  three  indentations,  which  give 
it  the  appearance  of  the  foot  of  a  feline  animal ;  it  is  named  pes  hippo- 
campi. 

All  along  the  inner  or  concave  margin  is  the  small  band  or  tii3nia  {d) 
that  is  prolonged  from  the  fornix;  it  ends  below  by  joining  the  small 
recurved  part  of  the  uncinate  convolution. 

Dissection.  To  examine  more  fully  the  hippocampus,  the  parts  of  the 
corpus  callosum  and  fornix,  which  remain  in  the  middle  line,  should  be 
divided  longitudinally,  and  the  posterior  part  of  the  right  hemisphere 
should  be  drawn  away  from  the  rest  of  the  brain.  When  the  pia  mater 
has  been  removed  from  the  inner  side  of  the  hippocampus,  and  this  pro- 
jection has  been  cut  across,  its  structure  will  be  manifest. 

The  hippocampus  is  covered  on  the  ventricular  sui-face  by  a  medullary 
layer,  with  which  the  taenia  or  the  band  of  the  fornix  blends.  On  its 
o])posite  surface  is  the  hollow  of  the  dentate  sulcus  on  the  exterior  of  the 
brain,  which  is  filled  with  gray  substance.  Along  the  free  margin  of  the 
hippocampus  the  gray  matter  projects  in  the  form  of  a  notched  ridge,  the 
lamina  dentata:  this  is  external  to  the  cavity  of  the  ventricle,  beneath 
the  taenia,  and  has  been  named  the  dentate  convolution  (p.  199). 

Transverse  Jissure  of  the  cerebrum.  By  drawing  the  separated  right 
hemisphere  away  from  the  crus  cerebri  and  the  optic  thalamus,  and  re- 
placing it,  the  dissector  will  comprehend  the  position,  and  the  boundaries 
of  the  great  cleft  at  the  posterior  part  of  the  brain. 

This  fissure  lies  beneath  the  fornix,  and  opens  into  the  lateral  ventricle, 
on  each  side,  along  the  edge  of  the  fornix,  from  the  foramen  of  Monro  to 
the  extremity  of  the  descending  cornu.  The  ])art  of  the  slit  entering  the 
lateral  ventricle  is  bounded  by  the  edge  of  the  fornix  on  the  one  side,  and 
by  the  optic  thalamus  and  crus  cerebri  on  the  other.  A  piece  of  pia  mater 
projects  into  the  transverse  fissure,  forming  a  horizontal  central  ])iece, 
velum  interpositum,   beneath   the  fornix  (fig.  64,  s),  and  thinner  lateral 


VELUM    INTERPOSITUM. 


205 


pieces  with  terminal  fringes  in  tlie  latter  ventricles  (/).  But  the  slit 
through  which  the  membrane  enters  the  ventricle  is  closed  by  the  lining 
structure  of  that  cavity  being  <x)ntinued  on  the  intruded  part. 

Fig,  64» 


Second  View  of  thk  Disskction  of  the  Brain,  the  Fornix  bring  Cut  throCOH 
IN  Front  and  Raised.     (From  a  oast  iu  the  University  College,  Loudou.) 

a.  Fornix.  '  d.  Corpus  striatum. 

b.  Hippocampus  major.  e.  Optic  thalamus. 

c.  Tecnia  hippocampi,  or  hli:der  crus  of  /.  Choroid  plexus. 

the  fornix.  ^.  Velum  interpositum. 

Parts  in  the  Middle  Line  of  Cerebrum.  The  student  is  now  to 
return  to  tlie  examination  of  the  parts  in  the  centre  of  the  brain,  viz.,  the 
fold  of  pia  mater  and  its  vessels,  with  the  third  ventricle.  At  the  same 
time  the  optic  thalamus  is  to  be  seen. 

The  velum  interpositum  (fig.  G4,  g)  is  the  central  part  of  the  fold  of 
pia  mater  entering  the  great  transverse  fissure.  Triangular  in  shape,  it 
has  the  same  extent  as  the  body  of  the  fornix,  and  reaches  in  front  to  the 
foramen  of  Monro.  The  upper  surface  is  in  contact  with  tlie  fornix,  to 
which  it  supplies  vessels.  And  the  lower  surlace,  looking  to  tlie  third 
ventricle,  covers  the  pineal  body,  and  a  part  of  each  optic  thalamus  :  un- 
derneath it  in  the  middle  line  are  the  two  choroid  plexuses  of  the  third  ven- 
tricle. Along  each  side  is  another  vascular  roll  of  the  membrane  (choroid 
plexus). 

The  choroid  plexus  of  the  lateral  ventricle  (fig.  64,  y)  is  the  red,  some- 
what rounded,  and  fringed  margin  of  the  piece  of  pia  mater  in  the  inte- 
rior of  the  lateral  ventricle,  which  extends  from  the  foramen  of  Monro  to 


206  DISSECTION    OF    THE    BRAIN. 

the  extremity  of  tlie  descending  cornu.  Its  lower  end  is  larger  tlian  the 
upper.  On  its  surface  the  clioroid  plexus  is  villous  ;  and  the  villi,  minutely- 
subdivided,  are  covered  by  flattened  nucleated  epithelium,  with  the  fat 
granules  and  pigment  in  the  cells.^ 

Vessels  of  the  velum.  Small  arteries  have  been  already  traced  to  the 
velum  and  the  choroid  plexus  from  the  cerebral  and  cerebellar  arteries  (p. 
175)  :  they  are  three  on  each  side,  and  supply  the  surrounding  cerebral 
substance.  The  veins  of  the  choroid  plexus  receive  branches  from  the 
ventricle,  and  end  in  the  following. 

Veins  of  Galen.  Along  the  centre  of  the  velum  are  placed  two  large 
veins  with  this  name  ;  they  begin  at  the  forfimen  of  Monro,  by  the  union 
of  branches  from  the  corpus  striatum  and  the  choroid  plexus.  Lying  side 
by  side  in  the  membrane  they  are  usually  united  into  one  at  the  posterior 
part  of  the  velum  ;  and  by  this  they  join  the  straight  sinus. 

Dissection.  When  the  velum  interpositum  has  been  raised  and  thrown 
backwards,  the  third  ventricle  will  be  visible  (fig.  68).  In  reflecting  the 
piece  of  pia  mater  the  student  must  be  careful  behind  of  the  pineal  body 
{g),  which  would  otherwise  be  detached,  as  it  is  surrounded  by  the  mem- 
brane. On  the  under  surface  of  the  velum  are  the  choroid  plexuses  of  the 
third  ventricle. 

The  choroid  plexuses  of  the  third  ventricle  are  two  short  and  narrow 
fringed  bodies  beneath  the  velum,  which  resemble  the  like  parts  in  the 
lateral  ventricle. 

The  third  ventricle  is  in  the  interval  between  the  optic  thalami  (fig. 
68).  Its  situation  is  in  the  middle  line  of  the  cerebrum,  below  the  level 
of  the  other  ventricles  with  wliich  it  communicates ;  and  it  reaches  to  the 
base  of  the  brain.  Its  boundaries  and  communications  are  the  follow- 
ing:— 

The  roof  is  formed  by  the  velum  interpositum  and  the  fornix.  The 
floor  is  very  oblique  from  behind  forwards,  so  th'at  the  depth  of  the  cavity 
is  about  an  inch  in  front  and  half  an  inch  behind :  it  corresponds  with 
the  parts  at  the  base  of  the  brain,  which  lie  between  the  crura  cerebri  and 
the  median  fissure  (fig.  59),  viz.',  locus  perforatus,  corpora  albicantia,  tuber 
cinereum,  commissure  of  the  optic  nerves,  and  lamina  cinerea.  On  the 
sides  of  the  cavity  are  situate  the  optic  thalami  {b).  In  front  of  the  space 
are  the  descending  pillars  of  the  fornix,  with  the  anterior  commissure  of 
the  cerebrum  (c)  in  the  interval  between  them.  Behind  are  the  posterior 
commissure  (e)  and  the  pineal  body  {g).  Crossing  the  centre  of  the  ven- 
tricle, from  one  optic  thalamus  to  another,  is  a  band  of  gray  matter — the 
soft  commissure  {d). 

This  space  communicates  with  the  other  ventricles  of  the  brain  in  the 
following  way: — In  front  it  joins  eacli  lateral  ventricle  through  the  fora- 
men of  Monro  ;  and  in  the  ftetus  it  opens  into  the  fifth  ventricle.  Behind 
is  a  passage  beneath  the  posterior  commissure  into  the  fourth  ventricle, 
which  is  named  aqueduct  of  Sylvius.  At  the  lower  part,  in  front,  there 
is  a  depression  opposite  the  infundibulum  (iter  ad  infundibulum). 

The  lining  of  the  ventricle  (ependyma)  is  continued  into  the  neighbor- 
ing cavities  through  the  difl'erent  apertures  of  communication,  and  closes 
the  iter  ad  infundibulum. 

Gray  matter  of  the  ventricle.  A  stratum  of  gray  matter  covers  most 
of  the  surface  of  the  ventricle.     At  the  lower  part  of  each  optic  thalamus 

'  Particles  of  brain  sand,  like  that  in  the  pineal  body,  are  sometimes  present 
in  the  choroid  plexus. 


THIRD    VENTRICLE.  207 


4 


it  envelops  the  crus  of  the  fornix,  and  ascends  to  the  septum  lucidum  ; 
and  in  tlie  floor  of  the  cavity  it  exists  in  abundance,  entering  into  the 
corpora  albicantia.  In  the  middle  of  the  space  it  reaches  from  side  to  side, 
and  forms  the  soft  commissure  {d). 

The  anterior  commissure  of  the  cerebrum  (e)  is  a  round  bundle  of  white 
fibres  about  as  large  as  a  crow-quill,  which  passes  through  both  corpoi-a 
striata,  and  connects  the  opposite  hemispheres.  To  see  it  in  one-half  of 
its  extent,  the  following  dissection  should  be  made  : — 

Dissection.  On  the  side  on  which  the  corpus  striatum  has  been  cut  into, 
the  commissure  is  to  be  followed  into  the  interior  of  that  body,  by  scraping 
away  the  intraventricular  gray  matter  with  the  handle  of  the  scalpel.  The 
commissure  may  be  seen  then  to  perforate  below  tlie  white  fibres  of  the 
corpus  striatum  ;  and  it  should  be  followed  througli  the  extraventricular 
mass  of  gray  matter  of  tiie  same  body. 

The  anterior  commissure  is  free  in  the  middle  line  for  about  the  eighth 
of  an  inch,  where  it  lies  before  the  pillars  of  the  fornix.  Laterally  it  per- 
forates the  corpus  striatum,  passing  in  succession  tlirough  the  intraven- 
tricular gray  mass,  the  white  fibres,  and  the  extra  gray  ventricular  gray 
mass.  Lastly,  the  commissure  pierces  the  white  layer  bounding  externally 
the  corpus  striatum,  and  spreads  in  the  hemisphere  over  the  inferior  cornu 
of  the  lateral  ventricle  communicating  with  the  temporo-sphenoidal  and 
central  lobes. 

The  posterior  commissure  of  the  cerebrum  {e)  is  smaller  than  the  ante- 
rior, and  is  placed  above  the  passage  into  the  fourth  ventricle.  Laterally 
it  enters  the  substance  of  the  optic  thalamus  ;  and  pierces  this  body  to  end 
in  the  hemisphere. 

The  connections  of  the  thalamus  opticus  (inferior  ganglion  of  the  cere- 
brum) (5)  will  be  best  seen  on  the  side  on  which  the  inferior  cornu  of  the 
lateral  ventricle  has  been  opened.  It  has  the  form  of  a  cube,  and  bounds 
the  lateral  and  third  ventricles. 

The  upper  surface  projects  in  the  floor  of  the  lateral  ventricle,  and  is 
marked  in  front  by  a  prominence — anterior  tubercle,  near  the  tienia  semi- 
circularis.  The  under  surface  forms  part  of  the  roof  of  the  inferior  cornu 
of  the  lateral  ventricle,  and  into  it  the  crus  cerebri  is  inserted. 

By  its  inner  side  it  enters  into  the  third  ventricle  ;  and  along  the  upper 
part  lies  the  peduncle  of  the  pineal  body.     On  the  outer  side  are  the  cor 
pus  striatum,  the  taenia  semicircularis,  and  the  substance  of  the  hemisphere. 

The  anterior  end  looks  to  the  foramen  of  Monro.  And  the  posterior 
part,  which  is  free  in  the  inferior  cornu  of  the  lateral  ventricle,  presents 
inferiorly  two  small  roundish  tubercles,  which  are  placed  one  outside  and 
the  other  inside  the  bend  (genu)  of  the  optic  nerve,  and  are  named  from 
their  position  to  it,  internal  and  external  geniculate  bodies. 

The  structure  of  the  optic  thalamus  will  be  subsequently  referred  to,  p. 
21L 

The  origin  of  the  optic  nerve  can  now  be  seen.  At  the  back  of  the  crus 
cerebri  the  optic  tract  receives  fibres  from  the  thalamus  which  it  touches, 
and  then  divides  into  tw^o  terminal  bands: — One  of  these  is  connected  with 
the  gray  matter  in  the  external  geniculate  body,  and  is  continued  onwards 
to  one  of  the  corpora  quadrigemina  (nates) ;  the  other  is  connected  with 
the  internal  geniculate  body. 

Dissection.  The  origin  of  the  fornix  in  the  optic  thalamus  may  be  fol- 
lowed out  next.  As  a  preparatory  step  the  anterior  commissure,  tlie 
anterior  part  of  the  corpus  callosum,   and  the  commissure  of  the  optic 


208  DISSECTION    OF    THE    BRAIN. 

i 

nerves,  should  be  cut  along  the  middle  line,  so  that  the  left  hemisphere  can 
be  sejjarated  f'rowi  the  other.  On  the  left  hemisphere  the  crus  of  the  fornix 
is  to  be  traced  downwards  through  the  gray  matter  of  the  third  ventricle 
to  the  corpus  albicans,  and  then  upwards  into  the  optic  thalamus. 

Anterior  pillar  of  the  fornix.  The  fornix  begins  in  the  thalamus  near 
the  tubercle  on  the  upper  surface.  From  this  spot  it  descends  in  a  curved 
direction  to  the  corpus  albicans,  where  it  makes  a  turn  like  half  of  the 
figure  8,  and  furnishes  a  white  envelope  to  the  gray  matter  of  tliat  body. 
The  crus  then  ascends  through  the  gray  substance  in  front  of  tiie  optic 
thalamus,  and  is  applied  to  the  like  part  of  the  op[)Osite  side  to  form  the 
body  of  the  fornix.  It  is  joined  by  bands  of  fibres  from  the  tainia  semi- 
circularis  and  peduncle  of  the  pineal  body. 

The  pineal  body  and  the  corpora  qnadrigemina,  which  are  placed  be- 
hind the  third  ventricle,  may  be  next  examined. 

Disaection.  All  the  pia  mater  should  be  carefully  removed  from  the  sur- 
face of  the  quadrigeminal  bodies,  especially  on  the  right  side,  on  which 
they  are  to  be  seen.  The  posterior  part  of  the  hemisi)here  of  the  same 
side  may  be  taken  away. 

T\\it  pineal  gland  (conarium)  is  a  small  conical  body  (fig.  Q'>^,g),  which 
is  situate  above  the  posterior  commissure,  and  between  the  anterior  pair 
of  the  corpora  quadrigemina.  In  sha|)e  like  the  cone  of  a  pine,  it  is  about 
a  quarter  of  an  inch  in  length,  and  has  the  base  or  wider  part  turned  for- 
wards. It  is  connected  to  the  optic  tlialami  by  two  white  bands, — [)edun- 
cles  of  the  pineal  body  (/' ) :  these  begin  at  the  base,  and  extending  for- 
wards, one  on  each  side  along  the  inner  part  of  the  thalamus,  end  by 
joining  the  crura  of  the  fornix.  At  the  base  of  the  gland  is  a  band  of  trans- 
verse white  fibres  which  unites  it  which  the  posterior  commissure. 

This  body  is  of  a  red  color  and  vascular,  and  incloses  two  or  more  cells 
containing  a  thick  fi.:id,  with  amyloid  bodies,  and  a  calcareous  material 
(brain  sand)  consisting  of  particles  of  phosphate  and  carbonate  of  lime, 
and  phosphate  of  magnesia  and  ammonia^  In  its  substance  are  large 
pale  nucleated  cells. 

The  corpora,  quadrigemina  (fig.  G8)  t^re  four  small  bodies,  which  are 
arranged  in  pairs,  right  and  left,  and  are  separated  by  a  median  groove. 
Each  pair  is  situate  on  the  upper  aspect  of  the  cerebral  peduncle  of  the 
same  side. 

The  anterior  eminence  (^,  nates)  is  somewhat  larger  than  the  posterior, 
from  which  it  is  separated  by  a  slight  depression ;  it  is  oblong  from  before 
backwards,  and  sends  forward  a  white  band  to  join  the  optic  tract  and 
thalamus. 

The  posterior  eminence  (/,  testis)  is  rounder  in  form  and  whiter  in 
color  than  the  preceding  :  it  has  also  a  lateral  white  band  wiiicli  is  directed 
beneath  the  corpus  geniculatum  internum,  and  blends  with  the  peduncular 
fibres  in  the  thalamus  opticus. 

Tliese  bodies  are  small  masses  of  gray  substance  enveloped  by  white, 
and  are  placed  on  the  band  of  the  fillet  which  forms  the  roof  of  the  aque- 
duct of  Sylvius.  The  processes  (brachia)  to  the  optic  thalamus  are  acces- 
sory parts  to  the  peduncular  fibres  ef  the  cerebrum  (p.  209). 

Fillet  of  the  olivary  body.     If  the  upjjcr  margin  of  the  cerebellum  be 

'  These  particles  are  referred  to  by  KoUiker,  as  pathological  products  ;  and  the 
concentrically  arranged  uiasses  amongst  them  ai'e  said  to  be  incrustations  of  fibrin 
coagula. 


FIBRES    OF    CEREBRUM.  209 

pulled  aside,  a  white  band,  about  a  quarter  of  an  inch  in  width,  will  be 
seen  to  issue  from  the  transverse  fibres  of  the  pons,  and  to  bend  upwards 
over  the  peduncle  of  the  cerebellum  to  the  corpora  quadrigemina  (fig. 

This  is  the  upper  or  commissural  piece  of  the  fillet  (p.  128),  which 
passes  beneath  the  corpora  quadrijjemina,  and  joins  with  the  similar  part 
of  the  opposite  side  over  the  Sylvan  aqueduct. 

Structure  of  the  Cerebrum.  In  each  cerebral  hemisphere  three 
principal  sets  of  constituent  fibres  are  recognized,  viz.,  diverging,  trans- 
verse, and  longitudinal.  The  former  are  in  part  derived  from  the  spinal 
cord ;  while  the  two  latter,  joining  distant  pieces  of  the  cerebrum,  are  con- 
sidered to  be  only  connecting  or  commissural  in  tlieir  office. 

Pedimcular  or  diverging  Jibres  (fig.  56).  In  the  crus  cerebri  two 
bundles  of  longitudinal  fibres  are  collected;  these  are  separated,  in  part, 
by  gray  matter,  and  are  derived  from  the  medulla  oblongata  (p.  191). 

JJissection,  A  complete  systematic  view  of  the  diverging  fibres  can- 
not be  now  obtained  on  the  imperfect  brain.  At  this  stage  the  chief  |)ur- 
pose  is  to  show  the  passage  of  the  radiating  fibres  from  the  crus  through 
the  two  cerebral  ganglia. 

To  trace  the  diverging  fibres  onwards  beyonds  the  crus  cerebri,  and 
througli  the  corpus  striatum,  the  nucleus  caudatus  of  this  body  should  be 
scraped  away  (fig.  65) ;  and  the  dissection  should  be  made  on  the  left  side 
on  which  the  striate  body  and  the  optic  thahimus  remain  uncut.  In  this 
proceeding  the  pecten  of  Reil  comes  into  view,  viz.,  gray  matter  passing 
between  tlie  white  fibres  in  the  corpus  striatum,  and  giving  the  appearance 
of  the  teeth  of  a  comb. 

On  taking  away  completely  the  prolonged  part  of  the  nucleus  caudatus, 
others  of  the  same  set  of  fibres  will  be  seen  issuing  from  the  outer  side  of 
the  optic  thalamus,  and  radiating  to  the  posterior  and  inferior  lobes. 

After  tracing  those  fibres,  the  upper  part  of  the  optic  thalamus  may  be 
taken  away  at  the  posterior  end,  to  denude  the  accessory  bundles  to  the 
peduncular  fibres,  from  the  corpora  quadrigemina  and  the  superior  pedun- 
cle of  the  cerebellum  (fig.  65,  ^) :  the  last  band  lies  beneath  the  corpora 
quadrigemina. 

T\\g\y  arrangement  (fig.  65,^).  Some  of  the  diverging  fibres  radiate 
from  the  peduncle  of  the  cerebrum  to  the  sui-face  of  the  hemisphere,  pass- 
ing in  their  course  through  the  two  cerebral  ganglia  (optic  thalamus  (^) 
and  corpus  striatum  (^)  ),  and  they  form  a  conically-shaped  bundle,  whose 
apex  is  below  and  base  above. 

The  fibres  forming  the  free  or  fasciculated  part  (crust)  of  the  peduncle 
(fig.  56)  pass  through  the  striate  body.  The  fibres  on  the  opposite  aspect, 
which  form  the  tegmentum  (fig.  57,  o?),  are  transmitted  through  tlie  under 
part  of  the  optic  thahimus,  and  through  the  cor[)US  striatum,  reaching  as 
far  forwards  as,  but  much  farther  back  than  tliose  of  tlie  crust. 

In  the  thalamus  and  the  corpus  striatum  the  fibres  are  greatly  increased 
in  number.  The  upper  or  sensory  set  receive  also  accessory  bundles  from 
the  superior  peduncle  of  the  cerebellum  (fig.  65,  ')  in  the  crus  cerebri 
(p.  191);  and  from  the  pair  of  the  cor{)ora  quadrigemina,  and  the  corpora 
geniculata  of  the  same  side,  in  the  thalamus. 

On  escaping  from  the  striate  body  and  the  thalamus,  the  fibres  decussate 
with  the  converging  fibres  of  the  corpus  callosum,  and  radiate  then  into 
the  anterior,  middle,  and  posterior  parts  of  the  cerebral  hemisphere,  form- 
ing the  corona  radiata.  In  the  hemisphere  the  fibres  are  continued  to 
14 


210 


DISSECTION    OF    THE    BRAIN. 


the  convolutions :  their  expansion  in  tlie  hemisphere  resembles  a  fan  bent 
down  in  front  and  behind,  forming  thus  a  layer  wliich  is  concave  on  the 
under  side. 

Their  extent.  All  the  fibres  of  the  peduncle  do  not  reach  the  surface  of 
the  brain,  for  some  end  in  the  corpus  striatum  and  the  optic  thalamus, 
especially  in  the  former.  And  some  of  the  fibres  in  the  convolutions  begin 
in  the  ganglionic  bodies  before  mentioned,  and  extend  to  the  surface  of 
the  hemisphere.^  Thus,  in  addition  to  the  fibres  continued  throughout, 
viz.,  from  the  crus  to  the  surface,  some  unite  the  peduncle  of  the  cerebrum 
with  the  ganglia,  and  others  connect  the  ganglia  with  the  convolutions  on 
the  exterior. 


Fig.  65. 


1.  Superior  peduncle. 

2.  Middle,  and  3,  inferior  pcduncleof 

the  cerebellum. 

4.  Process  from  the  fillet  of  the  oli- 
vary body  to  the  corpora  qiiadri- 
gemina:  on  the  right  side  it  is 
cut  and  reflectfd. 

5    Posterior  pyramid. 

6.  Continuation  of  the  lateral  tract 

into  the  optic  thalamus. 

7.  Corpora  quadrigemiua. 

8.  Optic  thalamus. 

9.  Corpus  striatum. 
10.  Corpus  callosum. 


Connection  posteriorlt  between  the  Cerkbkum  and  the  Meddlla  Oblongata  and 

Cerebellum. 

Their  source.  The  fibres  thus  entering  inferiorly  the  cerebrum  through 
its  peduncle,  and  continued  thence  to  the  periphery  of  the  hemisphere,  are 
derived  from  the  component  pieces  of  the  medulla  oblongata  except  the 
restiform  body  (fig.  57),  viz.,  from  anterior  pyramid,  lateral  column  and 
olivary  body,  and  posterior  pyramid  (p.  183)  :  they  serve  to  connect  the 
spinal  cord  with  the  cerebrum.  The  decussation  between  opposite  sides 
has  been  before  referred  to  (p.  186). 

The  transverse  or  commissural  Jihres  connect  the  hemispheres  of  the 
cerebrum  across  the  middle  line.  They  give  rise  to  the  great  commissure 
or  the  corpus  callosum  (p.  210)  :  and  to  the  anterior  and  posterior  com- 
missures (p.  207).     Those  bodies  have  been  already  examined. 

Longitudinal  Jihres.  Other  connecting  fibres  pass  from  before  back- 
wards, uniting  together  parts  of  the  same  hemisphere.  The  chief"  bands 
of  this  system  are  the  following,  the  fornix,  the  taenia  semicircularis,  and 
the  peduncles  of  the  pineal  body.     Other  longitudinal  fibres  may  be  enu- 

'  According  to  some  authors  none  of  the  fibres  of  the  peduncle  reach  farther 
than  the  corpus  striatum  and  the  optic  thalamus. 


SURFACES  OF  CEREBELLUM.  211 

tnerated  on  the  upper  and  under  surfaces  of  the  corpus  callosnm,  along  the 
middle  line,  together  with  the  band  of  the  convolution  of  the  corpus  caU 
losum  :  these  fibres  are  connected  with  the  anterior  perforated  spot  of  the 
base  of  the  brain. 

Structure  of  the  optic  thalamus.  The  thalamus  is  about  an  inch  deep, 
and  the  following  is  a  summary  of  its  structure,  as  displayed  in  the  pre- 
vious dissections. 

The  upper  and  inner  half  is  formed  chiefly  of  gray  matter,  with  which 
the  undermentioned  white  bands  are  connected :  Thus  through  it  pass  the 
fornix  in  front,  and  the  posterior  commissure  behind ;  whilst  the  pedun- 
cles of  the  pineal  body  lie  along  the  inner  side,  and  the  taenia  semicircu- 
laris  along  the  outer. 

The  lower  and  outer  part  consists  mainly  of  white  fibres  directed 
upwards,  and  these  are  derived  from  the  peduncle  of  the  cerebrum  in- 
feriorly,  and  from  the  peduncle  of  the  cerebellum  and  the  corpora  quadri- 
gemina  superiorly  :  to  the  hinder  part  of  them  two  slips  of  fibres  are  added 
from  the  corpora  geniculata. 

The  corpora  geniculata  contain  gray  substance  inside.  Into  these 
bodies  fibres  of  the  optic  tract  enter ;  and  from  each  issues  a  band  to  join 
the  fibres  of  the  crus  cerebi'i.  They  seem  to  serve  as  accessory  ganglia  to 
the  peduncular  fibres  of  the  cerebrum. 

Corpus  striatum.  By  slicing  through  the  corona  radiata  on  the  left 
side,  so  as  to  bring  into  view  the  extraventricular  nucleus  of  the  corpus 
striatum,  the  extent  and  form  of  that  mass,  and  the  situation  of  the  ante- 
rior commissure  in  it,  will  be  apparent. 

Grus  cerebri.  By  a  vertical  section  through  the  left  peduncle  of  the 
cerebrum,  the  disposition  and  the  thickness  of  the  two  layers  of  its  longi- 
tudinal fibres  ;  and  the  situation  and  extent  of  the  locus  niger  between 
them,  may  be  perceived. 


Section  V. 

THE  CEREBELLUM. 


Dissection.  The  cerebellum  (fig.  59,  h)  is  to  be  separated  from  the 
remains  of  the  cerebrum,  by  carrying  the  knife  through  the  optic  thala- 
mus so  that  the  small  brain,  the  corpora  quadrigemina,  the  crura  cerebri, 
the  pons,  and  the  medulla  oblongata,  may  remain  united  together. 

All  the  pia  mater  is  to  be  carefully  removed  from  the  median  fissure  on 
the  under  surface  ;  and  the  different  bodies  in  that  fissure  are  to  be  sepa- 
rated from  one  another.  Lastly  the  handle  of  the  scalpel  should  be  passed 
along  a  sulcus  at  the  circumference,  which  is  continued  from  the  crus,  be- 
tween the  upper  and  under  surfaces. 

The  cerebellum,  little  brain  (fig.  &^),  is  flattened  from  above  down,  so 
as  to  be  widest  from  side  to  side,  and  measures  about  four  inches  across. 
This  part  of  the  encephalon  is  situate  in  the  posterior  fossfe  of  the  base  of 
the  skull,  beneath  the  tentorium  cerebelli.  Like  the  cerebrum,  it  is  in- 
completely divided  into  two  hemispheres ;  the  division  being  marked  by  a 
wide  median  groove  along  the  under  surface,  and  by  a  notch  at  the  poste- 
rior border  which  receives  the  falx  cerebelli. 


21^ 


DISSECTION    OF    THE    BRAIN 


Upper  Surface.  On  the  upper  aspect  the  cerebellum  is  raised  in  the 
centre  (fig.  G8),  but  slopes  towards  the  circumference.  There  is  not  any 
median  sulcus  on  this  surface  ;  and  the  halves  are  united  by  a  central  con- 
stricted j)art — the  superior  vermiform  process.  Se{)arating  the  upper  from 
the  under  surface,  at  the  circumference,  is  the  horizontal Jiss are,  which  is 
wide  in  front,  and  extends'  backwards  from  the  pons  Varolii  to  the  middle 
line  of  the  cerebellum. 

The  UNDER  SURFACE  is  couvcx,  being  received  into  the  fossae  of  the 
base  of  the  skull,  and  is  divided  into  hemispheres  (fig.  66)  by  a  median 
hollow  (vallecula). 


USDEB  PART  OF  THE  CEREBELLUM,  SEEN   FROM  BEHIND,  THE  MeDPLLA  OBLONOATA,  6, 
BEING  CUT  AWAY  IN  GKEATEH  PAKT. 

a.  Pons  Varolii.  c  to  e.  Inferior  vermiform  process,  consisting 

2/.  Medulla  oblongata,  cat  through.  of;— c.   Uvula,     d.    Pyramid,     e.    Com- 

missural laminae. 
Lobes  of  each  half  of  the  Cerebellum  on  the  Under  Surface. 
/.  Snbpeduncnlar.  k.  Posterior. 

g.  Amygdaloid.  3    Third  nerve  attached  to  the  crus  cerebri. 

h.  Biventral.  6.  Two  roots  of  the  fifth  nerve  attached  to  the 

i.  Slender.  side  of  the  pons  Varolii. 

The  central  jissure,  or  the  vallecula,  is  wider  at  the  middle  than  at  either 
the  anterior  or  the  posterior  end,  and  receives  the  medulla  oblongata.  In 
the  bottom  of  the  fissure  is  a  mass  named  inferior  vermiform  process  (fig. 

66,  c  to  e),  which  corresponds  with  tiie  central  part  connecting  the  halves 
of  the  cerebellum  on  the  upper  surface.  The  two  vermiform  processes 
constitute  the  general  commissure  of  the  halves  of  the  cerebellum. 

Constituents  of  the  vermiform  process.  In  the  inferior  vermiform  pro- 
cess are  the  following  eminences,  which  may  be  easily  separated  from  one 
another  with  the  handle  of  the  scalpel : — Most  anteriorly  is  a  narrow  body, 
the  uvula  (fig.  66,  c),  which  is  named  from  its  resemblance  to  the  same 
])art  in  the  throat  ;  it  is  longer  from  before  backwards  tlian  from  side  to 
side,  and  is  divided  into  laminae.  Its  anterior  projection  into  the  fourth 
ventricle  is  named  nodule^  or  laminated  tubercle  (fig.  67)  ;  and  on  the  side 
is  a  band  of  giay  matter  with  ridges  and  sulci,  the  furrowed  hand.  (fig. 

67,  c?),  wliich  unites  it  with  'the  almond-like  lobe  of  the  hemisphere. 
Connected  with  the  nodule  is  a  thin  white  layer, — the  medullary  velum 


LOBES    OF    THE    CEREBELLUM.  213 

(h)  ;  but  this,  and  the  furrowed  band  will  be  seen  in  a  subsequent  dissec- 
tion (p.  214).  Behind  the  uvula  is  a  tongue-shaped  body,  named  pyramid 
(fig.  66,  </),  which  is  elongated  from  side  to  side,  and  isinarked  by  trans- 
verse laminae.  Further  back  are  certain  transverse  pieces  (e),  extending 
between  the  posterior  lobes  of  the  hemispheres,  of  which  they  were  con- 
sidered by  Reil  to  be  the  commissurf^s. 

Lamince.  The  surface  of  the  cerebellum  is  covered  by  plates  or  laminae 
(fig.  68),  instead  of  convolutions,  which  form  segments  of  circles  with 
tiieir  convexity  directed  backwards.  On  the  upper  aspect  the  anterior 
laminie  pass  from  the  one  hemisphere  to  the  other,  with  only  a  slight 
bending  forwards  in  the  superior  vermiform  process  ;  but  those  on  the 
under  aspect  join  tiie  sides  of  the  different  commissures  in  the  median 
fissure. 

Sulci.  Between  the  laminae  are  sulci,  which  are  lined  by  the  pia  mater, 
and  reach  to  different  depths  :  the  shallower  separate  the  laminae  ;  but  the 
deeper  limit  tlie  lobes,  and  reach  downwards  to  the  white  substance  of  the 
interior.     Here  and  there  the  sulci  are  interrupted  by  cross  laminae. 

Structure  of  the  lamince.  On  cutting  across  the  lamince  of  the  upper 
surface  on  the  right  side  they  will  be  seen  to  possess  a  white  internal,  and 
a  gray  external  layer  (fig.  68).  Tiie  white  part  is  derived  from  a  central 
medullary  mass  ;  and  dividing,  like  the  branching  of  a  tree,  it  ends  in 
small  lateral  offsets  which  enter  the  subdivisions  of  the  lamina?. 

Besides  the  white  stalk  of  the  laminae,  derived  from  the  central  mass, 
there  are  other  white  fibres  which  pass  from  one  lamina  to  another  beneath 
the  sulci. 

The  stratum  of  gray  matter  enveloping  the  white  substance  resembles 
the  cortical  covering  of  the .  convolutions  of  the  cerebrum.  It  is  con- 
structed of  two  strata,  inner  and  outer,  which  can  be  distinguished  by  a 
difference  in  their  color.  The  superficial  stratum  is  clear  gray,  and  about 
equal  to  the  other  in  thickness ;  but  the  deeper  one  is  of  a  rust-color,  and 
is  generally  thickest  in  the  hollows  between  the  laminae.  Between  the 
two  a  layer  of  ramified  cells  (Purkinje)  may  be  recognized  with  the  micro- 
scope. 

Lobes  of  the  Hemisphere.  Each  hemisphere  is  subdivided  into  lobes 
on  both  aspects. 

On  the  upper  surface  there  are  two  lobes,  anterior  and  posterior,  which 
are  separated  by  a  sulcus,  but  the  interval  between  them  is  not  well  marked. 
The  anterior  or  square  lobe  extends  back  to  a  level  with  the  posterior  edge 
of  the  vermiform  process ;  and  the  posterior  reaches  thence  to  the  great 
horizontal  fissure  at  the  circumference. 

On  the  under  surface  of  the  cerebellum  (fig.  66),  there  are  five  lobes ; 
and  three  of  them  are  separated  by  sulci  amongst  the  lamina?  of  the  hemi- 
sphere, but  they  are  scarcely  more  distinct  tlian  the  lobes  on  the  upper 
surface.  Beginning  behind,  the  student  will  meet  first  the  posterior  lobe 
(k),  which  joins  the  commissural  laminae  behind  the  pyramid  in  the  val- 
ley. Next  in  succession  is  the  slender  lobe  (i),  wliich  is  connected  with 
the  posterior  part  of  the  pyramid,  as  well  as  with  the  other  transverse 
lamina?  behind  that  body.  And  lastly,  attached  to  the  side  of  tlie  pyramid, 
is  the  bi ventral  lobe  (h). 

The  two  other  lobes,  though  smaller  are  more  separate,  and  appear  be- 
tween tlie  biventral  lobe  and  the  medulla  oblongata : — One  of  these  is  the 
amygdaloid  lobe  (g),  which  projects  into  the  vallecula  opposite  the  uvula, 
and  touches  the  medulla  oblongata.     The  other  is  a  small  pyramidal  slip, 


2U 


DISSECTION    OF    THE    BRAIN 


which  is  directed  outwards  over  (the  under  surface  of  the  cerebellum  being 
uppermost)  the  crus  cerebelli,  and  is  named  JioccvluSy  or  subpeduncular 
lobe  (/;. 

Dissection.  To  see  the  flocculus  and  the  posterior  medullary  velum, 
the  biventral  and  slender  lobes  are  to  be  sliced  off  on  the  left  side,  so  that 
the  amygdaloid  lobe  may  be  everted  from  the  valley  (fig.  G7).     The  floe- 


Fig.  67. 


View  from  behind  of  the  under  surface  of  the  Cerebellum,  with  some  of  the  lobes 

REMOVED  to  SHOW  THE  POSTERIOR  MEDULLARY  VeLUM. 


a.  Uvula. 

e.  Pyramid. 

&.  Posterior  medullary  velum,  with  a  bit  of 

whalebone  under  it. 
c.  Subpeduncular  lobe  or  flocculus. 


d.  Furrowed  band. 
/.  Amygdaloid  lobe,  turned  aside. 
g.  Medulla  oblongata  raised,  showing  posterior 
surface. 


cuius  is  laid  bare  by  this  proceeding,  and  passing  from  it  to  the  tip  of  the 
uvula  is  the  thin  and  soft  white  layer  of  the  posterior  velum  ;  beneath  the 
last  a  bit  of  paper  may  be  inserted.  The  furrowed  band  on  the  side  of 
the  uvula  can  be  fully  seen  now. 

Flocculvs  and  medullary  velum.  The  position  of  the  flocculus  to  the 
crus  cerebelli  has  been  before  mentioned.  This  body  (c)  resembles  tlie 
other  lobes  in  structure,  and  may  be  considered  a  rudimentary  lobe  ;  for 
it  is  divided  on  the  surface  into  laminae,  and  contains  a  white  medullary 
centre  which  furnishes  offsets  to  the  lamina?. 

Passing  from  the  flocculus  to  the  tip  of  the  inferior  vermiform  process 
(nodule)  is  the  half  of  a  thin  white  layer  (&),  i\\^  posterior  medullary  velum^ 
which  serves  as  a  commissure  to  the  flocculi.  On  each  side  this  band  is 
semilunar  in  form.  Its  anterior  edge  is  free ;  but  its  posterior  border  is 
attached  in  front  of  the  transverse  furrowed  band  {d).  In  front  of  the 
nodule  the  pieces  of  opposite  sides  are  united. 

Interior  of  the  Cerebellum.  In  the  cerebellum  there  is  not  any 
cavity  or  ventricle  inclosed  as  in  the  cerebrum.  In  the  interior  there  is  a 
large  white  centre,  corresponding  with  that  of  the  cerebrum,  which  fur- 
nishes offsets  to  the  laminae,  and  to  other  parts  of  the  encephalon. 

Dissection.  For  the  purpose  of  seeing  the  medullary  centre,  with  its 
contained  corpus  dentatum,  remove  all  the  laminae  from  the  upper  surface 
on  the  left  side.  Tliis  dissection  may  be  accomplished  by  placing  the 
scalpel  in  the  horizontal  fissure  at  the  circumference,  and  carrying  it  in- 
wards as  far  as  the  upper  vermiform  process,  so  as  to  detach  the  cortical 
stratum.  If  tlie  corj)us  dentatum  does  not  at  first  appear,  thin  slices  may 
be  made  anteriorly  till  it  is  reached. 


INTERIOR    OF    CEREBELLUM.  215 

Medullary  Centre.  In  the  centre  of  each  cerebellar  hemisphere  is 
a  large  white  mass,  containing  in  its  substance  a  dentate  body.  From  its 
surface  offsets  are  furnished  to  the  different  laminae.  And  from  the  ante- 
rior part  proceeds  a  large  stalk-like  process,  the  crus  cerebelli,  which  is 
subdivided  into  three  pieces  or  peduncles,  an  upper  for  the  cerebrum,  a 
middle  piece  for  the  pons,  and  a  lower  one  for  the  medulla  oblongata. 

The  superior  peduncle  (processsus  ad  cerebrum)  is  directed  forwards 
towards  the  corpora  quadrigemina  (fig.  65,  ^).  It  is  rather  flattened  in 
shape,  and  forms  part  of  the  roof  of  the  fourth  ventricle  :  between  the  pro- 
cesses of  opposite  sides  the  valve  of  Vieussens  is  situate.  Its  fibres,  con- 
tinuous behind  with  the  inferior  vermiform  process,  receive  an  offset  from 
the  interior  of  the  corpus  dentatum ;  and  passing  beneath  the  band  of  the 
fillet  and  the  pair  of  the  corpora  quadrigemina  of  the  same  side,  enter 
the  optic  thalamus,  and  are  applied  to  the  fibres  of  the  crus  cerebri  (p. 
209). 

Beneath  the  corpora  quadrigemina  the  internal  fibres  of  the  peduncle 
are  directed  across  the  middle  line,  through  the  bundle  prolonged  from  the 
fasciculus  teres.'  In  this  way  the  fibres  of  each  peduncle  end  partly  in 
the  same,  and  partly  in  the  opposite  hemisphere  of  the  cerebrum. 

Between  the  superior  peduncles  is  a  thin,  translucent,  white  layer — the 
imlve  of  Vieussens  (vellum  medullare  anterius),  which  enters  into  the  roof 
of  the  fourth  ventricle  (fig.  68,  k).  It  is  thin  and  pointed  anteriorly,  but 
widens  behind,  where  it  is  connected  with  the  under  part  of  the  vermiform 
process.  Near  the  corpora  quadrigemina  the  fourtli  nerve  (*)  is  attached 
to  the  surface  of  the  valve  ;  and  close  to  the  cerebellum  the  surface  is 
marked  by  some  gray  transverse  ridges. 

The  middle  peduncle  (processus  ad  pontem),  commonly  named  the  crus 
cerebelli  (fig.  65,  ^),  is  the  largest  of  the  three  peduncular  processes.  Its 
fibres  begin  in  the  lateral  part  of  the  cerebellum,  and  are  directed  forwards 
to  the  pons,  of  which  they  form  the  transverse  fibres,  and  unite  with  the 
peduncle  of  the  opposite  side.  This  peduncle  is  supposed  to  serve  as  a 
commissural  or  connecting  band  between  the  halves  of  the  cerebellum. 

The  inferior  peduncle  (fig.  65,  ^)  (processus  ad  medullam)  passes  down- 
wards to  the  medulla  oblongata,  and  gives  rise  to  the  restiform  body.  Its 
fibres  begin  chiefly  in  the  laminae  of  the  upper  surface  of  the  cerebellum. 
It  will  be  better  seen  when  the  fourth  ventricle  has  been  opened. 

The  fibres  in  the  peduncles  connect  one  cerebellar  hemisphere  with  tlie 
cerebrum;  with  its  fellow;  and  with  the  medulla  oblongata  of  the  same 
side,  in  the  manner  mentioned  above. 

The  dentate  body  (corpus  dentatum)  is  contained  in  the  white  mass  of 
the  cerebellum,  and  resembles  the  like  part  in  the  corpus  olivare  of  the 
medulla  oblongata.  This  body  measures  nearly  an  inch  from  before  back, 
and  is  situate  near  the  inner  part  of  the  white  centre.  It  consists  of  a 
small  plicated  capsule,  which,  when  cut  across,  appears  as  a  thin,  wavy, 
grayish-yellow  line ;  the  bag  is  open  at  the  interior  part,  and  incloses  a 
7uicleus  of  whitish  substance.  Through  its  aperture  issues  a  band  of  fibres 
from  the  nucleus  to  join  the  superior  peduncle. 

Dissection.  One  other  section  (fig.  GS)  must  be  made  to  show  the  fourth 
ventricle,  and  the  structure  of  the  vermiform  process.     The  cerebellum  still 

•  This  intercommunication  was  known  to  Reil,  and  was  named  "  ansa"  by  him, 
it  the  decii 
notens:  1846. 


216 


DISSECTION    OF    THE    BRAIN. 


restifjig  on  it>  under  surface,  let  the  knife  be  carried  vertically  through  the 
centre  of  the  vermiform  processes ;  and  then  the  structure  of  the  central 
uniting  part,  as  well  as  the  boundaries  of  the  fourth  ventricle,  may  be 
observed  on  separating  the  halves  of  the  cerebellum. 


Fig.  68. 


View  of  the  Third  and  Fourth  Ventricles. 
The  formpr  being  obtained  by  the  removal  of  the  velum  interpositum  ;  and  the  latter  by  di  vidinjir 
vertically  the  verniilorm  process  of  the  cerebellnm.     (From  a  cast  in  the  Museum  of  University 
College.)     The  third  ventricle  is  the  interval  in  the  middle  Hue  between  the  optic  thalami,  b. 

k.  Valve  of  Vieussens. 


a.  Corpus  striatum. 

b.  Optic  thalamus. 

c.  Anterior  commissure. 

d.  Middle  or  soft  commissure. 
(.  Posterior  commissure. 

g.  Pineal  body. 

/.  Pedunclf  of  the  pineal  body. 
h  and  i.  Left  pair  of  the  corpora  quadrigensina. 
The  fourth  ventricle,  n,  is  at  the  back  of  the 
medulla  oblangata. 


I.  Upper  peduncle  of  ihe  cerebellum, 
o.  Eminentia  teres. 
p.  Anterior  fossa. 
r.  Posterior  fossa. 
*.  Posterior  pyramid. 

4.  Origin  of  the  fourth  nerve  from  the  valve  of 
Vieussens. 


Structure  of  the  vermiform  process  (fig.  68).  The  upper  and  lower 
vermiform  processes  of  the  cerebeJlum  are  united  in  one  central  part,  which 
connects    together   the   hemispheres.     The    structure  of  this   connecting 


FOURTH    VENTRICLE.  217 

piece  is  the  same  as  that  of  the  rest  of  the  cerebellum,  viz.,  a  central  white 
portion  and  investing  laminai.  Here  the  branching  appearance  of  a  tree 
(arbor  vitag)  is  best  seen,  in  consequence  of  the  laminae  being  more  divided, 
and  the  white  central  pieces  being  longer  and  more  ramified. 

The  FOURTH  VENTRICLE  (fossa  rhomboidalis)  is  a  space  between  the 
cerebellum  and  the  posterior  surface  of  the  medulla  oblongata  and  pons 
(fig.  68).  It  has  the  form  of  a  lozenge,  with  the  points  placed  upwards 
and  downwards.  The  upper  angle  reaches  as  high  as  the  upper  border  of 
the  pons;  and  the  lower,  to  a  level  with  the  inferior  end  of  the  olivary 
body.  Its  greatest  breadth  is  opposite  the  lower  edge  of  the  pons;  and  a 
transverse  line  in  this  situation  would  divide  the  hollow  into  two  triangu- 
lar portions — upper  and  lower.  Tlie  lower  half  has  been  named  calamus 
scriptorius  from  its  resemblance  to  a  writing  pen. 

The  lateral  boundaries  are  more  marked  above  than  below.  For  about 
half  way  down,  the  cavity  is  limited  on  each  side  by  the  superior  peduncle 
of  the  cerebellum  (/),  which  projecting  over  it  forms  part  of  the  roof;  and 
along  the  lower  half  lies  the  eminence  of  the  restiform  body  (fig.  66^  ^). 

The  roof  of  the  space  is  somewhat  arched,  and  is  formed  above  by  the 
valve  of  Vieussens  (^),  and  the  under  part  of  the  vermiform  process ;  and 
below,  by  the  reflection  of  the  pia  mater  from  that  process  to  the  spinal 
cord. 

The ^oor  of  the  ventricle  is  constituted  by  the  posterior  surfaces  of  the 
medulla  oblongata  and  [)ons,  and  is  grayish  in  color.  Along  its  centre  is 
a  median  fissure,  which  ends  below,  near  the  point  of  the  calamus,  in  a 
minute  hole — the  aperture  of  the  canal  of  the  cord.  On  each  side  of  the 
groove  is  a  spindle-shaped  elevation,  the  fasciculus  s.  emine7itia  teres  (o). 
This  eminence  reaches  the  whole  length  of  the  floor,  and  is  pointed  and 
little  marked  inferiorly,  where  it  is  covered  by  gray  substance  ;  but  it  be- 
comes whiter  and  more  prominent  superiorly,  and  its  widest  point  is  oppo- 
site the  lower  border  of  the  pons. 

Tlie  outer  border  of  the  eminence  is  limited  externally  by  a  slight 
groove,  which  points  out  the  position  of  two  small  fossae  (fovea  anterior  et 
posterior).  The  posterior  (r)  is  near  the  lower  end  of  the  groove ;  and 
the  anterior  (/>)  is  opposite  the  crus  cerebelli.  Above  the  anterior  fossa 
is  a  deposit  of  very  dark  gray  substance,  which  has  a  bluish  appearance 
as  it  is  seen  througli  the  thin  stratum  covering  it  ;^  from  it  a  bluish  streak 
is  continued  upwards,  at  the  outer  edge  of  the  eminentia  teres,  to  the 
opening  in  the  top  of  the  fourth  ventricle. 

Crossing  the  floor  on  each  side,  opposite  the  lower  border  of  the  pons, 
are  some  white  lines,  which  vary  much  in  their  arrangement  (fig.  55)  : 
they  issue  from  the  central  median  fissure,  and  enter  tlie  auditory  nerve 
(p.  181). 

Besides  the  objects  above  mentioned,  there  are  other  eminences  in  tlie 
floor  of  the  ventricle  indicating  the  position  of  the  nuclei  of  origin  of  cer- 
tain nerves. 

In  the  lower  half  of  the  space  are  three  slight  eminences  on  each  side 
for  the  hypo-glossal,  vagus,  and  auditory  nerves  :  that  for  the  hypo-glossal 
is  close  to  the  middle  line  below,  and  corresponds  with  the  lower  pointed 
end  of  the  eminentia  teres.  The  other  two,  outside  that  eminence,  are 
placed  in  a  line  one  above  another,  but  separated  by  a  well-marked  groove 

'  Tlie  term  locus  csruleus  lias  been  applied  to  the  spot,  and  the  dark  vesicular 
matter  in  it  has  been  named  substantia  ftrriujinea. 


218  DISSECTION    OF    THE    BRAIN. 

(fovea  posterior)  ;  the  lower  is  tlie  nucleus  of  the  vagus  and  glosso-pharyn- 
geal  nerves,  and  the  upper  is  the  nucleus  of  the  auditory  nerve.  Running 
into  the  lower  part  of  the  vagus  nucleus,  is  the  nucleus  of  the  accessory 
portion  of  the  spinal  accessory  nerve.     (See  p.  189.) 

In  the  upper  half  of  the  space  some  other  nerves  take  origin  from  nu- 
clei, but  there  is  only  one  projection.  This  is  placed  over  the  common 
nucleus  of  the  sixth  and  the  facial  nerve  :  it  is  a  rounded  elevation  on  tlie 
outer  part  of  the  eminentia  teres,  about  a  line  above  the  white  cross  striae 
on  the  floor,  and  close  behind  the  fovea  anterior. 

The  fourth  ventricle  communicates  at  the  upper  part  with  the  third 
ventricle  through  tlie  Sylvian  aqueduct ;  and  with  the  subarachnoid  space 
of  the  cord  and  brain,  through  an  aperture  in  tlie  pia  mater  intervening 
between  the  medulla  and  the  cerebellum:  laterally,  the  ventricular  space 
is  extended  for  a  short  distance  between  the  cerebellum  and  the  side  of 
the  medulla  oblongata. 

The  lining  of  the  other  ventricles  is  prolonged  into  this  by  the  aperture 
of  communication  with  the  third.  Covering  the  floor  is  a  columnar  epi- 
thelium, which  is  continuous  with  that  in  the  upper  part  of  the  central 
canal  of  the  spinal  cord  (Clarke). 

In  this  ventricle  is  a  vascular  fold — choroid  plexus,  on  each  side,  simi- 
lar to  the  body  of  the  same  name  in  the  other  ventricles.  It  is  attached 
to  the  inner  surface  of  the  membrane  (pia  mater)  which  closes  the  ventricle 
between  the  medulla  and  the  cerebellum,  and  it  extends  upwards  on  the 
side  of  the  opening  into  the  sub-arachnoid  space.  Its  vessels  are  supplied 
by  the  inferior  cerebellar  artery. 

Gray  matter  of  fourth  ventricle.  The  gray  matter  forms  a  surface- 
covering  for  the  floor  of  the  fourth  ventricle.  It  is  continuous  below  with 
the  gray  commissure  of  the  cord,  and  extends  upwards  to  the  aqueduct  of 
Sylvius  (p.  187).  The  special  nuclei  have  been  referred  to  already 
(p.  217). 


ARTERIES  OF  THE  HEAD  AND  NECK, 


219 


TABLE  OF  THE  CHIEF  ARTERIES  OF  THE  HEAD  AND  NECK, 


1.  Common  < 
carotid 


5-1 


1.  Brachio-j; 
cephalic. 


Hyoid  branch 

1.  Superior  thyroid  . 

laryngeal 
thyroid. 

2.  lingual  . 

Hyoid  branch 

dorsal  lingual 

sublingual 

ranine. 

'Inferior  palatine  branch 

tonsil  litic 

glandular 

submental 

3.  facial      .        ,        ,        .- 

inferior  labial 

^  inferior 
coronary  .       .  J  ^^^^,i^,. 

1 

lateral  nasal 

^angular. 

4.  occipital 

1 

Meningeal  branch 
posterior  cervical. 
Stylo-mastoid  branch 

1.  External 

5.  posterior  auricular 

auricular 

carotid  .  -^ 

mastoid. 

6.  ascending  pharyngeal. 

Pharyngeal  branches 

meningeal. 

Auricular 

parotid 

articular 

7.  temporal 

transverse  facial 
middle  temporal 
anterior  temporal 
.posterior  temporal. 
Inferior  dental 
middle  meningeal 
muscular 
posterior  dental 

8.  internal  maxillary 

infraorbital 
spheno-palatine 
descending  palatine 
vidian 

pterygo-palatine. 

n  Arteriffi  receptaculi. 

Lachrymal 

supraorbital 

central  of  the  retina 

ciliary 

2.  ophthalmic     . 

muscular 
ethmoidal 

2.  internal  - 

1 

palpebral 

carotid  . 

3.  antero  cerebral 

4.  anterior  communicating 

5.  middle  cerebral 

6.  posterior  commuuicatin 
L7.  choroid. 

frontal 
.^nasal. 

s 

1.  Vertebral 


2.  subcli 
•  vian  . 


2.  left  common  carotid. 
^3.  left  subclavian. 


2.  internal 
mammary 

3.  thyroid 
axis  .     . 


4,  superior 
intercostal 


Anterior  spinal 
posterior  spinal 
inferior  cerebellar 
posterior  meningeal 
transverse  basilar 
anterior  inferior  cerebellar 
superior  cerebellar 
[^posterior  cerebral. 


r  Infra  thyroid 
■^  suprascapular  . 

[^transverse  cervical 
)  Deep  cervical. 


.    Ascending  cervical. 

i  Supraspinal 
infraspinal. 
i  Superficial  cervical 
posterior  scapular. 


220 


VEINS    OF    THE    HEAD    AND    NECK. 


TABLE  OF  THE  CHIEF  VEINS  OF  THE  HEAD  AND  NECK. 


'1.  Lateral  sinus 


2.  ascending 
pliaiyugeal. 


Brachio-ce- 
jihalic  is 
formed  ly 
tlie  union 
of 


Internal  ju- 
gular .     . 


3.  lingual 


4.  facial 


f  Superior  longitudinal 

i      sinus 
inferior  longitudinal 
sinus 
■{  straight  sinus 
occipital  sinuses 
oplitlialmic  ven 
superior  petrosal 
^inferior  petrosal. 

J  Meningeal  branches 
(  pharyngeal. 

(  Supprflcial  dorsal 
<  lingual 
(  ranine. 


Angular    . 

inferior  palpebral 

dorsal  and  lateral 
nasal  veins. 


anterior  internal  maxil- 
laiy 


Supraorbital 
frontal 
palpebral 
nasal. 


C  Alveolar  branches 
I  infraorbital 
-{  descending  palatine 

uaso-palatiue 
Lvidlan. 


a.  occipital 


coronary 

buccal 
masseteric 
lal>ial 
submental 
inferior  palatine 
tonsillitic 
-glandular. 

Mastoid  vein 
cervical. 


superior 
inferior 


superior  thyroid    \  Thyroid 

(  laryngeal. 


7.  middle  thyroid 


fl.  Vertebral   . 


(  Spinal 
<  deep  ce 
(  ascendi 


ervical 
ng  cervical. 


fl.  Internal  maxillary 


Hubclavian  -i  2.  external  jugular 


_8.  anterior  jugular    |^ 


2.  temporal 


3.  posterior  auricular 

4.  branch  to  the  internal 

jugular. 

o.  suprascapular 
transverse  cervical 


("Middle  meningeal 
I  inferior  dental 
■i  deep  temporal 

pterygoid 
^masseteric. 

{Anterior 
posterior 
middle  temporal 
parotid 
anterior  auricular 
transverse  facial. 

J.\uricalar 
Stylo-mas  told. 


<  Supraspinal 
I  infraspinal. 

J  Superficial  cervical 
posterior  scapular. 


CRANIAL  NERVES  OF  THE  HEAD  AND  NECK 


221 


TABLE    OF    THE    CRANIAL    NERVES. 


1.  First  nerve  . 

2.  Second  nerve 

3.  Third  nerve 

4.  Fourth  nerve 


Filaments  to  the  nose. 
To  retina  of  the  eyeball. 
To  muscles  of  the  orbit. 
To  superior  oblique  muscle. 

f  Meningeal 


6.  Fifth  or 
tri-facial 


lachrymal 

<  Lachrymal 
•  (  palbebral. 

Ophthalmic      ., 

f.ontal     . 

Supraorbital 
•  (  supratrochlear. 

rTo  lenticular  ganglion 

J  ciliary  nerves 

.nasal 

•    j  infratrochlear 

l^nasal. 

ophthalmic  or    (  Connecting  branches 

1  To  nasal  nerve 

lenticular 

■  to  the  third  nerve 

ganglion.     .. ' 

1  to  sympathetic. 

ciliary  nerves. 

r  Orbital  branch      . 

(>  Malar 
•  I  temporal. 

superior    max-J  to  Meckel's  ganglion 

illary    .        .  ]  posterior  dental 

anterior  dental 

"-  infraorbital 

Internal  branches 

J  Nasal 
•  (  nasopalatine. 

ascsndiug 

.    To  the  orbit. 

Meckel's  gang- 

lion 

(  Anterior  palatine 

descending 

.  <  posterior 

(  external. 

J  Vidian 
'  I  pharyngeal. 

^posterior 

inferior  maxil- 
lary 


TDeep  temporal 
„       ,,  ,  ^      masseteric 

Small  or  muscular  part  <  jj^cc^l 

[^pterygoid. 


Auriculo- temporal 


Jarge  or  sensory  part 


otic  ganglion     (  Connecting  branches 
(  branches  for  muscles. 

Connecting  bran'hes 

branches    to    the 

submaxillary   J       glands  and  the 

ganglion       .1       mucous     rae-n- 

brane     of     the 

t_     mouth. 


gustatory 


^inferior  dental 


f  Articular  and  to 
I      meatus 
-j  parotid 
I  auricular 
(^temporal. 

f  To  submaxillary 
I      and  sublingual 
•\      ganglia 
I  to  hypoglossal 
l_to  the  tongue. 

Mylo-hyoid 

labial 

incisor. 


To    Jacobson's    uprve 
the  fifth  and  sym- 
pathetic. 

To  the  gustatory, 
chorda  tyini)ani,  and 
sympathetic. 


222 


CRANIAL  NERVES  OF  THE  HEAD  AND  NECK, 


TABLE  OF  CRANIAL  NERVES — Continued, 


6.  Sixth  nerve 


.     To  external  rectus. 


f  Connecting 
branches 


7.  Snventh  nerve,  or  facial     -( 


Branches  for 
L     distribution 


S.  Ei^'hth  nerve,  or  auditory 


f  Connecting' 
branches 


Ninth    nerve,    or    glosso-  ' 
pharyngeal      .        .        .  j 


'  Connecting 
branches! 


10.  Tenth  nerve,  or  pneumo- 
gastric 


11.  Eleventh  nerve,  or  spinal 

accessory         .        •        .j  Branches  for 
(^      distrlliUtioii 


'  Connecting 
branches 


12.  Twelfth  nerve,  lingual  or ^ 
hypoglossal     . 


Branches  for 
\^      distribution 


To  join  auditory 
to  Meckel's  ganglion 
tympanic  and  sym- 
pathetic nerves 
the  chorda  tympani 


f  Posterior  auricular 
diirastric  branch 
Btylo-hyoid  branch 

■\  temporo-facial    . 


(^  cervlco-facial     . 
To  the  portio  dura 


rTol 
I  ner 

l^  nerve 


ve  to  cochlea. 


to  vestibule 


(Temporal 
malar 
infraorbital. 

r  Buccal 
,\  supramaxillary 
(inframaxillary. 


To  the  common  sac 
to  the  saccule 
to  the  semicircular 
canals. 


B-anches  for 
distribution 


To  vagus 

to  sympathetic. 

Jacobson's  nerve 

■  To  carotid  artery 
to  the  pharynx 
tonsillitic  branches 
muscular 
lingual. 

To  glosso-pharyngeal 
sympathetic  and   au- 
ricular nerves 
To  the  hypoglossal.    • 

("Pharyngeal  nerve. 


Joins  otic  ganglion, 
supplies  tympanum. 


■I 


Branches  for 
distiibution 


Connecting 
branchei 


superior  laryngeal 


cardiac  nerves. 


inferior  laryngeal 


f External  laryngeal 
ascending    ^  to  the 
\  ,  -..      { mucous 

.-j  descending  ^„e,„brane 
I  to  join  the  inferior  lar- 
[    yngeal. 

Cardiac 

ocsophaireal,  tracheal  to 
constrictor  and  mus- 
es of  larynx 
in  superior  laryn- 
geal. 


"I      cle.« 

to  joi 

L     gea 


J  To  pneumo-gastric 
\  to  the  cervical  plexus. 

<  To  sterno-mastoideus 
\     and  trapezius. 

r  To   the    pneumo-gas- 
(       trie  nerve 
4^  lo  the  sympathetic 
I  to  loop  of  atlas 
1^  to  gustatory  nerve. 

("descendens  noni 
J  thyro-hyoid  nerve 
i  to   the   lingual  mus- 

^_     clcB  and  tongue. 


SPINAL    AND    SYMPATHETIC    NERVES, 


223 


TABLE  OF  THE  SPINAL  AND  SYMPATHETIC  NERVES  OF  THE  HEAD  AND 

NECK. 


Spinal  Nerves. 


Superficial 
ascendiug 


/The  first  four  form 
tlie  Cervical  / 
Plkxcs,  which  \ 
gives 


/Anterior 
branches    ( 


superficial 
descending 


deep  internal 


C  Small  occipital  nerve 

<  great  auricular 

(  superficial  cervical. 

£  Supraacromial 

<  supraclavicular 
(  suprasternal. 

fTo  the  pneumo-gastric 
I  to  the  hypoglossal 
-{  to  the  sympathetic 
I  to  join  the  spinal  accessory 
I  nerves  to  descendens  noni. 


\deep  muscular 


The  cervical 
spinal  / 
nerves  ( 
divide  \ 
into 


•1 


posterior 
,    branches 


To  rectus  muscles 

to  diaphragm 

to  the  sterno-mastoideus 

to  the  trapezius 

to  the  levator  anguli  sch  pulse. 

The  rhomboid  nerve 
r-Rvart^'haa  oV./^»Ta  I  to  the  plirenic  nerve 
The  last  four  and      ^  ,tn  „io .  f  iL      J  suprascapular  nerve 
part  of  first  dor-        ^^^  ciavicie    .  -i  gu^clavian  branch 
sal  form  the        J  |  posterior  thoracic 

Brachial  j  (^to  the  scaleni  muscles. 

Plexus,  which 

«i^««  •        •        •  Lbranches  below  \  ^'it^jf;'"*''^  "^'^^  *^'  "P^"' 

Are  distributed  to 
the  muscles  of 
the  back,  and 
give  ofl"  cuta- 
neous nerves. 


Sympathetic  Nerve. 


''Ascending  branches, 
which  unite  in 
plexuses 


/I.  Superior 
cervical 
ganglion  > 


E 


2.  Middle 
cervical 
ganglion 


3.  Inferior 
cervical 
ganglion 


external  branches 

Internal  branches 

branches  to  vessels 
External  branches 


i; 


nternal    . 
f  Anterior  branches 
I  external    . 
internal     . 


'Carotid  plexus,  wh'ch 
gives 


Cavernous  plexus, 
which  gives 
branches  . 


J  to 


Branch  to  tympanic  plexus 
the  vidian 

the  sixth  and  fifth  cranial 
nerves. 


rTo  the  third  cranial  nerve 
I  to  the  fourth  cranial  nerve 

J  to  the  fifth  and  lenticular  gang- 

1      lion. 

to     the     carotid     artery    and 
I      branches. 


!To  join  pneumo-ga'^trlc  and 
hypoglossal  nerves 
to  tne  spinal  nerves, 

\  Pharyngeal  branches 
(  superficial  cardiac  nerve. 

Nervl  iTiolles. 

To  the  spinal  nerves. 

I  Middle  cardiac  nerve 

i  to  supply  thyroid  body  and 

(     join  the  external  laryngeal. 

To  the  subclavian  artery. 

J  To  the  spinal  nerves  forming 
(     vertebral  plexus. 


Inferior  cardiac  norve. 


224  DISSECTION    OF    THE    UPPER    LIMB. 


CHAPTEE  in. 

DISSECTION  OF  THE  UPPER  LIMB. 


Section  I. 

THE  WALL  OF  THE  THORAX  AND  THE  AXILLA. 

The  parts  included  in  this  section,  viz.,  the  wall  of  the  chest  and  the 
axilla,  are  to  be  learnt  within  a  fixed  time,  in  order  that  the  examination 
of  the  thorax  may  be  undertaken.  Whilst  the  dissection  of  the  thorax 
is  in  progress,  the  student  will  have  to  discontinue  his  labors  on  the  upper 
limb;  but,  on  the  completion  of  that  cavity,  he  must  be  ready  to  begin 
the  part  of  the  Back  that  belongs  to  him. 

Position.  Whilst  the  body  lies  on  the  Back,  the  thorax  is  to  be  raised 
to  a  convenient  height  by  a  block  ;  and  the  arm,  being  slightly  rotated 
outwards,  is  to  be  placed  at  a  right  angle  to  the  trunk. 

Directions.  Before  the  dissection  is  entered  on,  attention  should  be 
given  to  the  depressions  on  the  surface,  to  the  prominences  of  muscles, 
and  to  the  projections  of  the  bones ;  because  these  serve  as  guides  to  the 
position  of  parts  beneath  the  skin. 

Surface-marking.  Between  the  arm  and  the  chest  is  the  hollow  of 
the  arm-pit,  in  wliich  the  large  vessels  and  nerves  of  the  limb  are  lodged. 
The  extent  of  this  hollow  may  be  seen  to  vary  much  with  the  position  of 
the  limb  to  the  trunk  ;  for  in  proportion  as  the  arm  is  elevated,  the  fore 
and  hinder  boundaries  are  carried  upwards  and  rendered  tense,  and  the 
depth  of  the  space  is  diminished.  In  this  spot  the  skin  is  of  a  dark  color, 
and  is  furnished  with  hairs  and  large  sweat  glands. 

If  the  arm  is  forcibly  raised  and  moved  in  different  directions,  whilst 
the  fingers  of  one  hand  are  placed  in  the  arm-pit,  the  head  of  the  humerus 
may  be  recognized. 

On  the  outer  side  of  tlie  limb  is  the  prominence  of  the  shoulder ;  and 
immediately  above  it  is  an  osseous  arch,  which  is  formed  internally  by  the 
clavicle,  and  externally  by  the  spine  and  the  acromion  process  of  the 
scapula.  Continued  downwards  from  about  the  middle  of  the  clavicle,  is 
a  slight  depression  between  the  pectoral  and  deltoid  muscles,  in  which  the 
coracoid  process  can  be  felt  near  that  bone.  A  second  groove,  extending 
outwards  from  the  sternal  end  of  the  clavicle,  corresponds  with  the  inter- 
val between  the  clavicular  and  sternal  origin  of  the  great  pectoral  muscle. 

Along  the  front  of  the  arm  is  the  prominence  of  the  bice})S  muscle  ;  and 
on  each  side  of  that  eminence  is  a  groove,  which  subsides  inferiorly  in  a 
depression  in  front  of  the  elbow-joint.  The  inner  of  the  two  grooves,  the 
deepest,  indicates  the  position  of  the  brachial  vessels. 

If  the  elbow  joint  be  semiflexed,  the  prominences  of  the  outer  and  inner 
condyles   of  the  humerus  will  be  rendered  evident,  especially  the  inner. 


PARTS  ON  FRONT  OF  THORAX.  225 

Below  the  outer  condyle,  and  separated  from  it  by  a  slight  interval,  the 
head  of  the  radius  projects  ;  it  may  be  recognized  by  rotating  the  bone, 
the  fingers  at  the  same  time  being  placed  over  it.  At  the  back  of  the 
articulation  is  the  prominence  of  the  olecranon. 

Dissection.  As  the  first  step  in  the  dissection,  raise  the  skin  from  the 
side  of  the  chest  and  the  arm-pit,  over  the  great  pectoral  muscle  and  the 
hollow  of  the  axilla,  by  means  of  the  following  incisions : — One  is  to  be 
made  along  the  middle  of  the  sternum.  A  second,  carried  along  the  cla- 
vicle for  the  inner  two-thirds  of  that  bone,  is  to  be  continued  down  the 
front  of  the  arm  rather  beyond  the  anterior  fold  of  the  arm-pit,  and  then 
to  be  turned  across  the  inner  surface  of  the  arm  as  far  as  the  hinder  fold 
of  the  axilla.  From  the  xiphoid  cartilage  a  third  cut  is  to  be  directed 
outwards  over  the  side  of  the  chest,  as  far  back  as  to  a  level  with  the  pos- 
terior fold  of  the  arm-pit. 

The  flap  of  skin  now  marked  out  should  be  reflected  outwards  beyond 
the  axilla ;  but  it  should  be  left  attached  to  the  body,  in  order  that  it 
may  be  used  afterwards  for  the  preservation  of  the  part. 

The  subcutaneous  fatty  layer  of  the  thorax  resembles  the  same  structure 
in  other  parts  of  the  body;  but  in  this  region  it  does  not  contain  much  fat. 

Beneath  the  subcutaneous  layer  is  a  deeper  and  stronger  special  fascia 
which  closely  invests  the  muscles,  and  is  continuous  with  the  deep  fascia 
of  the  arm.  It  is  thin  on  the  side  of  the  chest,  but  becomes  much  thicker 
where  it  is  stretched  across  the  axilla.  An  incision  through  it,  over  the 
arm-pit,  will  render  evident  its  increased  strength  in  this  situation,  and 
the  casing  it  gives  to  the  muscles  bounding  the  axilla ;  and  if  the  fore 
finger  be  introduced  through  the  opening,  some  idea  will  be  gained  of  its 
capability  of  confining  an  abscess  in  that  hollow. 

Dissection.  The  cutaneous  nerves  of  the  side  of  the  chest  are  to  be 
next  sought.  At  the  spots  where  they  are  to  be  found  they  are  placed 
beneath  the  fat,  so  that  the  student  must  cut  through  it ;  and  those  on  the 
clavicle  lie  also  beneath  the  platysma  muscle.  Small  vessels  will  indicate 
the  position  of  the  nerves. 

Some  of  them  (from  the  cervical  plexus)  cross  the  clavicle  at  the  middle, 
and  the  inner  part.  Others  (anterior  cutaneous  of  the  thorax)  appear  at 
the  side  of  the  sternum — one  from  each  intercostal  space.  And  the  rest 
(lateral  cutaneous  of  the  thorax)  should  be  looked  for  along  the  side  of  the 
chest,  about  one  inch  below  the  anterior  fold  of  the  axilla,  there  being  one 
from  each  intercostal  space  except  the  first :  as  the  last-mentioned  nerves 
pierce  the  wall  of  the  thorax,  they  divide  into  an  anterior  and  a  posterior 
piece. 

The  posterior  pieces  of  the  highest  two  nerves  are  larger  than  the  rest. 
They  are  to  be  followed  across  the  arm-pit,  and  a  junction  is  to  be  found 
there  with  a  branch  (nerve  of  Wrisberg)  of  the  brachial  plexus. 

Cutaneous  nerves  of  the  cervical  plexus.  These  cross  the  clavicle  and 
are  distributed  to  the  integuments  over  the  pectoral  muscle.  The  most 
internal  branch  (sternal)  lies  near  the  inner  end  of  the  bone,  and  reaches 
but  a  short  distance  below  it.  Other  branches  (clavicular),  two  or  more 
in  number  and  larger  in  size,  cross  the  centre  of  the  clavicle  and  extend 
to  near  the  lower  border  of  the  pectoralis  major ;  they  join  one  or  more  of 
the  anterior  cutaneous  nerves  of  the  thorax. 

The  cutaneous  nerves  of  the  thorax  are  derived  from  the  trunks  of  the 
intercostal  nerves  between  the  ribs  (fig.  69).  Of  these  there  are  two 
sets :  One  set,  lateral  cutaneous  nerves  of  the  thorax,  arise  from  the 
15 


226  DISSECTION    OF    THE    UPPER    LIMB. 

trunks  of  the  nerves  about  midway  between  the  spine  and  the  sternum. 
The  other  set,  anterior  cutaneous  nerves  of  tlie  tliorax,  are  the  termina- 
tions of  the  same  intercostal  trunks  at  the  middle  line  of  the  body. 

The  anterior  cutaneous  nerves  [)iercinji  the  pectoral  muscle,  are  directed 
outwards  in  the  integuments  as  slender  filaments.  The  offset  of  the  second 
nerve  joins  a  cutaneous  branch  of  the  cervical  plexus ;  and  the  others 
supply  the  intejruments  and  the  mammary  gland.  Small  cutaneous 
branches  of  the  internal  mammary  vessels  accompany  the  nerves. 

The  lateral  cutaneous  nerves  (fig.  G9)  issue  with  companion  vessels 
between  the  digitations  of  the  seratus  muscle,  and  divide  into  an  anterior 
and  a  posterior  piece.  There  is  not  usually  any  lateral  cutaneous  nerve 
to  the  first  intercostal  trunk. 

The  anterior  offsets  {^)  bend  over  the  pectoral  muscle,  and  end  in  the 
integuments  and  the  mammary  gland:  they  increase  in  size  downwards, 
and  the  lowest  give  twigs  to  the  digitations  of  the  external  oblique  muscle. 
The  cutaneous  nerve  of  the  second  intercostal  trunk  wants  commonly  the 
antt^rior  offset. 

The  posterior  offsets  (®)  end  in  the  integuments  over  the  latissimus 
dorsi  muscle  and  the  back  of  the  scapula,  and  decrease  in  size  from  above 
down. 

The  branch  of  the  second  intercostal  nerve  is  larger  than  the  rest,  and 
perforates  the  fascia  of  the  axilla  ;  it  supplies  the  integument  of  the  arm 
(p.  251),  and  is  named  intercosto-humeral.  As  it  crosses  the  axilla  it  is 
divided  into  two  or  more  pieces,  and  is  connected  to  the  nerve  of  Wris- 
berg  (^)  by  a  filament  of  variable  size. 

The  branch  of  the  third  intercostal  gives  filaments  likewise  to  the  arm- 
pit and  the  inner  part  of  the  arm. 

The  MAMMA  is  the  gland  for  the  secretion  of  the  milk,  and  is  situate  on 
the  lateral  aspect  of  the  fore  part  of  the  chest.^ 

Resting  on  the  great  pectoral  muscle,  it  is  hemispherical  in  form,  but  it 
is  rather  most  prominent  at  the  inner  and  lower  aspects.  Its  dimensions 
and  weight  vary  greatly.  In  a  breast  not  enlarged  by  lactation,  the  width 
is  commonly  about  four  inches.  Longitudinally  it  extends  from  the  third 
to  the  sixth  or  seventh  rib,  and  transversely  from  the  side  of  the  sternum 
to  the  axilla.  Its  thickness  is  about  one  inch  and  a  half.  The  weight  of 
the  mamma  ranges  from  six  to  eight  ounces. 

Nearly  in  the  centre  of  the  gland  (rather  to  the  inner  side)  rises  the 
conical  or  cylindrical  projection  of  the  nipple  or  mamilla.  This  promi- 
nence is  about  half  an  inch  or  rather  more  in  length,  is  slightly  turned 
outwards,  and  presents  in  the  centre  a  shallow  depression,  where  it  is 
rather  redder.  Around  the  nipple  is  a  colored  ring, — the  areola,  about 
an  inch  in  width,  whose  tint  is  influenced  by  the  complexion  of  the  body, 
and  is  altered  during  the  times  of  menstruation,  pregnancy,  and  lactation. 
The  skin  of  the  nii)[)le  and  areola  is  {)rovided  with  numerous  papillae  and 
lubricating  glands  ;  and  on  the  surface  are  some  small  tubercles  marking 
the  position  of  the  ducts  of  the  glands. 

In  the  male  the  mammary  gland  resembles  that  of  the  female  in  general 
form,  though  it  is  less  prominent;  and  it  possesses  a  small  nij)ple,  which 
is  surrounded  by  an  areola  provided  with  hairs.  The  glandular  or  secre- 
tory structure  is  imperfect. 

'  If  the  8tufl<!nt  has  a  malo  body,  he  may  disrogard  the  description  of  tlie 
mamma ;  and  if  th<>  body  is  a  female,  he  may  set  aside  the  breast  for  a  more  con- 
venient examination  of  its  structure. 


MAMMARY    GLAND.  227 

Structure.  In  its  texture  the  mamma  resembles  those  compound  glands 
which  are  formed  by  the  vesicular  endings  of  branched  ducts.  It  consists 
of  small  vesicles  which  are  united  to  form  lobules  and  lobes.  Connected 
with  each  lobe  is  an  excretory  or  lactiferous  duct. 

A  layer  of  areolar  tissue,  containing  fat,  surrounds  the  gland,  and 
penetrates  into  the  interior,  subdiving  it  into  lobes ;  but  in  the  ultimate 
structure  of  the  gland,  and  in  the  nipple  and  areola,  there  is  not  any  fatty 
substance.  Some  fibrous  septa  fix  the  gland  to  the  skin,  and  support  it ; 
these  are  the  ligamenta  suspensoria  of  Sir  A.  Cooper. 

Vesicles,  The  little  vesicles  or  cells  at  the  ends  of  the  most  minute 
ducts  are  rounded  in  shape,  and  when  filled  with  milk  or  mercury  are  just 
visible  to  the  naked  eye,  being  about  the  size  of  a  small  pinliole  in  paper. 
(Cooper.)     Each  is  surrounded  externally  by  a  close  vascular  network. 

Lobules  and  lobes.  A  collection  of  the  vesicles  around  their  ducts  form 
the  lobule  or  glandule,  which  varies  in  size  from  a  pin's  head  to  a  small 
tare.  By  the  union  of  the  lobules  the  lobes  are  produced,  of  whicli  there 
are  about  twenty  altogether,  and  each  is  provided  with  a  distinct  duct. 

The  duds  issuing  from  the  several  lobes  (about  twenty)  are  named  from 
their  office  galactophorus;  they  converge  to  the  areola,  where  they  swell 
into  oblong  dilations  or  reservoirs  (sacculi)  of  one-sixth  to  one-third  of  an 
inch  in  width.  Onwards  from  that  spot  the  ducts  become  straight ;  and, 
surrounded  by  areolar  tissue  and  vessels,  are  continued  through  the  nipple, 
nearly  parallel  to  one  another,  and  gradually  narrowing  in  size,  to  open  on 
the  summit  by  apertures  varying  from  the  size  of  a  bristle  to  that  of  a 
common  pin. 

Like  many  other  excretory  ducts,  the  milk  tubes  consist  of  an  external 
or  fibrous,  and  of  an  internal  or  mucous  coat ;  they  and  the  vesicles  are 
sheathed  by  a  columnar  epitlielium,  which  becomes  flattened  towards  the 
outer  opening. 

Beneath  the  skin  of  the  nipple  and  areola-  are  branched  lubricating 
glands,  which  open  on  the  tubercles  before  mentioned. 

Bloodvefiseh. — The  arteries  are  supplied  by  the  axillary,  internal  mammary,  and 
intercostal,  and  enter  both  surfaces  of  the  gland.  The  veins  end  principally  in 
the  axillary  and  internal  mammary  trunks  ;  but  others  enter  the  intercostal  veins. 

The  nerves  are  supplied  from  the  anterior  and  lateral  cutaneous  branches  of  the 
thorax,  viz.,  from  the  third,  fourth,  and  fifth  intercostal  nerves. 

The  lymphatics  of  the  inner  side  open  into  the  anterior  mediastinal  glands  ;  but 
on  the  outer  side  they  reach  the  axillary  glands. 

Dissection  (fig.  69).  With  the  limb  in  the  same  position  to  the  trunk, 
the  student  is  first  to  remove  the  fascia  and  the  fat  from  the  surface  of  the 
great  pectoral  muscle.  In  cleaning  the  muscle  the  scalpel  should  be  car- 
ried in  the  direction  of  the  fibres,  viz.,  from  the  arm  to  thorax  ;  and  the 
dissection  may  be  begun  at  the  lower  border  on  the  right  side,  and  at  the 
upper  border  on  the  left  side. 

The  fascia  and  tlie  fat  are  to  be  taken  from  the  axilla,  without  injury 
to  the  numerous  vessels,  nerves,  and  glands  in  the  space.  The  dissection 
will  be  best  executed  by  cleaning  first  the  large  axillary  vessels  at  the  outer 
part,  where  these  are  about  to  enter  the  arm  :  and  then  following  their 
branches  which  are  directed  to  the  chest,  viz.,  the  long  thoracic  under 
cover  of  the  anterior  boundary,  and  the  circumflex  and  subscapular  vessels 
and  nerves  along  the  posterior  boundary.  Some  arterial  twigs  entering 
the  axillary  glands  should  be  traced  out. 

In  taking  away  the  fascia  and  fat  from   the   muscles  in   the  posterior 


228  DISSECTION    OF    THE    UPPER    LIMB. 

boundary  of  the  space,  the  small  internal  cutaneous  nerve  of  the  musculo- 
spiral  should  be  looked  for  near  the  great  vessels. 

The  large  nerves  of  the  brachial  plexus  are  then  to  be  defined.  The 
smallest  of  these,  which  possibly  may  be  destroyed,  is  the  nerve  of  Wris- 
berg :  it  lies  close  to  the  hinder  edge  of  the  axillary  vein,  and  joins  with 
the  intercosto-humeral  nerve. 

When  cleaning  the  serratus  muscle  on  the  ribs  the  student  is  to  seek 
on  its  surface  the  posterior  thoracic  nerve ;  and  to  trace  the  posterior  off- 
sets of  the  intercostal  nerves  crossing  the  axilla. 

THE  AXILLA. 

The  axilla  is  the  hollow  between  the  arm  and  the  chest  (fig.  69).  It  is 
somewhat  pyramidal  in  form,  and  its  apex  is  directed  upwards  to  the  root 
of  the  neck.  The  space  is  larger  near  the  thorax  than  at  the  arm,  and  its 
boundaries  are  as  follows  : — 

Boundaries.  In  front  and  behind  the  space  is  limited  by  folds,  which  are 
constructed  by  the  muscles  passing  from  the  trunk  to  the  upper  limb.  In 
the  anterior  fold  are  the  two  pectoral  muscles,  but  these  take  unequal  shares 
in  its  construction,  in  consequence  of  the  difference  in  their  size  and  shape : — 
thus  the  pectoralis  major  a  extends  over  the  whole  front  of  the  space, 
reaching  from  the  clavicle  to  the  lower  edge  of  the  anterior  fold ;  whilst 
the  pectoralis  minor  b,  which  is  a  narrow  muscle,  corresponds  only  with 
the  middle  third  of  the  space.  In  the  posterior  boundary,  from  above  down- 
wards, lie  the  subscapularis  f,  the  latissimus  dorsi  muscle  d,  and  the  teres 
major  e  :  this  boundary  reaches  further  out  than  the  anterior,  especially 
near  the  humerus  ;  and  its  lower  margin,  which  is  formed  by  the  latissimus 
dorsi,  projects  forwards  beyond  the  level  of  the  subscapularis. 

On  the  inner  side  of  the  axilla  lie  the  first  four  ribs,  with  their  inter- 
vening intercostal  muscles,  and  the  part  of  the  serratus  magnus  c  taking 
origin  from  those  bones.  On  the  outer  side  the  space  has  but  small  di- 
mensions, and  is  limited  by  the  humerus  and  the  coraco-brachialis  and 
biceps  muscles  (g  and  ii). 

The  apex  of  the  hollow  is  situate  between  the  clavicle,  the  upper  mar- 
gin of  the  scapula,  and  the  first  rib;  and  the  forefinger  may  be  introduced 
into  the  space  for  the  purpose  of  ascertaining  the  upper  boundaries,  and 
the  depth.  The  base  or  widest  part  of  the  pyramid  is  turned  downwards, 
and  is  closed  by  the  thick  aponeurosis  reaching  from  the  anterior  to  the 
posterior  fold. 

Contents  of  the  space.  In  the  axilla  are  contained  the  axillary  vessels 
and  the  brachial  plexus,  with  their  branches ;  some  branches  of  tlie  inter- 
costal nerves  ;  together  with  lymphatic  glands,  and  a  large  quantity  of 
loose  areolar  tissue  and  fat. 

Position  of  the  trunks  of  vessels  and  nerves.  The  large  axillary  artery 
(a)  and  vein  {b)  cross  the  outer  portion  of  the  space  in  passing  from  the 
neck  to  the  upper  limb.  The  part  of  each  vessel  now  seen  lies  close  to 
the  humerus,  reaching  beyond  tlie  line  of  the  anterior  fold  of  the  arm-pit, 
and  is  covered  only  by  the  common  superficial  coverings,  viz.,  the  skin, 
the  fatty  layer  or  sui)erficial  fascia,  and  the  deep  fascia.  Behind  the 
vessels  are  tlie  subscapularis  (k)  and  the  tendons  of  the  latissimus  and 
teres  muscles  (d  and  e).  To  their  outer  side  is  the  coraco-brachialis 
muscle  (g). 


BOUNDARIES    OF    AXILLA, 


229 


On  looking  into  the  space  from  below,  the  axillary  vein  (b)  lies  on  the 
thoracic  side  of  the  artery. 

After  the  vein  has  been  drawn  aside,  the  artery  will  be  seen  amongst 
the  large  nerves  of  the  upper  limb,  having  the  median  trunk  (^)  to  the 
outside,  and  the  ulnar  (^)  and  the  small  nerve  of  Wrisberg  (^)  to  the  inner 
side  ;  the  internal  cutaneous  (^)  generally  superficial  to,  and  the  musculo- 
spiral  (*)  and  circumflex  nerves  beneath  it.  This  part  of  the  artery  gives 
branches  to  the  side  of  the  chest  and  the  shoulder.  The  vein  receives 
some  branches  in  this  spot. 


Fig.  69. 


View  of  the  DrasECXED  Axilla  (Illustrations  of  Dissections). 


Muscles  : 

Nerves  : 

A.  Pectoralis  major. 

1.  Median. 

B.  Pectoralis  minor. 

2.  Internal  cutaneous. 

c.  Serratus  magnus. 

3.  Ulnar. 

D.  Lastissimus  dorsi. 

4.  Musculo-spiral. 

E.  Teres  major. 

6.  Nerve  of  Wrisberg. 

F.  Subscapularis. 

6    Internal  cutaneous  of  musculo-spiral. 

o,  Coraco-brachialis 

7.  Subscapular, 

H.  Biceps. 

8.  Posterior  pieces  of  the  lateral  cutaneous  of 

Vessels  : 

the  thorax. 

a.  Axillary  artery. 

9.  Anterior  pieces  of  cutaneous  of  the  thorax. 

b.  Axillary  vein. 

c.  Subscapular  vein. 

d.  Subscapular  artery. 

e.  Posterior  circumflex  artery. 

Position  of  the  branches  of  vessels  and  nerves.  The  several  branches  of 
the  vessels  and  nerves  have  the  undermentioned  position  with  respect  to 
the  boundaries : — 

Close  to  the  anterior  fold,   and   concealed   by  it,   the  long  thoracic 


230  DISSECTION    OF    THE    UPPER    LIMB. 

artery  runs  to  the  side  of  the  chest ;  and  taking  the  same  direction,  though 
nearer  the  middle  of  the  hollow,  are  the  small  external  mammary  artery 
and  vein. 

Extending  along  the  posterior  fold,  within  its  lower  margin  and  in  con- 
tact with  the  edge  of  the  subscapularis  muscle,  are  the  subsca[)uhir  vessels 
and  nerves  {d  and  ')  ;  and  near  the  humeral  end  of  the  subscapularis  the 
posterior  circumflex  vessels  and  nerve  (e)  bend  backwards  beneath  the 
large  axillary  trunks. 

On  the  inner  boundary,  at  the  upper  part,  are  a  few  small  branches  of 
the  superior  thoracic  artery,  which  ramify  on  the  serratus  muscle;  but 
these  are  commonly  so  unimportant,  that  this  part  of  the  axillary  space 
may  be  considered  free  from  vessels  with  respect  to  any  surgical  operation. 
Lying  on  the  surface  of  the  serratus  magnus,  is  the  nerve  to  that  muscle ; 
and  perforating  the  inner  boundary  of  the  space,  are  the  lateral  cutaneous 
nerves  of  the  thorax — two  or  more  offsets  of  whicli  are  directed  across  the 
axilla  to  the  arm,  and  receive  the  name  intercosto-humeral. 

The  lymphatic  glands  of  the  axilla  are  arranged  in  two  sets :  one  is 
placed  along  the  inner  side  of  the  bloodvessels ;  and  the  other  occupies  the 
lower  and  hinder  parts  of  the  space,  l;^ing  near  and  along  the  posterior 
boundary.  Commonly  they  are  ten  or  twelve  in  number;  but  in  number 
and  size  they  vary  much.  Small  vascular  twigs  from  the  brandies  of  the 
axillary  vessels  are  furnished  to  them. 

The  glands  by  the  side  of  the  bloodvessels  receive  the  lym|)hatics  of  the 
arm  ;  and  those  along  the  hinder  boundary  are  joined  by  the  lymphatics 
of  the  fore  part  of  the  thorax  and  posterior  surface  of  the  Back,  as  well  as 
by  some  from  the  mamma.  Most  of  the  eflTerent  ducts  unite  to  form  a 
trunk,  which  opens  into  the  lymphatic  duct  of  the  neck  of  the  same  side ; 
some  may  enter  separately  the  subclavian  vein. 

The  PECTORALis  MAJOR,  A,  is  triangular  in  shape,  with  the  base  at  the 
thorax  and  the  apex  at  the  arm.  It  arises  internally  from  tiie  front  of 
the  sternum,  and  the  cartilages  of  the  true  ribs  except  the  last ;  superiorly 
from  the  sternal  half  of  the  clavicle  ;  and  inferiorly  from  the  aponeurosis 
of  the  external  oblique  muscle  of  the  abdomen.  From  this  wide  origin 
the  fibres  take  different  directions — those  from  the  clavicle  being  inclined 
obliquely  downwards,  and  those  from  the  lower  ribs  upwards  beneath  the 
former ;  and  all  end  in  a  tendon,  which  is  inserted  into  the  outer  edge  of 
the  bicipital  groove  of  the  liumerus  for  about  two  inches. 

This  muscle  bounds  the  axilla  anteriorly,  and  is  connected  sometimes 
to  its  fellow  by  fibres  in  front  of  the  sternum.  Besides  the  su{>erficijd 
structures  and  the  mamma,  the  platysma  covers  the  pectoralis  major  close 
below  the  clavicle.  A  lengthened  interval,  which  corresponds  with  a  de- 
j)ression  on  the  surface,  se{)arates  the  clavicular  from  the  sternal  attach- 
ment. One  border  (outer)  is  in  contact  with  the  deltoid  muscle,  and  with 
the  cephalic  vein  and  a  small  artery ;  and  the  lower  border  forms  the 
margin  of  the  anterior  fold  of  the  axilla.  The  parts  covered  by  the  muscle 
will  be  seen  subsequently. 

Action.  If  the  humerus  is  hanging,  the  muscle  will  move  forwards  the 
limb  until  the  elbow  reaches  the  front  of  the  trunk,  and  will  rotate  it  in. 

When  the  limb  is  raised,  the  pectoralis  depresses  and  adducts  it  ;  and 
acting  with  other  muscles  inserted  into  tlie  oj^posite  side  of  the  humerus, 
it  may  dislocate  the  head  of  that  bone  when  the  lower  end  is  fixed,  as  in 
a  fall  on  the  elbow. 


PECTORALIS    MINOR    MUSCLE.  231 

Supposing  both  limbs  fixed  as  in  climbing,  the  trunk  will  be  raised  by 
both  muscles ;  and  the  ribs  can  be  elevated  in  laborious  breathing. 

Dissection  (fig.  70).  The  great  pectoral  muscle  is  to  be  cut  across  now 
in  the  following  manner  : — 

Only  the  clavicular  part  is  to  be  first  divided,  so  that  the  branches  of 
the  nerve  and  artery  to  the  muscle  may  be  found.  Reflect  the  cut  part  of 
muscle,  and  press  tlie  limb  against  the  edge  of  the  table,  for  the  purpose 
of  raising  the  clavicle  and  rendering  tight  the  fascia  attached  to  that 
bone ;  on  carefully  removing  the  fat,  and  a  piece  of  fascia  prolonged  from 
the  upper  border  of  the  small  pectoral  muscle,  the  membranous  costo- 
coracoid  sheath  will  be  seen  close  to  the  clavicle,  covering  the  axillary 
vessels  and  nerves. 

At  this  stage  the  cephalic  vein  is  to  be  defined  as  it  crosses  inwards  to 
the  axillary  vein.  A  branch  of  nerve  (anterior  thoracic),  and  the  acro- 
mial thoracic  artery,  which  perforate  the  tube  of  membrane  around  the 
vessels,  are  to  be  followed  to  the  pectoral  muscles. 

The  remaining  part  of  the  pectoralis  major  may  be  cut  about  its  centre, 
and  the  pieces  may  be  thrown  inwards  and  outwards.  Any  fat  coming 
into  view  is  to  be  removed ;  and  the  insertion  of  the  tendon  of  the  pecto- 
ralis is  to  be  followed  to  the  humerus. 

Insertion  of  the  pectoralis.  The  tendon  of  the  pectoralis  consists  of 
two  parts,  anterior  and  posterior,  at  its  attachment  to  the  bone ;  the  ante- 
rior receives  the  clavicular  and  upper  sternal  fibres,  and  joins  the  tendon 
of  the  deltoid  muscle ;  and  the  posterior  gives  attachment  to  the  lower 
ascending  fibres.  The  tendon  is  from  two  inches  to  two  inches  and  a  half 
wide,  and  sends  upwards  one  expansion  over  the  bicipital  groove  to  the 
capsule  of  the  shoulder-joint,  and  another  to  the  fascia  of  the  arm. 

Parts  covered  by  the  pectoralis.  The  great  pectoral  muscle  covers  the 
pectoralis  minor,  and  forms  alone,  above  and  below  that  muscle,  the  ante- 
rior boundary  of  the  axilla.  Between  the  pectoralis  minor  and  the  clavicle 
it  conceals  the  subclavius  muscle,  the  sheath  containing  the  axillary  ves- 
sels, and  the  branches  perforating  that  sheath.  Below  the  pectoralis 
minor  it  lies  on  the  side  of  the  chest,  on  the  axillary  vessels  and  nerves, 
and  on  the  biceps  and  coraco-brachialis  muscles  near  the  humerus. 

The  PECTORALIS  MINOR  (fig.  70,  ^)  rescmbles  the  preceding  muscle  in 
shape,  and  is  extended  like  it  from  the  thorax  to  the  arm.  Its  origin  is 
connected  by  slips  with  the  third,  fourth,  and  fifth  ribs,  external  to  their 
cartilages  ;  and  between  the  ribs,  with  the  aponeurosis  covering  the  inter- 
costal muscles.  The  fibres  converge  to  their  insertion  in  the  anterior  half 
of  the  upper  surface  of  the  coracoid  process  of  the  scapula. 

This  muscle  is  placed  before  the  axillary  space,  and  assists  the  pecto- 
ralis major  in  forming  the  middle  of  the  anterior  boundary:  in  that  po- 
sition it  conceals  the  axillary  vessels  and  the  accompanying  nerves.  The 
upper  border  lies  near  the  clavicle,  but  between  it  and  that  bone  is  an  in- 
terval of  a  somewhat  triangular  form.  The  lower  border  projects  beyond 
the  pectoralis  major,  close  to  the  chest ;  and  along  it  the  long  thoracic 
artery  lies.  The  tendon  of  insertion  is  united  with  the  short  head  of  the 
biceps  and  the  coraco-brachialis. 

Action.  Acting  with  the  serratus  magnus  it  moves  the  scapula  for- 
wards and  somewhat  downwards. 

In  laborious  breathing  it  becomes  an  inspiratory  muscle,  as  it  takes  its 
fixed  point  at  the  scapula. 


232  DISSECTION    OF    THE    UPPER    LIMB. 

Dissection.  Supposing  the  clavicle  raised  by  the  pressing  backwards 
the  arm,  as  before  directed,  the  tube  of  fascia  around  the  vessels  will  be 
demonstrated  by  making  a  transverse  cut  in  the  costo-coracoid  membrane 
near  the  clavicle,  so  that  the  handle  of  the  scalpel  can  be  passed  beneath 
it.  By  raising  the  lower  border  of  the  subclavius  this  muscle  will  be  seen 
to  be  incased  by  fascia,  which  is  attached  to  the  bone  both  before  and  be- 
hind it. 

The  costo-coracoid  membrane,  or  ligament  (fig.  70),  is  a  firm  membra- 
nous band,  which  receives  this  name  from  its  attachment  on  the  one  side 
to  the  rib,  and  on  the  other  to  the  coracoid  process  of  the  scapula.  Between 
those  points  it  is  inserted  into  the  clavicle,  inclosing  the  subclavius  muscle  ; 
and  is  joined  by  the  piece  of  fascia  that  incases  the  small  pectoral  muscle. 
From  its  strength  and  position  it  gives  protection  to  the  vessels  surrounded 
by  their  loose  sheath. 

When  traced  downwards  it  is  found  to  descend  on  the  axillary  vessels 
and  nerves,  joining  externally  the  fascia  on  the  coraco-brachialis  muscle, 
and  blending  with  the  sheath  of  the  axillary  vessels  beneath  the  small 
pectoral  muscle.  Its  extent  is  not  so  great  on  the  inner  as  on  the  outer  side, 
for  internally  it  reaches  but  a  very  short  distance  on  the  axillary  vein. 

The  sheath  of  the  axillary  vessels  and  nerves,  E,  is  derived  from  the 
deep  fascia  of  the  neck,  being  prolonged  from  that  on  the  scaleni  muscles  ; 
and  resembles,  in  its  form  and  office,  the  funnel-shaped  tube  of  membrane 
surrounding  the  femoral  vessels  in  the  upper  part  of  the  thigh.  It  is 
strongest  near  the  subclavius  muscle,  where  the  costo-coracoid  band  joins 
it.  The  anterior  part  of  the  tube  is  perforated  by  the  cephalic  vein  (e), 
the  acromial  thoracic  artery  (a),  and  the  anterior  thoracic  nerve  ('). 

Dissection.  After  the  costo-coracoid  membrane  has  been  examined, 
the  remains  of  it  are  to  be  taken  away  ;  and  the  subclavius  muscle,  and 
the  axillary  vessels  and  nerves  with  their  branches,  are  to  be  carefully 
cleaned. 

The  SUBCLAVIUS  muscle  (fig.  70,  ^)  is  roundish  in  form,  and  is  placed 
between  the  clavicle  and  the  rib.  It  arises  by  a  tendon  from  the  first  rib, 
at  the  junction  of  the  osseous  and  cartilaginous  parts,  and  in  front  of  the 
costo-clavicular  ligament.  The  fibres  ascend  obliquely,  and  are  inserted 
into  a  groove  on  the  under  surface  of  the  clavicle,  which  reaches  between 
the  two  tubercles  (internal  and  external)  for  the  attachment  of  the  costo 
and  coraco-clavicular  ligaments. 

The  muscle  overhangs  the  large  vessels  and  nerves  of  the  limb,  and  is 
inclosed,  as  before  said,  in  a  sheath  of  fascia. 

Action.  It  depresses  the  clavicle,  and  indirectly  the  scapula  ;  but  if  the 
shoulder  is  fixed  it  elevates  the  first  rib. 

The  AXILLARY  ARTERY  (fig.  70)  continucs  the  subclavian  trunk  to  the 
upper  limb.  The  part  of  the  vessel  to  which  this  name  is  applied  is  con- 
tained in  the  axilla,  and  extends  from  the  lower  border  of  the  first  rib  to 
the  lower  edge  of  the  teres  major  muscle  (h). 

In  the  axillary  space  its  position  will  be  marked  by  a  line  from  the 
middle  of  the  clavicle  to  the  inner  edge  of  the  coraco-brachialis.  Its  di- 
rection will  vary  with  the  position  of  the  limb  to  the  trunk  ;  for  when  the 
arm  lies  by  the  side  of  the  body  the  vessel  is  curved,  its  convexity  being 
upwards  ;  and  in  proportion  as  the  limb  is  removed  to  a  right  angle  with 
the  chest,  the  artery  becomes  straight.  In  the  upper  part  of  the  axilla  the 
vessel  is  deeply  placed,  but  it  becomes  superficial  as  it  approaches  tiie  arm. 


AXILLARY    ARTERY 


233 


Its  connections  with  surrounding  parts  are  numerous ;  and  the  descrip- 
tion of  these  will  be  methodized  by  dividing  the  artery  into  three  parts 

one  above,  one  beneath,  and  one  below  the  small  pectoral  muscle. 

Above  the  small  pectoral  muscle  the  artery  is  contained  in  the  axillary 
sheath  of  membrane,  e.  This  part  is  concealed  by  the  clavicular  portion 
of  the  great  pectoral  muscle.  Behind  it  are  the  intercostal  muscles  of  the 
first  space  and  the  first  digitation  of  the  serratus  magnus. 


Fig.  70. 


Second  View  of  the  Dissection  of  the  Thorax  (Illustrations  of  Dissections). 
MuscJes :  Vessels  : 

A.  Pectoralis  major,  cut.  a.  Acromial-thoracic  branch. 

B.  Pectoralis  minor.  6.  Long  thoracic  branch. 
Serratus  magnus.                                                     c.  Subscapular  branch. 
Subclavius.                                                             d.  Axillary  artery. 
Axillary  sheath.                                                    e.  Cephalic  vein. 
Subscapularis.                                                       /.  Brachial  veins  joining  the  axillary  veins,  g. 

Nerves : 


c. 

D. 

E. 

P. 

G.  Latissimus  dorsl. 

H.  Teres  major. 

J.  Coraco-trachialis. 

K.  Biceps. 


1  and  2.  Anterior  thoracic  branches. 

3.  Subscapular  branch. 

4.  Nerve  to  the  serratus. 

5.  Intercosto-humeral  branch. 


To  the  thoracic  side  is  placed  the  axillary  vein  (^).  The  cephalic  vein 
(e),  and  offsets  of  the  acromial  thoracic  artery  and  vein,  cross  over  it. 

On  the  acromial  side  lie  the  two  cords  of  the  brachial  plexus,  separated 
from  the  vessel  by  a  slight  interval.  Superficial  to  it  lies  an  anterior  tho- 
racic nerve ;  and  beneath,  is  the  posterior  thoracic. 

Beneath  the  pectoralis,  the  pectoralis  minor  and  major  b  and  A  are 
superficial  to  the  axillary  vessel.     But  there  is  not  any  muscle  immediately 


234  DISSECTION    OF    THE    UPPER    LIMB. 

in  contact  behind,  for  the  artery  is  placed  across  the  top  of  the  axilla, 
particularly  when  the  limb  is  in  the  position  required  by  the  dissection. 

The  companion  vein  (g)  lies  to  the  inner  side,  but  separated  from  the 
arterial  trunk  by  a  bundle  of  nerves. 

In  this  position  the  cords  of  the  brachial  plexus  lie  around  it,  one 
being  outside,  a  second  inside,  and  a  third  beneath  the  artery. 

Beyond  the  pectoralis  minor  the  artery  is  concealed  in  part  by  the  lower 
border  of  the  great  pectoral  muscle  a,  but  thence  to  its  termination  it  is 
covered  only  by  the  integuments  and  the  fascia.  Beneath  it  are  the  sub- 
scapularis  muscle,  f,  and  the  tendons  of  the  latissimus  and  teres,  G  and  h. 
To  the  outer  side  is  the  coraco-brachialis  muscle,  J. 

The  axillary  vein  remains  as  above  on  the  thoracic  side  of  the  artery. 
Here  the  artery  lies  in  the  midst  of  the  large  trunks  of  nerves  into 
which  the  brachial  plexus  has  been  resolved :  On  the  outer  side  is  the 
median  nerve,  with  the  musculo-cutaneous  for  a  short  distance;  and  on 
the  inner  side  are  the  ulnar,  and  the  nerve  of  Wrisberg.  Superficial  to 
the  vessel  is  the  internal  cutaneous;  and  behind  are  the  musculo-spiral 
and  circumflex  nerves,  the  latter  extending  only  as  far  as  the  border  of 
the  subscapular  muscle. 

The  branches  of  the  axillary  artery  are  furnished  to  the  wall  of  the 
thorax  and  the  shoulder.  The  thoracic  branches  are  four  in  number ;  two 
(superior  and  acromial  thoracic)  arise  from  the  artery  above  the  pectoralis 
minor;  one  (alar  thoracic)  beneath  the  muscle;  and  one  (long  thoracic) 
at  the  lower  border.  Three  branches  are  supplied  to  the  shoulder,  viz., 
subscapular  and  two  circumflex ;  the  first  springs  opposite  the  edge  of  the 
muscle  of  the  same  name,  and  the  others  wind  round  the  neck  of  the 
humerus.  The  last  offsets  are  the  external  mammary  and  some  muscular 
twigs. 

The  superior  thoracic  branch  is  the  highest  and  smallest  offset,  and 
arises  opposite  the  first  intercostal  space;  it  ramifies  on  the  side  of  the 
chest,  anastomosing  with  the  intercostal  arteries. 

The  acromial  thoracic  branch  (fig.  70,  a)  is  a  short  trunk  on  the  front 
of  the  artery,  which  appears  at  the  upper  border  of  the  pectoralis  minor, 
and  opposite  the  interval  between  the  large  pectoral  and  deltoid  muscles. 
Its  branches  are  directed  inwards,  outwards,  and  upwards : — 

a.  The  inner  set  supply  the  thoracic  muscles,  and  give  a  few  offsets  to 
the  side  of  the  chest  to  anastomose  with  the  intercostal  and  other  thoracic 
arteries. 

h.  The  outer  or  acromial  set  end  mostly  in  the  deltoid;  but  one  small 
artery  accompanies  the  cephalic  vein  for  a  short  distance ;  and  another 
{inferior  acromial)  perforates  the  deltoid  muscle,  and  anastomoses  on  the 
acromion  with  a  branch  of  the  suprascapular  artery  of  the  neck. 

c.  One  or  two  small  twigs  ascend  to  the  subclavius  and  deltoid  muscles. 
The  alar  thoracic  is  very  inconstant  as  a  separate  branch,  and  its  place 
is  taken  by  offsets  of  the  subscapular  and  long  thoracic  arteries;  it  is  dis- 
tributed to  the  glands  and  fat  of  the  axillary  space. 

The  long  thoracic  branch  is  directed  along  the  border  of  the  pectoralis 
minor  (fig.  70,  h)  to  about  the  sixth  intercostal  space ;  it  supplies  the  pec- 
toral and  serratus  muscles,  and  anastomoses,  like  the  other  branches,  with 
the  intercostal  and  thoracic  arteries.  In  the  female  it  gives  branches  to 
the  mammary  gland. 

An  external  mammary  artery  is  commonly  met  with,  especially  in  the 
female;  its  position  is  near  the  middle  of  the  axilla  with  a  companion  vein. 


BRACHIAL    PLEXUS.  235 

It  supplies  the  glands,  and  ends  in  the  wall  of  the  thorax  below  tlie  pre- 
ceding. 

Tl»e  subscapular  branch  (fig.  70,  c)  courses  with  a  nerve  of  the  same 
name  along  the  subscapularis,  as  far  as  the  lower  angle  of  the  scapula, 
where  it  ends  in  branches  for  the  serratus  magnus,  and  the  latissimus  dorsi 
and  teres  muscles:  it  gives  many  offsets  to  the  glands  of  the  space. 

Near  its  origin  the  artery  sends  backwards  a  considerable  dorsal  branch 
round  the  edge  of  the  subscapular  muscle:  this  gives  an  infrascapular 
offset  to  the  ventral  aspect  of  the  scapula,  and  then  turns  to  the  dorsum  of 
that  bone,  where  it  will  be  afterwards  dissected. 

The  subscapular  artery  is  frequently  combined  at  its  origin  with  other 
branches  of  the  axillary,  or  with  branches  of  the  brachial  artery. 

The  circumflex  branches  (anterior  and  posterior)  arise  near  the  border 
of  the  subscapular  muscle.  One  turns  in  front  of,  and  the  other  behind 
the  humerus.     They  will  be  followed  in  the  examination  of  the  arm. 

Small  muscular  offsets  enter  the  coraco-brachialis  muscle. 

The  AXILLARY  VEIN  {g)  continues  upwards  the  basilic  vein  of  the  arm 
and  has  the  same  extent  and  connections  as  the  axillary  artery.  It  lies  to 
the  thoracic  side  of  its  artery,  and  receives  thoracic  and  shoulder  branches. 
Opposite  the  subscapular  muscle  it  is  joined  externally  by  a  large  vein, 
which  is  formed  by  the  union  of  the  vense  comites  of  the  brachial  artery; 
and  near  the  clavicle  the  cephalic  vein  opens  into  it. 

Dissection.  To  follow  out  the  branches  of  the  brachial  plexus,  cut 
through  the  pectoralis  minor  near  its  insertion  into  the  coracoid  process, 
and  turn  it  towards  the  chest,  but  without  injuring  the  thoracic  nerves  in 
contact  with  it.  The  axillary  vessels  are  next  to  be  cut  across  below  the 
second  rib,^  and  to  be  drawn  down  with  hooks;  and  their  thoracic  branches 
may  be  removed  at  the  same  time.  A  dense  fascia  is  to  be  cleared  away 
from  the  large  nerves  of  the  plexus. 

The  BRACHIAL  PLEXUS  results  from  the  union  of  the  anterior  branches 
of  the  four  lower  cervical  nerves  with  the  first  dorsal  (in  part)  ;  and  a  slip 
is  added  to  it  above  from  the  lowest  nerve  in  the  cervical  plexus.  It  is 
placed  partly  in  the  neck,  and  partly  in  the  axilla,  and  is  divided  opposite 
the  coracoid  process  into  large  trunks  for  the  supply  of  the  limb.  The 
part  of  the  plexus  above  the  clavicle  is  described  in  the  dissection  of  the 
head  and  neck  (p.  79).  The  part  below  the  clavicle  has  the  same  connec- 
tions with  the  surrounding  muscles  as  the  axillary  artery.  The  nerve 
trunks  interlace  in  it  generally  in  the  following  manner: — 

At  first  the  plexus  consists  of  two  bundles  of  nerves,  which  lie  on  the 
outer  side  of  the  artery,  and  are  thus  constituted  ; — the  one  nearest  the 
vessel  is  formed  by  the  last  cervical  with  the  part  of  the  first  dorsal  nerve; 
and  the  other,  by  the  fifth,  sixth,  and  seventh  cervical  nerves.  A  little 
lower  down  a  third  or  posterior  cord  is  produced  by  the  union  of  two  fas- 
ciculi, one  .from  each  of  the  other  bundles  ;  so  that,  beneath  the  small  pec- 
toral muscle,  the  plexus  consists  of  three  large  cords,  one  being  on  the 
outer  side,  another  on  the  inner  side,  and  the  third  behind  the  vessel. 
Occasionally  there  may  be  some  d(;viation  from  the  above  mentioned 
arrangement. 

The  branches  of  the  plexus  below  the  clavicles  arise  from  the  several 
cords  in  the  following  way  : — 

'  The  student  must  be  careful  not  to  cut  the  vessels  higher  than  the  spot  men- 
tioned, otherwise  he  Mill  injure  the  dissection  of  the  neck. 


236  DISSECTION    OF    THE    UPPER    LIMB. 

The  outer  cord  gives  origin  to  one  anterior  thoracic  branch,  the  musculo- 
cutaneous trunk,  and  the  outer  head  of  the  median  nerve. 

The  inner  cord  produces  a  second  anterior  thoracic  nerve,  the  inner 
head  of  the  median,  the  internal  cutaneous,  the  nerve  of  Wrisberg,  and 
the  ulnar  nerve. 

The  posterior  cord  furnishes  the  subscapular  branches,  and  ends  in  the 
circumflex  and  musculo-spiral  trunks. 

Only  the  thoracic  and  subscapular  nerves  are  dissected  to  their  termina* 
tion  at  present ;  the  remaining  nerves  will  be  seen  in  the  arm. 

The  anterior  thoracic  branches  (fig.  70,  ^  and  ^),  two  in  number,  are 
named  outer  and  inner,  like  the  cords  from  which  they  come. 

The  outer  nerve  crosses  inwards  over  the  axillary  artery,  to  the  under 
surface  of  the  great  pectoral  muscle  in  which  it  ends.  On  the  inner  side 
of  the  vessel  it  communicates  with  the  following  branch. 

The  inner  thoracic  branch  turns  upwards  between  the  artery  and  vein, 
and  after  receiving  the  offsets  from  the  other,  ends  in  many  branches  to 
the  under  surface  of  the  pectoralis  minor.  Some  twigs  enter  the  great 
pectoral  muscle,  after  passing  either  through  tlie  pectoralis  minor  or  above 
its  border. 

The  subscapular  nerves  are  three  in  number,  and  take  their  names  from 
the  muscles  supplied  : — 

The  branch  of  the  subscapularis  is  the  highest  and  smallest,  and  enters 
the  upper  part  of  that  muscle. 

The  nerve  of  the  teres  major  gives  a  small  offset  to  the  inferior  part  of 
the  subscapularis,  and  ends  in  its  muscle. 

A  long  nerve  of  the  latissimus  dorsi  (•'')  takes  the  course  of  the  sub- 
scapular artery  along  the  posterior  wall  of  the  axilla,  and  enters  the  fleshy 
fibres  near  the  outer  end. 

Another  small  nerve,  nerve  to  the  serratus  (*)  (posterior  thoracic),  lies 
on  the  surface  of  the  serratus  muscle.  It  arises  above  the  clavicle  (p. 
80),  from  the  fifth  and  sixth  cervical  nerves  ;  it  descends  behind  the  axil- 
lary artery,  and  enters  that  surface  of  the  serratus  magnus  which  is  turned 
towards  the  axilla. 

The  LATISSIMUS  DORSI  MUSCLE,  G,  may  be  examined  as  far  as  it  enters 
into  the  posterior  fold  of  the  axilla.  Arising  from  the  spinal  column  and 
the  back  of  the  trunk,  and  crossing  the  lower  angle  of  the  scapula,  the 
muscle  ascends  to  be  inserted  into  the  bottom  of  the  bicipital  groove  by  a 
tendon,  one  inch  and  a  half  in  width,  in  front  of  the  teres ;  at  the  lower 
border  aponeurotic  fibres  connect  the  two,  but  a  bursa  intervenes  between 
them  near  the  insertion. 

Dissection.  To  lay  bare  the  serratus  muscle  between  the  side  of  the 
chest  and  the  base  of  the  scapula,  the  arm  is  to  be  drawn  from  the  trunk, 
so  as  to  separate  the  scapula  from  the  thorax.  Tlie  nerves  of  the  brachial 
plexus  may  be  cut  through  opposite  the  third  rib ;  and  the  fat  and  fascia 
should  be  cleaned  from  the  muscular  fibres. 

The  SERKATUS  MAGNUS  MUSCLE  (fig.  71,  a)  cxteuds  between  the 
scapula  and  the  thorax.  It  arises  by  nine  pointed  processes  from  the  outer 
surface  of  the  eight  upper  ribs, — the  second  rib  having  two  pieces  ;  and 
between  the  ribs  it  takes  origin  from  the  aponeurosis  covering  the  inter- 
costal muscles.  The  fibres  converge  towards  the  base  and  angles  of  the 
scapula,  but  from  a  difference  in  their  direction  the  muscle  appears  to 
consist  of  three  parts. 

The  upper  part   is  attached   internally  to  the  first  two  ribs  and  an 


INTERCOSTAL    MUSCLES 


237 


aponeurotic  arch  between  tliem  ;  and  externally,  to  an  impression  on  the 
ventral  surface  of  the  upper  angle  of  the  scapula.  A  middle  part,  which 
is  very  thin,  extends  from  the  second,  third,  and  fourth  ribs,  to  the  base 
of  the  shoulder  bone.  And  a  lower  part,  which  is  the  strongest,  is  con- 
nected on  the  one  side  with  four  ribs  (fifth,  sixth,  seventh,  and  eighth), 
where  it  digitates  with  like  processes  of  origin  of  the  external  oblique 
muscle ;  and,  on  the  other  side,  it  is  fixed  into  the  special  surface  on  the 
costal  aspect  of  the  lower  angle  of  the  scapula. 

The  serratus  is  applied  against  the  ribs  and  the  intercostal  muscles,  and 
is  partly  concealed  by  the  pectoral  muscles  and  the  axillary  vessels  and 
nerves :  in  the  ordinary  position  of  the  arm  the  scapula  and  subscapularis 
are  in  contact  with  it. 

Action.  The  whole  muscle  acting,  the  scapula  is  carried  forwards.  But 
the  lower  and  stronger  fibres  can  move  forwards  the  lower  angle,  rotating 
the  bone  around  an  axis  through  the  centre,  and  raise  the  acromion. 

Dissection.  The  intercostal  muscles  will  be  brought  into  view  by  de- 
taching the  processes  of  origin  of  the  serratus  from  the  ribs  for  a  couple 
of  inches,  and  by  taking  away  the  loose  tissue  on  the  surface.  Towards 
the  front  of  the  chest  is  a  thin  aponeurosis,  which  is  continued  forwards 
from  each  external  intercostal  to  the  sternum  ;  this  is  to  be  retained  in 
the  third  intercostal  space.  Some  of  the  lateral  cutaneous  nerves  should 
be  preserved. 

The  INTERCOSTAL  MUSCLES  are  named  from  their  position  between  the 
ribs.  There  are  two  layers  in  each  space,  but  neither  occupies  the  whole 
length  of  the  space.  Tlie  direction  of  the  fibres  differs  in  each  stratum ; 
for,  whilst  the  fibres  of  the  external 

muscle   run    very   obliquely  down-  Fig-  71. 

wards  and  forwards,  those  of  the 
internal  have  an  opposite  direction 
between  the  osseous  parts  of  the 
ribs,  so  that  the  two  sets  cross. 

The  external  muscle  is  fixed  to 
the  outer  margin  of  the  ribs  of  each 
intercostal  space,  and  consists  of 
fleshy  and  tendinous  fibres.  Pos- 
teriorly the  fibres  begin  at  or  near 
the  tubercle  of  tlie  rib  ;  and  ante- 
riorly they  end  short  of  the  middle 
line,  but  after  a  different  manner  in 
the  upper  and  lower  spaces  : — In 
the  intervals  between  the  true  ribs, 
they  cease  near  the  costal  cartilages, 
and  a  thin  aponeurosis  is  continued 
onwards  from  the  point  of  ending  to 
the  sternum.  In  the  lower  spaces 
they  are  continued  between  the  car- 
tilages (Theile)  reaching  the  end 
of  the  ribs  in  the  last  two. 

Dissection.     The   internal  inter- 
costal muscle  will  be  seen  by  cutting  through  and  removing  the  external 
layer  and  the  fascia  in  one  of  the  Avidest  spaces,  say  the  second  ;  it  will  be 
recognized  by  the  difference  in  the  direction  of  the  fibres. 

Far  back  between  the  two  muscles,  and  close  to  the  rib  above,  the  inter- 


Diagram  of  the  Serratus  Maqnds  Muscle. 
A.  Attachmeuts. 


238  DISSECTION    OF    THE    UPPER    LIMB. 

costal  nerve  and  artery  will  appear.  A  branch  of  the  nerve  to  the  surface 
(lateral  cutaneous  of  the  thorax)  should  be  followed  througli  the  external 
muscle  ;  and  the  trunk  of  the  nerve  is  to  be  traced  forwards  in  one  or 
more  spaces  to  the  sternum,  and  the  surface  of  the  thorax. 

The  hinder  part  of  these  muscles  will  be  seen  in  the  dissection  of  the 
Back  and  thorax. 

The  internal  intercostal  muscle,  attached  to  the  inner  border  of  the  ribs 
bounding  the  intercostal  space,  begins  in  front  at  the  extremity  of  tlie 
ribs,  and  ceases  behind  near  their  angles.  Posteriorly  they  do  not  end  at 
the  same  distance  from  the  spine,  for  the  upper  and  lower  approach  nearer 
than  the  middle ;  and,  anteriorly,  in  the  two  lowest  spaces,  the  muscular 
fibres  are  continuous  with  the  internal  oblique  of  the  abdomen.  One  sur- 
face is  covered  by  the  external  muscle  and  in  part  by  the  intercostal  ves- 
sels and  nerve  ;  and  the  opjjosite  surface  is  in  contact  with  the  pleura. 

Action.  By  the  alternate  action  of  the  intercostal  muscles  the  ribs  are 
moved  in  respiration. 

The  external  intercostals  elevate  the  ribs  and  evert  the  lower  edges,  so 
as  to  enlarge  the  thorax  in  tlie  antero-posterior  and  transverse  directions  : 
they  come  into  play  during  inspiration. 

The  internal  intercostals  act  in  a  different  way  at  the  side  and  fore  part 
of  the  chest. 

Between  the  osseous  parts  of  the  ribs  they  dej)ress  and  turn  in  those 
bones,  diminishing  the  size  of  the  thorax ;  and  th(y  are  brought  into  use 
in  expiration. 

Between  the  rib-cartilages  they  raise  the  ribs,  and  become  muscles  of 
inspiration  like  the  outer  layer. 

If  both  stt.s  of  muscles  contract  simultaneously,  the  motion  of  the  ribs 
will  be  arrested  ;  or  if  two  or  more  ribs  are  broken  near  the  spinal  column, 
the  muscles  of  the  space  or  spaces  injured  will  be  unable  to  move  these 
bones. 

Dissection.  To  bring  into  view  the  triangularis  sterni  muscle  and  the 
internal  mammary  vessels,  the  cartilages  of  the  true  ribs,  except  the  first 
and  seventh,  are  to  be  taken  away  with  the  intervening  njuscles  on  the 
right  side  of  the  body  ;^  but  the  two  ribs  menti  )ned  are  to  be  left  un- 
touched for  the  benefit  of  the  dissectors  of  the  abdomen  and  head  and 
neck.  Small  arteries  to  each  intercostal  space  and  the  surface  of  the 
thorax,  and  the  intercostal  nerves,  are  to  be  preserved.  The  surface 
of  the  triangularis  sterni  will  be  apparent  when  the  loose  tissue  and  fat 
are  removed. 

The  TRIANGULARIS  STERNI  (fig.  72,  a)  is  a  thin  muscle  beneath  the 
costal  cartilages.  It  arises  internally  from  the  side  of  tlie  xiphoid  carti- 
lage, from  the  side  of  the  sternum  as  high  as  the  third  costal  cartilage, 
and  usually  from  the  inner  ends  of  the  lower  three  true  costjil  cartilages. 
Its  fibres  are  directed  outwards,  the  upper  being  most  oblique,  and  are 
inserted  by  fleshy  fasciculi  into  the  true  ribs  ex{;ept  the  last  two  and  the 
first,  at  the  junction  of  the  bone  and  cartilage,  and  into  an  aponeurosis  in 
the  intercostal  sj)aces. 

Tiie  muscle  is  covered  by  the  ribs  and  the  internal  intercostals,  and  by 
the  internal  mammary  vessels  and  the  intercostal  nerves.  It  lies  on  the 
pleura.     Its  lower  fibres  touch  those  of  the  trans versalis  abdominis. 

»  On  the  left  side  the  vessels  and  the  muscle  will  have  been  destroyed  by  the 
injection  of  the  body. 


INTERNAL    MAMMARY    VESSELS, 


239 


Action.  The  muscle  assists  in  depressing  the  anterior  ends  of  tlie  ribs  ; 
and  by  diminishing  the  size  of  the  thorax,  it  becomes  an  expiratory 
muscle. 

The  internal  mammary  artery  is  a  branch  of  the  subclavian  (p.  77), 
and  enters  the  thorax  beneath  the  cartilage  of  the  first  rib.  It  is  con- 
tinued through  the  thorax,  lying  beneath  the  costal  cartilages  and 
about  half  an  inch  from  the  sternum,  as  far  as  the  interval  between  the 
sixth  and  seventh  ribs;  there  it  gives  externally  a  large  muscular  branch 
(musculo-phrenic),  and  passing  beneath  the  seventh  rib,  enters  the  sheath 
of  the  rectus  muscle  in  the  wall 
of  the  abdomen.  In  the  chest 
the  artery  lies  on  the  pleura 
and  the  triangularis  sterni,  and 
is  crossed  by  the  intercostal 
nerves.  It  is  accompanied  by 
two  veins,  and  by  a  chain  of 
lymphatic  glands.  The  follow- 
ing branches  take  origin  in  the 
thorax : — 

a.  A  small  branch  {comes 
nervi  phrenici)  arises  as  soon 
as  the  artery  enters  the  chest, 
and  descends  to  the  diaphragm 
along  the  phrenic  nerve. 

h.  A  few  small  mediastinal 
branches  are  distributed  to  the 
remains  of  the  thymus  gland, 
the  pericardium,  and  the  tri- 
angularis sterni  muscle. 

c.  Two  anterior  intercostal 

branches  turn  outwards  in  each  space,  one  being  placed  on  the  border  of 
each  costal  cartilage,  and  terminate  by  anastomosing  witli  the  aortic  inter- 
costal arteries.  . 

d.  Perforating  branches^  one  or  two  opposite  each  space,  pierce  the  in- 
ternal intercostal  and  pectoral  muscles,  and  are  distributed  on  the  surface 
of  the  thorax  with  the  anterior  cutaneous  nerves:  the  lower  branches  sup- 
ply the  mamma  in  the  female. 

e.  The  musculo-phrenic  branch  courses  outwards  beneath  the  cartilages 
of  the  seventh  and  eighth  ribs,  and  enters  the  wall  of  the  abdomen  by 
perforating  the  diaphragm:  it  supplies  anterior  branches  to  the  lower 
intercostal  spaces.  Its  termination  will  appear  in  tiie  dissection  of  the 
abdomen. 

Two  veins  accompany  the  artery;  these  join  into  one  trunk,  which 
opens  into  the  innominate  vein. 

The  intercostal  nerves,  seen  now  in  the  anterior  part  of  their  extent, 
are  the  anterior  primary  branches  of  t;he  dorsal  nerves,  and  supply  the 
wall  of  the  thorax.  Placed  at  first  between  the  layers  of  the  intercostal 
muscles,  each  gives  off  the  lateral  cutaneous  nerve  of  the  thorax,  about 
midway  between  the  spine  and  tlie  sternum.  Diminished  in  size  by  the 
emission  of  that  offset,  the  trunk  is  continued  onwards,  at  first  in,  and 
afterwards  beneath  the  internal  intercostal  muscle  as  far  as  tlie  side  of  the 
sternum,  where  it  ends  as  the  anterior  cutaneous  nerve  of  the  thorax. 
Branches  supply  the  intercostal  muscles,  and  the  triangularis  sterni. 


View  from  behind  of  the  Attachments  of  the 
Triangulakis  Sterni  Muscle,  a. 


240  DISSECTION    OF    THE    UPPER    LIMB. 

The  aortic  intercostal  arteries  lie  with  the  nerves  between  the  strata  of 
intercostal  muscles,  and  nearer  the  upper  than  the  lower  rib  bounding  the 
intercostal  space.  About  the  mid  point  of  the  space  (from  before  back) 
the  artery  bifurcates: — one  branch  follows  the  line  of  the  upper  rib,  and 
the  other  descends  to  the  lower  rib ;  both  anastomose  anteriorly  with  the 
intercostal  offsets  of  the  internal  mammary  artery. 

A  small  cutaneous  offset  is  distributed  with  the  lateral  cutaneous 
nerve  of  the  thorax;  and  other  branches  are  furnished  to  the  thoracic 
wall. 

Directions.  The  dissector  of  the  upper  limb  waits  now  the  appointed 
time  for  the  examination  of  the  thorax.  But  as  soon  as  the  body  is  turned 
he  is  to  take  his  share  in  the  dissection  of  the  Back,  and  to  proceed  with 
the  parts  marked  for  him  in  Chapter  V. 

After  the  Back  is  finished  the  limb  is  to  be  detached  from  the  trunk  by 
sawing  the  clavicle  about  the  middle,  and  cutting  through  the  soft  parts 
connected  with  the  scapula. 


Section  II. 

SCAPULAR  MUSCLES,  VESSELS,  NERVES,  AND  LIGAMENTS. 

Position.  After  the  limb  has  been  separated  from  the  trunk  it  is  to  be 
placed  with  the  subscapularis  uppermost. 

Dissection.  The  different  muscles  that  have  been  traced  to  the  scapula 
in  the  dissection  of  the  front  of  the  thorax  and  the  Back,  are  now  to  be 
cleaned,  and  to  be  followed  to  their  insertion  into  the  bone.  A  small 
part  of  each,  about  an  inch  in  length,  should  be  left  for  the  purpose  of 
ascertaining  the  osseous  attachment. 

Between  the  larger  rhomboid  muscle  and  the  serratus  magnus  at  the 
base  of  the  scapula,  run  the  posterior  scapular  artery  and  vein,  whose 
ramifications  are  to  be  traced. 

To  the  borders  and  the  angles  of  the  scapula  the  following  muscles  are 
connected: — 

From  the  upper  margin  of  the  scapula  arises  one  muscle,  the  omo-hyoid 
(fig.  73,  e).  At  its  origin  that  muscle  is  about  half  an  inch  wide;  it  is 
attached  to  the  edge  of  the  bone  behind  the  notch,  and  sometimes  to  the 
ligament  which  converts  the  notch  into  a  foramen. 

•  The  lower  margin,  or  costa,  gives  origin  to  the  long  head  of  the  triceps 
(fig.  79,  a),  and  to  some  fibres  of  the  teres  major;  but  these  attachments 
will  be  ascertained  in  the  progress  of  the  dissection. 

The  base  of  the  bone  has  many  muscles  inserted  into  it  (fig.  74).  Be- 
tween the  superior  angle  and  the  spine  is  the  levator  anguli  scapulye,  h. 
Opposite  the  spine  the  rhomboideys  minor,  j,  is  fixed.  And  between  the 
spine  and  the  inferior  angle  the  rhomboideus  major,  k,  is  attached:  the 
upper  fibres  of  this  muscle  end  often  in  an  aponeurotic  arch,  and  are  con- 
nected indirectly  to  the  bone  by  means  of  an  expansion  from  it.  Internal 
to  those  muscles,  and  inserted  into  all  the  base  of  the  scapula,  is  the  ser- 
ratus magnus  muscle  (fig.  73,  d). 

On  the  inner  surface  of  the  upper  and  lower  angles  of  the  scapula  the 


SUBSCAPULARIS    MUSCLE. 


241 


fibres  of  the  serratus  magnus  are  collected.  On  the  outer  surface  of  the 
inferior  angle  lies  tlie  teres  major  (fig.  79,  g)  which  will  be  subsequently 
seen. 

The  insertion  of  the  small  pectoral  muscle  into  the  fore  part  of  the 
upper  surface  of  the  coracoid  process  may  be  ascertained  at  this  stage  of 
the  dissection  (tig.  73,  f). 

•       Fiff.  73. 


A.  Subscapiilaris. 

B.  Teres  major. 

c.  Latissimus  dorsi. 

D.  Serratus  magnus. 

E.  Omo-hyoideus. 

F.  Pectoralis  minor. 

G.  Biceps. 

H.  Coraco-brachialis. 
a.  Supra-scapular  artery. 
1.  Supra-scapular  nerve  passing  through 
the  notch. 


View  of  the  Si-bscapiti.akis  and  the  sprroundino  Muscles.    The  other  muscles  fixed  into 
the  base  of  the  scapula  as  shown  in  fig.  74. 


Dissection.  By  the  separation  of  the  seri-atus  from  the  subscapularis  a 
thin  fascia  comes  into  view,  which  belongs  to  the  last  muscle,  and  is  fixed 
to  the  bone  around  its  margins ;  after  it  has  been  observed,  it  may  be  re- 
moved. 

The  subscapularis  muscle  is  to  be  followed  forwards  to  its  insertion  into 
the  humerus.  Next,  the  axillary  vessels  and  nerves,  and  the  offsets  of 
these  to  the  muscles,  should  be  well  cleaned. 

The  suBSCAPrLARis  MUSCLE  (fig.  73,  a)  occupies  the  under  surface 
of  the  scapula,  and  is  concealed  by  that  bone  when  the  limb  is  in  its 
natural  position.  The  muscle  arises  from  the  concave  surface  on  the 
ventral  aspect  of  the  scapula,  except  at  the  angles,  and  this  attachment 
reaches  forwards  nearly  to  the  neck  ;  it  is  united  also  to  tlie  ridges  of  the 
bone  by  tendinous  processes.  Externally  it  is  inserted  by  a  tendon  into 
the  small  tuberosity  of  tlie  humerus,  and  by  fleshy  fibres  into  the  neck  for 
nearly  an  incli  below  that  process. 

By  one  surface  the  muscle  bounds  the  axilla,  and  is  in  contact  with  tlie 
axillary  vessels  and  nerves  and  the  serratus  magnus.  By  the  other,  it 
rests  against  the  scapula  and  the  shoulder  joint ;  and  between  its  tendon 
and  the  root  of  the  coracoid  process  is  a  bursa,  which  communicates  gene- 
rally with  the  synovial  membrane  of  the  joint.  The  lower  border  projects 
much  beyond  the  bone ;  it  is  contiguous  to  the  teres  major,  the  latissimus 
16 


242  DISSECTION    OF    THE    UPPER    LIMB. 

dorsi,  and  the  long  head  of  the  triceps  :  along  this  border  is  the  subscapular 
artery,  which  gives  backwards  its  dorsal  branch. 

Action.  It  rotates  in  the  hanging  limb  ;  and  when  the  humerus  is  raised 
it  depresses  the  bone. 

If  the  humerus  is  fixed  the  subscapularis  supports  the  shoulder  joint  with 
the  other  scapular  muscles. 

jyissection.  The  subsca[)ular  muscle  is  to  be  separated  from  the  scapula, 
but  a  thin  layer  of  fibres,  in  which  the  vessels  lie,  is  to  be  left  on  the  bone : 
as  it  is  raised  its  tendinous  processes  of  origin,  the  connection  between  its 
tendon  and  the  capsule  of  the  shoulder  joint,  and  the  bursa,  are  to  be  ob- 
served. A  small  arterial  anastomosis  on  the  ventral  surface  of  the  bone 
is  to  be  dissected  out  of  the  fleshy  fibres. 

The  infrascapular  artery  ramifies  on  the  ventral  surface  of  the  scapula, 
and  is  an  offset  of  the  dorsal  branch  of  the  scapular  vessel  (p.  335):  en- 
tering beneath  the  subscapularis  muscle,  it  forms  an  anastomosis  with  small 
twigs  of  the  supra  and  posterior  scapular  branches. 

Position.  The  examination  of  the  muscles  on  the  opposite  surface  of  the 
scapula  may  be  next  undertaken.  For  this  purpose  the  scapula  is  to  be 
turned  over ;  and  a  block,  which  is  deep  enough  to  make  tlie  shoulder 
prominent,  is  to  be  placed  between  that  bone  and  the  arm. 

Dissection.  The  skin  is  to  be  removed  from  the  prominence  of  the 
shoulder,  by  beginning  at  the  anterior  border  of  the  deltoid  muscle.  After 
its  removal  some  small  cutaneous  nerves  are  to  be  found  in  the  fat: — the 
upper  of  these  extend  over  the  acromion  ;  and  another  comes  to  the  sur- 
lace  about  half  way  down  the  posterior  border  of  the  deltoid  muscle. 

Superjicial  nerves.  Branches  of  nerves,  super- acromial^  descend  to  the 
surface  of  the  shoulder  from  the  cervical  plexus  (p.  66).  A  cutaneous 
branch  of  the  circumflex  nerve  (fig.  74,'"')  turns  forwards  with  a  small 
companion  artery  from  beneath  the  posterior  border  of  the  deltoid,  and 
supplies  the  integuments  covering  the  lower  two-thirds  of  the  muscle. 

Dissection.  The  fat  and  fascia  are  now  to  be  taken  from  the  fleshy  del- 
toid, its  fibres  being  made  tense  at  the  same  time.  Beginning  at  the 
anterior  edge  of  the  muscle,  the  dissector  is  to  carry  the  knife  upwards  and 
downwards  along  the  fibres,  in  order  that  its  coarse  muscular  fasciculi  may 
bi  more  easily  cleaned.  As  the  posterior  edge  is  approached,  the  cuta- 
neous nerve  and  artery  escaping  from  beneath  it,  are  to  be  dissected  out. 

At  the  same  time  the  fascia  may  be  removed  from  the  back  of  tiie 
scapula,  so  as  to  denude  the  muscles  there. 

The  DELTOID  MUSCLE  is  triangular  in  form  (fig.  74,  ^),  with  the  base  at 
the  scapula  and  clavicle,  and  the  apex  at  the  humerus.  It  arises  from 
n;^arly  all  the  lower  edge  of  the  spine  of  the  scapula,  from  the  anterior 
edge  of  the  acromion,  and  from  the  outer  half  or  third  of  the  clavicle.  Its 
fibres  converge  to  a  tendon,  which  is  inserted  into  a  triangular  imjjression, 
two  or  three  inches  long  and  about  one  inch  wide  at  the  base,  above  the 
middle  of  the  outer  surface  of  the  humerus. 

The  anterior  border  is  contiguous  to  the  pectoralis  major  muscle  and  the, 
cephalic  vein  ;  and  the  posterior  rests  on  the  infraspinatus  and  triceps 
muscles.  The  origin  of  the  muscle  corresponds  with  the  attachment  of 
the  trapezius  to  the  bones  of  the  shoulder;  the  insertion  is  united  witli 
the  tendon  of  the  pectoralis  major,  and  a  fasciculus  of  the  brachialis 
amicus  is  attached  on  each  side  of  it. 

Action The  whole  muscle  raises  the  humerus,  and  abducts  it  from 


DELTOID    MUSCLE, 


243 


the  trunk.  The  linil)  bein*^  rjiised,  the  anterior  fibres  will  carry  it  for- 
Avards,  and  the  posterior  fibres  will  move  it  backwards. 

When  the  humerus  is  fixed  as  in  climbing,  the  muscle  assists  in  sup- 
porting the  w^eight  of  the  body,  and  strengtiiening  the  shoulder-joint. 

Dissection  (fig.  74).  The  deltoid  is  to  be  divided  near  its  origin,  and 
is  to  be  thrown  down  as  much  as  the  circumflex  vessels  and  nerve  beneath 
will  permit.  As  the  muscle  is  raised  a  large  thick  bursa  between  it  and 
the  head  of  the  humerus  comes  into  sight.  The  loose  tissue  and  fat  are 
to  be  taken  away  from  the  circumflex  vessels  and  nerve  ;  and  the  size  of 
the  bursa  having  been  looked  to,  the  remains  are  to  be  removed.  Tlie 
insertion  of  the  muscle  should  be  examined. 

Fiff.  74. 


ViKW    OF   THE   MUSCLKS   OF   THE  DORSUM    OF   THE   SCAPCLA,    AXD   OF   THE   CiRCrMFI.EX  VESSELS 

AXD  Kerve.     (Illustrations  of  Dissections.) 

Muscles:  Arteries: 

A.  Supra-sp'natus.  a.  Posterior  circumflex  artery. 

B.  Infra-spinatus.  b.    Branch  to  teres  minor. 

c.  Teres  minor.  c.   Dorsal  scapular  branch  of  sub- 

».  Teres  major.  scapular. 

E.  Latissimus  dorsi.  Nerves  : 

F.  Deltoid.  1.  Posterior  circumflex. 

o.  Triceps  (long  head).  2.  Its  cutaneous  ofl"sot  to  the  arm. 

H.   Levator  anguli  scapula?.  3.  Branch  to  the  teres  minor  muscle. 
J.   Rhomboideus  minor. 
K.  Rhomboideus  m  ijor. 


Parts  covered  hy  deltoid.  The  deltoid  conceals  the  head  and  upper 
end  of  the  humerus,  and  those  ])arts  of  the  dorsal  scapular  muscles  which 
are  fixed  to  the  great  tuberosity.  A  large  bursa,  sometimes  divided  into 
sacs,  intervenes  between  the  head  of  the  humerus  and  the  under  surface 
of  tlie  deltoid  muscle  and  the  acromion  process.     Below  the  head  of  the 


244  DISSECTION    OF    THE    UPPER    LIMB. 

bone  are  the  circumflex  vessels  and  nerve,  and  the  upper  part  of  the 
biceps  muscle.  In  front  of  the  humerus  is  the  coracoid  process  with  its 
muscles. 

Dissection.  By  following  back  the  posterior  circumflex  vessels  and 
nerve  through  a  space  between  the  humerus  and  the  long  head  of  the  tri- 
ceps, G,  their  connection  with  the  axillary  trunks  will  be  arrived  at.  In 
clearing  the  fat  from  the  space  a  branch  of  the  nerve  to  the  teres  minor 
muscle  is  to  be  sought  close  to  the  border  of  the  scapula,  where  it  is  sur- 
rounded by  dense  fibrous  tissue. 

Arching  outwards  in  front  of  the  neck  of  the  humerus,  is  the  sm^U 
anterior  circumflex  artery :  this  is  to  be  cleaned. 

The  circumflex  arteries  arivSe  near  the  termination  of  the  axillary  trunk 
(p.  335)  ;  they  are  two  in  number,  and  are  named  anterior  and  posterior 
from  their  position  to  the  neck  of  the  humerus. 

The  anterior  branch  is  a  small  artery,  which  courses  beneath  the 
coraco-brachialis  and  biceps  muscles,  and  ascends  in  the  bicipital  groove 
to  the  articulation  and  the  head  of  the  humerus :  it  anastomoses  with 
small  offsets  of  the  posterior  circumflex. 

The  posterior  circumflex  artery  (fig.  74,  «),  larger  in  size,  winds  back- 
wards through  a  space  between  the  humerus  and  the  long  head  of  the 
triceps,  and  is  distributed  chiefly  to  the  deltoid  muscle,  in  which  it  anasto- 
moses with  the  acromial  thoracic  and  upper  profunda  arteries. 

Branches  are  given  from  it  to  the  head  of  the  humerus  and  the  shoulder 
joint,  and  to  anastomose  with  the  anterior  circumflex  artery.  It  supplies 
branches  likewise  to  the  teres  minor,  the  long  head  of  the  triceps,  and  the 
integuments. 

The  circumflex  nertw  (fig.  74,  ^)  leaves  the  arm-pit  with  the  posterior 
circumflex  artery  (p.  335),  and  bends  round  the  neck  of  the  humerus; 
beneath  the  deltoid  muscle  in  which  it  ends.  Many  and  large  branches 
enter  the  deltoid,  and  terminate  in  it;  one  or  two  filaments  pierce  the 
fibres  and  become  cutaneous. 

Branches.  In  the  axilla  it  gives  an  articular  filament  to  the  under  part 
of  the  shoulder-joint.  Behind  the  humerus  it  furnishes  an  ofl^set  to  the 
teres  minor  (^),  which  has  a  reddiwsh  gangliform  swelling  on  it.  And  at 
the  edge  of  the  deltoid  it  gives  origin  to  the  cutaneous  nerve  (^)  before 
noticed. 

The  INFRASPINATUS  MUSCLE  (fig.  74,  b)  occupies  the  infraspinal  part 
of  the  scapula,  and  extends  to  the  head  of  the  humerus.  The  muscle 
arises  from  the  infraspinal  fossa,  except  at  three  spots,  viz.,  the  neck,  and 
the  low^er  angle  and  inferior  border  where  the  teres  muscles  are  attached ; 
it  arises  also  from  the  lower  side  of  the  spinous  process,  and  from  the  special 
fascia  covering  the  surface.  Its  fibres  converge  to  a  tendon,  which  is  in- 
serted into  the  middle  impression  on  the  great  tuberosity  of  the  humerus, 
and  joins  the  tendons  of  the  supraspinatus  and  teres  minor. 

A  part  of  the  muscle  is  subcutaneous,  and  the  fibres  arising  from  the 
spine  of  tlie  scapula  overlay  the  tendon  :  the  upper  portion  is  concealed 
by  the  deltoid  ;  and  the  lower  end,  by  the  latissimus  dorsi.  The  lower 
border  is  f)arallel  to  tlie  teres  minor,  with  which  it  is  sometimes  united. 
The  muscle  lies  on  the  scapula  and  the  humero-scapular  articulation,  but 
between  it  and  the  joint  is  a  small  bursa. 

Action.  With  the  humerus  hanging  it  acts  as  a  rotator  outwards;  and 
when  the  bone  is  raised  it  will  move  the  same  backwards  in  concert  with 
the  hinder  part  of  the  deltoid. 


DORSAL  SCAPULAR  MUSCLES.  245 

The  TERES  MINOR  (fig.  74,  c)  is  a  narrow  fleshy  slip,  which  is  often 
united  inseparably  with  the  preceding  muscle,  along  whose  lower  border 
it  lies.  It  arises  on  the  dorsum  of  tlie  scapula  from  a  special  surface  alono- 
the  upper  two-thirds  of  the  inferior  costa  of  the  bone,  and  from  the  invest- 
ing fascia  ;  and  it  is  inserted  by  a  tendon  into  the  lowest  of  the  three  marks 
on  the  great  tuberosity  of  the  humerus,  as  well  as  by  fleshy  fibres  into  the 
humerus  below  that  spot — about  an  inch  together. 

This  muscle  is  partly  covered  by  the  deltoid  ;  it  rests  on  the  long  head 
of  the  trice))S  and  the  shoulder  joint.  Underneath  it  the  dorsal  branch  of 
the  subscapular  artery  turns. 

Action,  The  arm  hanging  the  muscle  rotates  it  out  and  moves  it  back  ; 
the  arm  being  raised  the  teres  depresses  the  humerus. 

In  climbing  it  sui)ports  the  joint  like  the  preceding  scapular  muscles. 

The  TERES  MAJOR  musclc  (fig.  74,  d)  is  extended  from  the  inferior 
angle  of  the  scapula  to  the  humerus.  Its  origin  is  from  the  rough  surface 
on  tlie  dorsum  of  the  bone  at  the  inferior  angle  ;  from  the  inferior  costa 
as  far  forwards  as  an  inch  from  the  long  head  of  the  triceps ;  and  from 
the  fascia  cov^ering  the  teres  minor.  The  fibres  end  in  a  tendon  which  is 
inserted  partly  into,  and  partly  behind  the  inner  edge  of  the  bicipital  groove 
of  the  humerus. 

This  muscle  assists  in  forming  the  posterior  fold  of  the  axilla ;  and  is 
situate  beneath  the  axillary  vessels  and  nerves  near  the  humerus  (fig.  70). 
At  its  origin  it  is  covered  by  the  latissimus  dorsi.  The  upper  border  is 
contiguous  to  the  subscapularis  muscle,  and  the  lower  is  received  into  a 
hollow  formed  by  the  fibres  of  the  latissimus  dorsi  At  the  humerus  the 
tendon  of  the  muscle  is  one  inch  and  a  half  to  two  inches  wide,  and  is 
placed  behind  that  of  the  latissimus:  the  two  are  separated  above  by  a 
bursa ;  but  they  are  united  below,  and  an  expansion  is  sent  from  them  to 
the  fascia  of  the  arm.    A  second  bursa  lies  between  the  tendon  and  the  bone. 

Action.  If  the  limb  hangs  it  is  carried  back  behind  the  trunk  and  is 
rotated  inwards  by  the  muscle.  The  humerus  being  raised,  the  muscle 
depresses  and  adducts  it. 

With  the  limb  fixed  by  the  hand  the  teres  will  cause  the  lower  angle  of 
the  scapula  to  move  forwards. 

Below  the  scapula  (inferior  costa),  where  the  teres  muscles  separate 
from  one  another,  is  a  triangular  interval,  which  is  bounded  in  front  by 
the  shaft  of  the  humerus,  and  above  and  below  by  the  teres  muscles.  This 
space  is  divided  into  two  by  the  long  head  of  the  triceps.  Through  the 
anterior  part,  which  is  of  a  quadrilateral  shape,  the  posterior  circumflex 
vessels  and  the  circumflex  nerve  pass  :  and  opposite  the  posterior  trian- 
gular space,  the  dorsal  branch  (c)  of  the  subscapular  artery  bends  back- 
wards. 

Dissection  (fig.  75).  In  order  that  the  acromion  process  may  be  sawn 
through  to  expose  the  supraspinatus  muscle,  the  ligaments  of  the  scapula 
and  clavicle,  which  would  be  injured  by  such  a  proceeding,  should  next  be 
dissected. 

A  ligament  (coraco-clavicular)  ascends  from  the  coracoid  process  to  the 
under  part  of  the  clavicle  :  on  removing  the  areolar  tissue  it  will  be  seen 
to  consist  of  two  parts,  anterior  and  posterior,  differing  in  size,  and  in  the 
direction  of  the  fibres. 

A  capsular  ligament,  connecting  the  outer  end  of  the  clavicle  with  the 
acromion,  will  be  recognized  by  taking  away  the  fibres  of  the  trapezius 
and  deltoid  muscles. 


246 


DISSECTION    OF    THE    UPPER    LIMB 


Another  strong  band  (coraco-acromial)  passing  transversely  between 
the  acromion  and  the  coracoid  process  ;  and  a  small  fasciculus  (posterior 
proper  ligament),  placed  over  the  notch  in  the  superior  costa,  are  then  to 
be  defined.  ,    . 

Ligaments  of  the  Clavicle  anp  Scapula  (fig.  75).  The  clavicle 
is  connected  to  the  scapula  by  a  distinct  joint  with  the  acromion,  and  by 
a  strong  ligament  (coraco-clavicular)  between  it  and  the  coracoid  process. 

The  coraco-clavicnlar  ligament  consists  of  two  parts,  each  having  a 
different  direction  and  designation. 

The  posterior  piece  (^),  called  conoid  from  its  shape,  is  fixed  by  its  apex 
to  the  posterior  and  inner  part  of  the  coracoid  process ;  and  by  its  base  to 
the  tubercle  and  the  contiguous  part  of  the  under  surface  of  the  clavicle, 
at  the  junction  of  the  outer  with  the  middle  third  of  tlie  bone. 

The  anterior  part  (^),  trapezoid  ligament,  is  larger  than  the  conoid 
piece :  it  is  connected  inferiorly  to  the  inner  border  of  the  carocoid  pro- 
cess along  the  hinder  half;  and  superiorly  to  the  line  on  the  under  surface 
of  the  clavicle  which  extends  outwards  Irom  the  tubercle  before  mentioned. 
The  two  pieces  of  the  ligament  ai*e  in  apposition  posteriorly,  but  are  sepa- 
rated by  an  interval  in  iront. 

Use.  Both  pieces  of  the  ligament  support  the  scapula  in  a  state  of  rest : 
they  serve  also  to  restrain  the  rotatory  movements  of  that  bone  ;  thus 

Fig.  75. 


1.  Conoid  lli?ament. 

2.  Trapezoid  ligament. 

3.  Anteiior  ligament  of  the  scapnia. 

4.  Posterior  scapular  ligament. 

5.  Capsule  of  the  shoulder  joint. 

6.  Tendon  of  the  long  head  of  the  bi- 

ceps entering  the  joint. 

7.  Tendon  of  the  subscapular  muscle. 

8.  Coraco  humeral  ligament. 


LlOAMEXTS  OF  THE  Cl.AVICLE  AND  SCAPUI.A,  AND  OF  THE  SHOULDER  JoiNT 

(altered  from  Bourgery  and  Jacob). 


when  the  acromion  is  rotated  down,  the  motion  is  checked  by  the  trapezoid 
band  ;  and  when  upwards,  by  the  conoid  piece. 

Acromio-clavicular  articulation.  The  articular  surfaces  of  the  clavicle 
and  acromion  process  of  the  scapula  are  retained  in  contact  by  a  capsule 
formed  of  strong  fibres.  Some  of  the  fibres  are  thicker  above  and  below, 
and  are  considered  to  constitute  a  superior  and  an  inferior  ligament. 

An  inter  articular  Jibro-cartilage  generally  exists  at  the  upper  part  of 
the  joint ;  but  sometimes  it  forms  a  complete  interarticular  septum.  If 
the  fibro-cartilage  is  perfect,  there  are  two  synoviol  membranes  {)resent  in 
the  joint ;  if  it  is  imperfect,  there  is  only  one.  The  joint  should  be  opened 
to  see  the  cartilage  and  the  synovial  membrane. 

Movements.  In  this  articulation  there  are  limited  fore  and  back  and  up 
and  down  movements  of  the  scapula. 


SCAPULAR    LIGAMENTS.  247 

Besides,  there  is  a  glidinjr  movement  of  the  acromion  on  the  clavicle 
in  rotation  of  the  scapula.  For  instance,  when  the  acromion  is  depressed, 
its  articular  surface  moves  from  above  down  at  the  fore  part  of  the  joint, 
and  from  below  up  at  the  back.  When  the  acromion  is  elevated  the  sur- 
iace  moves  in  exactly  the  opposite  way. 

Scapular  Ligaments.  The  special  ligaments  of  the  scapula  are  two 
in  number,  anterior  and  posterior,  and  extend  from  one  part  of  the  bone 
to  another. 

The  posterior  ligament  (*)  is  a  narrow  fasciculus  of  fibres  stretching 
across  the  notch  in  the  upper  costa  of  the  scapula.  By  one  end  it  is  at- 
tached to  the  base  of  the  coracoid  process,  and  by  the  other  to  the  costa 
behind  the  notch.  It  converts  the  notch  into  a  foramen,  through  which 
the  suprascapular  nerve  passes. 

The  anterior  or  coraco-acromial  ligament  (')  is  triangular  in  form,  and 
extends  transversely  between  the  acromion  and  the  coracoid  process.  Ex- 
ternally it  is  inserted  by  its  point  or  apex  into  the  tip  of  the  acromion  ; 
and  internally,  where  it  is  much  wider,  it  is  attached  to  all  the  outer 
border  of  the  coracoid  process,  reaching  backwards  to  the  capsule  of  the 
shoulder  joint.  The  ligament  consists  usually  of  two  thickened  bands, 
anterior  and  j)OSterior,  witii  a  thin  intervening  part.  It  forms  part  of  an 
arch  above  the  shoulder  joint,  which  stops  the  ascent  of  the  head  of  the 
humerus. 

Dissection,  To  lay  bare  the  supraspinatus  muscle,  the  acromion  pro- 
cess is  to  be  sawn  tlirough,  and  to  be  turned  aside  with  the  outer  end  of 
the  clavicle :  but  in  the  repetition  of  the  dissection  of  the  upper  limb,  the 
bone  may  be  left  uncut  for  the  purpose  of  seeing  the  use  of  the  coraco- 
acromial  arch.  A  strong  fascia  covers  tlie  surface  of  the  muscle  ;  this  is 
to  be  taken  away  after  it  has  been  observed. 

The  SUPRASPINATUS  MUSCLE  (fig.  74,  ^)  has  the  same  form  as  the 
hollow  of  the  bone  it  fills.  It  arises  from  tlie  surface  of  the  supra-spinal 
fossa  of  the  scapula,  except  from  the  cervical  part ;  from  the  upper  side  of 
the  spine  of  the  bone  ;  and  from  the  fascia  covering  the  surface.  Its  fibres 
end  in  a  tendon,  which  crosses  over  tlie  shoulder  joint,  and  is  inserted  into 
the  upper  im[)ression  of  tlie  great  tuberosity  of  the  humerus. 

The  mui-cle  is  concealed  by  the  trapezius  and  the  acromion  process  ; 
and  it  rests  upon  the  scaj)ula,  the  shoulder  joint,  and  the  suprascapular  ves- 
sels and  nerve.  Its  tendon  joins  that  of  the  infraspinatus  at  the  attach- 
ment to  the  humerus. 

Action.  It  comes  into  use  with  the  deltoid  in  raising  the  limb,  and 
supporting  the  joint. 

Dissection  (fig.  78).  The  vessels  and  nerves  on  the  dorsum  of  the 
scapula  can  be  traced  by  detaching  from  beliind  forwards  the  supra  and 
infraspinatus  muscles,  so  as  to  leave  a  thin  layer  of  the  fleshy  fibres  with 
the  ramifying  bloodvessels  on  the  surface  of  tlie  bone.  In  the  supraspinal 
fossa  are  the  suprascapular  vessels  and  nerve,  which  are  to  be  followed 
beneath  the  acromion  to  the  intraspinal  fossa ;  and  entering  the  infra- 
spinal  fossa,  beneath  the  teres  minor  muscle,  is  the  dorsal  branch  of  ti»e 
subscapular  artery.  The  anastomosis  between  those  vessels  should  be  pur- 
sued in  the  fleshy  fibres  and  cleaned. 

The  suprascapular  artery  (a)  is  derived  from  the  subclavian  trunk, 
and  is  one  of  the  branches  of  the  thyroid  axis  (p.  78).  After  a  siiort 
course  in  the  neck  it  passes  over  the  ligament  at  the  superior  costa,  and 
crossing  beneath  the  supraspinatus  muscle,  ends  in  the  intraspinal  fossa, 


248  DISSECTION    OF    THE    ARM. 

where  it  gives  offsets  to  the  infraspinatus  muscle  and  the  scapuhi,  and 
anastomoses  with  the  dorsal  branch  of  the  subscapular,  and  the  posterior 
scapular  artery  of  the  subclavian. 

Beneath  tlie  suj)raspinatus  it  furnishes  a  supraspinal  branch  for  the 
supply  of  the  muscle,  the  bone,  and  the  shoulder-joint. 

The  companion  vein  of  the  suprascapular  artery  joins  the  external  jugu- 
lar vein. 

The  suprascapular  nerve  Q)  is  a  branch  of  the  brachial  plexus  (p.  80). 
When  it  reaches  the  costa  of  tlie  scapula,  it  enters  the  supraspinal  fossa 
beneath  the  posterior  special  ligament.  In  the  fossa  it  supplies  two 
branches  to  the  supraspinatus ;  and  is  continued  beneath  a  fibrous  band  to 
the  infraspinatus  muscle,  in  which  it  ends. 

The  nerve  gives  some  articular  filaments  to  the  shoulder-joint,  and  other 
offsets  to  the  scapula. 

Tlie  posterior  scapular  artery  runs  along  the  base  of  the  scapula  beneath 
the  rhomboid  muscles,  furnishing  offsets  to  them  and  the  surfaces  of  the 
bone.     It  is  more  fully  noticed  with  the  dissection  of  tlie  Back. 

The  dorsal  branch  of  the  subscapular  artery  (b)  (p.  335)  turns  below 
the  inferior  costa  of  the  scapula,  opposite  the  posterior  of  the  two  spaces 
between  the  teres  muscles.  Entering  the  intraspinal  fossa  beneath  the 
teres  minor,  it  supplies  that  muscle  and  the  infraspinatus,  and  communi- 
cates with  the  suprascapular  artery.  This  vessel  sends  a  branch  along 
the  dorsum  of  the  scapula  between  the  teres  muscles,  towards  the  inferior 
angle  of  the  bone. 


Section  III. 

THE  FRONT  OF  THE  ARM. 


Position.  For  the  dissection  of  the  superficial  vessels  and  nerves  on 
the  front  of  the  arm,  the  limb  should  lie  flat  on  the  table,  with  the  front 
uppermost. 

Dissection.  The  skin  is  to  be  raised  from  the  fore  and  hinder  parts  of 
the  arm  and  elbow-joint.  To  reflect  it,  make  one  incision  along  the  centre 
of  the  limb  as  far  as  two  inches  below  the  elbow  ;  and  at  the  termination, 
a  second  cut  half  round  the  forearm.  Strip  now  the  skin  from  the  limb, 
as  low  as  the  transverse  incision,  so  that  the  fat  which  contains  the  cuta- 
neous vessels  and  nerves  may  be  denuded.  Between  the  skin  and  the 
prominence  of  the  olecranon  a  bursa  may  be  seen. 

The  cutaneous  veins  (fig.  76)  may  be  sought  first  in  the  fat:  they  are 
very  numerous  below  the  bend  of  the  elbow,  as  they  issue  from  beneath 
the  integument.  One  in  the  centre  of  the  forearm  is  the  median  vein, 
which  bifurcates  rather  below  the  elbow.  External  to  this  is  a  small  vein 
(radial)  ;  and  internal  to  it  are  the  anterior  and  posterior  ulnar  veins, 
coming  from  the  front  and  back  of  the  forearm.  At  the  elbow  these  veins 
are  united  into  two ;  one  (basilic)  is  to  be  followed  along  the  inner  side, 
and  the  other  (cephalic)  along  the  outer  side  of  the  arm. 

The  cutaneous  nerves  may  be  next  traced  out.  Where  tliey  perforate 
the  deep  fascia  they  lie  beneath  the  fat ;  and  this  layer  must  be  scra[)ed 
through  to  find  them. 


CUTANEOUS    VEINS.  249 

On  the  outer  side  of  the  arm,  about  its  middle,  two  external  cutaneous 
branches  of  the  rausculo-spiral  are  to  be  sought.  In  the  outer  bicipital 
groove,  in  front  of  the  elbow  or  rather  below  it,  the  cutaneous  part  of  the 
musculo-cutaneous  nerve  will  be  recognized. 

On  the  inner  part  of  the  limb  the  nerves  to  the  surface  are  more  nume- 
rous. Taking  the  basilic  vein  as  a  guide,  the  internal  cutaneous  nerve  of 
the  forearm  will  be  found  by  its  side,  about  the  middle  of  the  arm  ;  and 
rather  external  to  this  nerve  is  a  small  cutaneous  offset  from  it,  which 
pierces  the  fascia  higher  up.  Scrape  through  the  fat  behind  the  internal 
cutaneous,  in  the  lower  third  of  the  arm,  for  the  small  nerve  of  Wrisberg ; 
and  in  the  upper  third,  seek  the  small  nerves  which  have  been  already 
met  with  in  the  dissection  of  the  axilla,  viz.,  the  intercosto-humeral,  and 
the  internal  cutaneous  of  the  musculo-spiral. 

Superficial  fascia.  The  subcutaneous  fatty  layer  forms  a  continuous 
investment  for  the  limb,  but  it  is  thicker  in  front  of  the  elbow  than  in  the 
other  parts  of  the  arm.  In  that  spot  it  incloses  the  superficial  vessels  and 
the  lymphatics. 

Cutaneous  Veins.  The  position  and  the  connections  of  the  superficial 
veins  in  front  of  the  elbow  are  to  be  attentively  noted  by  the  dissector, 
because  the  operation  of  venesection  is  practised  in  one  of  them. 

The  median  vein  of  the  forearm  (fig.  76,  =*),  divides  into  two  branches, 
internal  and  external,  rather  below  the  bend  of  the  elbow  ;  at  its  point  of 
division  it  is  joined  by  an  offset  from  a  deep  vein.  The  internal  branch 
(median  basilic)  crosses  to  the  inner  border  of  the  biceps,  and  unites  with 
the  ulnar  veins  (^)  to  form  the  basilic  vein  of  the  inner  side  of  the  arm. 
The  external  branch  (median  cephalic)  is  usually  longer  than  the  other, 
and  by  its  junction  with  the  radial  vein  (J)  gives  rise  to  the  cephalic  vein 
of  the  arm. 

The  connections  of  the  two  veins  into  which  the  median  bifurcates,  are 
described  below : — 

The  median  cephalic  vein  (fig.  7G)  is  directed  obliquely,  and  lies  over 
the  hollow  between  the  biceps  and  the  outer  mass  of  muscles  of  the  fore- 
arm. Beneath  it  is  the  trunk  of  the  musculo-cutaneous  nerve  ;  and  over 
it  some  small  offsets  from  the  nerve  are  directed.  This  vein  is  altogether 
removed  from  the  brachial  artery,  and  is  generally  smaller  than  tlie  me- 
dian basilic  vein.  If  opened  with  a  lancet,  it  does  not  generally  yield 
much  blood,  in  consequence  of  its  position  in  a  hollow  between  muscles 
rendering  compression  of  it  very  uncertain  and  difficult. 

The  median  basilic  vein  (fig.  76,  ^)  is  more  horizontal  in  direction  than 
the  preceding,  and  crosses  the  brachial  artery.  It  is  larger  than  the  cor- 
responding vein  of  the  outer  side  of  the  arm,  and  is  firmly  supported  by 
the  underlying  fascia — the  aponeurosis  of  the  arm,  strengthened  by  fibres 
from  the  biceps  tendon,  intervening  between  it  and  the  brachial  vessels. 
Branches  of  the  internal  cutaneous  nerve  lie  beneath  it,  and  some  twigs 
of  the  same  nerve  are  placed  over  it. 

The  median  basilic  is  the  vein  on  which  the  operation  of  blood-letting 
is  commonly  performed.  It  is  selected  in  consequence  of  its  usually  larger 
size,  and  more  superficial  position,  and  of  the  ease  with  which  it  may  be 
compressed ;  but  from  its  close  proximity  to  the  brachial  vessels,  the  spot 
to  be  opened  should  not  be  immediately  over  the  trunk  of  the  artery. 

The  basilic  vein  (fig.  76,  ^),  commencing  as  before  said,  ascends  near 
the  inner  border  of  the  biceps  muscle  to  the  middle  of  the  arm,  where  it 


250 


DISSECTION    OF    THE    ARM. 


passes  beneath  the  deep  fascia,  and  is  continuous  with  the  axillary  vein. 
In  this  course  it  lies  to  the  inner  side  of  the  brachial  artery. 

The  cephalic  vein  (fig.  76,  ^)  is  derived  chiefly  from  the  external  branch 
of  the  median,  for  the  radial  vein  is  oftentimes  very  small :  it  is  continued 
to  the  shoulder  along  the  outer  side  of  the  biceps,  and  sinks  between  the 
deltoid  and  pectoral  muscles,  near  the  clavicle,  to  open  into  the  axillary 
vein. 


Fig.  7(J. 


1.  Median  basilic  vein. 

2.  Median  vein  of  the  forearm  bifurcating. 
.3.  Anterior  ulnar  veins. 

4.  Cephalic  vein  formed  by  radial  from  behind  and  the  median 
cephalic  in  front.  The  musculo-cutaneous  nerve  is  by  the  side 
of  it. 

').  Basilic  vein,  with  large  internal  cutaneous  nerve  by  its  side. 

6.  Brachial  artery,  with  its  companion  veins  (one  cut). 

7.  Kadial  vein. 


CcTAXEOus  Veins  and  NsRVts  at  the  Bend  of  the  Elbow.  (Quain's  "  Arteries.") 

The  superficial  lymphatics  of  the  arm  lie  for  the  most  part  along  the 
basilic  vein,  and  enter  into  the  glands  of  the  axilla.  A  few  lympliatics 
accompany  the  cephalic  vein,  and  end  as  the  others  in  the  axillary  glands. 

One  or  more  superficial  lymphatic  glands  are  commonly  found  near  the 
inner  condyle  of  the  humerus. 

Cutaneous  Nerves.  The  superficial  nerves  of  the  arm  appear  on  the 
inner  and  outer  sides,  and  spread  so  as  to  cover  the  surface  of  the  limb. 
With  one  exception  (intercosto-humeral)  all  are  derived  from  the  brachial 
plexus,  either  as  distinct  branches,  or  as  offsets  of  other  nerves.  On  the 
outer  side  of  the  limb  are  branches  of  the  musculo-sjiiral  and  musculo- 
cutaneous nerves.  On  the  inner  side  are  two  internal  cutaneous  nerves, 
large  and  small  (from  the  plexus),  a  third  internal  cutaneous  from  the 
musculo-spiral,  and  the  intercosto-humeral  nerve. 

External  cutaneous  Nerves.  The  external  cutaneous  branches  of 
the  musculo-spiral  nerve  are  two  in  number,  and  appear  at  the  outer  side 
of  the  limb  about  the  middle.  The  upper  small  one  turns  forwards  with 
the  cephalic  vein,  and  reaches  the  front  of  the  elbow,  supplying  the  ante- 
rior part  of  the  arm.  The  lower  and  larger  pierces  the  fascia  somewhat 
farther  down,  and  after  supplying  some  cutaneous  filaments,  is  continued 
to  the  forearm. 

The  cutaneous  part  of  the  musculo-cutaneous  nerve  pierces  the  fascia 
in  front  of  the  elbow  ;  it  lies  beneath  the  median  cephalic  vein,  and  divides 
into  branches  for  the  forearm. 

Internal  cutaneous  Nerves.  The  larger  internal  cutaneous  nerve 
perforates  the  fascia  in  two  parts,  or  as  one  trunk   that  divides  almost 


INTERNAL    CUTANEOUS    NERVES.  251 

directly  into  two  : — Its  external  branch  passes  beneath  the  median  basilic 
vein  to  the  front  of  the  forearm  ;  and  the  internal  winds  over  tlie  inner 
condyle  of  the  humerus  to  the  back  of  the  forearm. 

A  cutaneous  offset  of  the  nerve  pierces  the  fascia  near  the  axilla,  and 
reaches  as  far,  or  nearly  as  far  as  the  elbow  :  it  supplies  tlie  integuments 
over  the  inner  part  of  the  biceps  muscle. 

The  small  internal  cutaneous  nerve  (Wrisberg)  appears  below  the  pre- 
ceding, and  extends  to  the  interval  between  the  olecranon  and  the  inner 
condyle  of  the  humerus,  where  it  ends  in  filaments  over  the  back  of  the 
olecranon.  The  nerve  give  offsets  to  the  lower  tliird  of  the  arm  on  the 
inner  and  posterior  surfaces,  and  joins  above  the  elbow  the  inner  branch 
of  the  larger  internal  cutaneous  nerve. 

The  internal  cutaneous  branch  of  the  musculo-spiral  nerve  becoming 
subcutaneous  in  the  upper  tliird,  winds  to  the  back  of  the  arm,  and  reaches 
nearly  as  far  as  the  olecranon. 

The  intercosto-humeral  branch  of  the  second  intercostal  nerve  (p.  226), 
perforates  the  fascia  near  the  axilla,  and  ramifies  in  the  inner  side  and 
posterior  surface  of  the  arm  in  the  upper  half.  But  the  size  and  distribu- 
tion of  the  nerve  will  depend  upon  the  development  of  the  small  internal 
cutaneous  and  the  offsets  of  the  musculo-spiral. 

Tlie  aponeurosis  of  the  arm  is  a  white  shining  membrane  which  sur- 
rounds the  limb,  and  sends  inwards  processes  between  the  muscle.  Over 
the  biceps  muscle  it  is  thinner  than  elsewhere.  At  certain  points  it  re- 
ceives accessory  fibres  from  the  subjacent  tendons  : — thus  in  front  of  the 
elbow  an  offset  from  the  tendon  of  the  biceps  joins  it ;  and  near  the  axilla 
the  tendons  of  the  pectoralis  major,  latissimus  dorsi,  and  teres,  send  pro- 
longations to  it. 

At  the  upper  part  of  the  limb  the  fascia  is  continuous  with  that  of  the 
axilla,  and  is  prolonged  over  tlie  deltoid  and  pectoral  muscles  to  the  scapula 
and  the  clavicle.  Inferiorly  it  is  continued  to  the  forearm,  and  is  con- 
nected to  the  prominences  of  bone  around  the  elbow  joint,  especially  to  the 
condyloid  ridges  of  the  humerus  so  as  to  give  rise  to  the  intermuscular 
septa  of  the  arm. 

Directions.  As  the  back  of  the  arm  will  not  be  dissected  now,  the  skin 
may  be  replaced  on  it  until  the  front  has  been  examined.  And  to  keep 
in  place  the  vessels  and  nerves  at  the  upper  part  of  the  limb,  these  should 
be  tied  together  with  string  in  their  natural  position  to  one  another,  and 
fastened  to  the  coracoid  process. 

Position.  The  limb  is  still  to  lie  on  the  back,  but  the  scapula  is  to  be 
raised  by  means  of  a  small  block ;  and  the  bladebone  is  to  be  fixed  in 
such  a  position  as  to  render  tense  the  muscles.  The  inner  surface  of  the 
arm  is  to  be  placed  towards  the  dissector. 

Dissection.  The  aponeurosis  is  to  be  reflected  from  the  front  of  the 
arm  by  an  incision  along  the  centre,  like  that  through  the  integuments; 
and  it  is  to  be  removed  on  the  outer  side  as  far  as  the  outer  condyloid 
ridge  of  the  humerus,  but  on  the  inner  side  rather  farther  back  than  the 
corresponding  line,  so  as  to  lay  bare  {)art  of  the  triceps  muscle.  In  rais- 
ing the  fascia  the  knife  must  be  carried  in  the  direction  of  the  fibres  of 
the  biceps  muscle ;  and  to  prevent  the  displacement  of  the  brachial  artery 
and  its  nerves,  fasten  them  here  and  there  with  stitches. 

In  front  of  the  elbow  is  a  hollow  containing  the  brachial  vessels:  the 
artery  should  be  followed  into  it,  to  show  its  ending  in  the  radial  and 
ulnar  trunks. 


252  DISSECTION    OF    THE    ARM. 

Muscles  on  the  Front  of  the  Arm.  There  are  only  three  muscles 
on  the  fore  part  of  the  arm.  The  one  along  tlie  centre  of  the  Fimb  is  the 
biceps ;  and  that  along  its  inner  side,  reaching  about  half  way  down,  is 
the  coraco-brachialis.  The  brachialis  anticus  lies  beneath  the  biceps. 
Some  muscles  of  the  forearm  are  connected  to  the  inner  and  outer  condyles 
of  the  humerus,  and  to  the  line  above  the  outer  condyle. 

The  biceps  muscle  (fig.  78,  ^)  forms  the  ])rominence  observable  on 
the  front  of  the  arm.  It  is  wider  at  the  middle  than  at  either  end;  and 
the  upper  part  consists  of  two  tendinous  pieces  of  different  lengths,  which 
are  attached  to  the  scapula.  Tiie  short  head  arises  from  the  apex  of  the 
coracoid  process  in  common  with  the  coraco-brachialis  muscle  (fig.  73) ; 
and  the  long  head  is  attached  to  the  upper  part  of  the  glenoid  cavity  of 
the  scapula,  within  the  capsule  of  the  shoulder  joint  (fig.  89).  Muscular 
fibres  spring  from  each  tendinous  head,  and  blend  about  the  middle  of  the 
arm  in  a  fleshy  belly,  which  is  somewhat  flattened  from  before  back.  In- 
feriorly  the  biceps  ends  in  a  tendon,  and  is  inserted  into  the  tubercle  of 
the  radius. 

The  muscle  is  superficial  except  at  the  extremities.  At  the  upper  part 
it  is  concealed  by  the  pectoralis  major  and  deltoid  muscles;  and  at  the 
lower  end  the  tendon  dips  into  the  hollow  in  front  of  the  elbow,  having 
previously  given  an  offset  to  the  fascia  of  the  arm.  Beneath  the  biceps 
are  the  brachialis  anticus  muscle,  the  musculo-cutaneous  nerve,  and  the 
upper  part  of  the  humerus.  Its  inner  border  is  the  guide  to  the  brachial 
artery  below  the  middle  of  the  humerus,  but  above  that  spot  the  coraco- 
brachialis  muscle  intervenes  between  them.  The  connection  of  the  long 
head  of  the  biceps  with  the  shoulder  joint,  and  the  insertion  of  the  muscle 
into  the  radius,  will  be  afterwards  learnt. 

Action.  It  bends  the  elbow-joint,  and  acts  powerfully  in  supinating 
the  radius.  When  the  body  is  hanging  by  the  hands  it  will  apply  the 
scapula  firmly  to  the  humerus,  and  will  assist  in  raising  the  trunk. 

With  the  arm  hanging  and  the  radius  fixed,  the  long  head  will  assist 
the  abductors  in  removing  the  limb  from  the  thorax ;  and  after  the  limb 
is  abducted,  the  short  head  will  aid  in  restoring  it  to  the  pendent  position. 

The  CORACO-BRACHIALIS  (fig.  73,  ")  is  roundish  in  form,  and  is  named 
from  its  attaehments.  Its  origin  is  fleshy  from  the  tip  of  the  coracoid 
process,  and  from  the  tendinous  short  head  of  the  biceps.  Its  fibres  be- 
come tendinous,  and  are  inserted,  below  the  level  of  the  deltoid  muscle, 
into  the  ridge  on  the  inner  side  of  the  humerus:  from  tlie  insertion  an 
aponeurotic  slip  is  continued  upw^ards  to  the  head  of  the  humerus,  and  is 
joined  by  fleshy  fibres. 

Part  of  the  muscle  is  beneath  the  pectoralis  major  (fig.  78),  and  forms 
a  prominence  in  the  axilla;  but  the  rest  is  superficial,  except  at  the  inser- 
tion where  it  is  covered  by  the  brachial  vessels  and  the  median  nerve. 
The  coraco-brachialis  conceals  the  subscapular  muscle,  the  anterior  cir- 
cumflex artery,  and  the  tendons  of  the  latissimus  and  teres.  Along  the 
inner  border  are  the  large  artery  and  nerves  of  the  limb.  Perforating  it 
is  the  musculo-cutaneous  nerve. 

Action.  Tlie  hanging  limb  is  adducted  to  the  thorax  by  this  muscle; 
and  the  action  is  greater  in  proportion  as  the  humerus  is  removed  from 
the  trunk. 

The  humerus  being  fixed,  the  muscle  will  bring  down  the  scapula,  and 
assist  in  keeping  the  articular  surfaces  of  the  shoulder  joint  in  apposition. 


BRACHIAL    ARTERY. 


253 


The  BRACHIAL  ARTERY  (fig.  77,  *)  is  a  continuation  of  the  axillary- 
trunk,  and  supplies  vessels  to  the  upper  limb.  It  begins  at  the  lower 
border  of  the  teres  major  muscle,  and  terminates  rather  below  the  bend  of 
the  elbow,  or  "opposite  the  neck  of  the  radius"  (Quain),  in  two  branches 
— radial  and  ulnar,  for  the  forearm. 

In  the  upper  part  of  its  course,  the  vessel  is  internal  to  the  humerus, 
but  afterw^ards  in  front  of  that  bone;  and  its  situation  is  indicated  by  the 
surface  depression  along  the  inner  border  of  the  biceps  and  coraco-brachi- 
alis  muscles. 


Fig.  77. 


1.  Axillaryartery  and  branches:  the  small 

branch  above  the  figure  is  the  highest 
thoracic,  and  the  larger  branch  close 
below,  the  acromial  thoracic. 

2.  Long  thoracic  branch. 

3.  Subscapular  branch. 

4.  Brachial  artery  and  branches. 

5.  Superior  profunda  branch. 

6.  Inferior  profunda  branch. 

7.  Anastomotic  branch. 

8.  Biceps  muscle. 

9.  Triceps  muscle. 

The  median  and  ulnar  nerves  are  shown  in 
the  arm  ;  the  median  is  close  to  the  bra- 
chial artery. 


Axillary  and  Brachial  Arteries  and  their  Branches.     (Qualirs  ".Arteries.") 

In  all  its  extent  the  brachial  artery  is  superficial,  being  covered  by  tlie 
integuments  and  the  deep  fascia;  but  at  the  bend  of  the  elbow  it  becomes 
deeper,  and  is  crossed  by  the  prolongation  from  the  tendon  of  the  bice|)S. 
Posteriorly  the  artery  has  the  following  muscular  connections  (fig.  78) : — 


254  DISSECTION    OF    THE    ARxM. 

Whilst  it  is  inside  the  humerus  it  is  placed  over  the  long  head  of  the  tri- 
ceps F,  for  two  inches,  but  separated  partly  by  the  musculo-spiral  nerve 
and  profunda  vessels;  and  over  the  inner  head,  G,  of  the  same  muscle  for 
about  an  inch  and  a  half.  But  when  the  vessel  turns  to  the  front  of  the 
bone,  it  lies  on  the  insertion  of  the  coraco-brachialis,  c,  and  on  the  brachi- 
alis  anticus,  h.  To  the  outer  side  are  laid  the  coraco-brachialis  and 
biceps  muscles,  c,  and  b,  the  latter  overlapping  it. 

Veins.  Veniie  comites  lie  on  the  sides  of  the  artery  (fig.  78,  d),  encir- 
cling it  with  branches,  and  the  median  basilic  vein  crosses  over  it  at  the 
elbow.  The  basilic  vein  is  near,  and  inside  the  artery  above,  but  is 
superficial  to  the  fascia  in  the  lower  half  of  the  arm. 

The  nerves  in  relation  with  the  artery  are  the  following:— Tiie  internal 
cutaneous  {^)  is  in  contact  with  the  vessel  until  it  perforates  the  fascia 
about  the  middle  of  the  arm.  The  ulnar  nerve;  (*)  lies  to  the  inner  side 
as  far  as  the  insertion  of  the  coraco-brachialis  muscle;  and  the  musculo- 
spiral  (fig.  69,  *)  is  behind  for  a  distance  of  two  inches.  The  median 
nerve  (*)  is  close  to  the  vessel  throughout,  but  alters  its  position  in  this 
way: — as  low  as  the  insertion  of  the  coraco-brachialis  it  is  placed  on  the 
outer  side,  but  it  then  crosses  obliquely  either  over  or  under  the  artery, 
and  becomes  internal  about  two  inches  above  the  elbow  joint. 

Peculiarities  in  position.  The  brachial  trunk  may  leave  the  inner  border  of  the 
biceps  in  the  lower  half  of  the  arm,  and  course  along  tlie  intermuscular  septum, 
with  or  without  the  median  nerve,  to  the  inner  condyle  of  the  humerus.  At  this 
spot  the  vessel  is  directed  to  its  ordinary  position  in  front  of  the  elbow,  either 
through  or  beneath  the  fibres  of  the  pronator  teres,  which  has  then  a  wide  origin. 
In  this  unusual  course  the  artery  lies  behind  a  projecting  bony  point  of  the  hu- 
merus. 

Muscular  covering.  In  some  bodies  the  humeral  artery  is  covered  by  an  addi- 
tional slip  of  origin  of  the  biceps,  or  of  the  brachialis  anticus  muscle.  And  some- 
times a  slip  of  the  brachialis  may  conceal,  in  cases  of  high  origin  of  the  radial, 
the  remainder  of  the  arterial  trunk  continuing  to  the  forearm. 

Branches  spring  both  externally  and  internally  from  the  brachial  artery 
(fig.  77).  Those  on  the  outer  side,  musciilar.,  supply  tbe  coraco-braciii- 
alis,  biceps,  and  brachialis  anticus;  those  on  the  inner  side  are  named 
superior  and  inferior  profunda,  nutritious,  and  anastomotic. 

The  superior  profunda  branch  (*)  is  larger  than  the  others,  and  leaves 
the  artery  near  the  lower  border  of  the  teres  major;  it  winds  backwards 
with  the  musculo-spiral  nerve  to  the  triceps  muscle,  and  will  be  dissected 
with  the  back  of  tlie  arm. 

The  inferior  profunda  branch  (*)  arises  opposite  the  coraco-brachialis 
muscle,  and  accompanies  the  ulnar  nerve  to  the  interval  between  the 
olecranon  and  the  inner  condyle  of  the  humerus.  There  it  anastomoses 
with  the  posterior  ulnar  recurrent  and  anastomotic  branches,  and  sup- 
])lies  the  triceps.  It  arises  often  in  common  with  the  superior  profunda 
artery. 

A  nutritious  artery  of  the  bone  shaft  begins  near  the  preceding  branch, 
and  enters  the  large  aperture  about  the  middle  of  the  humerus;  it  is  dis- 
tributed to  the  osseous  and  the  medullary  substance. 

The  anastomotic  branch  (')  arises  one  to  two  inches  above  the  elbow, 
and  courses  inwards  througii  the  intermuscular  septum  to  the  hollow  be- 
tween the  olecranon  and  the  inner  condyle  of  the  humerus.  Here  the 
artery  inosculates  with  the  inferior  profunda  and  [)OSterior  ulnar  recurrent 
branches,  and  gives  twigs  to  the  triceps  muscle:  one  of  the  offsets  forms 


NERVES    OF    THE    ARM, 


255 


an  arch  across  the  back  of  the  humerus  with  a  branch  of  the  superior  pro- 
funda. 

In  front  of  the  elbow  joint  the  anastomotic  branch  sends  an  offset  to 
the  pronator  teres  muscle:  this  joins  tiie  anterior  ulnar  recurrent  branch. 

Vasa  aherrantia.  Occasionally  long  slender  vessels  connect  the  bra- 
chial or  the  axillary  trunk  with  the  radial  artery ;  the  accessory  vessel 
very  rarely  ends  in  the  ulnar  artery. 

The  BRACHIAL  VEINS  (tig.  78,  d)  accompany  the  artery,  one  on  each 
side,  and  have  branches  of  communication  across  that  vessel;  they  receive 
contributing  veins  corresponding  with  the  branches  of  the  arteries.  Su- 
periorly they  unite  into  one,  which  joins  the  axillary  vein  near  the  sub- 
scapular muscle. 

Nerves  of  the  Arm  (fig.  78).  The  nerves  on  the  front  of  the  arm 
are  derived  from  the  terminal  cords  of  the  brachial  plexus.  Few  of  them 
furnish  offsets  above  the  elbow,  but  they  are  continued,  for  the  most  part 
without  branching,  to  the  forearm  and  the  hand.  The  cutaneous  branches 
of  some  of  them  have  been  referred  to  (p.  250). 


MnscLEs  AND  Deep  Vessels  and  Nervi  s  of  the  Arm,     (Illustrations  of  Dissections.) 

Muscles  :  Nerves : 

A.  Pectoralis  major.  1.  Median. 

B.  Biceps.  2.  Internal  cutaneous, 
c.  Coraco-brachialis.  3.  Nerve  of  Wrisbeiy. 
D  and  K.  Latissimus  and  teres.  4.  Ulnar. 

F.  Long  head  of  the  triceps.  5.  Muscular  to  the  triceps. 

«.  Inner  head  of  triceps.            *  6.  Internal  cutanexiis  from  ihe 

H.  Brachialis  anticus.  niusculo-spiral. 


The  median  nerve  (' )  arises  from  the  brachial  plexus  by  two  roots,  one 
from  the  outer,  and  the  other  from  the  inner  cord  (p.  236).  Its  destina- 
tion is  to  tlie  palm  of  the  hand;  and  it  accompanies  tlie  brachial  artery 
to  the  forearm.  Beginning  on  the  outer  side  of  the  artery,  the  nerve 
crosses  over  or  under  it  about  the  middle  of  the  arm,  and  is  placed  on  tlie 
inner  side  a  little  above  the  elbow.  It  does  not  give  any  branch  in  tlie 
arm;  but  there  may  be  a  fasciculus  connecting  it  with  the  musculo-cuta- 
neous  nerve.  Its  connections  with  muscles  are  the  same  as  those  of  the 
artery. 

The  ulnar  7urve  (*),  derived  from  the  inner  cord  of  the  brachial  plexus, 


256  DISSECTION    OF    THE    ARM. 

ends  fit  the  inner  side  of  the  hand.  In  the  arm  the  nerve  lies  at  first  close 
to  the  inner  side  of  the  axillary,  and  the  brachial  artery,  as  far  as  tlie 
insertion  of  the  coraco-brachialis ;  then  leaving  the  bloodvessel,  it  is  di- 
rected inwards  through  the  inner  intermuscular  septum  to  the  interval  be- 
tween the  olecranon  and  the  inner  condyle,  being  surrounded  by  the  mus- 
cular fibres  of  the  triceps.  There  is  not  any  branch  from  the  nerve  till  it 
reaches  the  elbow-joint. 

The  internal  cutaneous  (^)  is  a  tegumentary  nerve  of  the  forearm,  to 
which  it  is  prolonged  like  the  others.  Arising  from  the  inner  cord  of  the 
plexus,  it  is  at  first  superficial  to  the  humeral  artery  as  far  as  the  middle 
of  the  arm,  where  it  divides  into  two  branches  that  perforate  the  investing 
fascia  and  reach  the  forearm  (p.  250).  Near  the  axilla  it  furnishes  a 
small  cutaneous  offset  to  the  integuments  of  the  arm. 

The  small  internal  cutaneous  nerve  (^)  (nerve  of  Wrisberg)  arises  with 
the  preceding.  Concealed  at  first  by  the  axillary  vein,  it  is  directed  in- 
wards beneath  (but  sometimes  through)  that  vein,  and  joins  with  the  inter- 
costo-humeral  nerve.  Afterwards  it  lies  along  the  inner  part  of  the  arm 
as  far  as  the  middle,  where  it  perforates  the  fascia  to  end  in  the  integu- 
ment (p.  251).  • 

The  musculo-cutaneous  nerve  (nerv.  perforans,  Casserii),  named  from 
supplying  muscles  and  integuments,  ends  on  the  surface  of  the  forearm. 
It  leaves  the  outer  cord  of  the  brachial  plexus  opposite  the  lower  border 
of  the  pectoralis  minor  (fig.  70)  and  perforates  directly  the  coraco-brach- 
ialis :  it  is  then  directed  obliquely  to  the  outer  side  of  the  limb  between 
the  bicejjs  and  brachialis  anticus  muscles.  Near  the  elbow  it  becomes  a 
cutaneous  nerve  of  the  forearm. 

Branches.  The  nerve  furnishes  branches  to  the  muscles  in  front  of  the 
humerus,  viz.,  to  the  coraco-brachialis  as  it  passes  through  the  fibres,  and 
to  the  biceps  and  brachialis  anticus  where  it  is  placed  between  them. 

Dissection.  The  brachialis  anticus  muscle  will  be  brought  into  view 
by  cutting  through  the  tendon  of  the  biceps  near  the  elbow,  and  turning 
upwards  this  muscle.  The  fascia  and  areolar  tissue  should  be  taken  from 
the  fleshy  fibres ;  and  the  lateral  extent  of  the  muscle  should  be  well  de- 
fined on  each  side,  so  as  to  show  that  it  reaches  the  intermuscular  septum 
largely  on  the  inner  side,  but  only  for  a  short  distance  above  on  the  outer 
side. 

Some  care  is  required  in  detaching  the  brachialis  externally  from  the 
muscles  of  the  forearm,  to  which  it  is  closely  applied.  As  the  muscles  are 
separated  the  musculo-spiral  nerve  with  a  small  artery  comes  into  sight. 

The  BRACHIALIS  ANTICUS  (fig.  78,  ^)  covers  the  elbow-joint,  and  the 
lower  half  of  the  front  of  the  humerus.  It  drises  from  the  anterior  sur- 
face of  the  humerus  below  the  insertion  of  the  deltoid  muscle ;  and  from 
the  intermuscular  septa  on  the  sides,  viz.,  from  all  the  inner,  but  from 
only  the  u[)per  part  of  the  outer  (about  one  inch  and  a  half.)  The  fleshy 
fibres  converge  to  a  tendon,  which  is  inserted  into  the  impression  on  the 
front  of  the  coronoid  process  of  the  ulna  (p.  271). 

This  muscle  is  concealed  by  the  biceps.  On  it  lies  the  brachial  artery, 
with  the  median,  musculo-cutaneous,  and  musculo-spiral  nerves.  It  covers 
tlie  humerus  and  the  articulation  of  the  elbow.  Its  origin  embraces  by 
two  parts  the  attachment  of  the  deltoid  ;  and  its  insertion  is  placed  between 
two  fleshy  pieces  of  the  flexor  profundus  digitorum.  The  inner  border 
reaches  the  intermuscular  septum  in  all  its  length  ;  but  the  outer  is  sepa- 
rated from  the  external  intermuscular  septum  below  by  two  muscles  of 


TRICEPS    EXTENSOR    OF    MUSCLE 


25' 


the  forearm  (supinator  longus  and  extensor  carpi  radialis  longior),  which 
extend  upwards  on  the  humerus. 

Action.  The  brachialis  brings  forwards  the  ulna  towards  tlie  humerus, 
and  bends  the  elbow-joint. 

If  the  ulna  is  fixed,  as  in  climbing  with  the  hands  above  the  head,  the 
muscle  bends  the  elbow-joint  by  raising  the  humerus. 


BACK  OF  THE  ARM. 

Position.  During  the  examination  of  the  back  of  the  arm,  the  limb  is 
to  be  raised  in  a  semiflexed  position  by  means  of  a  block  beneath  the  elbow. 
The  scapula  is  to  be  brought  nearly  in  a  line  with  the  humerus,  so  as  to 
tighten  the  muscular  fibres ;  and  it  is  to  be  fastened  with  hooks  in  that 
position. 

Fig.  79. 


Muscles : 

A.  Long  head  of  the  triceps. 

B.  Outer  head,  with  a  bit  of  whalebone  beneath  it 

to  mark  the  extent  of  its  attachment  down  the 

humerus, 
c.  Inner  head  of  the  triceps. 
D.  Anconeus- 
K.  Supinator  longns. 

F.  Extensor  carpi  radialis  longus. 

G.  Teres  major. 
H.  Teres  minor. 

I.  Infra-spinatus,  cut  across. 
J.  Supra-spinatus,  cut  through. 
Arteries : 
a.  Supra-scapular. 
6.  Dorsal  scapular. 
c.  Posterior  circumflex. 

Nerves  : 

1.  Supra-scapular. 

2.  Posterior  circumflex. 


Dissection  of  thk  Dorsal  Scapitlar  Ykssels  and  Xerve,  and  of  the  Triceps  Mcsclb 
•  OF  THE  Arm. 

Dissection  (fig.  79).  On  the  back  of  the  arm  there  is  one  muscle,  the 
triceps,  with  the  musculo-spiral  nerve  and  superior  profunda  vessels.  The 
skin  having  been  reflected  already,  the  muscle  will  be  laid  bare  readily, 
for  it  is  covered  only  by  fascia.  To  take  away  the  fascia,  carry  an  inci- 
sion along  the  middle  of  the  limb  to  a  little  below  the  elbow  ;  and  in  reflect- 
ing it,  the  subaponeurotic  loose  tissue  should  be  removed  at  the  same  time. 
17 


258  DISSECTION    OF    THE    ARM. 

Separate  the  middle  from  the  inner  and  outer  heads  of  the  muscle,  and 
trace  the  musculo-spiral  nerve  and  vessels  beneath  it.  Define  the  outer 
head  which  reaches  down  to  the  spot  at  which  the  musculo-spiral  nerve 
ap})ears  on  the  outer  side. 

The  TRICEPS  MUSCLE  (fig.  79),  is  divided  superiorly  into  three  parts  or 
heads  of  origin,  inner,  outer,  and  middle  :  two  of  these  are  attached  to 
the  humerus,  and  one  to  the  scapula. 

The  middle  piece,  or  head,  a,  is  the  longest,  and  has  a  tendinous  origin, 
about  an  inch  wide,  from  the  inferior  costa  of  the  scapula  close  to  the 
glenoid  cavity,  where  it  is  united  with  the  capsule  of  the  shoulder  joint. 
The  outer  head,  b,  is  narrow  and  arises  from  the  back  of  the  humerus 
above  the  spiral  groove,  extending  from  the  root  of  the  large  tuberosity 
to  that  groove.  The  inner  head,  c,  fleshy  and  wide,  arises  from  the 
posterior  surface  of  the  humerus  below  the  spiral  groove,  reaching  laterally 
to  the  intermuscular  septa,  and  gradually  tapering  upwards  as  far  as  the 
insertion  of  the  teres  major  (Theile).  From  the  different  heads  the  fibres 
are  directed  with  varying  degrees  of  inclination  to  a  common  tendon  at 
the  lower  part.  Inferiorly  the  muscle  is  inserted  into  the  end  of  the  ole- 
cranon process  of  the  ulna,  and  gives  an  expansion  to  the  ai)oneurosis  of 
the  forearm.  Between  the  tip  of  the  olecranon  and  the  tendon  is  a  small 
bursa. 

The  triceps  is  superficial,  except  at  the  upper  part  where  it  is  overlapped 
by  the  deltoid  muscle.  It  lies  on  the  humerus,  and  conceals  the  musculo- 
spiral  nerve,  the  superior  profunda  vessels,  and  the  articulation  of  the 
elbow.  On  the  sides  the  muscle  is  united  to  the  intermuscular  septa  ;  and 
the  lower  fibres  are  continuous  externally  with  the  anconeus — a  muscle  of 
the  forearm. 

Action.  All  the  parts  of  the  triceps  combining  in  their  action  will  bring 
the  ulna  into  a  line  with  the  humerus,  and  extend  the  elbow-joint.  As 
the  long  head  passes  the  shoulder  it  can  depress  the  raised  humerus,  and 
adduct  the  bone  to  the  thorax. 

The  intermuscular  septa  are  fibrous  processes  continuous  with  the  in- 
vesting aponeurosis  of  the  arm,  which  are  fixed  to  the  ridges  leading  to 
the  condyles  of  the  humerus  :  they  intervene  between  the  muscles  on  the 
front  and  back  of  the  limb,  and  give  attachment  to  fleshy  fibres. 

The  internal  is  the  strongest,  and  reaches  as  high  as  the  coraco-brachialis 
muscle,  from  which  it  receives  some  tendinous  fibres.  Tiie  brachialis  an- 
ticus  is  attached  to  it  in  front,  and  the  triceps  behind  ;  and  the  ulnar 
nerve,  and  the  inferior  profunda  and  anastomotic  vessels  pierce  it. 

The  external  septum  is  thinner,  and  ceases  at  the  deltoid  muscle.  Be- 
liind  it  is  the  triceps ;  and  in  front  are  the  brachialis  anticus,  and  the 
muscles  of  the  forearm  (supinator  longus  and  extensor  carpi  radialis 
longus)  arising  above  the  condyle  of  the  humerus  :  it  is  i)ierced  by  the 
musculo-spiral  nerve  and  the  accompanying  vessels. 

Dissection.  To  follow  the  superior  profunda  vessels  and  the  musculo- 
spiral  nerve,  the  middle  head  of  the  triceps  should  be  cut  across  over  them, 
and  the  fatty  tissue  should  be  removed.  The  trunks  of  the  artery  and 
nerve  are  to  be  afterwards  followed  below  the  outer  head  of  the  trice[)S  to 
the  front  of  the  humerus. 

To  trace  out  tiie  branches  of  the  nerve  and  artery,  which  descend  to  the 
olecranon  and  the  anconeus  muscle,  the  tricei)S  is  to  be  divided  along  the 
line  of  union  of  the  outer  with  the  middle  head. 

The  superior  profunda  branch  of  the  brachial  artery  (p.  254)  turns  to 


MUSCULO-SPIRAL    NERVE.  259 

the  back  of  the  humerus  between  the  inner  and  outer  heads  of  the  triceps; 
in  tliis  position  it  supplies  branches  to  tlie  triceps  and  deltoid  muscles,  and 
is  continued  onwards  in  the  groove  in  the  bone  to  the  outer  part  of  the 
arm,  where  it  divides  into  its  terminal  offsets : — One  of  these,  which  is 
very  small,  courses  on  the  musculo-spiral  nerve  to  the  front  of  the  elbow, 
anastomosing  with  the  recurrent  radial  branch  :  Avhilst  others  continue 
along  the  intermuscular  septum  to  the  elbow,  and  join  the  radial  and  pos- 
terior interosseous  recurrent  branches. 

Branches.  Most  of  the  muscular  offsets  of  the  vessels  descend  to  the 
olecranon,  supplying  the  triceps,  and  communicate  with  the  inferior  pro- 
funda and  anastomotic  branches  of  the  brachial  artery  (p.  254)  ;  and  with 
the  recurrent  branches  of  the  arteries  of  the  forearm  except  the  anterior 
ulnar.  One  slender  offset  accompanies  a  branch  of  the  musculo-spiral 
nerve,  and  ends  in  the  anconeus  muscle  below  the  outer  condyle  of  the 
humerus. 

Two  or  more  cutaneous  offsets  arisi;  on  the  outside  of  the  arm,  and 
accompany  the  superficial  nerves. 

The  musculo-spiral  nerve  (fig.  70)  is  the  largest  trunk  of  the  posterior 
cord  of  the  brachial  plexus  (p.  236)  and  is  continued  along  the  back  and 
outer  part  of  the  limb  to  the  hand.  In  the  arm  the  nerve  winds  with  the 
profunda  artery  beneatli  the  triceps  muscle.  At  the  outer  aspect  of  the 
arm  it  is  continued  between  the  brachialis  anticus  and  supinator  longus 
muscles  to  the  external  condyle  of  the  humerus,  in  front  of  which  it  divides 
into  the  radial  and  posterior  interosseous  nerves.  The  nerve  gives  muscu- 
lar branches,  and  the  following  cutaneous  offsets  to  the  inner  and  outer 
parts  of  the  limb. 

a.  The  internal  cutaneous  branch  of  the  arm  (fig.  78,  ^)  is  of  small 
size,  and  arises  in  the  axillary  space  in  common  with  the  branch  to  the 
inner  head  of  the  triceps ;  it  is  directed  across  the  posterior  boundary  of 
the  axilla  to  the  inner  side  of  the  arm,  where  it  becomes  cutaneous  in  the 
upper  third,  and  is  distributed  as  before  said  (p.  250). 

b.  The  external  cutaneous  branches  springing  at  the  outer  side  of  the 
limb  are  two  in  number :  they  are  distributed  in  the  integuments  of  the 
arm  and  forearm  (p.  250). 

c.  The  muscular  branches  to  the  triceps  are  numerous,  and  supply  all 
three  heads.  One  slender  offset  for  the  inner  head,  arises  in  common  with 
the  inner  cutaneous  branch,  and  lies  close  to  the  ulnar  nerve  till  it  enters 
the  muscular  fibres  at  the  lower  third  of  the  arm.  Another  long  and 
slender  branch  behind  tiie  humerus,  appearing  as  if  it  ended  in  the  triceps, 
can  be  followed  downwards  to  the  anconeus  muscle. 

d.  On  the  outer  side  of  the  limb  the  musculo-spiral  nerve  supplies  the 
brachialis  anticus  in  part,  and  two  muscles  of  the  forearm,  viz.,  supinator 
longus  and  extensor  carpi  radialis  longior. 

ISubanconeus  muscle.  A  thin  flesliy  stratum  of  the  under  part  of  the 
triceps  near  the  elbow  has  been  so  named.  It  is  described  as  consisting 
of  two  fasciculi,  inner  and  outer,  which  are  attached  above  the  fossa  for 
the  olecranon,  and  end  in  the  synovial  sac  of  the  joint.  A  corresponding 
muscle  is  placed  beneath  the  extensor  of  the  knee  joint. 

Action.  It  is  said  to  raise  the  synovial  membrane  in  extension  of  the 
joint. 

Directions.  As  the  dissection  of  the  arm  has  been  completed  as  far  as 
the  elbow,  it  will  be  advisable  to  keep  moist  the  shoulder  joint  until  it  is 
examined  with  the  other  ligaments. 


260  DISSECTION    OF    THE    FRONT    OF    THE    FOREARM. 

Section  IV. 

THE  FRONT  OF  THE  FOREARM. 

Position.  The  limb  is  to  be  placed  with  the  palm  of  the  hand  upper- 
most ;  and  the  marking  of  the  surface,  and  the  projections  of  the  bone,  are 
first  to  be  noted. 

Surface-marking.  On  the  anterior  aspect  of  the  forearm  are  two  lateral 
depressions,  corresponding  with  the  position  of  the  main  vessels.  The 
external  is  placed  over  the  radial  artery,  and  inclines  towards  the  middle 
of ,  the  limb  as  it  approaches  the  elbow.  The  internal  groove  is  evident 
only  beyond  the  middle  of  the  forearm,  and  points  out  the  place  of  the 
ulnar  artery. 

The  bones  (radius  and  ulnar)  are  sufficiently  near  the  surface  to  be 
traced  in  their  whole  length  :  each  ends  below  in  a  point — the  styloid 
process  ;  and  that  of  the  radius  is  the  lowest.  A  transverse  line  separates 
the  forearm  from  the  hand,  and  the  articulation  of  the  wrist  is  about  an 
inch  above  it. 

On  each  side  of  the  palm  of  the  hand  is  a  lateral  projection  ;  the  exter- 
nal of  these  (thenar)  is  formed  by  muscles  of  the  thumb,  and  the  internal 
(hypo-thenar)  by  muscles  of  the  little  finger.  Between  the  projections  is 
the  hollow  of  the  palm,  which  is  pointed  towards  the  wrist.  Two  trans- 
verse lines  are  seen  in  the  palm,  but  neither  reaches  completely  across  it : 
the  anterior  one  will  direct  to  the  line  of  the  articulations  between  the 
metacarpus  and  the  phalanges,  but  is  about  a  quarter  of  an  inch  behind 
the  three  inner  joints  when  the  fingers  are  extended. 

The  superficial  palmar  arch  of  arteries  reaches  forwards  a  little  way 
into  the  hollow  of  the  hand,  and  its  position  may  be  marked  by  a  line 
across  the  palm  from  the  root  of  the  thumb,  when  that  digit  is  placed  at  a 
right  angle  to  the  hand. 

Transverse  lines  are  seen  on  both  aspects  of  the  joints  of  the  thumb  and 
fingers.  The  lines  on  the  palmar  surface  of  the  fingers  may  be  used  to 
detect  the  articulations  of  the  phalanges.  Thus  the  joint  between  the 
metacarpal  phalanx  and  the  next  will  be  found  about  a  line  in  front  of  the 
chief  transverse  groove ;  whilst  the  articulation  between  the  last  two  pha- 
langes is  situate  about  a  line  in  front  of  the  single  mark. 

Dissection.  With  the  limb  lying  flat  on  the  table,  an  incision  is  to  be 
carried  through  the  skin  along  the  middle  of  the  front  of  the  forearm,  as 
far  as  an  inch  beyond  the  wrist ;  and  at  its  termination  a  transverse  one  is 
to  cross  it.  The  skin  is  to  be  reflected  carefully  from  the  front  and  back 
of  the  forearm,  without  injury  to  tlie  numerous  superficial  vessels  and 
nerves  beneath  ;  and  it  should  be  taken  also  from  the  back  of  the  hand, 
by  prolonging  the  ends  of  the  transverse  cut  along  each  margin  to  a  little 
beyond  the  knuckles.  The  whole  of  the  forefinger  should  have  the  integ- 
ument removed  from  it,  in  order  that  the  nerves  may  be  followed  to  the 
end. 

The  superficial  vessels  and  nerves  can  be  now  traced  in  the  fat ;  they 
have  the  following  position,  and  most  of  them  liave  been  partly  dissected  : 
Along  the  inner  side,  in  front  of  the  forearm  witli  the  ulnar  veins,  is  the 
continuation  of  the  internal  cutaneous  uerve  ;  and  near  the  wrist  there  is 


CUTANEOUS  VEINS  OF  FOREARM.  261 

occasionally  a  small  offset  from  the  ulnar  nerve.  On  the  outer  side  with 
the  radial  vein  is  the  superficial  part  of  the  musculo-cutaneous  nerve. 

Close  to  the  hand,  in  the  centre  of  the  forearm,  and  inside  the  tendon 
of  the  flexor  car[)i  radialis  which  can  be  rendered  prominent  by  extending 
the  wrist,  the  small  palmar  branch  of  the  median  nerve  should  be  sought 
beneath  the  fat.  On  the  ulnar  artery,  close  inside  the  pisiform  bone,  a 
small  palmar  branch  of  the  ulnar  nerve  is  to  be  looked  for. 

At  the  back  of  the  forearm  the  largest  external  cutaneous  branch  of  the 
musculo-spiral  nerve  is  to  be  traced  onwards  ;  and  offsets  are  to  be  followed 
to  this  surface  from  the  nerves  in  front. 

On  the  posterior  part  of  the  hand  is  an  arch  of  superficial  veins.  Wind- 
ing back  below  the  ulna  is  the  dorsal  branch  of  the  ulnar  nerve  ;  and  lying 
along  the  outer  border  of  tlie  liand  is  the  radial  nerve :  these  should  be 
traced  to  the  fingers. 

Cutaneous  Veins.  The  superficial  veins  are  named  median,  radial, 
and  ulnar,  from  their  position  in  the  limb. 

Superficial  arch  on  the  hack  of  the  hand.  This  arch  is  more  or  less  per- 
fect, and  receives  the  posterior  superficial  digital  veins.  At  the  sides  the 
arcli  terminates  in  the  radial  and  ulnar  veins. 

The  radial  vein  begins  in  the  outer  part  of  the  arch  above  mentioned, 
and  in  some  small  radicles  a,t  the  back  of  the  thumb.  It  is  continued 
along  the  forearm,  at  first  behind  and  then  on  tlie  outer  border  as  far  as 
the  elbow,  where  it  gives  rise  to  the  cephalic  vein  by  its  union  with  the 
outer  branch  of  the  median  vein  (fig.  76,  ''). 

The  ulnar  veins  are  anterior  and  posterior,  and  occupy  the  front  and 
back  of  the  limb  : — 

The  anterior  arises  near  the  M^rist  by  the  junction  of  small  roots  from 
the  hand,  and  runs  on  the  inner  part  of  the  forearm  to  the  elbow ;  here  it 
unites  with  the  inner  branch  of  the  median,  and  forms  the  basilic  vein 
(fig.  76,^). 

The  posterior  ulnar  vein  is  situate  on  the  back  of  the  limb.  It  com- 
mences by  the  union  of  a  branch,  '*  vena  salvatella,"  from  the  back  of  the 
little  finger,  with  an  offset  of  the  venous  arch ;  it  is  continued  along  the 
back  of  the  forearm  nearly  to  the  elbow,  and  bends  forwards  to  open  into 
the  anterior  ulnar  vein. 

The  median  vein  takes  origin  near  the  wrist  by  small  branches  which 
are  derived  from  the  palmar  surface  of  the  hand ;  and  it  is  directed  along 
the  centre  of  the  forearm  nearly  to  the  elbow.  Here  the  vein  divides  into 
external  and  internal  branches  (median  basilic  and  median  cephalic), 
which  unite,  as  before  seen  (fig.  76,  *),  with  radial  and  ulnar  veins.  At 
its  point  of  bifurcation  the  median  receives  a  communicating  branch  from 
a  vein  (vena  comes)  beneath  the  fascia. 

Cutaneous  Nerves.  Some  of  the  superficial  nerves  of  the  forearm 
are  continued  from  the  arm : — those  on  the  inner  side  from  the  large  in- 
ternal cutaneous  nerve ;  and  those  on  the  outer,  from  the  two  external 
cutaneous  nerves  of  the  musculo-spiral,  and  the  musculo-cutaneous.  On 
the  forepart  of  the  limb  there  is  occasionally  a  small  offset  of  the  ulnar 
nerve  near  the  wrist.  On  the  back  of  the  hand  is  the  termination  of  the 
radial  nerve,  together  with  a  branch  of  the  ulnar  nerve. 

The  internal  cutaneous  nerve  (p.  2r)6)  is  divided  into  two  parts.  The 
anterior  branch  extends  on  the  front  of  the  forearm  as  far  as  the  wrist, 
and  supplies  the  integuments  on  the  inner  half  of  the  anterior  surface. 
Near  the  wrist  it  communicates  sometimes  with  a  cutaneous  offset  from 


262     DISSECTION  OF  THE  FRONT  OF  THE  FOREARM. 

the  ulnar  nerve.  The  posterior  branch  continues  along  the  back  of  the 
forearm  (ulnar  side)  to  rather  below  the  middle. 

The  cutaneous  part  of  the  musculo-cutaneous  nerve  (p.  250)  is  pro- 
longed on  the  radial  border  of  the  limb  to  the  ball  of  the  thumb,  over 
which  it  terminates  in  cutaneous  offsets.  Near  the  wrist  the  nerve  is 
placed  over  the  radial  arter}',  and  some  twigs  pierce  the  fascia  to  ramify 
on  the  vessel  and  supply  the  carpus.  A  little  above  the  middle  of  the 
forearm  the  nerve  sends  backwards  a  branch  to  the  posterior  aspect,  which 
reaches  nearly  to  the  wrist,  and  communicates  with  the  radial,  and  the 
following  cutaneous  nerve. 

The  external  cittaneous  branch  of  the  musculo-spiral  nerve  (p.  259)  after 
passing  the  elbow,  turns  to  the  hinder  part  of  the  forearm,  and  reaches  as 
far  Us  the  wrist.  Near  its  termination  it  joins  the  pi-eceding  cutaneous 
nerve. 

The  radial  nerve  ramifies  in  the  integument  of  the  back  of  the  hand 
and  some  of  the  digits.  It  becomes  cutaneous  at  the  outer  border  of  the 
forearm  in  the  lower  third,  and  after  giving  some  filaments  to  the  poste- 
rior aspect  of  the  limb,  divides  into  two  branches: — 

One  (external)  is  joined  by  the  musculo-cutaneous  nerve,  and  is  dis- 
tributed on  the  radial  border  and  the  ball  of  the  thumb. 

The  other  branch  (internal)  supplies  the  remaining  side  of  the  thumb, 
both  sides  of  the  next  two  digits,  and  half  the  ring  finger  ;  so  that  the 
radial  nerve  distributes  tlie  same  number  of  digital  branches  to  the  dorsum 
as  the  median  nerve  furnishes  to  the  palmar  surface.  This  portion  of  the 
radial  nerve  communicates  with  the  musculo-cutaneous  and  ulnar  nerves  ; 
and  the  offsets  to  the  contiguous  sides  of  the  ring  and  middle  fingers  is 
joined  by  a  twig  from  the  dorsal  branch  of  the  ulnar  nerve. 

On  the  side  of  the  fingei-s  each  of  these  dorsal  digital  branches  is  united 
with  an  offset  from  the  digital  nerve  on  the  palmar  surface. 

The  dorsal  branch  of  the  ulnar  nerve  gives  offsets  to  the  rest  of  the 
fingers  and  the  back  of  the  hand.  Appearing  by  the  styloid  process  of  the 
ulnar,  it  joins  the  radial  nerve  in  an  arch  across  the  back  of  the  hand,  and 
is  distributed  to  both  sides  of  the  little  finger,  and  to  the  ulnar  side  of  the 
ring  finger  :  it  communicates  with  the  part  of  the  radial  nerve  supplying 
the  space  between  the  ring  and  middle  fingers.  The  ulnar  nerve  furnishes 
branches  to  the  same  digits  on  the  palmar  surface. 

The  aponeurosis  of  the  forearm  is  continuous  with  a  similar  investment 
of  the  arm.  It  is  of  a  pearly  Avhite  color,  and  is  formed  of  fibres  which 
cross  obliquely  :  it  furnishes  sheaths  to  the  muscles,  and  is  thicker  behind 
tlian  before. 

Near  the  elbow  it  is  stronger  than  towards  the  hand;  and  at  that  part  it 
receives  fibres  from  the  tendons  of  the  biceps  and  brachialis  anticus,  and 
gives  origin  to  the  muscles  attached  to  the  inner  condyle  of  the  humerus. 
On  the  back  of  the  limb  the  aponeurosis  is  connected  to  the  margins  of  the 
ulna,  so  as  to  leave  tlie  upper  part  of  the  bone  subcutaneous  ;  and  it  is 
joined  by  fibres  from  the  tendon  of  the  triceps. 

Horizontal  processes  are  sent  downwards  from  tlie  aponeurosis  to  sepa- 
rate the  superficial  and  deep  layers  of  muscles,  both  on  the  front  and  back 
of  the  forearm  ;  and  longitudinal  white  bands  indicate  the  position  of  the 
intermuscular  [)rocesses  which  isolate  one  muscle  from  another,  and  give 
origin  to  the  muscular  fibres. 

At  the  wrist?  tlie  fascia  joins  the  anterior  annular  ligament ;  and  near 
that  band  the  tendon  of  the  palmaris  longus  pierces  it,  and  receives  a  sheath 


APONEUROSIS    OF    FOREARM.  263 

from  it.  Close  to  the  pisiform  bone  there  is  an  aperture  through  wliich 
the  ulnar  vessels  and  nerve  enter  the  fat  of  the  hand.  Behind  the  wrist 
it  is  thickened  by  transverse  fibres,  giving  rise  to  the  posterior  annular 
ligament ;  but  on  the  back  of  the  hand  and  fingers  the  fascia  becomes 
very  thin. 

Dissection.  The  skin  is  to  be  replaced  on  the  back  of  the  forearm  and 
hand,  in  order  that  the  denuded  parts  may  not  become  dry.  Beginning 
the  dissection  on  the  anterior  surface  of  the  limb,  let  the  student  divide  the 
aponeurosis  as  far  as  the  wrist,  and  take  it  away  with  the  cutaneous  vessels 
and  nerves,  except  the  small  palmar  cutaneous  offsets  of  the  median  and 
ulnar  nerves  near  the  wrist.  In  cleaning  the  muscles  it  will  be  impossible 
to  remove  the  aponeurosis  from  them  at  the  upper  part  of  the  forearm 
without  detaching  muscular  fibres. 

In  front  of  the  elbow  is  the  hollow,  already  partly  dissected,  between 
the  two  masses  of  muscles  arising  from  the  inner  and  outer  sides  of  the 
humerus.  The  space  should  be  carefully  cleaned,  so  as  to  display  the 
brachial  and  forearm  vessels,  the  median  nerve  and  branches,  the  musculo- 
spiral  nerve,  and  the  recurrent  radial  and  ulnar  arteries. 

In  th.e  lower  half  of  the  ibrearm  a  large  artery,  radial,  is  to  be  laid  bare 
along  tiie  radial  border  ;  and  at  the  ulnar  side,  close  to  the  annular  liga- 
ment, the  trunk  of  the  ulnar  artery  will  be  recognized,  as  it  becomes 
superficial.  These  vessels  and  their  branches  should  be  carefully  cleaned  ; 
but  the  collateral  muscles  should  be  fixed  with  stitches  to  prevent  their 
displacement. 

The  anterior 'annular  ligament  of  the  wrist,  which  arches  over  the  ten- 
dons passing  to  the  hand,  is  next  to  be  defined.  This  strong  band  is  at 
some  depth  from  the  surface  ;  and  whilst  the  student  removes  the  fibrous 
tissue  superficial  to  it,  he  must  take  care  of  the  small  branches  of  the 
median  and  ulnar  nerves  to  the  palm  of  the  hand.  The  ulnar  vessels  and 
nerve  pass  over  the  ligament,  and  will  serve  as  a  guide  to  its  depth. 

Hollow  in  front  of  the  elbow  (fig.  80).  Ihis  hollow  corresponds  with 
the  popliteal  space  at  the  knee,  and  is  situate  between  the  inner  and  the 
outer  muscles  of  the  forearm.  The  interval  is  somewhat  triangular  in 
shape,  and  the  wider  part  is  towards  the  humerus.  It  is  bounded  on  the 
outer  side  by  the  supinator  longus  muscle,  and  on  the  inner  side  by  the 
pronator  teres.  The  aponeurosis  of  the  limb  is  stretched  over  the  sj)ace ; 
and  the  bones,  covered  by  tlie  brachialis  anticus  and  supinator  brevis,  form 
the  deep  boundary. 

Contents.  In  the  hollow  are  lodged  the  termination  of  the  brachial 
artery  with  its  veins,  and  the  median  nerve  ;  the  musculo-spiral  nerve  ;  the 
tendon  of  the  biceps  muscle  ;  and  small  recurrent  vessels,  with  much  fat 
and  a  few  glands. 

These  several  parts  have  the  following  relative  position  :  The  tendon  of 
the  biceps  is  directed  towards  the  outer  boundary  to  reach  the  radius  ;  on 
the  outer  side,  concealed  by  the  supinator  longus  muscle,  is  the  musculo- 
spiral  nerve.  Nearly  in  tlie  centre  of  the  space  are  the  brachial  artery  and 
veins  and  the  median  nerve,  the  nerve  being  internal  ;  but  as  the  artery  is 
inclined  to  the  outer  part  of  the  limb,  they  soon  become  distant  from  one 
another  about  half  an  inch.  The  brachial  artery  divides  here  into  two 
trunks — radial  and  ulnar  ;  and  the  recurrent  radial  and  ulnar  branches 
appear  in  the  space,  one  on  the  outer  and  the  other  on  the  inner  side. 

Two  or  three  lymphatic  glands  lie  on  the  sides  of  the  artery,  and  one 
below  its  point  of  splitting. 


264 


DISSECTION    OF    THE    FRONT    OF    THE    FOREARM, 


■12 


Fig.  80.  Muscles  on  the  front  of  the  forearm  (fig. 

80).  The  muscles  on  the  front  of  the  forearm  are 
divided  into  a  superficial  and  a  deep  layer. 

In  the  superficial  layer  there  are  five  muscles, 
which  are  fixed  to  the  inner  condyle  of  the  hu- 
merus, mostly  by  a  common  tendon,  and  lie  in  the 
undermentioned  order  from  the  middle  to  tlie  inner 
side  of  the  limb  :  pronator  radii  teres,  fiexor  carpi 
radialis,  palmaris  longus,  flexor  carpi  ulnaris  ;  and 
deeper  and  larger  than  any  of  these  is  the  fiexor 
sublimis  digitorum. 

The  deep  layer  will  be  met  with  in  a  subsequent 
dissection  (p.  270). 

The  pronator  radii  teres  (fig.  80°,  3)  arises 
from  the  inner  condyle  of  the  humerus  by  the 
common  tendon  ;  from  the  ridge  above  the  condyle 
by  fleshy  fibres  ;  from  the  inner  part  of  the  coro- 
noid  process  by  a  second  tendinous  slip  ;  and  from 
the  fascia,  and  the  septum  between  it  and  the  next 
muscle.  It  is  inserted  by  a  flat  tendon  into  an  im- 
pression, an  inch  in  length,  on  the  middle  of  the 
outer  surface  of  the  radius. 

The  muscle  is  superficial  except  at  the  insertion, 
where  it  is  covered  by  tlie  radial  artery,  and  some 
of  the  outer  set  of  muscles,  viz.,  supinator  longus, 
and  radial  extensors  of  the  wrist.  The  j)ronator 
forms  the  inner  boundary  of  the  triangular  space 
in  front  of  the  elbow  ;  and  its  inner  border  touches 
the  flexor  carpi  radialis.  By  gently  se[)arating  the 
muscle  from  the  rest,  it  will  be  found  to  lie  on  the 
brachialis  anticus,  the  flexor  sublimis  digitorum, 
and  the  ulnar  artery  and  the  median  nerve  :  the 
second  small  head  of  origin  is  directed  inwards 
between  that  artery  and  nerve. 

Action.  Tlie  pronator  assists  in  bringing  for- 
wards the  radius  over  the  ulna,  so  as  to  pronate 
the  hand.  AVhen  the  radius  is  fixed  the  muscle 
raises  that  bone  towards  the  humerus,  bending  the 
elbow-joint. 

The  flexor  carpi  radialis  (fig.  80,  *)  takes 
its  origin  from  the  common  tendon,  from  the 
aponeurosis  of  the  limb,  and  from  the  intermuscular 
septum  on  each  side.  The  tendon  of  tlie  muscle, 
becoming  free  from  fleshy  fibres  about  tlie  middle 
of  the  forearm,  passes  through  a  groove  in  the  os 
trapezium,  outside  the  anterior  annular  ligament, 
to  be  inserted  mainly  into  the  base  of  the  meta- 
carpal bone  of  the  index  finger,  and  by  a  slip  into 
that  of  the  middle  finger. 

The  muscle  rests  chiefly  on  the  flexor  sublimis 
digitorum  ;  but  near  the  wrist  it  lies  over  the  flexor 
longus  pollicis — a  muscle  of  the  deep  layer.  As  low  as  the  middle  of  the 
forearm  the  muscle  corresponds  externally  with  the  pronator  teres,  and 


H 


ri. 


10 


SCPBRFICIAL   VIEW   OF   THE 

FOREARM    (Quain's   Arte- 
ries). 

1.  Radial    artery    with    its 

nerve  outside. 

2.  Uluar   artery  and    nerve 

where   they  are    suiier- 
ficial. 

3.  Pronator  teres. 

4.  Flexor  carpi  radialis. 

5.  Paluians  longus. 

6.  Flexor  sublimis, 

7.  Flexor  carpi  ulnaris. 

8.  Supinator  longus. 

9.  Biceps. 


RADIAL  ARTERY  AND  BRANCHES.  265 

below  that  with  the  radial  artery  to  which  its  tendon  is  taken  as  the  guide. 
The  ulnar  border  is  in  contact  at  first  with  tlie  palmaris  longus  muscle, 
and  for  about  two  inches  above  the  wrist,  with  the  median  nerve.^ 

Action.  The  hand  being  free  the  muscle  flexes  first  the  wrist  joint, 
inclining  the  hand  somewhat  to  the  radial  side  ;  and  will  assist  in  bringing 
forwards  the  lower  end  of  the  radius  in  pronation.  Still  continuing  to 
contract,  it  bends  the  elbow. 

Tlie  PALMARIS  LONGUS  (fig.  80,  ^)  is  often  absent :  or  it  may  present 
great  irregularity  in  the  proportion  between  the  fleshy  and  tendinous  parts. 
Its  origin  is  connected,  like  tiiat  of  the  preceding  muscle,  to  the  common 
tendon,  the  fascia,  and  the  intermuscular  septa.  Its  long  thin  tendon  is 
continued  along  the  centre  of  the  forearm  ;  and  piercing  the  aponeurosis, 
it  passes  over  the  annular  ligament  to  end  in  the  palmar  fascia,  and  to  join 
by  a  tendinous  slip  the  short  muscles  of  the  thumb. 

The  palmaris  is  situate  between  the  flexor  carpi  radialis  and  ulnaris,  and 
rests  on  the  flexor  sublimis  digitorum. 

Action.  Rendering  tense  the  palmar  fascia,  the  palmaris  will  afterwards 
bend  the  wrist  and  elbow,  like  the  other  muscles  of  the  superficial  layer. 

The  FLEXOR  CARPI  ULNARIS  (fig  80,  ')  has  an  aponeurotic  origin  from 
the  inner  condyle  of  the  humerus ;  from  the  inner  side  of  the  olecranon  ; 
and  from  the  ridge  of  the  ulna  between  the  internal  and  posterior  surfaces 
for  three-fourths  of  the  length.  Most  of  the  fibres  are  continued  vertically 
downwards,  but  others  obliquely  forwards  to  a  tendon  on  the  anterior  part 
of  the  muscle  in  the  lower  half,  some  joining  it  as  low  as  the  wrist ;  and 
the  tendon  is  inserted  into  the  pisiform  bone,  an  offset  being  sent  to  the 
muscles  of  the  little  finger. 

One  surface  of  the  muscle  is  in  contact  with  the  fascia ;  and  its  tendon, 
which  can  be  felt  readily  through  the  skin,  may  be  taken  as  the  guide  to 
the  ulnar  artery.  To  its  radial  side  are  the  palmaris  and  flexor  digitorum 
sublimis  muscles.  When  the  attachment  to  the  inner  condyle  has  been 
divided,  the  muscle  will  be  seen  to  conceal  the  flexor  digitorum  sublimis 
and  flexor  profundus,  the  ulnar  nerve,  and  the  ulnar  vessels  ;  between  the 
attachments  to  the  condyle  and  the  olecranon  the  ulnar  nerve  enters  the 
forearm. 

Action.  The  wrist  is  bent  and  the  hand  is  drawn  inwards  by  the  con- 
traction of  the  muscle. 

The  RADIAL  ARTERY  (fig.  80,  ^)  is  onc  of  the  vessels  derived  from  the 
bifurcation  of  the  brachial  trunk ;  and  its  destination  is  the  [)alm  of  the 
hand.  It  is  placed  first  along  the  outer  side  of  the  forearm  as  far  as  the 
end  of  the  radius ;  next  it  winds  backwards  below  the  extremity  of  that 
bone  :  and  it  enters  finally  the  palm  of  the  hand  through  the  first  inter- 
osseous space.  In  consequence  of  this  circuitous  course  the  artery  will  be 
found  in  three  diflerent  dissections,  viz.,  the  front  of  the  forearm,  the  back 
of  the  wrist,  and  the  palm  of  the  hand. 

In  the  front  of  the  forearm.  In  this  part  of  the  limb  the  position  of  the 
artery  will  be  marked,  on  the  surface,  by  a  line  from  the  centre  of  the 
hollow  of  the  elbow  to  the  fore  part  of  the  styloid  process  of  the  radius. 
At  first  it  lies  on  the  inner  side  of  the  radius,  but  afterwards  over  that 
bone.  This  vessel  is  smaller  than  the  ulnar  artery,  though  it  appears  in 
direction  to  be  the  continuation   of  the  brachial  trunk  ;  and  it  is  partly 

'  In  the  body  of  a  woman  which  was  well  developed,  the  muscle  was  absent  on 
both  sides. 


266  DISSECTION    OF    THE    FRONT    OF    THE    FOREARM. 

deep  and  }'artly  superficial,  but  where  it  is  more  superficial  in  the  lower 
half  it  cai)  be  felt  beating  as  the  pulse  near  the  wrist  during  life. 

In  its  upper  half  the  vessel  is  placed  beneath  the  supinator  longus  (^)  ; 
and  rests  successively  on  the  following  muscles,  the  fleshy  supinator  brevis, 
the  pronator  teres  (^),  part  of  the  thin  origin  of  the  flexor  sublimis  (^),  and 
sometimes  on  the  biceps  tendon  ('). 

Veins.  Venae  comites  lie  on  the  sides,  with  cross  branches  over  the 
artery. 

Nerve.  The  radial  nerve  is  parallel  to,  and  outside  it,  but  separated  by 
a  slight  interval. 

In  its  lower  half  the  artery  with  its  vena3  comites  is  superficial,  being 
covered  only  by  the  teguments  and  the  deep  fascia.  Here  it  is  placed  in 
a  hollow  between  the  tendons  of  the  supinator  longus  (^)  and  flexor  carpi 
radicalis  (*).  It  lies  from  above  down  on  the  origin  of  the  flexor  sublimis, 
on  two  other  muscles  of  the  deep  layer,  viz.,  flexor  poUicis  longus  and 
pronator  quadratus,  and  lastly  on  the  end  of  the  radius. 

Nerves.  The  radial  nerve  is  still  on  the  outer  side  until  it  passes  back- 
wards beneath  the  tendon  of  the  supinator  longus,  and  becomes  cutaneous. 
Superficial  to  the  lower  end  are  the  ramifications  of  the  muscnlo-cutaneous 
nerve,  some  of  which  reach  the  vessels  (p.  2G2). 

Branches.  The  radial  artery  furnishes  many  unnamed  muscular  and 
nutrient  offsets  to  the  surrounding  parts  ;  and  three  named  branches,  viz., 
recurrent  radial,  superficial  volar,  and  anterior  carpal. 

a.  The  radical  recurrent  is  the  first  brancli,  and  supplies  the  muscles 
of  the  outer  side  of  the  limb.  Its  course  is  almost  transverse  to  the  supi- 
nator longus,  beneath  which  it  terminates  in  that  muscle  and  the  two 
radial  extensors  of  the  wrist.  One  offset  ascends  beneath  the  supinator, 
and  anastomoses  with  the  superior  profunda  branch  of  the  brachial  artery. 

b.  The  superjicial  volar  branch  (fig.  83,  c)  arises  usually  near  the  lower 
end  of  the  radius.  It  is  directed  towards  the  palm  of  the  hand,  across  or 
through  the  mass  of  muscles  in  the  ball  of  the  tliumb,  and  it  either  ends  in 
those  muscles,  or  joins  the  superficial  palmar  arch. 

c.  The  anterior  carpal  branch  is  very  inconsiderable  in  size,  and  will 
be  seen  in  the  examination  of  the  deep  layer  of  muscles.  Arising  rather 
above  the  end  of  the  radius,  it  passes  transversely  at  the  lower  border  of 
the  pronator  quadratus,  and  anastomoses  with  a  similar  branch  from  the 
ulnar  artery  :  from  the  arch  thus  formed,  offsets  are  given  to  the  corpus. 

Peculiarities  of  the  radial  artery.  When  the  radial  arises  high  in  the  arm,  its 
course  is  close  to  the  brachial  artery,  along  the  edge  of  tlie  biceps  muscle  ;  and  in 
passing  the  bend  of  the  elbow  it  may  be  occasionally  subcutaneous,  viz.,  above 
the  deep  fascia,  and  be  liable  to  injury  in  venesection.  In  the  forearm  it  may  be 
likewise  subcutaneous  and  superficial  to  the  supinator  longus  muscle. 

Dissection.  To  bring  into  view  the  flexor  sublimis  digitorum,  tlie  flexor 
carpi  radialis  and  palmaris  longus  must  be  cut  through  near  the  inner  con- 
dyle of  the  humerus,  and  turned  to  one  side.  Small  branches  of  the  ulnar 
artery  and  median  nerve  may  be  seen  entering  the  under  surfaces  of  those 
muscles.     For  the  present,  tlie  pronator  teres  may  be  left  uncut. 

The    FLEXOR    DIGITOKUM    SUliLIMIS   vcl    PP^KFOKATUS   (fig.  80,^)   is  the 

largest  of  the  muscles  of  the  superficial  layer,  and  is  named  from  its  posi- 
tion to  {mother  flexor  in  the  deep  layer.  It  arises  from  the  inner  condyle 
of  the  humerus  and  the  internal  lateral  ligament,  and  from  the  intermus- 
cular septa  in  common  with  other  muscles  ;  it  takes  origin  in  addition  from 


ULNAR    ARTERY    AND    BRANCHES.  267 

the  bones  of  the  forejirm,  viz.,  fi'om  the  inner  part  of  the  coronoid  process 
of  the  ulna ;  from  the  oblique  line  below  the  radial  tubercle  ;  and  from  the 
anterior  margin  of  the  radius  as  far  as,  or  one  or  two  inches  below  the 
insertion  of  the  pronator  teres.  Rather  below  the  middle  of  the  forearm 
the  muscle  ends  in  four  tendons,  which  are  continued  beneath  the  annular 
ligament  and  across  the  hand,  to  be  inserted  into  the  middle  })halanges  of 
the  fingers,  after  being  perforated  by  the  tendons  of  the  deep  flexor. 

The  flexor  sublimis  is  concealed  by  the  other  muscles  of  the  superficial 
layer ;  and  the  radial  vessels  lie  on  the  attachment  to  the  radius.  Along 
the  inner  border  is  the  flexor  carpi  ulnaris,  with  the  ulnar  vessels  and 
nerve.  The  tendons  of  the  muscle  are  arranged  in  pairs  before  they  pass 
beneath  the  annular  ligament  of  the  wrist ; — the  middle  and  ring  finger 
tendons  being  anterior,  and  those  of  the  index  and  little  finger  posterior  in 
position.  On  dividing  the  coronoid  and  condyloid  attachments,  the  muscle 
will  be  seen  to  cover  two  flexors  of  the  deep  layer  (flexor  digitorum  pro- 
fundus and  flexor  poUicis),  the  median  nerve,  and  the  upper  part  of  the 
ulnar  artery. 

Action.  This  flexor  bends  primarily  the  middle  joint  of  each  finger  ;  and 
is  then  able  to  bring  the  nearest  phalanx  towards  the  palm  in  consequence 
of  being  bound  thereto  by  a  sheath.  But  when  the  nearest  phalanx  is 
fixed  by  the  extensor  of  the  fingers,  it  remains  straight  whilst  the  super- 
ficial flexor  moves  the  second  phalanx. 

After  the  fingers  are  bent  the  muscle  will  help  in  flexing  the  wrist  and 
elbow  joints. 

The  ULNAR  ARTERY  (fig  81,  ^)  is  the  larger  of  the  two  branches  coming 
from  the  bifurcation  of  the  brachial  trunk  ;  and  is  directed  along  the  inner 
side  of  the  limb  to  the  palm  of  the  hand,  where  it  forms  the  superficial 
palmar  arch,  and  joins  offsets  of  the  radial  artery.  In  the  forearm  the 
vessel  has  an  arched  direction  ;  and  its  depth  from  the  surface  varies  in 
the  first  and  last  parts  of  its  course. 

In  the  iij^per  half  the  artery  is  inclined  obliquely  inwards  from  the 
centre  of  the  elbow  to  the  inner  part  of  the  limb,  midway  between  the 
elbow  and  wrist.  It  courses  between  the  superficial  and  deep  layers  of 
muscles,  being  covered  by  the  pronator  teres,  flexor  carpi  radialis,  palmaris 
longus,  and  flexor  sublimis.  Beneath  it  lie  the  brachialis  anticus,  for  a 
short  distance,  and  the  flexor  profundus,  c. 

Veins.  Two  companion  veins  are  situate  on  the  sides  of  the  artery, 
and  join  freely  over  it. 

Nerves.  The  median  nerve  (^)  lies  to  the  inner  side  of  the  vessel  for 
about  an  inch,  but  then  crosses  over  it  to  gain  the  outer  side.  About  the 
middle  of  the  forearm  the  ulnar  nerve  {*)  approaches  the  artery  and  con- 
tinues thence  on  the  inner  side. 

In  the  lower  half  it  has  a  straight  course  to  the  pisiform  bone,  and  is 
covered  by  the  teguments  and  fascia,  and  the  flexor  carpi  ulnaris  as  far  as 
the  wrist.  To  the  outer  side  are  the  tendons  of  the  flexor  sublimis.  Be- 
neath it  is  the  flexor  profundus,  c. 

Veiiis.  Two  companion  veins  accompany  the  artery,  as  in  the  upper 
part,  and  are  united  across  it  at  intervals. 

Nerves.  The  ulnar  nerve  (*)  lies  close  to,  and  on  the  inner  side  of  the 
vessels  ;  and  a  small  branch  (^),  sending  twigs  around  the  artery,  courses 
to  the  ]mlm  of  the  hand. 

On  the  annular  ligament  of  the  wrist  the  artery  has  passed  through  the 


268 


DISSECTION  OF  THE  FRONT  OF  THE  FOREARM. 


fascia  and  lies  close  to  the  pisiform   bone.     The  ulnar  nerve,  with  its 
palmar  branch,  still  accompanies  the  vessel  on  the  inner  side. 


Fig.  81. 


ifuscles  : 

A.  Pronator  teres. 

B.  Flexor  longiis  pollicis. 

c.  Flexor      digitoruni      per- 

forans. 

D.  Pronator  quadratas. 

E.  Flexor  carpi  ulnaris. 

Arteries  : 

a.  Radial  trunk. 

b.  Cutaneous  branch  of  it  to 

the  palm  of  the  hand. 
G.  Ulnar  trunk. 

d.  Its  recurrent  branch. 

/.  Branch  with  the   median 
nerve. 

e.  Anterior  interosseous. 
g.  Brachial  trunk. 

Nerves  : 

1.  Median. 

2.  Anterior  interosseous. 

3.  Cutaneous  palmar  branch. 

4.  Ulnar  trunk. 

5.  Cutaneous  palmar  branch 

of  ulnar. 


Dissection  op  the  Deep  Later  op  Mpscles  op  the  Forearm,  and  op  the  Vessels  and 
Nerves  between  the  Two  Layers  op  Muscles  of  the  Forearm.  (Illustrations  of 
Dissections.) 


Branches.  The  greater  number  of  the  collateral  offsets  of  the  artery  are 
distributed  to  the  muscles.     But  the  named  branches  are  the  following : — 

a.  Tlie  anterior  ulnar  recurrent  branch  (c?)  arises  generally  in  common 
with  the  next,  and  ascending  on  the  brachialis  anticus  muscle  inosculates 
with  the  small  anastomotic  artery  beneath  the  pronator  radii  teres.  It 
gives  offsets  to  the  contiguous  muscles. 


ULNAR    NERVE.  •  269 

h.  The  posterior  ulnar  recurrent  branch  (c?),  of  larger  size  than  the 
anterior,  is  inclined  beneath  the  flexor  sublimis  muscle  to  the  interval 
between  the  inner  condyle  and  the  olecranon.  There  it  passes  with  the 
ulnar  nerve  between  the  attachments  of  the  flexor  carpi  ulnaris,  and  joins 
the  ramifications  of  the  inferior  profunda  and  anastomotic  arteries  on  the 
inner  side  of  the  elbow  joint.  Some  of  its  offsfets  enter  the  muscles,  and 
others  supply  the  articulation  and  the  ulnar  nerve. 

c.  The  interosseous  branch  is  a  short  thick  trunk,  about  an  inch  long, 
which  is  directed  backwards  towards  the  interosseus  membrane,  and  divides 
into  anterior  and  posterior  interosseous  :  these  branches  will  be  afterwards 
followed. 

^  d.  The  metacarpal  branch  arises  from  the  artery  near  the  lower  end  of 
the  ulna,  and  runs  along  the  metacarpal  bone  of  the  little  finger,  of  which 
it  is  the  inner  dorsal  branch. 

e.  The  carpal  branches  (anterior  and  posterior)  ramify  on  the  front  and 
back  of  the  carpus,  on  which  they  anastomose  with  corresponding  offsets 
of  the  radial  artery,  and  form  arches  across  the  wrist. 

Peculiarities  of  the  ulnar  artery.  The  origin  of  the  artery  may  be  transferred  to 
any  point  of  the  main  vessel  in  the  arm  or  axilla.  Once  the  origin  was  found 
between  two  and  three  inches  below  the  elbow.     (Quain.) 

When  it  begins  higher  than  usual  it  is  generally  superficial  to  the  flexor 
muscles  at  the  bend  of  the  elbow  (only  one  exception,  Quain),  but  beneath  the 
aponeurosis  of  the  forearm  ;  though  sometimes  it  is  subcutaneous  with  the  super- 
ficial veins. 

The  ULNAR  NERVE  (fig.  81,  *)  cntcrs  the  forearm  between  the  attach- 
ments of  the  flexor  carpi  ulnaris  to  the  olecranon  and  inner  condyle  of  the 
humerus.  Under  cover  of  that  muscle  the  nerve  reaches  the  ulnar  artery 
about  the  middle  (in  length)  of  the  forearm,  and  is  continued  on  the  inner 
side  of  the  vessel  to  the  hand.  On  the  annular  ligament  the  nerve  is  rather 
deeper  than  the  artery.  It  furnishes  articular,  muscular,  and  cutaneous 
branches  as  below  : — 

a.  Articular  nerves.  In  the  interval  between  the  olecranon  and  the 
inner  condyle,  slender  filaments  to  the  joint  arise. 

h.  Muscular  branches.  It  furnishes  offsets  near  the  elbow  to  two 
muscles  of  the  forearm  ;  one  enters  the  upper  i)art  of  the  flexor  carpi 
ulnaris,  and  the  other  supplies  the  inner  half  of  the  flexor  profundus 
digitorum. 

c.  Cutaneous  nerve  of  the  forearm  and  hand.  About  the  middle  of  the 
forearm  arises  a  small  palmar  branch  (*),  which  courses  on  the  ulnar 
artery,  sending  twigs  around  that  vessel,  to  the  end  in  the  integuments  of 
the  palm  of  the  hand  :  sometimes  a  cutaneous  ofl'set  perforates  the  aponeu- 
rosis near  the  wrist,  and  joins  the  internal  cutaneous  nerve. 

d.  The  dorsal  cutaneous  nerve  of  the  hand  arises  about  two  inches  above 
the  end  of  the  ulna,  and  passes  obliquely  backwards  beneath  the  flexor 
carpi  ulnaris  :  perforating  the  aponeurosis  it  is  lost  on  the  back  of  the  hand 
and  fingers  (p.  262). 

The  MEDIAN  NERVE  (fig.  81,  ^)  leaves  the  hollow  of  the  elbow  between 
the  heads  of  origin  of  the  pronator  teres,  and  takes  the  middle  line  of  the 
limb  to  the  hand.  It  is  placed  beneath  the  flexor  sublimis  as  low  as  two 
inches  from  the  annular  ligament,  where  it  becomes  superficial  along  the 
outer  border  of  the  tendons  of  tliat  muscle.  Lastly  the  nerve  passes  be- 
neath the  annular  ligament  to  the  palm  of  the  hand.     The  nerve  supplies 


270     DISSECTION  OF  THE  FRONT  OF  THE  FOREARM. 

the  muscles  on  tlie  front  of  the  forearm,  and  furnishes  a  cutaneous  offset 
to  the  hand. 

a.  Muscular  offsets  leave  the  trunk  of  the  nerve  near  the  elbow,  and 
are  distributed  to  all  the  muscles  of  the  superficial  layer  except  the  flexor 
carpi  ulnaris  ;  in  addition,  the  nerve  supplies  the  deep  layer  througli  the 
interosseous  branch  (p.  271),  except  the  inner  half  of  the  flexor  profun- 
dus din^itorum. 

b.  The  cutaneous  palmar  branch  (^)  arises  in  the  lower  fourth  of  the 
forearm  ;  it  pierces  the  fascia  near  the  annular  ligament,  and  crosses  over 
that  ligament  to  reach  the  palm  of  the  hand. 

The  RADIAL  NEKVE  is  the  smaller  of  the  two  branches  into  whicli  the 
musculo-spiral  divides  at  the  elbow.  This  nerve  is  placed  along  the  outer 
border  of  the  limb,  under  cover  of  the  supinator  longus  (fig.  80),  and  on 
the  outer  side  of  tlie  radial  artery  till  witliin  three  inclies  of  the  wrist, 
•where  it  becomes  cutaneous  at  the  posterior  border  of  the  supinator  tendon. 
On  the  surface  of  the  limb  it  divides  into  two  branches,  which  are  dis- 
tributed on  the  dorsum  of  the  hand,  and  digits  (3|^)  (p.  2G2).  No  muscular 
offset  is  furnished  by  the  nerve. 

Dissection  (fig.  81).  To  examine  the  deep  layer  of  muscles  it  will  be 
necessary  to  draw  well  over  to  the  radial  side  of  the  forearm  the  pronator 
teres ;  to  detach  the  flexor  sublimis  from  tlie  radius,  and  to  remove  its 
fleshy  part.  The  areolar  tissue  is  to  be  taken  from  the  deep  muscular  fibres  ; 
and  the  anterior  interosseous  vessels  and  nerve,  which  lie  on  the  interosse- 
ous membrane,  and  are  concealed  by  the  muscles,  are  to  be  traced  out. 

Above  the  ends  of  the  forearm-bones  the  arch  of  the  anterior  carpal 
arteries  may  be  defined. 

Deep  Layer  of  Muscles.  Only  three  deep  muscles  are  present  on  the 
front  of  the  forearm.  One  lies  on  the  ulna,  and  is  the  deep  flexor  of  the 
fingers;  a  second  covers  the  radius,  viz.,  the  long  flexor  of  the  thumb; 
and  the  third  is  the  pronator  quadratus,  which  lies  beneath  the  other  two, 
near  the  lower  end  of  the  bones. 

The  flexor  digitorum  profundus  vel  perforans  (fig.  81,  ^)  arises 
from  the  anterior  and  inner  surfaces  of  the  ulna  for  three-fourths  of  the 
length  of  the  bone  ;  from  the  inner  half  of  the  interosseous  ligament  for 
the  same  distance  ;  and  from  an  a})oneurosis  common  to  the  muscle  and 
the  flexor  carpi  ulnaris.  The  muscle  has  a  thick  fleshy  belly,  and  ends  in 
tendons  which,  united  together,  {)ass  beneath  the  annular  ligament,  and  are 
inserted  into  the  last  phalanges  of  the  fingers. 

The  cutaneous  surface  of  the  muscle  is  in  contact  with  the  ulnar  nerve 
and  vessels,  the  superficial  flexor  of  the  fingers,  and  the  flexor  car[)i  ulna- 
ris. The  deep  surface  rests  on  the  ulna  and  the  pronator  quadratus  mus- 
cle. The  outer  border  touches  the  flexor  poUicis  longus  and  the  anterior 
interosseous  vessels  and  nerve  ;  and  the  inner  is  connected  by  aponeurosis 
to  the  posterior  margin  of  the  ulna. 

Action.  The  muscle  bends  the  last  joints  of  the  fingers  and  the  wrist ; 
but  it  does  not  act  on  the  last  phalanx  till  after  the  second  has  been  moved 
by  the  flexor  sublimis. 

The  fingers  are  approximated  and  the  joints  bent  in  the  following  order : — 
first,  the  articulation  between  the  metacar[)al  and  the  middle  [)halaiix  is 
flexed,  secondly,  the  last  phalangeal  joint,  and  thirdly  the  metacarpo-pha- 
langeal. 

The  FLEXOR  LONGUS  POLLicis  (fig.  81,^)  arises^Yom  the  hollowed  an- 
terior surface  of  the  radius,  as  low  as  the  pronator  quadratus ;  from  the 


DEEP    LAYER    OF    MUSCLES.  271 

outer  part  of  the  interosseous  membrane  ;  and  by  a  round  distinct  slip  from 
the  coronoid  process  of  the  ulna,  internal  to  the  attachment  of  the  brachi- 
alis  anticus.  Tlie  fleshy  fibres  descend  to  a  tendon,  which  is  continued 
beneath  the  annular  ligament,  and  is  inserted  into  the  last  phalanx  of  the 
thumb. 

On  the  cutaneous  surface  of  the  muscle  is  the  flexor  sublimis,  with  the 
radial  vessels  for  a  short  distance  inferiorly.  The  muscle  lies  on  the  radius 
and  the  pronator  quadratus.  To  tlie  inner  side  is  the  flexor  profundus 
digitorum. 

Action.  It  bends  both  joints  of  the  thumb,  but  first  the  distal  or  un- 
gual. After  the  phalanges  are  drawn  downwards  the  muscle  flexes  the 
wrist. 

The  PRONATOR  QUADRATUS  (fig.  81,  ^)  is  a  flat  muscle,  and  lies  on  the 
lower  fourth  of  the  bones  of  the  forearm.  It  arises  from  the  anterior  and 
inner  surfaces  of  the  ulna,  where  it  is  somewhat  widened,  and  is  inserted 
into  the  forepart  of  the  radius  for  about  two  inches. 

The  anterior  surface  is  covered  by  the  tendons  of  the  flexor  muscles  of 
the  fingers,  and  by  tlie  radial  vessels ;  and  the  posterior  surface  rests  on 
the  radius  and  ulna  with  the  intervening  membrane,  and  on  the  interosse- 
ous vessels  and  nerve.  Along  its  lower  borders  is  the  arch  formed  by  the 
anterior  carpal  arteries. 

Action.  The  end  of  the  radius  is  moved  forwards  over  the  ulna  by  this 
muscle,  and  the  hand  is  pronated. 

The  anterior  interosseous  artery  (fig.  81,  e)  is  continued  on  the  front  of 
the  interosseous  membrane,  between  tlie  two  flexors  or  in  the  fibres  of  the 
flexor  digitorum,  till  it  readies  an  aperture  beneath  the  pronator  quadratus. 
At  that  spot  the  artery  turns  from  the  front  to  the  back  of  the  limb,  and 
descends  to  the  back  of  the  carpus,  where  it  ends  by  anastomosing  with 
the  posterior  interosseous  and  carpal  arteries. 

Branches.  Numerous  offsets  are  given  to  the  contiguous  muscles. 

a.  One  long  branch  (/),  median^  accompanies  the  median  nerve,  sup- 
plying it,  and  either  ends  in  the  flexor  sublimis,  or  extends  beneath  the 
annular  ligament  to  the  palmar  arch. 

h.  About  the  middle  of  the  forearm  two  nutrient  vessels  of  the  radius 
and  ulna  arise  from  the  artery. 

c.  Where  it  is  about  to  pass  through  the  interosseous  membrane  it  fur- 
nishes twigs  to  the  pronator  quadratus  ;  and  one  branch  is  continued  be- 
neath that  muscle  to  anastomose  with  the  anterior  carpal  arteries. 

The  anterior  interosseous  nerve  is  derived  from  the  median  (fig.  81,  '■^), 
and  accompanies  the  artery  of  the  same  name  to  the  pronator  quadratus 
muscle,  the  under  surface  of  which  it  enters.  Some  lateral  branches  are 
distributed  by  it  to  the  deep  flexor  muscles. 

Dissection,  The  attachment  of  the  biceps  and  brachialis  anticus  to  the 
bones  of  the  forearm  may  be  now  cleaned  and  examined. 

The  insertion  of  the  brachialis  anticus  takes  place  by  a  broad  thick 
tendon,  about  an  inch  in  length,  which  is  fixed  into  the  coronoid  process  ot 
the  ulna,  except  at  the  inner  edge  ;  and  into  the  contiguous  rough  part  o' 
the  bone. 

Insertion  of  the  biceps.  The  tendon  of  the  biceps  is  inserted  into  the 
inner  part  of  the  tubercle  of  the  radius,  and  slightly  into  the  bone  behind 
it.  A  bursa  intervenes  between  it  and  the  forepart  of  the  tubercle.  At 
its  attachment  the  anterior  surface  becomes  external  ;  and  the  opposite. 
The  supinator  brevis  muscle  partly  surrounds  the  insertion. 


272  DISSECTION    OF    THE    HAND. 


Section  V. 

THE  PALM  OF  THE  HAND. 

Dissection  (fig.  83).  The  digits  being  separated  and  fixed  firmly  with 
tacks,  the  skin  is  to  be  reflected  from  the  palm  of  the  hand  by  means  of 
two  incisions.  One  is  to  be  carried  along  the  centre  from  the  wrist  to  the 
fingers ;  and  the  other  is  to  be  made  from  side  to  side,  at  the  termination 
of  the  first.  In  raising  the  inner  flap,  the  small  pal  maris  brevis  muscle 
w^ill  be  seen  at  the  inner  margin  of  the  hand  ;  and  its  insertion  into  the 
skin  may  be  left  till  the  muscle  has  been  learnt.  In  the  fat  the  ramifica- 
tions of  the  small  branches  (palmar)  of  the  median  and  ulnar  nerves  are 
to  be  traced. 

The  student  should  remove  the  fat  from  the  palmaris  muscle,  and  from 
the  strong  palmar  fascia  in  the  centre  of  the  hand  ;  and  he  should  take 
care  not  to  destroy  a  transverse  fibrous  band  (transverse  ligament)  which 
lies  across  the  roots  of  the  fingers.  When  cleaning  the  fat  from  the  palmar 
fascia  he  will  recognize,  near  the  digits,  the  digital  vessels  and  nerves  ;  and 
must  be  especially  careful  of  two, — viz.,  those  of  the  inner  side  of  the  lit- 
tle finger  and  outer  side  of  the  index  finger,  which  appear  farther  back 
than  the  rest,  and  are  most  likely  to  be  injured.  By  the  side  of  the  vessels 
and  nerves  to  the  fingers  four  slender  lumbricales  muscles  are  to  be  defined. 

Lastly,  the  skin  and  the  fat  may  be  reflected  from  the  thumb  and  fingers 
by  an  incision  along  each,  in  order  that  the  sheaths  of  the  tendons  with 
the  collateral  vessels  and  nerves  may  be  laid  bare. 

Cvtaneous  palmar  nerves.  Some  unnamed  twigs  are  furnished  to  the 
integument  from  both  the  median  and  ulnar  nerves  in  the  hand  ;  and  two 
named  cutaneous  nerves  ramify  in  the  palm. 

One  is  an  offset  of  the  median  nerve  (p.  270),  and  crosses  the  annular 
ligament :  it  extends  to  about  the  middle  of  the  palm,  and  is  united  with 
the  palmar  branch  of  the  ulnar :  a  few  filaments  are  furnished  to  the  ball 
of  the  thumb. 

The  other  palmar  branch  is  derived  from  the  ulnar  nerve  (p.  269)  ;  it 
has  been  traced  on  the  ulnar  artery  to  the  hand,  and  its  distribution  in  the 
palm  may  be  now  observed. 

The  PALMARIS  BREVIS  (fig.  83,  ")  is  a  small  subcutaneous  muscle,  about 
two  inches  wide,  whose  fibres  are  collected  into  separate  bundles.  It  is 
attached  on  the  outer  side  to  the  palmar  aponeurosis,  and  its  fibres  are  di- 
rected inwards  to  join  the  skin  at  the  inner  border  of  the  hand. 

This  muscle  lies  over  the  ulnar  artery  and  nerve.  After  it  has  been  ex- 
amined it  may  be  thrown  inwards  with  tlie  skin. 

Action.  Drawing  inwards  the  skin  of  the  inner  border  of  the  hand  to- 
wards the  centre,  it  deepens  the  hollow  or  cup  of  the  palm. 

The  palmar  fascia  or  aponeurosis  consists  of  a  central  and  two  lateral 
parts ;  but  the  lateral,  which  cover  tlie  muscles  of  the  thumb  and  little 
finger,  are  so  thin  as  not  to  require  separate  notice. 

The  central  part  is  a  strong,  white  layer,  which  is  pointed  at  the  wrist, 
but  is  expanded  towards  the  fingers,  where  it  nearly  covers  the  palm  of  the 
hand.  Posteriorly  the  fascia  receives  the  tendon  of  the  [)almai'i8  longus, 
and  is  connected  to  the  annular  ligament ;  and  anteriorly  it  ends  in  four 


ULNAR    VESSELS    AND    NERVE. 


273 


Fig.  82. 


processes,  which  are  continued  forwards,  one  for  each  finger,  to  the  sheaths 
of  the  tendons.  At  the  point  of  separation  of  the  processes  from  one  an- 
other some  transverse  fibres  are  placed,  whicli  arch  over  the  lumbricalis 
muscle,  and  the  digital  artery  and  nerve  appearing  at  this  spot.  From  the 
pieces  of  the  fascia  a  few  superficial  longitudinal  fibres  are  prolonged  to 
the  integuments  near  the  cleft  of  the  fingers. 

Dissection.  To  follow  one  of  the  digital  processes  of  the  fascia  to  its 
termination,  the  superficial  fibres  being  first  removed,  it  must  be  divided 
longitudinally  by  inserting  the  knife  beneath  it 
opposite  the  head  of  the  metacarpal  bone. 

Ending  of  the  processes.  Each  process  of  the 
fascia  sends  downwards  an  ofi'set  on  each  side  of 
the  tendons,  which  is  fixed  to  the  deep  ligament 
connecting  together  the  ends  of  the  metacarpal 
bones,  and  to  the  edge  of  the  metacarpal  bone  for 
a  short  distance. 

The  superficial  transverse  ligament  of  the  fingers 
is  a  thin  fibrous  band,  which  stretches  across  the 
roots  of  the  four  fingers,  and  is  contained  in  the 
fold  of  skin  forming  the  rudiment  of  a  web  be- 
tween them.  Beneath  it  the  digital  nerves  and 
vessels  are  continued  onwards  to  their  termina- 
tions. 

Sheath  of  the  flexor  tendons  (fig.  82).  Along 
each  finger  the  flexor  tendons  are  retained  in  posi- 
tion against  the  phalanges  by  a  fibrous  sheath. 
Opposite  the  middle  of  each  of  the  two  nearest 
phalanges  the  sheath  is  formed  by  a  strong  fibrous 
band  (e  and^')  (ligamentum  vaginale),  which  is 
almost  tendinous  in  consistence ;  but  opposite  the 
joints  it  consists  of  a  thin  membrane  with  scat- 
tered and  oblique  fibres.  If  the  sheath  be  opened 
it  will  be  seen  to  be  lined  by  a  synovial  membrane, 
which  forms  long  and  slender  vascular  folds  (vin- 
cula  vasculosa)  between  the  tendons  and  the 
bones. 

Dissection.  The  palmar  fascia,  and  the  thinner 
parts  of  the  digital  sheaths  opposite  the  joints  of 
the  fingers,  may  be  taken  away.  On  the  removal 
of  the  fascia  the  palmar  arch  of  the  ulnar  artery, 
and  the  median  and  ulnar  nerves,  become  ap- 
parent. 

Palmar  Pakt  of  the  Ulnar  Artery  (fig. 
83).  In  the  palm  of  the  hand  the  ulnar  artery  is 
directed  towards  the  muscles  of  the  thumb,  where 
it  communicates  with  two  offsets  of  the  radial 
trunk,  viz.,  the  superficial  volar  branch  (c),  and 
the  branch  to  the  radial  side  of  the  forefinger  (/"). 

The  curved  part  of  the  artery,  which  lies  across  the  hand,  is  named  the 
superficial  palmar  arch  (d).  Its  convexity  is  turned  towards  the  fingers, 
and  its  position  in  the  palm  would  be  nearly  marked  by  a  line  across  the 
hand  from  the  cleft  of  the  thumb. 

The  arch  is  comparatively  superficial ;  it  is  covered  in  greater  part  by 
18 


Thr  Ektensor  Tendon  of 
the  finqer  with  its  ac- 
cessory    mcscles     and 
THE     Sheath     of     thk 
Flexor  Tendons. 
n.  Extensor  teadon,  with  6, 
interosseous,  and  c,  lu/n- 
bricales  muscles  joining 
it. 
d.  Flexor  tendon;  e  and/, 
thicker      parts     of     its 
sheath. 


274  DISSECTION    OF    THE    HAND. 

the  integuments  and  tlie  palmar  fascia,  but  at  the  inner  border  of  the  hand 
the  i)alraaris  brevis  muscle  (iij  lies  over  it.  Beneath  it  are  the  flexor 
tendons  and  the  branches  of  the  ulnar  and  median  nerves.  Vense  comites 
lie  on  its  sides. 

Branches.  From  the  convexity  of  the  arch  j)roceed  the  digital  arteries, 
and  from  the  concavity  some  small  offsets  to  the  palm  of  the  hand.  A 
small  branch  (profunda)  arises  as  soon  as  the  artery  enters  the  hand. 

a.  The  profunda  or  communicating  branch  (fig.  84,  6),  passes  down- 
wards wMth  a  branch  of  the  ulnar  nerve  between  the  abductor  and  short 
flexor  muscles  of  the  little  finger,  to  inosculate  with  the  deep  palmar  arch 
of  the  radial  artery. 

b.  The  digital  branches  (g)  are  four  in  number,  and  supply  both  sides  of 
the  three  inner  fingers  and  one  side  of  the  index  finger.  The  branch  to 
the  inner  side  of  the  hand  and  little  finger  is  undivided ;  but  the  others, 
corresponding  with  the  three  inner  interosseous  spaces,  bifurcate  anteriorly 
to  supply  the  contiguous  sides  of  the  above  said  digits.  In  the  hand  these 
branches  are  accompanied  by  the  digital  nerves,  which  they  sometimes 
pierce. 

Near  the  root  of  the  fingers  they  receive  communicating  branches  from 
offsets  of  the  deep  arch  ;  but  the  digital  artery  of  the  inner  side  of  the 
little  finger  has  its  communicatinor  branch  about  the  middle  of  the  hand. 

From  the  point  of  bifurcation  the  branches  extend  along  the  sides  ot 
the  fingers ;  and  over  the  last  phalanx  the  vessels  of  opposite  sides  unite 
in  an  arch,  from  whose  convexity  offsets  proceed  to  supply  the  ball  of  the 
finger.  Collateral  offsets  are  furnished  to  the  finger  and  the  sheath  of  the 
tendons ;  and  small  twigs  are  supplied  to  the  phalangeal  articulations  from 
small  arterial  arches  on  the  bones — an  arch  being  close  behind  each  joint. 
On  the  dorsum  of  the  last  phalanx  is  another  arch  near  the  nail,  from 
which  the  nail-pulp  is  supplied. 

Palmar  Part  of  the  Ulnar  Nerve  (fig.  83,  ^).  The  ulnar  nerve 
divides  on  or  near  the  annular  ligament,  into  a  superficial  and  a  deep 
branch. 

The  deep  branch  accompanies  the  profunda  artery  to  the  muscles,  and 
will  be  subsequently  dissected  with  that  vessel  (fig.  84). 

The  superficial  branch  furnishes  an  offset  to  the  palmaris  brevis  muscle, 
and  some  filaments  to  the  integument  of  the  inner  part  of  the  hand,  and 
ends  in  two  digital  nerves,  for  the  supply  of  both  sides  of  the  little  finger 
and  half  the  next. 

Digital  nerves  (^).  The  more  internal  nerve  is  undivided,  like  the  cor- 
responding artery. 

The  other  is  directed  to  the  cleft  between  the  ring  and  little  fingers,  and 
bifurcates  for  the  sujiply  of  their  opposed  sides :  in  the  palm  of  the  hand 
this  last  branch  is  connected  with  an  offset  (*)  of  the  median  nerve. 

Along  the  sides  of  the  fingers  the  digital  branches  have  the  same 
arrangement  as  those  of  the  median  nerve. 

Palmar  Part  of  the  Median  Nerve  (fig.  83,^).  As  soon  as  the 
median  nerve  issues  from  beneath  the  annular  ligament  it  becomes  enlarged 
and  somewhat  flattened,  and  divides  into  two  nearly  equal  parts  for  the 
supply  of  digital  nerves  to  the  thumb  and  the  remaining  two  fingers  and 
a  half:  the  more  external  of  the  two  portions  furnishes  a  small  muscular 
branch  to  the  ball  of  the  thumb.  The  trunk  of  the  nerve  and  its  branches 
are  covered  by  the  palmar  fascia ;  and  beneath  them  are  the  tendons  of 
the  flexor  muscles. 


MEDIAN    NERVE    AND    BRANCHES 


275 


«.  The  branch  to  muscles  of  the  thumb  (*)  supplies  the  outer  half  of  the 
short  flexor,  and  ends  in  tlie  abductor,  and  opponens  pollicis  muscles. 

b.  The  digital  nerves  {^)  are  five  in  number.  Three  of  tiiem,  which 
are  distributed  to  the  sides  of  the  thumb  and  the  radial  side  of  the  fore 
finger,  are  undivided,  and  come  from  the  external  of  the  two  pieces  into 


Fig.  83. 


Dissection  of  the  Superficial  Vessels  and  Nerves  of  the  Palm  of  the  Hand  with  some 


OF  the  Superficial  Muscles. 
Muscles  : 

A.  Abductor  policis. 

c.  Flexor  brevis. 

D.  Adductor  policis. 

H.  Palraaris  brevis. 
Arteries: 

a.  Trunk  of  ulnar,  and  6,  of  radial. 

c.  Superficial  volar  branch. 

d.  Superficial  palmar  arch. 

e.  Branch  uniting  the  arch  with  /  the   radial 

digital  branch  of  the  forefinger. 
g.  Four  digital  branches  of  the  superficial  arch. 


(Illustrations  of  Dissections.) 
Nerves  : 
1.  Ulnar,  and  2,  its  two  digital  branches. 

3.  Median,  and   5,  its  digital  branches  to 

three  fingers  and  a  half. 

4.  Branch  of  the  median  to  some  muscles 

of  the  thumb 

5.  Communicating  branch  from  the  median 

to  the  ulnar. 


which  the  trunk  of  the  median  splits.  The  other  two  spring  from  the  in- 
ner piece  of  the  nerve,  and  are  bifurcated  to  supply  the  opposed  sides  of 
the  middle  and  fore,  and  the  middle  and  ring  fingers. 

The  Jirst  two  nerves  belong  to  the  thumb,  one  being  on  each  side,  and 
the  most  external  is  said  to  communicate  with  branches  of  the  radial  nerve. 


276  DISSECTION    OF    THE    HAND. 

The  third  is  directed  to  tlie  radial  side  of  the  index  finger,  and  gives  a 
branch  to  the  most  external  lumbrical  muscle. 

The  fourth  furnishes  a  nerve  to  the  second  lumbrical  muscle,  and  di- 
vides to  supply  the  contiguous  sides  of  the  fore  and  middle  fingers. 

The  jijth^  like  the  fourth,  is  distributed  by  two  branches  to  the  opposed 
sides  of  the  middle  and  ring  fingers  :  it  communicates  with  a  branch  of  the 
ulnar  nerve. 

On  the  fingers.  On  the  sides  of  the  fingers  the  nerves  are  superficial  to 
the  arteries,  and  reach  to  the  last  phalanx,  where  they  end  in  filaments  for 
the  ball  and  the  pulp  beneath  the  nail.  In  their  course  forwards  the  nerves 
supply  chiefly  tegumentary  branches  :  one  of  these  is  directed  backwards 
by  the  side  of  the  metacarpal  [Jialanx,  and  after  uniting  with  the  digital 
nerve  on  the  back  of  the  finger  (p.  262),  is  continued  to  the  dorsum  of  the 
last  phalanx. 

Dissection.  The  tendons  of  the  flexor  muscles  may  be  followed  next  to 
their  termination.  To  expose  them  the  ulnar  artery  should  be  cut  through 
below  the  origin  of  the  profunda  branch  ;  and  the  small  superficial  volar 
branch  (of  the  radial)  having  been  divided,  the  palmar  arch  is  to  be  thrown 
towards  the  fingers.  The  ulnar  and  median  nerves  are  also  to  be  cut  be- 
low the  annular  ligament,  and  turned  forwards. 

A  longitudinal  incision  is  to  be  made  through  tlie  centre  of  the  annular 
ligament,  without  injuring  the  small  muscles  that  arise  from  it,  and  the 
pieces  of  the  ligament  are  to  be  thrown  to  the  sides. 

Finally  the  sheaths  of  the  fingers  may  be  opened  for  the  purpose  of  ob- 
serving the  insertion  of  the  tendons. 

Flexor  tendons.  Beneath  the  annular  ligament  the  tendons  of  the 
deep  and  superficial  flexors  are  surrounded  by  a  large  and  loose  synovial 
membrane,  which  projects  upwards  into  the  forearm  and  downwards  into 
the  hand,  and  sends  an  oflfset  into  the  digital  sheath  of  the  thumb  and  that 
of  the  little  finger.^ 

Flexor  sublimis.  The  tendons  of  the  flexor  sublimis  are  superficial  to 
those  of  the  deep  flexor  beneath  the  ligament ;  and  all  four  are  nearly  on 
the  same  level,  instead  of  being  arranged  in  pairs,  as  in  the  forearm. 
After  crossing  the  palm  of  the  hand  they  enter  the  sheath  of  the  fingers 
(fig.  82,  e),  and  are  inserted  each  by  two  processes  into  the  margins  of  the 
middle  phalanx,  about  the  centre.  When  first  entering  the  digital  sheath, 
the  tendon  of  the  flexor  sublimis  conceals  that  of  the  flexor  profundus  ; 
but  near  the  front  of  the  first  phalanx  it  is  split  for  the  passage  of  the 
tendon  of  the  latter  muscle. 

Dissection.  To  see  the  tendons  of  the  deep  flexor  and  the  lumbrical  mus- 
cles, the  flexor  sublimis  must  be  cut  through  above  the  wrist,  and  thrown 
towards  the  fingers.     Afterwards  the  areolar  tissue  should  be  taken  away. 

Flexor  profundus.  At  the  lower  border  of  the  annular  ligament  the  ten- 
dinous mass  of  the  flexor  profundus  is  divided  into  four  pieces,  though  in 
the  forearm  only  the  tendon  of  the  forefinger  is  distinct  from  the  rest. 
From  the  ligament  the  four  tendons  are  directed  through  the  hand  to  the 
fingers,  and  give  origin  to  the  small  lumbricales  muscles.  At  the  root  of 
the  fingers  each  enters  the  digital  sheath  with  a  tendon  of  the  flexor  sub- 
limis, and  having  passed  through  that  tendon,  is  inserted  into  the  base  of 
the  last  phalanx. 

'  Theile  refers  the  notice  of  this  fact  to  M.  Maslieurat-Lagdmard,  in  No.  18  of 
the  "Gazette  M^dicale,"  for  1839. 


MUSCLES    OF    THUMB.  277 

Between  both  flexor  tendons  and  the  bones  are  thin  membranes,  one  for 
each.  By  means  of  this  each  tendon  is  connected  with  the  capsule  of  the 
joint,  and  the  fore  part  of  the  phahinx  immediately  behind  the  bone  into 
which  it  is  inserted. 

The  himhricales  muscles  (fig.  84,  i)  are  four  small  fleshy  slips,  which 
arise  from  the  tendons  of  the  deep  flexor  near  the  annular  ligament ; 
and  are  directed  to  the  radial  side  of  each  finger,  to  be  inserted  into  an 
aponeurotic  expansion  on  the  dorsal  aspect  of  the  metacarpal  phalanx 
(fig.  82,  c). 

Ttiese  muscles  are  concealed  for  the  most  part  by  the  tendons  and  ves- 
sels that  have  been  removed;  but  they  are  subcutaneous  for  a  short  distance 
between  the  processes  of  the  palmar  fascia.  The  outer  two  arise  from 
single  tendons,  but  each  of  the  others  is  connected  with  two  tendons. 

Action.  By  their  insertion  into  the  long  extensor  tendon  they  will  aid 
it  in  straightening  the  two  last  phalangeal  joints  ;  and  when  the  metacarpo- 
phalangeal joints  are  much  bent  they  may  assist  in  maintaining  the  flexion 
of  these  articulations. 

Tendon  of  the  flexor  poUicis  longus.  Beneath  the  annular  ligament  this 
tendon  is  external  to  the  flexor  profundus,  and  turns  outwards  between  the 
heads  of  the  flexor  brevis  poUicis  (fig.  84),  to  be  inserted  into  the  last 
phalanx  of  the  thumb.  The  common  synovial  membrane  surrounds  it  be- 
neath the  annular  ligament,  and  sends  a  prolongation,  as  before  said,  into 
its  digital  sheath. 

Dissection  (fig.  84).  The  deep  palmar  arch  of  the  radial  artery,  with 
the  deep  branch  of  the  ulnar  nerve,  and  the  interossei  muscles,  will  come 
into  view  if  the  flexor  profundus  is  cut  above  the  wrist,  and  thrown  with 
the  lumbricales  muscles  towards  the  fingers  ;  but  in  raising  the  tendons 
the  student  should  preserve  two  fine  nerves  and  vessels  entering  the  two 
inner  lumbrical  muscles. 

The  dissection  of  the  muscles  of  the  ball  of  the  thumb  and  the  little 
finger  is  next  to  be  prepared.  Some  care  is  necessary  in  making  a  satis- 
factory separation  of  the  ditferent  small  thumb  muscles ;  but  those  of  the 
little  finger  are  more  easily  defined. 

Short  Muscles  of  the  Thumb  (fig.  84).  These  are  four  in  number, 
and  are  named  from  their  action  on  the  thumb.  The  most  superficial  is 
the  abductor  pollicis  ;  beneath  it  is  the  opponens  pollicis,  which  will  be 
recognized  by  its  attachment  to  the  whole  length  of  the  metacarpal  bone. 
To  the  inner  side  of  the  last  is  the  short  flexor.  And  the  wide  muscle 
coming  from  the  third  metacarpal  bone  is  the  adductor  of  the  thumb. 

The  ABDUCTOR  POLLICIS,  A,  is  about  an  inch  wide,  and  is  thin,  and 
superficial  to  the  rest.  It  «nses  from  the  upper  part  of  the  annular  liga- 
ment at  the  radial  side,  and  from  the  ridge  of  the  os  trapezium ;  and  is 
inserted  into  the  base  of  the  first  phalanx  of  the  thumb. 

The  muscle  is  subcutaneous,  and  rests  on  the  opponens  pollicis :  it  is 
connected  oftentimes  at  its  origin  with  a  slip  from  the  tendon  of  the  ex- 
tensor ossis  metacarpi  pollicis. 

Action.  It  removes  the  metacarpal  bone  of  the  thumb  from  the  other 
digits  ;  and  when  it  has  so  acted  it  may  assist  slightly  the  short  flexor  in 
bending  the  metacarpo-phalangeal  joint. 

Dissection.  The  opponens  pollicis  will  be  seen  on  cutting  through  the 
abductor.  To  separate  the  muscle  from  the  short  flexor  on  the  inner  side, 
the  student  should  begin  near  the  fore  part  of  the  metacarpal  bone,  where 
there  is  usually  a  slight  interval. 


278  DISSECTION    OF    THE    HAND. 

The  orpoNENS  pollicis,  b,  arises  from  the  annular  ligament  beneath 
the  preceding,  and  from  the  os  trapezium  and  its  ridge  ;  it  is  inserted  into 
the  front  and  outer  border  of  the  metacarpal  bone  for  the  whole  length. 

This  muscle  is  partly  concealed  by  the  preceding,  though  it  projects  on 
the  outer  side.  Along  its  inner  border  is  the  flexor  brevis  pollicis.  An 
insertion  into  the  external  sesamoid  bone  is  described  by  Theile. 

Action,  From  its  attachment  to  the  metacarpal  bone  it  is  able  to  draw 
that  bone  inwards  over  the  palm  of  the  hand,  turning  it  at  the  same  time, 
so  as  to  allow  the  ball  of  the  thumb  to  be  applied  to  the  ball  of  each  of  the 
fingers,  as  in  picking  up  a  pin. 

The  FLEXOR  BREVIS  POLLICIS,  c,  is  the  largest  of  the  short  muscles  of 
the  thumb  :  it  consists  of  two  pieces  (inner  and  outer)  at  the  insertion,  but 
these  are  united  at  the  origin.  Posteriorly  it  arises  from  the  os  trapezoides 
and  OS  magnum  ;  from  the  bases  of  the  second  and  third  metacarpal  bones  ; 
and  from  the  annular  ligament,  at  the  lower  part.  In  front  it  is  inserted 
by  two  heads  into  the  sides  of  the  base  of  the  first  phalanx  of  the  thumb, — 
the  inner  piece  being  united  with  the  adductor,  and  the  outer  with  the 
abductor  pollicis.  A  sesamoid  bone  is  connected  with  each  head  at  its 
insertion. 

The  tendon  of  the  long  flexor  lies  on  this  muscle,  occupying  the  interval 
between  the  processes  of  insertion  ;  and  the  deep  palmar  arch  of  the  radial 
artery  issues  from  beneath  the  inner  head. 

Action.  The  muscle  bends  the  metacarpo-phalangeal  joint,  and  assists 
the  opponens  in  drawing  the  thumb  forwards  and  inwards  over  the  palm. 

The  ADDUCTOR  POLLICIS,  D,  is  pointed  at  the  thumb,  and  wide  at  the 
opposite  end.  Its  origin  is  fixed  to  the  anterior  or  lower  two-thirds  of  the 
metacarpal  bone  of  the  middle  digit,  on  the  palmar  aspect ;  and  its  inser- 
tion is  attached,  with  that  of  the  short  flexor,  to  the  inner  side  of  the  first 
phalanx  of  the  thumb. 

The  cutaneous  surface  is  in  contact  with  the  .tendons  of  the  flexor  pro- 
fundus and  the  lumbrical  muscles ;  and  the  deep  surface  lies  over  (in  this 
position)  the  first  dorsal  interosseous  muscle,  j,  and  the  second  and  third 
metacarpal  bones  with  the  intervening  muscle. 

Actions.  By  its  contraction  the  thumb  is  applied  to  the  radial  border  of 
the  hand,  and  approximated  to  the  fingers. 

Short  Muscles  of  the  Little  Finger  (fig.  84).  There  are  com- 
monly two  muscles  in  the  ball  of  the  little  finger, — an  abductor  and  an 
adductor.     Sometimes  there  is  a  short  flexor  between  the  other  two. 

The  abductor  minimi  digiti,  e,  is  the  most  internal  of  the  short 
muscles.  It  arises  from  the  pisiform  bone  and  the  tendon  of  the  flexor 
carpi  ulnaris,  and  is  inserted  into  the  ulnar  side  of  the  base  of  the  first 
phalanx  of  the  little  finger;  an  oft'set  from  it  reaches  the  extensor  tendon 
on  the  back  of  the  phalanx.  The  palmaris  brevis  partly  conceals  the 
muscle. 

Action.  First  it  draws  the  little  finger  away  from  the  others ;  but  con- 
tinuing to  act  it  bends  the  metacarpo-phalangeal  joint. 

The  FLEXOR  brevis  minimi  digiti,  f,  appears  often  to  be  a  part  of 
the  abductor.  Placed  at  the  radial  border  of  the  preceding  muscle,  it 
takes  origin  from  the  tip  of  the  process  of  tiie  unciform  bone,  and  sliglitly 
from  the  annular  ligament ;  it  is  inserted  with  the  abductor  into  the  first 
phalanx. 

It  lies  on  the  adductor  ;  and  near  its  origin  it  is  separated  from  the 
abductor  muscle  by  the  deep  branches  of  the  ulnar  artery  and  nerve. 


MUSCLES    OF    LITTLE    FINGER, 


279 


Action.  The  first  phalanx  is  moved  towards  the  palm  by  this  muscle, 
and  the  metacarpo-phalangeal  joint  is  bent. 

The  ADDUCTOR  vel  opponens  minimi  digiti,  g,  resembles  the  opponens 
poUicis  in  being  attached  to  the  metacarpal  bone.  Its  origin  is  from  the 
process  of  the  unciform  bone,  and  the  lower  part  of  the  annular  ligament ; 
its  insertion  is  fixed  into  the  ulnar  side  of  the  metacarpal  bone  of  the  little 
finger. 

Fig.  84. 


Deep  Dissection  of  the  Palm  of  the  Hand.   (Illustrations  of  Dissectioas.) 


fuscles : 

A.  Abductor  pollicis. 

B.  Opponens  pollicis. 

c.  Flexor  brevis  pollicis. 

D.  Adductor  pollicis. 

B.  Abductor  minimi  digiti. 

P.  Flexor  brevis  minimi  digiti. 

Q.  Opponens  minimi  digiti. 

I.  Lmnbricales. 

J.  First  dorsal  interosseous. 


Vessels  : 
a.  Ulnar  artery,  cut. 
6.  Profunda  branch. 
e.  Deep  palmar  arch. 

d.  Radial  digital  artery  of  the  index  finger. 

e.  Arteria  magna  pollicis. 
/.  Interosseous  arteries. 

Nerves  : 

1.  Ulnar  nerve,  cut. 

2.  Deep  branch  of  the  palm  of  the  hand,  and  4, 

its  continuation  to  end  in  some  of  the 
thumb  muscles. 

3.  Offsets  to  the  inner  two  lumbricales. 


The  adductor  is  partly  overlaid  by  the  preceding  muscles  ;  and  beneath 
it  the  deep  branches  of  the  ulnar  artery  and  nerve  pass. 

Action.  It  raises  the  inner  metacarpal  bone,  and  moves  it  towards  the 
others,  so  as  to  deepen  the  palm  of  the  hand. 

Dissection.     The  radial  artery  comes  into  the  hand  between  the  first 


280  DISSECTION    OF    THE    HAND. 

two  metacarpal  bones  ;  and  to  lay  bare  the  vessel,  it  will  be  requisite  to 
detach  the  orij2!;in  of  the  flexor  brevis  pollicis.  The  deep  palmar  arch,  and 
the  branch  of  the  ulnar  nerve  accompanying  it,  together  with  their  offsets, 
are  to  be  dissected  out. 

A  fascia,  which  covers  the  interossei  muscles,  is  to  be  removed,  when 
the  dissector  has  observed  its  connection  with  the  transverse  ligament 
uniting  the  heads  of  the  metacarpal  bones. 

Radial  Artery  in  the  Hand  (llg.  84).  The  radial  artery  enters 
the  palm  at  the  first  interosseous  space,  between  the  heads  of  the  first  dorsal 
interosseous  muscle  :  and  after  furnishing  one  branch  to  the  thumb,  and 
another  to  the  index  finger,  turns  across  the  hand  towards  the  ulnar  side, 
with  its  venae  comites,  forming  the  deep  arch. 

The  deep  palmar  arch  (c)  extends  from  the  interosseous  space  to  the 
base  of  the  metacarpal  bone  of  the  little  finger,  where  it  joins  the  profunda 
communicating  branch  (6).  Its  convexity,  which  is  but  slight,  is  directed 
forwards  ;  and  its  position  is  nearer  the  carpal  bones  than  that  of  the 
superficial  arch.  The  arch  has  a  deep  position  in  the  hand,  and  lies  on 
the  metacarpal  bones  and  the  interossei  muscles.  It  is  covered  by  the 
long  flexor  tendons,  and  in  part  by  the  flexor  brevis  pollicis.  The  branches 
of  the  arch  are  the  following  : — 

a.  Recurrent  branches  pass  from  the  concavity  of  the  arch  to  the  front 
of  the  carpus  ;  these  supply  the  bones,  and  anastomose  with  the  other  carpal 
arteries. 

b.  Three  perforating  arteries  pierce  the  three  inner  dorsal  interossei 
muscles,  and  communicate  with  the  interosseous  arteries  on  the  back  of 
the  hand. 

c.  Usually  there  are  three  palmar  interosseous  arteries  (/),  which 
occupy  the  three  inner  metacarpal  spaces,  and  terminate  by  joining  the 
digital  branches  of  the  superficial  palmar  arch  at  the  cleft  of  the  fingers. 
These  branches  supply  the  interosseous  muscles,  and  the  two  or  three  inner 
lumbricales ;  they  vary  much  in  their  size  and  distribution. 

d.  Digital  branches  of  the  radial.  The  large  artery  of  the  thumb  (^) 
(art.  princeps  pollicis)  runs  between  the  first  metacarpal  bone  and  the 
flexor  brevis  pollicis,  to  the  interval  between  the  heads  of  the  muscle, 
where  it  divides  into  the  two  collateral  branches  of  the  thumb  :  these  are 
distributed  like  the  arteries  of  the  superficial  arch. 

e.  The  digital  branch  of  the  index  finger  {d)  (art.  radialis  indicis)  is 
directed  over  the  first  dorsal  interosseous  muscle,  .i,  and  beneath  the  short 
flexor  and  the  adductor  pollicis,  to  the  radial  side  of  the  forefinger.  At 
the  free  or  anterior  border  of  the  adductor  pollicis,  d,  this  branch  is  usually 
connected  by  an  offset  with  the  superficial  palmar  arch  ;  and  at  the  end  of 
the  digit  it  unites  with  the  branch  furnished  to  the  0})posite  side  by  the 
ulnar  artery. 

The  deep  branch  of  the  ulnar  nerve  {^^  accompanies  the  arch  of  the 
radial  artery  as  far  as  the  muscles  of  the  thumb,  and  terminates  in  oflTsets 
to  the  adductor  pollicis  and  the  inner  head  of  the  short  flexor. 

Branches,  Near  its  origin  the  nerve  furnislies  branches  to  the  muscles 
of  the  little  finger.  In  the  palm  it  gives  offsets  to  all  the  palmar  and 
dorsal  interosseous  muscles,  and  to  the  inner  two  lumbrical  muscles  ('), 
besides  the  terminal  branches  before  mentioned. 

The  transverse  metacarpal  ligament  connects  togetlier  the  heads  of  the 
four  inner  metacarpal  bones.  Its  cutaneous  surface  is  hollowed  where  the 
flexor  tendons  cross  it ;  and  beneath  the  interossei  nmscles  pass   to   their 


RADIAL    ARTERY    AND    OFFSETS. 


281 


insertion.  To  the  posterior  border  tlie  fascia  covering  tlie  interossei 
muscles  is  united.  The  ligament  should  now  be  taken  away  to  see  the 
interossei  muscles. 

The  INTEROSSEI  MUSCLES,  SO  named  from  their  position  between  the 
metacarpal  bones,  are  seven  in  number.  Two  muscles  occupy  each  space, 
except  in  the  first  where  there  is  only  one  ;  they  arise  from  the  meta- 
carpal bones,  and  are  inserted  into  the  first  phalanx  of  the  fingers.  They 
are  divided  into  palmar  and  dorsal  interossei  ;  but  all  the  small  muscles 
are  evident  in  the  palm  of  the  hand,  though  some  project  more  than  the 
others. 

The  palmar  muscles  (fig.  85),  three  in  number,  are  smaller  than  the 
dorsal  set,  and  are  most  prominent  in  the  palm  of  the  hand.  They  arise 
from  the  palmar  surface  of  the  metacarpal  bones  of  the  fingers  on  which 
they  act,  viz.,  those  of  the  fore,  ring,  and  little  fingers;  and  they  are  in- 
serted into  the  ulnar  side  of  the  fore,  and  the  radial  side  of  the  other  two 
digits. 


Fig.  85. 


Fig.  86. 


Three  Palmar  Interosseous  Musclks. 
a.  Muscle  of  the  little  finger;  b,  of  the  rins 
finger;  and  c,  of  the  forefinger. 


Four  Dorsal  Interosseous  Musclks. 
d.  Muscle  of  the  forefinger,  called  sometimes 

abductor  indicia. 
e  and/.  Muscles  of  the  middle  finger. 
g.  Muscle  of  the  ring  finger. 


Both  sets  of  muscles  have  a  similar  termination  (fig.  82,  b)  : — the  fibres 
end  in  a  tendon,  which  is  inserted  into  the  side  of  the  first  or  metacarpal 
phalanx,  and  sends  an  expansion  to  join  the  extensor  tendon  on  the  dor- 
sum of  the  bone. 

The  dorsal  interossei  (fig.  86)  extend  farther  back  than  the  palmar  set, 
and  arise  by  two  heads  from  the  lateral  surfaces  of  the  metacarpal  bones 
between  which  they  lie.  The  dorsal  muscles  are  thus  allotted  to  the 
digits : — two  belong  to  the  second  finger,  a  third  is  connected  with  the 
radial  side  of  the  fore,  and  the  fourth  with  the  ulnar  side  of  the  ring 
finger. 

Action,     They  help  to  bend  the  metacarpo-phalangeal  joints  by  their 


282  DISSECTION    OF    THE    FOREARM. 

attachment  to  the  first  phalanx  ;  and  assist  in  the  extension  of  the  two 
last  phalangeal  joints  through  tiieir  union  with  the  extensor  tendon. 

F'urther  they  can  separate  and  approximate  the  fingers  :  thus  the  palmar 
set  adduct  to  the  second  finger ;  and  the  dorsal  abduct  from  the  middle 
line  of  the  second  finger — the  two  attached  to  this  digit  moving  it  to  the 
right  and  left  of  that  line. 

Dissection.  The  attachments  of  the  annular  ligament  to  the  carpal 
bones  on  each  side  are  to  be  next  dissected  out  by  taking  away  the  small 
muscles  of  the  thumb  and  little  finger.  Before  reading  its  description, 
the  ends  of  the  cut  ligament  irniy  be  placed  in  apposition. 

The  anterior  annular  ligament  is  a  firm  ligamentous  band,  which  arches 
over  and  binds  down  the  flexor  tendons  of  the  fingers.  It  is  attached  ex- 
ternally to  the  front  of  the  os  scaphoides,  and  to  the  fore  and  inner  parts, 
and  ridge  of  the  os  trapezium  ;  and  internally  to  the  unciform  and  pisiform 
bones.  By  its  upper  border  it  is  connected  with  the  aponeurosis  of  the 
forearm  ;  and  by  its  anterior  surface  it  joins  the  palmar  fascia.  On  it  lie 
the  palmaris  longus  and  the  ulnar  artery  and  nerve. 

Dissection.  Next  follow  the  tendon  of  the  flexor  carpi  radialis  through 
the  OS  trapezium  to  its  insertion  into  the  metacarpal  bones. 

The  tendon  of  the  flexor  carpi  radialis,  in  passing  from  the  forearm  to 
the  hand,  lies  in  the  groove  in  the  os  trapezium  between  the  attachments 
of  the  annular  ligament  to  the  bone,  but  outside  the  arch  of  that  ligament ; 
here  it  is  bound  down  by  a  fibrous  sheath  lined  by  a  synovial  membrane. 
The  tendon  is  inserted  into  the  base  of  the  metacarpal  bone  of  the  index 
finger,  and  sends  a  slip  to  that  of  the  middle  digit. 


Section  VI. 

THE  BACK  OF  THE  FOREARM. 


Position.  During  the  dissection  of  the  back  of  the  forearm  the  limb  lies 
■with  the  forepart  undermost,  and  a  small  block  is  to  be  placed  beneath  the 
wrist  for  the  purpose  of  stretching  the  tendons. 

Dissection  (fig.  87).  The  fascia  and  the  cutaneous  nerves  and  vessels 
are  to  be  reflected  from  the  muscles  of  the  forearm,  and  from  the  tendons 
on  the  back  of  the  hand ;  but  in  removing  the  fascia  in  the  forearm,  the 
student  must  be  careful  not  to  cut  away  the  posterior  interosseous  vessels, 
which  are  in  contact  with  it  on  the  inner  side  in  the  lower  third.  A  thick- 
ened band  of  the  fascia  opposite  the  carpus  (the  posterior  annular  ligament) 
is  to  be  left. 

Let  the  integument  be  removed  from  the  fingers,  in  order  that  the  ten- 
dons may  be  traced  to  tlie  end  of  the  digits. 

The  several  muscles  should  be  separated  from  one  another  up  to  their 
origin,  especially  the  two  radial  extensors  of  the  wrist. 

The  posterior  annular  ligament,  k,  consists  of  the  special  aponeurosis 
of  the  limb,  thickened  by  the  addition  of  some  transverse  fibres,  and  is 
situate  opposite  the  lower  end  of  the  l>ones  of  the  forearm.  This  band  is 
connected  at  the  outer  part  to  the  radius,  and  at  the  inner  to  the  cuneiform 
and  pisiform  bones.     Processes  from  it  are  fixed  to  the  bones  beneatii,  and 


SUPERFICIAL    LAYER    OF    MUSCLES 


283 


confine  the  extensor  tendons.    The  ligament  will  be  subsequently  examined 
more  in  detail. 

Superficial  layer  of  muscles  (fig.  87).    The  muscles  are  arranged 
in  a  superficial  and  a  deep  layer,  as  on  the  anterior  part  of  the  forearm. 

Fiff.  87. 


Mttscles  : 

A.  Supinator  longus. 

B.  Extensor  carpi  radialis  longus. 

0.  Extensor  carpi  radialis  breris. 
D.  Extensor  communis  digitorum. 
B.  Extensor  minimi  digiti. 

P.  Extensor  carpi  ulnaris. 

G.  Anconeus. 

H.  Extensor  ossis  metacarpi  pollicis. 

1.  Extensor  primi  iiiternodii. 

J.  Extensor  secundi  internodii  pollicis. 

K.  Posterior  annular  ligament. 

L.  Bands  uniting  the  tendons  of  the  common  ex- 
tensor on  the  back  of  the  hand. 

N.  Insertion  of  the  common  extensor  into  the 
last  two  phalanges. 

Arteries : 
a.  Posterior  interosseous. 

1.  Radial. 

2.  Posterior  carpal  arch. 
d.  Metacarpal  branch. 

4.  Dorsal  branche.s  of  thumb  and  forefinger. 


Superficial  Layer  of  Mcsct.es  on  the  Back  op  the  Forearm,  with  some  Vessels. 
(Illustrations  of  Dissections.) 

The  superficial  layer  contains  seven  muscles,  which  arise  mostly  by  a  com- 
mon tendon  from  the  outer  condyle  of  the  humerus,  and  liave  tlie  under- 
mentioned position  one  to  another  from  without  inwards  ; — the  long  supi- 


284  DISSECTION    OF    THE    FOREARM. 

nator,  a,  the  two  radial  extensors  of*  the  wrist,  b  and  c  (long  and  short), 
the  common  extensor  of  the  fingers,  d,  the  extensor  of  the  little  finger,  e, 
and  the  ulnar  extensor  of  the  wrist,  f.  There  is  one  other  small  muscle 
near  the  elbow,  the  anconeus,  G. 

The  SUPINATOR  RADII  LONGUS,  A,  reachcs  upwards  into  the  arm,  and 
limits  on  the  outer  side  the  hollow  in  front  of  the  elbow.  The  muscle 
arises  from  the  upper  two-thirds  of  the  outer  condyloid  ridge  of  the  hu- 
merus, and  the  front  of  the  external  intermuscular  septum.  The  fleshy 
fibres  end  about  the  middle  of  the  forearm  in  a  tendon,  which  is  inserted 
into  the  lower  end  of  the  radius,  close  above  the  styloid  process. 

In  the  arm  the  margins  of  the  supinator  are  directed  towards  the  sur- 
face and  the  bone,  but  in  the  forearm  and  muscle  is  flattened  over  the  others, 
with  its  edges  forwards  and  backwards.  Its  anterior  border  touches  the 
biceps  and  the  pronator  teres ;  and  the  posterior  is  in  contact  with  both 
radial  extensors  of  the  wrist.  Near  its  insertion  the  supinator  is  covered 
by  two  extensors  of  the  thumb.  Beneath  the  muscle  are  the  brachialis 
anticus  and  musculo-spiral  nerve,  the  extensors  of  the  wrist,  the  radial 
vessels  and  nerve,  and  the  radius. 

Action.  The  chief  use  of  this  supinator  is  to  bend  the  elbow-joint.  But 
if  the  radius  is  either  forcibly  pronated  or  supinated  the  muscle  can  put  the 
hand  into  a  state  intermediate  between  pronation  and  supination, — the 
thumb  being  brought  above  the  forefinger. 

If  the  radius  is  fixed  as  in  climbing,  the  muscle  will  bring  up  the  hu- 
merus, bending  the  elbow. 

The  EXTENSOR  CARPI  RADiALis  LONGiOR,  B,  arises  fVom  the  lower  third 
of  the  outer  condyloid  ridge  of  the  humerus,  and  the  front  of  the  contigu- 
ous intermuscular  septum  ;  and  from  the  septum  between  it  and  the  next 
muscle.  The  muscle  lies  on  the  short  radial  extensor,  being  partly  cov- 
ered by  the  supinator  longus  ;  and  its  tendon  passes  beneath  the  extensors 
of  the  thumb,  and  the  annular  ligament,  to  be  inserted  into  the  base  of  the 
metacarpal  bone  of  the  index  finger.  Along  its  outer  border  lies  the  radial 
nerve. 

Action.  The  long  extensor  straightens  first  the  wrist,  and  bends  next 
the  elbow  joint. 

If  the  hand  is  fixed  in  climbing,  it  will  act  on  the  humerus  like  the 
long  supinator. 

The  EXTENSOR  CARPI  RADIALIS  BREViOR,  c,  is  attached  to  the  outer 
condyle  of  the  humerus  by  a  tendon  common  to  it  and  the  three  following 
muscles,  viz.,  common  extensor  of  the  fingers,  extensor  of  the  little  finger 
and  ulnar  extensor  of  the  wrist :  it  takes  origin  also  from  the  capsular 
ligament  of  the  elbow  joint.  The  tendon  of  the  muscle  is  closely  con- 
nected with  the  preceding,  and  after  passing  with  it  through  the  same  com- 
partment of  the  annular  ligament,  is  inserted  into  the  base  of  the  meta- 
carpal bone  of  the  middle  finger. 

Concealed  on  the  outer  side  by  the  two  preceding  muscles  this  extensor 
rests  on  the  radius  and  some  of  the  muscles  attached  to  it,  that  is  to  say, 
on  the  supinator  brevis,  and  the  pronator  teres.  Along  the  ulnar  side  is 
the  common  extensor  of  the  fingers;  and  the  extensors  of  the  thumb  come 
between  it  and  the  digital  extensor.  Both  radial  extensors  of  the  carpus 
have  usually  a  bursa  at  the  insertion. 

Action.  This  muscle  resembles  its  fellow  in  extending  the  wrist,  but 
differs  from  it  in  extendin";  the  elbow. 


EXTEN'SORS    OF    DIGITS.  285 

Acting  with  the  long  extensor  of  the  wrist  it  will  move  the  lower  end 
of  the  radius  in  supination. 

The  EXTENSOR  COMMUNIS  DiGiTORUM,  D,  is  single  at  its  origin,  but  is 
divided  inferiorly  into  four  tendons.  It  arises  from  the  common  tendon, 
from  aponeurotic  septa  between  it  and  the  muscles  around,  and  from  the 
aponeurosis  of  the  limb.  Near  the  lower  part  of  the  forearm  the  muscle 
ends  in  three  tendons,  which  pass  through  a  compartment  of  the  annular 
ligament  with  the  indicator  muscle;  below  the  ligament,  the  most  internal 
tendon  divides  into  two,  and  all  four  are  directed  along  the  back  of  the 
hand  to  their  insertion  into  the  two  last  phalanges  of  the  fingers. 

On  the  back  of  the  fingers  the  tendons  have  the  following  arrangement. 
On  the  dorsum  of  the  first  phalanx  each  forms  an  expansion  with  the  ten- 
dons of  the  lumbricales  and  interossei  muscles  (fig.  82).  At  the  front  of 
that  phalanx  it  divides  into  three  parts  (fig.  87,  ^)  : — the  central  one  is  fixed 
into  the  base  of  the  second  phalanx,  whilst  the  lateral  pieces  unite,  and  are 
inserted  into  tlie  base  of  the  last  phalanx.  On  the  fore  and  little  fingers 
the  expansion  is  joined  by  the  special  tendons  of  those  digits ;  and  oppo- 
site the  first  two  articulations  of  each  finger  the  tendon  sends  down  lateral 
bands  to  join  the  capsule  of  the  joint. 

Tliis  muscle  is  placed  between  the  extensors  of  the  wrist  and  little  finger, 
and  conceals  the  deep  layer.  On  the  back  of  the  hand  the  tendons  are 
joined  by  cross  pieces,  l,  wliich  are  strongest  between  the  ring  finger  ten- 
don and  its  collateral  tendons ;  they  prevent  the  ring  finger  being  raised  if 
the  others  are  closed. 

Action.  The  muscle  straightens  the  three  phalanges  of  the  fingers  from 
root  to  tip,  and  separates  the  four  digits  from  each  other.  It  can  extend 
tiie  nearest  joint  of  each  finger  whilst  the  two  farthest  are  kept  bent  by  the 
flexors  ;  and  it  can  straighten  the  last  two  articulations  when  the  nearest 
is  bent. 

The  digits  being  straightened,  it  will  assist  the  other  muscles  in  extend- 
ing the  wrist  and  the  elbow. 

The  EXTENSOR  MINIMI  DiGiTi,  E,  is  the  most  slender  muscle  on  the  back 
of  the  forearm,  and  appears  to  be  but  a  part  of  the  common  extensor.  Its 
origin  is  in  common  with  that  of  the  extensor  communis,  but  it  passes 
through  a  distinct  sheath  of  the  annular  ligament.  Beyond  the  ligament 
the  tendon  splits  into  two,  and  only  one  unites  by  a  cross  piece  with  the 
tendon  of  the  common  extensor :  both  finally  join  the  common  expansion 
on  the  first  phalanx  of  the  little  finger. 

Action.  It  extends  the  little  finger  and  moves  back  the  wrist  and  elbow. 
As  the  inner  piece  of  the  split  tendon  is  not  united  with  the  common  ex- 
tensor it  can  straighten  the  digit  during  flexion  of  tlie  other  fingers. 

The  EXTENSOR  CARPI  ULNARis  MUSCLE,  F,  aHscs  from  the  common 
tendon,  and  the  aponeurosis  of  tlie  forearm  ;  it  is  also  fixed  by  fascia  to 
the  posterior  border  of  the  ulna  below  the  anconeus  muscle  (about  the 
middle  third).  Its  tendon  becomes  free  from  flesliy  fibres  near  the  annu- 
lar ligament,  and  passes  tiirough  a  separate  sheath  in  that  structure  to  be 
inserted  into  the  base  of  the  metacarpal  bone  of  the  little  finger. 

Beneath  this  extensor  are  some  of  the  muscles  of  the  deep  layer,  with 
part  of  the  ulna.  On  the  outer  side  is  the  extensor  of  the  little  finger, 
with  the  posterior  interosseous  vessels. 

Action.  As  the  name  expresses,  the  muscle  puts  back  the  wrist  and  in- 
clines the  hand  towards  the  ulnar  side  :  it  can  then  extend  the  elbow  joint. 

The  ANCONEUS,  G,  is  a  small  triangular  muscle  near  the  elbow.     It  arises 


286 


DISSECTION    OF    THE    FOREARM, 


from  the  outer  condyle  of  the  humerus  by  a  tendon  distinct  from,  and  on 
the  uhiar  side  of  the  common  tendon  of  origin  of  tlie  other  muscles.  From 
this  origin  the  fibres  diverge  to  tlieir  insertion  into  the  outer  side  of  the 
olecranon,  and  into  the  impression  on  the  upper  third  of  the  posterior  sur- 
face of  the  ulna. 


Fij 


Muscles : 

A.  Supinator  longus, 

B.  and  c.  Kadial  extensors  of  the  cai'pus,  cut. 

D.  Supinator  brevis. 

E.  Extensor  ossis  metacarpi  pollicis. 

F.  Extensor  primi  internodii. 

0.  Extensor  secundi  internodii. 
H,  Extensor  iudicis. 

1.  Posterior  annular  ligament. 
Arte-ries  : 

a.  Posterior  interosseous. 
6.  Recurrent  interosseous. 

c.  Dorsal  part  of  the  anterior  interosseous. 

d.  Dorsal  part  of  the  radial. 

€.  Dorsal  branches  to  the  thumb  and  forefinger. 
/.  Dorsal  carpal  arch. 

ff.  Two  posterior  interosseous  (ulnar)   of  the 
hand. 
Nerves  : 

2.  Radial. 

3.  Posterior  interosseous  at  its  origin,  and  4, 

near  its  ending  in  a  swelling  on  the  back 
of  the  carpus. 


Dissection  of  the  Deep  Later  of  Mcscles,  and  the  VEasELS  anp  Nerve  on  the  Back  op 
THK  Forearm.    (Illustrations  of  Dissections.) 

The  upper  fibres  are  nearly  transverse,  and  are  contiguous  to  the  lowest 
of  the  triceps  muscle.  Beneath  the  anconeous  lie  llie  supinator  brevis 
muscle,  and  the  recurrent  interosseous  vessels. 

Action.  Commonly  it  acts  on  the  ulna,  and  assists  the  triceps  in  ex- 
tending the  elbow. 


DEEP    EXTENSOR    MUSCLES.  287 

Dissection  (fig.  88).  For  the  display  of  the  deep  muscles  at  the  back  of 
the  forearm,  and  tlie  posterior  interosseous  artery  and  nerve,  three  of  the 
superficial  muscles,  viz.,  extensor  communis,  extensor  minimi  digiti,  and 
extensor  carpi  ulnaris,  are  to  be  detached  from  their  origin  and  turned 
aside  :  in  this  proceeding  the  small  branches  of  the  nerve  and  artery  enter- 
ing the  muscles  may  be  divided. 

The  loose  tissue  and  fat  are  then  to  be  removed  from  the  muscles,  and 
the  ramifications  of  the  artery  and  nerve  ;  and  a  slender  part  of  the  nerve, 
which  sinks  beneath  the  extensor  of  the  second  phalanx  of  the  thumb 
about  the  middle  of  the  forearm,  should  be  traced  beyond  the  wrist. 

The  separation  of  the  muscles  should  be  made  carefully,  because  the 
highest  two  of  the  thumb  are  not  always  very  distinct  from  each  other. 

Deep  layer  of  muscles  (fig.  88).  In  this  layer  there  are  five  small 
muscles,  viz.,  one  supinator  of  the  forearm,  and  four  special  extensor  mus- 
cles of  the  thumb  and  forefinger.  The  highest  muscle,  surrounding  partly 
the  upper  end  of  the  radius,  is  the  supinator  brevis,  d.  Below  this  are  the 
three  muscles  of  the  thumb  in  the  following  order : — the  extensor  of  the 
metacarpal  bone,  e,  the  extensor  of  the  first,  f,  and  that  of  the  second 
phalanx,  o.     On  the  ulna  the  indicator  muscle,  h,  is  placed. 

The  EXTENSOR  ossis  METACARPi  poLLicis,  E,  is  the  largest  and  highest 
of  the  extensor  muscles  of  the  thumb,  and  is  sometimes  united  with  the 
supinator  brevis.  It  arises  from  the  posterior  surface  of  the  radius  for 
three  inches  below  the  supinator  brevis  ;  from  the  ulna  for  the  same  dis- 
tance by  a  narrow  special  impression  on  the  upper  and  outer  part  of  the 
posterior  surface  ;  and  from  the  intervening  interosseous  membrane.  The 
tendon  is  directed  outwards  over  the  radial  extensors  of  the  wrist,  and 
through  the  annular  ligament,  to  be  inserted  into  the  base  of  the  metacarpal 
bone  of  the  thumb,  and  by  a  slip  into  the  os  trapezium. 

The  muscle  is  concealed  at  first  by  the  common  extensor  of  the  fingers ; 
but  it  becomes  cutaneous  between  the  last  muscle  and  the  extensors  of  the 
wrist,  about  two  inches  above  the  end  of  the  radius  (fig.  87).  Opposite 
the  carpus  the  radial  artery  winds  backwards  beneath  its  tendon.  Between 
the  contiguous  borders  of  this  muscle  and  the  supinator  brevis  the  posterior 
interosseous  artery  (a)  appears. 

Action.  By  this  muscle  the  thumb  is  moved  backwards  from  the  palm 
of  the  hand,  and  the  wrist  is  extended  on  the  radial  side. 

The  EXTENSOR  PRiMi  iNTERNODii  POLLICIS,  F,  is  the  Smallest  muscle 
of  the  deep  layer,  and  its  tendon  accompanies  that  of  the  preceding  ex- 
tensor. Its  origin,  about  one  inch  in  width,  is  from  the  radius  and  the 
interosseous  membrane,  close  below  the  attachment  of  the  preceding  muscle. 
The  tendon  passes  through  the  same  space  in  the  annular  ligament  as  the 
extensor  of  the  metacarpal  bone,  and  is  inserted  into  the  metacarpal  end 
of  the  first  phalanx  of  the  thumb.  With  respect  to  surrounding  parts  this 
muscle  has  the  same  connections  as  the  preceding. 

Action.  It  extends  first  the  nearest  phalanx,  and  then  the  wrist,  like 
its  companion. 

The  EXTENSOR  SECUNDi  INTERNODII  POLLICIS,  G,  ariscs  from  the  ulna 
for  four  inches  below  the  anconeus,  along  the  ulnar  side  of  the  extensor  of 
the  metacarpal  bone ;  and  from  the  interosseous  membrane,  below,  for  one 
inch.  Its  tendon  passing  through  a  sheath  in  the  annular  ligament,  dis- 
tinct from  that  of  the  other  two  extensor  muscles,  is  directed  along  the 
dorsum  of  the  thumb  to  be  fixed  to  the  base  of  the  last  phalanx. 

It  is  covered  by  the  same  muscles  as  the  other  extensors  of  the  thumb, 


288  DISSECTION    OF    THE    FOREARM. 

but  it  becomes  superficial  nearer  the  lower  end  of  the  radius.  Below  the 
annular  ligament  its  tendon  crosses  the  radial  artery,  and  the  extensors  of 
the  wrist. 

Action.  Its  use  is  similar  to  that  of  the  extensor  of  the  first  phalanx. 
When  the  phalanges  are  straight,  the  two  extensors  will  assist  in  carrying 
back  the  metacarpal  bone. 

The  EXTENSOR  iNDicis,  H  (indicator),  arises  from  the  ulna  for  tliree  or 
four  inches,  usually  beyond  the  middle,  and  internal  to  the  preceding  mus- 
cles ;  and  from  the  interosseous  ligament  below.  Near  the  annular  liga- 
ment the  tendon  becomes  free  from  muscular  fibres,  and  passing  through 
that  band  witli  the  common  extensor  of  the  fingers,  is  applied  to,  and  blends 
with,  the  external  tendon  of  that  muscle  in  the  expansion  on  the  phalanx 
of  the  forefinger. 

Until  this  muscle  has  passed  the  ligament  it  is  covered  by  the  superfi- 
cial layer,  but  it  is  afterwards  subaponeurotic. 

Action.  The  muscle  can  point  the  fore  finger  even  when  the  three  inner 
fingers  are  bent,  inclining  it  towards  the  others  at  the  same  time.  And  it 
will  help  the  common  extensor  of  the  digits  in  pulling  back  the  hand. 

Dissection.  To  lay  bare  the  supinator  brevis,  it  will  be  necessary  to 
detach  the  anconeus  from  the  external  condyle  ot  the  humerus,  and  to  cut 
through  the  supinator  longus  and  the  radial  extensors  of  the  wrist.  After 
those  muscles  have  been  divided,  the  fleshy  fibres  of  the  supinator  are  to 
be  followed  forwards  to  their  insertion  into  the  radius ;  and  that  part  of 
the  origin  of  the  flexor  profundus  digitorum,  which  lies  on  the  outer  side 
of  the  insertion  of  the  brachialis  anticus,  is  to  be  removed. 

The  SUPINATOR  BREVIS,  D,  surrounds  the  upper  part  of  the  radius, 
except  at  the  tubercle  and  along  a  slip  of  bone  below  it.  It  arises  from  a 
depression  below  the  small  sigmoid  cavity  of  the  ulna,  from  the  external 
margin  of  the  bone  for  two  inches  below  that  pit,  and  from  the  orbicular 
ligament  of  the  radius  and  the  external  lateral  ligament  of  the  elbow  joint. 
The  fibres  i)ass  outwards,  and  are  inserted  into  the  upper  third  or  more  of 
the  radius,  except  at  the  inner  part,  reaching  downwards  to  the  insertion 
of  the  pronator  teres,  and  forw^ards  to  the  hollowed  anterior  surface. 

The  supinator  is  concealed  altogether  at  the  posterior  and  external 
aspects  of  the  limb  by  the  muscles  of  the  superficial  layer;  and  anteriorly 
the  radial  vessels  and  nerve  lie  over  it.  The  lower  border  is  contiguous 
to  the  extensor  ossis  metacarpi  pollicis,  only  the  posterior  interosseous 
artery  (a)  intervening.  Through  the  substance  of  the  muscle  the  posterior 
interosseous  nerve  (")  winds  to  the  back  of  the  limb. 

Action.  When  the  radius  has  been  moved  over  the  ulna  as  in  prona- 
tion, the  short  supinator  comes  into  play  to  bring  that  bone  again  to  the 
outer  side  of  the  ulna. 

The  posterior  interosseous  artery  (fig.  88,  a)  is  an  offset  from  the  com- 
mon interosseous  trunk  (p.  269),  and  reaches  the  back  of  the  forearm 
above  the  ligament  between  the  bones.  Appearing  between  the  contiguous 
borders  of  the  supinator  brevis  and  extensor  ossis  metacarpi,  the  artery 
descends  at  first  between  the  superficial  and  deep  layers  of  muscles  ;  and 
afterwards,  with  a  superficial  position  in  the  lower  third  of  the  forearm, 
along  the  tendon  of  the  extensor  carpi  ulnaris  as  far  as  the  wrist,  where  it 
ends  by  anastomosing  with  the  carpal  and  anterior  interosseous  arteries. 
It  furnishes  muscular  offsets  to  the  contiguous  muscles,  except  the  two  or 
three  outer ;  and  the  following  recurrent  branch: — 

The  recurrent  branch  {h)  springs  from  the  artery  near  the  commence- 


RADIAL    ARTERY.  289 

ment,  and  ascends  on  or  tlirougli  the  fibres  of  the  supinator,  but  beneath 
the  anconeus,  to  supply  both  those  muscles  and  the  elbow  joint,  and  to 
anastomose  with  the  superior  profunda  artery  in  the  last-named  muscle,  as 
well  as  with  the  recurrent  radial. 

The  posterior  interosseous  nerve  (')  takes  origin  from  the  musculo-spiral 
trunk  (p.  259),  and  winds  backwards  through  the  fibres  of  the  supinator 
brevis.  Escaped  from  the  supinator,  the  nerve  is  placed  between  the 
superficial  and  deep  layers  of  muscles  as  far  as  the  middle  of  the  forearm. 
Much  reduced  in  size  at  that  spot,  it  sinks  beneath  the  extensor  of  the 
second  phalanx  of  the  tliumb,  and  runs  on  the  interosseous  membrane  to 
the  back  of  tlie  carpus.  Finally  the  nerve  enlarges  beneath  the  tendons 
of  the  extensor  communis  digitorum,  and  terminates  in  filaments  to  the 
ligaments  and  the  articulations  of  the  carpus. 

Branches.  It  furnishes  offsets  to  all  the  muscles  of  the  deep  layer ; 
and  to  those  of  the  superficial  layer  with  the  exception  of  the  three  follow- 
ing, viz.,  anconeus,  supinator  longus,  and  extensor  carpi  radialis  longior. 

Radial  Artery  at  the  Wrist  (fig.  88).  The  radial  artery  (c?), 
with  its  venae  comites,  winds  below  the  radius  to  the  back  of  the  carpus, 
and  enters  the  palm  of  the  hand  at  the  first  interosseous  space,  between  the 
heads  of  the  first  dorsal  interosseous  muscle.  At  first  the  vessel  lies 
deeply  on  the  external  lateral  ligament  of  the  wrist  joint,  and  beneath  the 
tendons  of  the  extensors  of  the  metacarpal  bone,  e,  and  first  phalanx  of 
the  thumb,  f  ;  but  afterwards  it  is  more  superficial,  and  is  crossed  by  the 
tendon  of  the  extensor  of  the  second  phalanx  of  the  thumb,  g. 

Offsets  of  the  external  cutaneous  nerve  entwine  around  the  artery,  and 
the  radial  nerve  is  superficial  to  it.  Its  branches  are  numerous  but  incon- 
siderable in  size: — 

a.  The  dorsal  carpal  branch  (f)  passes  transversely  beneath  the  ex- 
tensor tendons,  and  forms  an  arch  with  a  corresponding  oflTset  of  the  ulnar 
artery  ;  with  this  arch  the  posterior  interosseous  artery  joins. 

From  the  carpal  arch  branches  (g)  descend  to  the  third  and  fourth 
interosseous  spaces,  and  constitute  two  of  tlie  three  dorsal  interosseous 
arteries:  at  the  cleft  of  the  fingers  each  divides  into  two,  which  are  con- 
tinued along  the  dorsum  of  the  digits.  In  front  they  communicate  with 
the  digital  arteries ;  and  behind  they  are  joined  by  the  perforating 
branches  of  the  palmar  arch. 

b.  The  metacarpal  or  Jlrst  dorsal  interosseous  branch  (fig.  87,  b), 
reaches  the  space  between  the  second  and  third  metacarpal  bones,  and 
anastomoses,  like  the  corresponding  arteries  of  the  other  spaces,  with  a 
perforating  branch  of  the  deep  palmar  arch.  Finally  it  is  continued  to 
the  cleft  of  the  fingers,  where  it  joins  the  digital  artery  of  the.  superficial 
palmar  arch,  and  gives  small  dorsal  branches  to  the  index  and  second 
fingers. 

c.  Two  small  dorsal  arteries  of  the  thumb  (c)  arise  opposite  the  meta- 
carpal bone,  along  which  they  extend,  one  on  each  border,  to  be  distributed 
on  its  posterior  aspect. 

d.  The  dorsal  branch  of  the  index  finger  is  distributed  on  the  radial 
edge  of  that  digit. 

The  ditferent  compartments  of  the  annular  ligament  may  be  seen  more 
completely  by  dividing  the  sheaths  of  the  ligament  over  the  several  ten- 
dons passing  beneath.  Tliere  are  six  different  spaces,  and  each  is  lubri- 
cated by  a  synovial  membrane.  The  most  external  one  lodges  the  first 
two  extensors  of  the  thumb.  The  next  is  a  large  hollow  for  the  two  radial 
19 


290  DISSECTION    OF    THE    UPPER    LIMB. 

extensors  of  the  wrist ;  and  a  very  small  space  for  the  extensor  of  the 
second  phalanx  of  the  thumb  follows  on  the  ulnar  side.  Farther  to  the 
inner  side  is  the  common  sheath  for  the  extensor  of  the  fingers,  and  tliat 
of  the  fore  finger  ;  and  then  comes  a  separate  compartment  for  the  exten- 
sor of  the  little  finger.  Internal  to  all  is  the  space  for  the  extensor  carpi 
ulnaris.  The  last  muscle  grooves  the  ulna ;  but  the  others  lie  in  hollows 
in  the  radius  in  the  order  mentioned  above,  with  the  exception  of  the  ex- 
tensor minimi  digiti,  which  is  situate  between  the  bones. 

Dissection.  If  the  supinator  brevis  be  divided  by  a  vertical  incision, 
and  reflected  from  the  radius,  its  attachment  to  the  bone  will  be  better 
understood. 

The  posterior  interosseous  nerve,  and  the  offsets  from  its  gangliform 
enlargement,  may  be  traced  more  completely  after  the  tendons  of  the  ex- 
tensor of  the  fingers  and  indicator  muscle  have  been  cut  at  the  wrist. 

The  dorsal  surface  of  the  posterior  interossei  muscles  of  the  hand  may 
be  cleaned,  so  that  their  double  origin,  and  their  insertion  into  the  side, 
and  on  the  dorsum  of  the  phalanges,  may  be  observed.  Between  the  heads 
of  origin  of  these  muscles  the  posterior  perforating  arteries  appear. 


Section  VII. 
ligaments  of  the  shoulder,  elbow,  wrist,  and  hand. 

Directions.  The  ligaments  of  the  remaining  articulations  of  the  limb, 
which  are  still  moist,  may  be  examined  at  once ;  but  if  any  of  them  have 
become  dry,  they  may  be  softened  by  immersion  in  water,  or  with  a  wet 
cloth,  whilst  the  student  learns  the  others. 

Dissection.  For  the  preparation  of  the  external  ligaments  of  the 
shoulder-joint  the  tendons  of  the  surrounding  muscles,  viz.,  subscapularis, 
supra  and  infraspinatus,  and  teres  minor,  must  be  detached  from  the  cap- 
sule ;  and  as  these  are  united  with  it,  some  care  will  be  needed  not  to 
open  the  joint. 

Shoulder  Joint.  This  ball  and  socket  joint  (fig.  89)  is  formed  be- 
tween the  head  of  the  humerus  and  the  glenoid  fossa  of  the  scapula.  In- 
closing the  articular  ends  of  the  bones  is  a  fibrous  capsule  lined  by  a  syno- 
vial membrane.  A  ligamentous  band  (glenoid  ligament)  deepens  the 
shallow  scapular  cavity  for  the  reception  of  the  large  head  of  the  humerus. 

The  bones  are  but  slightly  bound  together  by  ligamentous  bands,  for, 
on  the  removal  of  the  muscles,  the  head  of  the  humerus  may  be  drawn 
from  the  scapula  for  the  distance  of  an  inch. 

The  capsular  ligament  (fig.  TT),  *)  surrounds  loosely  the  articular  ends 
of  the  bones ;  it  is  thickened  above  and  below,  and  receives  fibres  from 
the  contiguous  tendons. 

At  the  upper  edge  it  is  fixed  around  the  articular  surface  of  the  scapula, 
where  it  is  connected  with  the  long  head  of  the  triceps.  At  the  lower 
edge  the  ligament  is  fixed  (fig.  89)  to  the  neck  of  the.  humerus  close  to 
the  articular  surface  above,  but  at  a  little  distance  therefrom  below  ;  and 
its  continuity  is  interrupted  between  the  tuberosities  (ft)  by  the  tendon 
of  the  biceps  muscle,  over  which  it  is  continued  along  the  bicipital 
groove  (fig.  7o).     On  the  inner  side  there  is  generally  an  aperture  in  the 


LIGAMENTS    OF    SHOULDER 


291 


capsule,  below  the  coracoid  process,  through  which  the  synovial  mem- 
brane of  the  joint  is  continuous  with  the  bursa  beneath  the  tendon  of  the 
subscapularis. 

Tlie  following  muscles  surround  the  articulation  :  above  and  behind 
are  the  supraspinatus,  infraspinatus,  and  teres  minor ;  below,  the  capsule 
is  only  partly  covered  by  the  subscapularis ;  but  internally  it  is  well  sup- 
ported by  the  last-named  muscle. 

On  the  front  of  the  capsule  is  a  rather  thick  band  of  fibres — the  coraco- 
humeral  or  accessory  ligament  (fig.  75,  ^),  which  springs  from  the  base  of 
the  coracoid  process  of  the  scapula,  and  widening  over  the  front  of  the 
joint,  is  attached  to  the  margins  of  the  bicipital  groove,  and  to  the  tube- 
rosities. 

Dissection.  To  see  the  interior  of  the  articulation,  cut  circularly  through 
the  capsule  near  the  scapula.  When  this  has  been  done  the  attachment 
of  the  capsule  to  the  bones,  the  glenoid  ligament,  and  the  tendon  of  the 
biceps  will  be  manifest. 

The  tendon  of  the  biceps  muscle  arches  over  the  head  of  the  humerus, 
and  serves  the  purpose  of  a  ligament  in  restraining  the  upward  and  out- 
ward movements  of  that  bone.  It  is  attached  to  the  upper  part  of  the 
glenoid  fossa  of  the  scapula  (fig.  89,  d),  and  is  united  on  each  side  with 
the  glenoid  ligament.  At  first  flat,  it  afterwards  becomes  round,  and  en- 
tering the  groove  between  the  tuberosities  of  the  humerus,  it  is  surrounded 
by  the  synovial  membrane. 

Fig.  89. 


View  op  the  Interior  of  the  Shoclder-joint. 

c.  Glenoid  ligament  around  the  glenoid  fossa. 


a.  Attachment  of  the  capsule  to  the  neck  of 

the  humerus. 
6.  Interval  of  the  bicipital  groove. 


d.  Tendou  of  the  biceps  fixed  to  the  top  of  the 
fossa. 


The  glenoid  ligament  (fig.  89,  c)  is  a  firm  fibro-cartilaginous  band, 
which  surrounds  tiie  fossa  of  the  same  name,  deepening  it  for  the  reception 
of  the  head  of  the  humerus.  It  is  about  two  lines  in  depth,  and  is  con- 
nected in  part  with  the  sides  of  the  tendon  of  the  biceps  ;  but  most  of  its 
fibres  are  fixed  separately  to  the  margin  of  the  glenoid  fossa. 

The  synovial  membrane  lines  the  articular  surface  of  the  capsule,  and  is 
continued  through  the  aperture  on  the  inner  part  to  join  the  bursa  beneath 
the  subscapular  muscle.  Tiie  membrane  is  reflected  around  the  tendon  of 
the  biceps,  and  lines  the  bicipital  groove  of  the  humerus. 


292  DISSECTION    OF    THE    UPPER    LIMB. 

Articular  surfaces  (fig.  89).  The  convex  articular  head  of  the  humerus 
is  two  or  three  times  larger  than  tlie  hollow  in  the  scapula,  and  forms  rather 
less  than  the  half  of  a  sphere.  The  head  of  the  bone  is  joined  to  the 
shaft  at  an  angle  as  it  is  in  the  femur,  and  a  rotatory  movement  is  pos- 
sessed by  the  humerus  in  consequence. 

The  glenoid  surface  of  the  scapula  is  oval  in  form  with  the  large  end 
down,  and  is  very  shallow  ;  it  is  not  large  enough  to  cover  the  head  of  the 
humerus. 

Movements.  In  this  joint  there  is  the  common  motion  in  four  direc- 
tions, with  the  circular  or  circumductory ;  and  in  addition  a  movement  of 
rotation. 

In  the  swinging  or  to  and  fro  movement,  the  carrying  forwards  of  the 
humerus  constitutes  flexion,  and  the  moving  it  backwards,  extension. 
Flexion  is  freer  than  extension  ;  and  when  the  joint  is  most  bent  the 
scapula,  rotating  on  its  axis,  follows  the  head  of  the  humerus,  so  as  to 
keep  the  centre  of  the  glenoid  fossa  applied  to  the  middle  of  the  articular 
surface  of  the  arm-bone.  In  extension  the  articular  surface  of  the  scapula 
does  not  move  after  the  humerus. 

During  these  movements  the  head  of  the  bone  rests  in  the  bottom  of 
the  glenoid  fossa,  turning  forwards  and  backwards  around  a  line  represent- 
ing the  axis  of  the  head  and  neck  ;  and  it  cannot  be  dislodged  by  either 
the  rapidity  or  the  degree  of  the  motion. 

The  muscles  have  more  influence  than  the  loose  capsule  in  controlling 
the  swingring:  motion. 

Abduction  and  adduction.  AVhen  the  limb  is  raised,  it  is  abducted, 
and  when  depressed,  adducted ;  and  in  both  cases  the  humerus  rolls  on  the 
scapula  which  is  fixed. 

During  abduction  the  head  of  the  humerus,  descends  to  the  lower  and 
larger  part  of  the  glenoid  fossa,  and  projects  beyond  it  against  the  cap- 
sule ;  whilst  the  great  tuberosity  rubs  against  the  arch  of  the  acromion. 
In  this  condition  a  little  more  movement  down  of  tlie  head  either  by 
muscles  depressing  it,  or  by  force  elevating  the  farther  end  of  the  bone, 
will  throw  it  out  of  place,  giving  rise  to  dislocation. 

In  adduction  the  head  of  the  bone  rises  into  the  socket,  the  limb  meets 
the  trunk,  and  the  tense  capsule  is  set  at  rest.  After  the  reduction  of  a 
dislocation  the  limb  is  fixed  to  the  side  in  this  position  of  security  against 
further  displacement. 

In  circumduction  the  humerus  passes  in  succession  through  the  four 
different  states  before  mentioned,  and  the  limb  describes  a  cone,  whose 
apex  is  at  the  shoulder  and  base  at  the  digits. 

Rotation.  There  are  two  kinds  of  rotatory  movement,  viz.,  in  and 
out ;  and  in  each  the  motion  of  the  head  and  shaft  of  the  bone  has  to  be 
considered. 

In  rotation  in,  the  great  tuberosity  is  turned  forwards,  and  the  liead 
rolls  from  before  back  across  the  glenoid  fossa  so  as  to  projec^t  behind. 
The  shaft  is  moved  forwards  round  a  line  lying  on  its  inner  side,  which 
reaches  from  the  centre  of  the  head  to  tlie  inner  condyle. 

In  rotation  out,  the  osseous  movements  are  reversed  ;  thus  the  tuberosity 
turns  back,  the  head  rolls  forward  so  as  to  project  in  front,  and  the  shaft 
is  carried  back  around  the  line  before  said. 

The  upper  thickened  part  of  the  capsule  will  be  tightened  in  rotation, 
but  the  muscles  are  the  chief  agents  in  checking  the  movements. 

Dissection.     To  make  the  necessary  dissection  of  the  ligaments  of  the 


LIGAMENTS    OF    ELBOW 


293 


Fiff.  90. 


elbow,  the  brachialis  anticus  must  be  taken  away  from  the  front,  and  the 
triceps  from  the  back  of  the  joint.  The  muscles  connected  with  the  outer 
and  inner  condyles  of  the  humerus,  as  well  as  the  supinator  brevis  and 
the  flexor  profundus,  are  to  be  removed.  With  a  little  cleaning  the  four 
ligaments — anterior,  posterior,  and  two  lateral — will  come  into  view. 

The  interosseous  membrane  between  the  bones  of  the  forearm  will  be 
prepared  by  the  removal  of  the  muscles  on  both  sui-faces. 

The  Elbow  Joint  (fig.  90).  In  this  articulation  the  lower  end  of  the 
humerus  is  received  into  the  hollow  of  the  ulna,  so  as  to  produce  a  hinge- 
like arrangement ;  and  the  upper  end  of  the  radius  assists  to  form  part  of 
the  joint.  Where  the  bones  touch  the  surfaces 
are  covered  with  cartilage,  and  their  articular  ends 
are  kept  in  place  by  the  following  ligaments : — 

The  external  lateral  ligament  is  a  roundish  fas- 
ciculus, which  is  attached  by  one  end  to  the  outer 
condyle  of  the  humerus,  and  by  the  other  to  the 
orbicular  ligament  around  the  head  of  the  radius. 
A  few  of  the  posterior  fibres  pass  backwards  to  the 
external  margin  of  the  ulna. 

The  internal  lateral  ligament  is  triangular  in 
shape.  It  is  pointed  at  its  upper  extremity,  and 
is  connected  to  the  inner  condyle  of  the  humerus. 
The  fibres  diverge,  and  are  inserted  in  this  way: — 
The  anterior,  which  are  the  strongest,  are  fixed  to 
the  edge  of  the  coronoid  process ;  the  posterior  are 
attached  to  the  side  of  the  olecranon ;  whilst  a  few 
middle  fibres  join  a  transverse  ligamentous  band 
over  the  notch  between  the  olecranon  and  the  coro- 
noid process.  The  ulnar  nerve  is  in  contact  witli 
the  ligament;  and  vessels  enter  the  joint  by  an 
aperture  beneath  the  transverse  band. 

The  anterior  ligament  is  thin,  and  its  fibres  are 
separated  by  intervals  in  which  masses  of  fat  are 
lodged.  By  its  upper  edge  the  ligament  is  inserted 
into  the  front  of  the  humerus,  and  by  its  lower 
into  the  front  of  the  coronoid  process  and  the  or- 
bicular ligament.  The  brachialis  anticus  muscle 
covers  it. 

The  posterior  ligament  is  much  thinner  and 
looser  than  the  anterior,  and  is  covered  completely 
by  the  triceps  muscle.  Superiorly  it  is  attached 
to  the  humerus  above  the  fossa  for  the  olecranon ; 
and  inferiorly  it  is  inserted  into  the  olecranon. 
Some  few  fibres  are  transverse  between  the  mar- 
gins of  the  fossa  before  mentioned. 

Dissection.  Open  the  joint  by  an  incision 
across  the  front  near  the  humerus,  and  disarticu- 
late the  bones,  in  order  that  the  articular  surfaces 
may  be  seen. 

The  synovial  tnemhrane  of  the  joint  can  be  traced  from  one  bone  to 
another  along  the  inner  surface  of  the  connecting  ligaments.  It  projects 
between  the  radius  and  the  orbicular  ligament,  and  serves  for  the  articu- 
lation of  the  head  of  that  bone  with  the  small  sigmoid  cavity  of  the  ulna. 


The  Lioamen-ts  op  the  El- 
bow Joint,  and  thb 
Shaft  of  the  Radios 
AND  Ulna  (Bourgery  and 
Jacob). 

1.  Capsule    of    the    elbow 

joint. 

2.  Oblique  lig^ament 

.3.  Interosseous  ligament. 

4.  Aperture    for    bloodves- 

sels. 

5.  Tendon  of  the  biceps. 


294  DISSECTION    OF    THE    UPPER    LIMB. 

Articular  surfaces.  The  humerus  presents  inferiorly  two  distinct  ar- 
ticular faces  for  tlie  bones  of  the  forearm.  The  one  for  the  radius,  on  the 
outer  side,  consists  of  a  rounded  eminence  (capitellum)  on  the  front  of  the 
bone,  which  is  covered  with  cartihige  only  on  the  interior  aspect.  The 
surface  in  contact  with  the  ulna  is  limited  internally  and  externally  by  a 
prominence,  and  hollowed  out  in  the  centre  (trochlea).  On  the  front  of 
the  humerus  above  the  articular  surface  are  two  depressions  which  receive 
the  coronoid  process  and  tlie  head  of  the  radius  during  flexure  of  the 
joint ;  and  on  the  posterior  aspect  is  a  large  fossa  for  the  reception  of  the 
olecranon  in  extension  of  the  joint. 

On  the  end  of  the  ulna  the  large  sigmoid  cavity  is  narrowed  in  the  cen- 
tre, but  expanded  in  front  and  behind  (fig.  91).  A  slightly  raised  line 
extends  from  front  to  back,  and  is  received  into  the  hollow  of  the  trochlea 
of  the  humerus.  Across  the  bottom  of  the  cavity  the  cartilage  is  wanting 
completely,  or  for  a  greater  or  smaller  distance. 

The  end  of  the  radius  presents  a  circular  depression  with  a  raised  mar- 
gin. In  the  bent  state  of  the  joint  the  hollow  of  the  radius  fits  on  the 
outer  eminence  of  the  humerus,  and  the  bone  is  supported  during  rotation 
of  the  limb. 

Movement.  This  joint  is  like  a  hinge  in  its  movements,  and  permits 
only  flexion  and  extension. 

In  flexion  the  bones  of  the  forearm  move  forwards,  each  on  its  own 
articular  surface,  so  g,s  to  leave  the  back  of  the  humerus  uncovered.  The 
extent  is  checked  by  the  meeting  of  the  bones  of  the  arm  and  forearm. 
Owing  to  the  slanting  surface  of  the  humerus  the  hand  falls  inside  the 
limb  when  the  joint  is  fully  bent. 

The  ligaments  are  relaxed,  with  the  exception  of  the  following,  viz., 
the  posterior,  and  the  hinder  part  of  the  internal  lateral. 

In  extension  the  ulna  and  radius  are  carried  back  over  the  articular  sur- 
face of  the  humerus  until  they  come  into  a  line  with  the  arm-bone.  This 
movement  is  checked  by  the  olecranon  touching  the  humerus. 

The  anterior  ligament,  and  the  fore  part  of  the  internal  lateral  ligament 
are  made  tight,  but  the  hinder  fibres  of  the  internal  lateral  are  relaxed. 

Union  of  the  Radius  and  Ulna.  The  radius  is  connected  with  the 
ulna  at  both  ends  by  means  of  distinct  ligaments  and  synovial  membrane; 
and  the  shafts  of  the  bones  are  united  by  interosseous  ligaments. 

Upper  radio-ulnar  articulation.  In  this  joint  the  head  of  the  radius  is 
received  into  the  small  sigmoid  cavity  of  the  ulna,  and  is  kept  in  place  by 
the  following  ligamentous  band : — 

The  annular  or  orbicular  ligameiit  (fig.  91,  a)  is  about  one-third  of  an 
inch  wide,  and  is  stronger  behind  than  before;  it  is  ])laced  around  the 
prominence  of  the  head  of  the  radius,  and  is  attached  to  the  anterior  and 
posterior  edges  of  the  small  sigmoid  cavity  of  tlie  ulna.  Its  upper  border, 
the  widest,  is  connected  with  the  ligaments  of  the  elbow  joint;  but  the 
lower  is  free,  and  is  applied  around  the  neck  of  the  radius.  In  the  socket 
formed  by  this  ligament  and  the  cavity  of  the  ulna,  the  radius  moves 
freely. 

Tlie  synovial  membrane  is  a  prolongation  of  that  lining  the  elbow  joint; 
it  projects  inferiorly  between  the  neck  of  the  radius  and  the  lower  margin 
of  the  annular  ligament. 

Ligaments  of  the  shafts  of  the  bones.  The  aponeurotic  stratum  con- 
necting togetiier  the  bones  in  nearly  their  whole  length  consists  of  the  two 
following  parts : — 


RADTO-ULXAR    JOINTS, 


295 


Fig.  91. 


View  of  the  Orbicular   Ligament 
(a)  OF  THE  Radius,  which  retains 

THKUPPER  KNDOF  THE  BoNK  AGAINST 

THE  Ulna. 


The  interosseous  memhrane  (.fig.  90,  ')  is  a  thin  fibrous  layer,  which  is 
attached  to  the  contiguous  margins  of  the  radius  and  ulna,  and  forms  an 
incomplete  septum  between  the  muscles  on  the  front  and  back  of  the  fore- 
arm. Most  of  its  fibres  are  directed  obliquely  inwards  towards  the  ulna, 
though  a  few  on  the  posterior  surface  have 
an  opposite  direction.  Superiorly  the 
membrane  is  wanting  for  a  considerable 
space,  and  through  the  interval  the  poste- 
rior interosseous  vessels  pass  backwards. 
Some  small  apertures  exist  in  it  for  the 
passage  of  vessels ;  and  the  largest  of  these 
(*)  is  about  two  inches  from  the  lower 
end,  through  which  the  anterior  interos- 
seous artery  turns  to  the  back  of  the  wrist. 
The  membrane  gives  attachment  to  the 
deep  muscles. 

The  round  ligame^it  (fig.  90,  ^)  is  a 
slender  band  above  the  interosseous  mem- 
brane, whose  fibres  have  a  direction  oppo- 
site to  tliose  of  the  membrane.  By  one 
end  it  is  fixed  to  the  front  of  the  coronoid 
process,  and  by  the  other  to  the  radius  be- 
low the  tubercle.  The  ligament  divides 
the  space  above  the  interosseous  membrane 
into  two  parts.  Oftentimes  this  band  is 
not  to  be  recognized. 

The  lower  radio-ulnar  articulation  cannot  be  well  seen  till  after  the 
examination  of  the  wrist  joint  (p.  297). 

Movement  of  the  radius.  Tlie  radius  moves  forwards  and  backwards 
around  the  ulna.  The  forward  motion,  directing  the  palm  of  the  hand 
towards  the  ground,  is  called  pronation ;  and  the  backward,  by  which  the 
palm  of  tl)e  hand  is  placed  upwards,  is  named  supination. 

In  pronation  the  upper  end  of  the  bone  rotates  within  the  band  of  the 
orbicular  ligament  without  shifting  its  position  to  the  ulna.  The  lower 
end,  on  the  contrary,  moves  over  the  ulna  from  the  outer  to  the  inner 
side,  describing  half  a  circle ;  and  the  shaft  crosses  obliquely  that  of  the 
ulna. 

In  supination  the  lower  end  of  tlie  radius  turns  backwards  over  the 
ulna  ;  the  shafts  come  to  be  placed  side  by  side,  the  radius  being  external ; 
and  the  upper  end  rotates  from  within  out  in  its  circular  band. 

In  these  movements  the  radius  revolves  round  a  line,  internal  to  the 
shaft,  which  is  prolonged  upwards  through  the  neck  and  head  of  the  bone, 
and  downwards  through  the  centre  of  a  circle  of  which  the  small  sigmoid 
cavity  of  the  ulna  is  a  segment  (Ward). 

The  upper  end  of  the  bone  is  kept  in  place  by  the  orbicular  ligament ; 
the  lower  end  by  the  triangular  fibro-cartilage;  and  the  shafts  are  united 
by  the  interosseous  ligament,  which  is  tightened  in  supination,  and  is  re- 
laxed in  pronation. 

In  fracture  of  either  bone  the  movements  cease ;  in  the  one  case  be- 
cause the  radius  cannot  be  moved  except  it  is  entire  ;  and  in  the  other, 
because  the  ulnar  support  is  wanting  for  the  revolving  radius. 

Dissection.  To  see  the  ligaments  of  the  wrist-joint,  the  tendons  and 
the  annular  ligaments  must  be  removed  from  both  the  front  and  back  ;  and 


296 


DISSECTION    OF    THE    UPPER    LIMB. 


Fiff.  92. 


the  fibrous  structures  and  the  small  vessel^  should  be  taken  from  the  sur- 
face of  the  ligaments. 

The  Wrist  Joint  (fig.  92).  The  lower  end  of  the  radius,  and  the 
first  row  of  the  carpal  bones,  except  the  os  pisiforme,  enter  into  the  wrist- 
joint.  Four  ligaments  maintain  in  contact  the  osseous  surfaces,  viz.,  an- 
terior and  posterior,  and  two  lateral. 
The  ulna  is  shut  out  from  this  ai'ticu- 
lation  by  means  of  a  piece  of  fibro- 
cartilage. 

The  external  lateral  ligament  is  a 
short  and  strong  band,  which  inter- 
venes between  the  styloid  process  of 
the  radius  and  the  outer  part  of  the 
scaphoid  bone. 

The  internal  lateral  ligament  is 
smaller  than  the  external,  but  is 
longer  than  it.  It  is  attached  by  one 
end  to  the  styloid  process  of  the  ulna, 
and  by  the  other  to  the  rough,  upper 
part  of  the  cuneiform  bone.  Some  of 
the  anterior  fibres  are  continued  to  the 
pisiform  bone. 

The  anterior  ligament  (fig.  92,  ^) 
takes  origin  from  the  radius  and  the 
fibro-cartilage,  and  is  inserted  into 
the  first  row  of  carpal  bones,  except 
the  pisiform,  at  the  anterior  surface. 

The  posterior  ligament  (fig.  95,  ^) 
is  membranous,  like  the  anterior,  and 
its  fibres  are  directed  downwards  and 
inwards.  Superiorly  it  is  attached  to 
the  radius  and  the  fibro-cartilage  ;  and 
inferiorly  it  is  fixed,  like  the  anterior, 
to  the  three  outer  carpal  bones  of  the  first  row,  but  on  the  posterior 
aspect. 

Dissection.  To  see  the  form  of  the  articulating  surfaces,  the  joint 
may  be  opened  by  a  transverse  incision  through  the  posterior  ligament, 
near  the  bones  of  the  carpus. 

Articular  surfaces.  The  end  of  the  radius,  and  the  fibro-cartilage 
uniting  it  with  the  ulna,  form  an  arch  for  the  reception  of  the  carpal 
bones  (fig.  93)  ;  and  tlie  surface  of  tlie  radius  is  divided  by  a  prominent 
line  into  an  external  triangular,  and  an  internal  square  impression.  The 
three  bones  of  the  first  carpal  row  constitute  a  convex  eminence  (fig.  94), 
which  is  received  into  the  hollow  before  mentioned  in  this  way :  The 
scaphoid  bone  (a)  is  opposite  the  external  mark  of  the  radius  ;  the  semi- 
lunar bone  {h)  touches  the  square  impression,  and  all  or  part  of  the  trian- 
gular fibro-cartilage  ;  whilst  the  cuneiform  bone  (^)  is  in  contact  with  the 
capsule  (Henle),  and  sometimes  with  part  of  tlie  fibro-cartilage. 

The  synovial  membrane  has  the  arrangement  common  to  simple  joints. 
This  joint  communicates  occasionally  with  tlie  lower  radio-ulnar  articula- 
tion by  means  of  an  aperture  in  the  fibro-cartilage  se[)arating  tlie  two. 

Movement.  The  wrist  is  a  condyloid  articulation,  and  possesses  angular 
motion  in  four  different  directions,  with  circumduction. 


Fkont  View  of  the  Articulations  of  the 
Wrist  Joint,  and  Carpal  and  Meta- 
carpal Bones  (Bourgery  and  Jacob). 

1.  Anterior  ligament  of  the  wrist  joint. 

2.  Capsule  of  the  joint  o^  the  metacarpal  bone 

of  the  thumb  with  the  os  trapezium. 

3.  Pisiform  bone,  with  its  separate  joint  and 

ligamentons  bands. 

4.  Transverse  bands  to  the  head  of  the  meta- 

carpal bones. 


LIGAMENTS    OF    WRIST    JOINT, 


297 


Fiff.  93. 


Flexion  and  extension.  In  flexion  the  hand  is  moved  forwards  and  in- 
wards, whilst  the  carpus  rolls  on  the  radius  from  before  back,  and  projects 
behind,  stretching  the  posterior  ligament.  In  extension  the  hand  is  car- 
ried backwards  and  outwards,  and  the  row  of  carpal  bones  moves  in  the 
opposite  direction,  viz.,  from  behind  forwards,  so  as  to  cause  the  anterior 
ligament  to  be  tightened.     The  hinder  movement  is  freer  than  the  forward. 

Abduction  and  adduction.  The  row  of  carpal  bones  moves  transversely 
inwards  in  the  former,  and  outwards  in  the  latter  state ;  and  the  move- 
ment is  freer  towards  the  ulnar  than  the  radial  side. 

The  latter  ligaments  are  put  on  the  stretch,  the  inner  in  abduction  and 
the  outer  in  adduction  ;  and  the  motion  is  limited  on  the  outer  side  by 
the  meeting  of  the  styloid  processes  of  the  radius  with  the  scaphoid  bone. 

Circumduction.  The  hand  describes  a  cone  in  this  movement,  whose 
apex  is  at  the  wrist  and  base  at  the  digits  ;  and  it  moves  more  freely  in 
extension  and  adduction  than  in  the  opposite  directions. 

Lower  Radio-ulnar  Articulation.  In  this  articulation  the  con- 
vexity of  the  end  of  the  ulna  is  received  into  a  concavity  on  the  radius ; 
an  arrangement  just  the  opposite  to  that  be- 
tween the  upper  ends  of  the  bones. 

The  chief  bond  of  union  between  the 
bones  is  a  strong  fibro-cartilage  ;  but  a  kind 
of  capsule  consisting  of  scattered  fibres,  sur- 
rounds loosely  the  end  of  the  ulna. 

The  triangular  fibro-cartilage  (fig.  93,  c) 
is  placed  transversely  beneath  the  end  of  the 
ulna,  and  is  thickest  at  its  margins  and  apex. 
By  its  base  the  cartilage  is  fixed  to  the  ridge 
which  separates  the  carpal  from  the  ulnar 
articulating  surface  of  the  radius  ;  and  by  its 
apex  to  the  styloid  process  of  the  ulna,  and 
the  depression  at  the  root  of  that  point  of 
bone.  Its  margins  are  united  with  the  con- 
tiguous anterior  and  posterior  ligaments  of 
the  wrist  joint ;  and  its  surfaces  enter  into 
different  joints,  viz.,  the  wrist,  and  the  lower 
radio-ulnar.  It  serves  to  unite  the  radius 
and  ulna,  and  to  form  part  of  the  socket  for  the  carpal  bones 
ally  it  is  perforated  by  an  aperture. 

The  synovial  membrane  (membrana  sacciformis)  is  very  loose,  from 
which  circumstance  it  has  received  its  name,  and  ascends  between  the 
radius  and  the  ulna  :  it  is  separated  from  that  of  the  wrist-joint  by  the 
triangular  fibro-cartilage. 

The  use  of  this  articulation  is  referred  to  with  the  movements  of  the 
radius  (p.  295). 

Union  of  the  Carpal  Bones.  The  several  bones  of  the  carpus  are 
united  into  two  rows  by  dorsal,  palmar,  and  interosseous  bands :  and  the 
two  rows  are  connected  to  each  other  by  separate  ligaments. 

Dissection.  The  articulation  of  the  carpal  bones  with  each  other  will 
be  prepared  by  taking  away  all  the  tendons  from  the  hand,  and  cleaning 
carefully  the  wiiole  of  the  connecting  ligamentous  bands.  Two  distinct 
ligaments  of  tlie  pisifbim  bone  to  the  uncilbrm  and  fifth  metacarpal  are 
to  be  defined  in  the  palm. 


The  Wkist  Joint  opened  to  show 
the  arch  formed  by  the  bones 
OF  THE  Forearm  with  the  unit- 
ing FlBKO-CARTILAQE,  C. 

a.  Radius. 

b.  Ulna. 


Occasion- 


298 


DISSECTION    OF    THE    UPPER    LIMB. 


At  the  same  time  the  ligamentous  bands  uniting  the  metaearpal  with 
the  carpal  bones  and  with  one  another  should  be  dissected. 

Bones  of  the  first  roxo  (fig.  94).  The  os  semilunare  is  united  to  the 
lateral  bones,  viz.,  scaphoid  and  cuneiform  by  a  dorsal  (fig.  94,  o?),  and  a 
palmar  transverse  band  ;  as  well  as,  it  is  said,  by  an  interosseous  ligament 
at  the  upper  part  of  the  continuous  surfaces.^ 

The  pisiform  bone  is  articulated  to  the  front  of  the  cuneiform  by  a  dis- 
tinct capsule  and  a  synovial  membi'ane  (fig.  92,  ^).  It  has  further  two 
special  firm  ligaments :  one  of  these  is  attached  to  the  process  of  the  os 
unciforme,  and  the  other  to  the  base  of  the  fifth  metacarpal  bone. 

The  bones  of  the  second  row  are  connected  together  in  the  same  way  as 
those  of  the  first,  viz.,  by  a  dorsal  and  a  palmar  band  of  fibres  from  one 
bone  to  another.  Between  the  contiguous  rough  surfaces  of  the  several 
ossicles  are  interosseous  ligaments,  one  in  each  interval. 

Movement.  Only  a  small  degree  of  gliding  motion  is  permitted  between 
the  different  carpal  bones,  in  consequence  of  the  fiattened  articular  sur- 
faces, and  the  interosseous  ligaments  uniting  one  to  anotlier ;  and  this  is 
less  in  the  second  than  in  the  first  row. 

One  row  with  another  (transverse  carpal  joint,  fig.  94).  The  two  rows 
of  carpal  bones  are  connected  by  an  anterior  and  posterior,  and  two  lateral 
ligaments. 

The  anterior  ligament  (p)  consists  of  strong  irregular  fibres,  and  inter- 
venes between  the  two  rows  (except  the  pisiform)  on  the  palmar  aspect. 
The  posterior  ligament,  which  is  longer  and  looser,  and  the  greater  num- 
ber of  whose  fibres  are  transverse,  has  a  corresponding  attachment  on  the 
dorsal  aspect  of  the  same  bones. 

Fig.  94. 


a.  Scaphoid  bone. 

b.  Semilunar. 

c.  Cuneiform. 

d.  Dorsal    transverse    bands  between    those 

bones. 

e.  Trapezium  bone. 
/.  Trapezoid. 

g.  Os  magnum. 

h.  Unciform. 

i.  Dorsal  transverse  bands  joining  the  bones. 

k.  External  lateral  ligament  of  the  intercarpal 

joint. 
I.  Internal  lateral. 
p    Anterior  ligaments. 


Aeticulations  of   one  Carpal  Bone  with  another,  and   of  the  two  rows  with  each 
OTHER.    Thk  Joint  between  the  two  rows  is  opened  behind. 

Of  the  lateral  ligaments  the  external  {k)  is  the  best  marked,  and  ex- 
tends between  the  os  trapezium  and  the  scaphoid  bone  ;  the  internal  liga- 
ment (/)  reaches  between  the  cuneiform  and  unciform  bones. 

Dissection.     After  the  division  of  the  lateral  and  posterior  ligaments, 


•  Interosseous  ligaments  in  this  row,  distinct  from  the  other  bands,  can  scarcely 
be  said  to  exist. 


CARPO-METACARPAL    JOINTS. 


299 


the  one  row  of  bones  may  be  separated  far  enough  from  the  other,  to  allow 
a  siglit  of  the  articular  surfaces. 

Articular  surfaces.  The  first  row  of  carpal  bones  (except  pisiform) 
forms  internally  an  arch  with  the  scaphoid  {a),  semilunar  {d),  and  cunei- 
form bone  (c),  whose  hollow  is  turned  towards  the  second  ;  and  externally 
a  prominence  with  tlie  scaphoid  {a)  which  is  received  into  a  concavity  in 
the  other  row.  In  the  second  row  the  os  magnum  (g)  and  os  unciforme 
(A)  present  a  condyloid  projection,  which  is  received  into  the  arch  before 
mentioned;  but  the  two  outer  bones  (trapezium  and  trapezoid,  e  and/) 
are  much  below  the  level  of  the  otliers,  and  form  a  slight  hollow  for  the 
reception  of  the  outer  part  of  the  scaphoid  bone. 

One  synovial  membrane  serves  for  the  articulation  of  all  the  carpal 
bones,  except  the  pisiform  with  the  cuneiform.  Lining  the  joint  between 
the  two  rows  of  the  carpus,  the  membrane  sends  upwards  and  downwards 
prolongations  between  the  individual  bones.  The  offsets  upwards  are  two, 
and  they  sometimes  join  the  synovial  membrane  of  the  wrist  joint ;  but 
the  offsets  in  the  opposite  direction  are  three,  and  may  be  continued  to  all, 
or  only  to  some  of  the  articulations  between  the  four  inner  metacarpal  with 
their  carpal  bones. 

Movements.  The  transverse  carpal  joint  is  partly  condyloid,  but  only 
forward  and  backward  motion  is  permitted.  All  lateral  and  circumduc- 
tory  movement  is  arrested,  if  the  rows  are  closely  applied  together,  by  the 
scaphoid  striking  against  the  os  magnum  on  the  one  side,  and  the  cunei- 
form against  the  unciform  on  the  other. 

Flexion.     As  the  hand  is  bent  forwards  the  lower  row  of  carpal  bones 


moves  backwards,  and    renders  pro- 


Fig.  95. 


minent  the  posterior  ligament.  This 
motion  is  also  brouglit  into  play  in 
full  bending  of  the  wrist. 

Extension.  The  backward  move- 
ment is  freer  than  flexion.  As  the 
lower  carpal  row  moves  towards  the 
palm,  its  progress  is  checked  by  the 
anterior  ligament  of  the  joint,  and  by 
the  strong  flexor  tendons. 

Union  of  the  Metacarpal 
Bones.  The  metacarpal  bones  of 
the  four  fingers  are  connected  at 
their  bases  by  the  following  liga- 
ment :  A  superficial  dorsal  (fig.  95) 
and  palmar  fasciculus  of  fibres  passes 
transversely  from  one  bone  to  the 
next ;  and  the  bands  in  the  palm  are 
the  strongest  (fig.  92).  Besides, 
there  is  a  short  interosseous  ligament 
between  the  contiguous  rough  sur- 
faces of  the  bones. 

Lateral  union.     Where  the  meta- 
carpal bones  touch  they  are  covered 
by  cartilage  ;  and  the  articular  sur- 
faces are  furnished  with  prolongations  of  the  synovial  membrane  serving 
for  their  articulation  with  tlie  carpus. 

At  the  anterior  extremities   the  same  four  metacarpal  bones  are  con- 


PosTEKioR  Ligaments  of  the  Wrist,  and 
Carpal  and  Metacarpal  Bones  (Boar- 
geiy  and  Jacob). 

1.  Posterior  raJio-carpaL 

2.  Carpo-inetacarpal  joint  of  tho  thumb. 

.3,  3.  Transverso  bands  between  the  bases  of 
the  metacarpal  bones. 


300  DISSECTION    OF    THE    UPPER    LIMB. 

nected  by  the  deep  transverse  ligament  which  was  seen  in  the  dissection 
of  the  hand  (p.  280). 

Union  of  the  Metacarpal  and  Carpal  Bones.  The  metacarpal 
bones  of  tlie  finorers  are  articulated  with  the  carpal  bones  after  one  phin  ; 
but  the  bone  of  the  thumb  has  a  separate  joint. 

Tlie  metacarpal  hone  of  the  thiunh  articulates  with  the  os  trapezium  ; 
and  the  ends  of  the  bones  are  incased  in  a  separate  capsular  ligament  (fig. 
92,  ^).  The  joint  is  furnished  with  a  synovial  membrane  which  is  simple 
in  its  arrangement. 

The  thumb-joint  possesses  angular  movement  in  opposite  directions,  with 
opposition  and  circumduction,  thus  : — 

Flexion  and  extension.  When  the  joint  is  flexed  the  metacarpal  bone 
is  brought  into  the  })alm  of  the  hand,  without  the  ball  of  the  thumb  being 
turned  to  the  tips  of  the  fingers.  Extension  of  the  joint  is  very  free,  and 
by  it  the  metacarpal  bone  is  removed  from  the  palm  towards  the  outer 
border  of  the  forearm. 

Abduction  and  adduction.  By  these  movements  the  metacarpal  bone 
is  placed  in  contact  with,  or  removed  from  the  fore  finger. 

Opposition.  In  this  movement  the  ball  of  the  thumb  is  turned  towards 
the  tip  of  each  finger  by  a  half  circumductory  motion  of  the  metacarpal 
bone ;  and  in  picking  up  a  pin  the  joints  of  the  thumb,  and  the  two  last 
joints  of  the  fingers  will  be  bent. 

The  metacarpal  bones  of  the  fingers  receive  longitudinal  bands  from  the 
carpal  bones  on  both  aspects,  thus : — 

The  dorsal  ligaments  (fig.  95)  are  two  to  each,  except  to  the  bone  of 
the  little  finger.  The  bands  of  the  metacarpal  bone  of  the  fore  finger  come 
from  the  os  trapezium  and  os  trapezoides;  those  of  the  third  metacarpal 
are  attached  to  the  os  magnum  and  os  trapezoides;  the  bone  of  the  ring 
finger  receives  its  bands  from  the  os  magnum  and  os  unciforme  ;  and  to 
the  fifth  metacarpal  bone  there  is  but  one  ligament  from  the  unciform. 

The  palmar  ligaments  (fig.  92)  are  weaker  and  less  constant  than  the 
dorsal.  There  is  one  to  each  metacarpal  bone,  except  that  of  the  little 
finger.  These  ligaments  may  be  oblique  in  direction  ;  and  a  band  may  be 
divided  between  two,  as  in  the  case  of  the  ligament  attached  to  the  os  tra- 
pezium and  the  second  and  third  metacarpals.  Sometimes  one  or  more 
may  be  wanting. 

On  the  ulnar  side  of  the  metacarpal  bone  of  the  middle  digit  is  a  longi- 
tudinal lateral  band,  which  is  attached  above  to  the  os  magnum  and  unci- 
forme, and  below  to  the  rough  ulnar  side  of  the  base  of  the  above  mentioned 
bone.  Sometimes  this  band  isolates  the  articulation  of  the  last  two  meta- 
carpals with  the  unciform  bone  from  the  remaining  carpo- metacarpal  joint; 
but  more  frequently  it  is  divided  into  two  parts,  and  does  not  form  a  com- 
plete partition. 

This  band  may  be  seen  by  opening  behind  the  articulation  between  the 
unciform  and  the  last  two  metacarpal  bones ;  and  by  cutting  through  the 
transverse  ligaments  joining  the  third  and  fourth  metacarpals  so  as  to 
allow  their  separation. 

Movement.  Scarcely  any  appreciable  antero-posterior  movement  exists 
in  the  articulations  of  the  bases  of  the  metacarpal  bones  of  the  fore  and 
middle  fingers;  but  in  the  ring  and  little  fingers  the  motion  is  greater,  with 
slight  abduction  and  adduction. 

Dissection.  The  articulating  surfaces  of  the  bones  in  the  carpo-meta- 


METACARPAL  BONE  AND  FIRST  PHALANX 


301 


carpal  articulation  may  be  seen   by  cutting  through  the  rest  of  the  liga- 
ments on  the  posterior  aspect  of  the  hand. 

ArticiUar  surfaces.  Tiie  metacarpal  bone  of  the  fore  finger  presents  a 
hollowed  articular  surface,  which  receives  the  prominence  of  the  os  tra- 
pezoides,  and  articulates  laterally  with  the  os  trapezium  and  os  magnum. 
The  middle  finger  metacarpal  articulates  with  the  os  magnum.  The 
metacarpal  bone  of  the  ring  finger  touches  the  unciform  bone  and  the  os 
magnum.     And  the  little  finger  bone  is  opposed  to  the  os  unciforme. 

Synovial  membranes.  Usually  two  synovial  membranes  are  interposed 
between  the  carpal  and  metacarpal  bones,  viz.,  a  separate  one  for  the  bone 
of  tlie  thumb,  and  offsets  of  the  common  carpal  synovial  sac  (p.  299)  for 
the  others.  Sometimes  there  is  a  distinct  synovial  sac  for  tiie  articulation 
of  the  OS  unciforme  with  the  two  inner  metacarpals. 

Interosseous  ligaments.  The  interosseous  ligaments  between  the  bases 
of  the  metacarpal  bones  may  be  demonstrated  by  detaching  one  bone  from 
another.  There  are  also  strong  fibrous  pieces  between  all  the  carpal  bones 
in  the  second  row  ;  and  slight  ones  are  described  as  present  on  each  side 
of  the  OS  semilunare  in  the  first  row. 

Dissection.  For  the  examination  of  the  joint  between  the  head  of  the 
metacarpal  bone  and  the  first  phalanx  of  the  finger,  it  will  be  requisite  to 
clear  away  the  tendons  and  the  tendinous  expansion  around  it.  A  lateral 
ligament  on  each  side,  and  an  anterior  thick  band  are  to  be  defined.  One 
of  the  joints  may  be  opened  to  see  the  articular  surfaces. 

The  same  dissection  may  be  made  for  the  articulations  between  the  pha- 
langes of  the  finger. 

Union  of  Metacarpal  Bone  and  First  Phalanx  (fig.  96).  In 
this  joint  the  convex  head  of  the  metacarpal  bone  is  received  into  the 
glenoid  fossa  of  the  phalanx,  and  the  two 
are  retained  in  contact  by  the  extensor  and 
flexor  tendons,  and  by  the  following  liga- 
ments : — 

The  lateral  ligament  (a)  is  the  same  on 
both  sides  of  the  joint.  P^ach  is  triangular 
in  form  :  it  is  attached  by  its  upper  part  to 
the  tubercle  on  the  side  of  the  head  of  the 
metacarpal  bone,  and  below  it  is  inserted  into 
the  side  of  the  phalanx  and  the  anterior 
ligament. 

The  anterior  ligament  {b)  is  a  longitu- 
dinal band,  which  is  fixed  firmly  to  the 
phalanx,  but  loosely  to  the  metacarpal 
bone.     It  is  fibro-cartilaginous    in  texture, 

and  is  grooved  for  the  flexor  tendon :  to  its  sides  the  lateral  ligaments  are 
attached. 

Covering  the  upper  part  of  the  joint  is  the  extensor  tendon  ;  this  takes 
the  place  of  a  dorsal  ligament,  and  sends  down  an  expansion  on  each  side 
which  serves  as  a  capsule  to  the  articulation.  The  synovial  membrane  of 
the  joint  is  a  simple  sac. 

In  the  articulation  of  the  thumb  two  sesamoid  bones  are  connected  with 
the  anterior  ligament,  and  receive  most  of  the  fibres  of  the  lateral  liga- 
ments. 

Movements.  Motion  in  four  opposite  directions,  and  circumduction,  exist 
in  these  condyloid  joints. 


Fig.  96. 


302  DISSECTION    OF    THE    UPPER    LIMB. 

Extension  and  flexion.  The  phalanx  moves  backwards  in  extension,  so 
as  to  give  an  angle  with  the  metacarpal  bone.  The  anterior  ligament  and 
the  flexor  tendons  are  stretched,  and  control  the  movement.  In  flexion 
the  phalanx  glides  forwards  under  the  head  of  the  metacarpal  bone,  and 
leaves  this  exposed  to  form  the  knuckle  when  tlie  finger  is  shut.  The 
lateral  ligaments  and  the  extensor  tendon  are  put  on  the  stretch  as  the 
joint  is  bent. 

Abduction  and  adduction  are  the  lateral  movements  of  the  finger  from 
or  towards  the  middle  line  of  the  hand.  The  lateral  ligament  of  the  side  of 
the  joint  which  is  convex  will  be  tightened,  and  the  other  will  be  relaxed. 

The  circumductory  motion  is  less  impeded  in  the  thumb,  and  in  the  fore 
and  little  fingers  tlian  in  the  others ;  and  in  tlie  thumb  it  allows  the  turn- 
ing of  the  last  phalanx  towards  the  other  digits  in  the  movement  of  oppo- 
sition. 

Union  of  the  Phalanges.  The  ligaments  of  the  first  joint  are  simi- 
lar to  those  in  the  metacarpo-phalangeal  articulation,  viz.,  two  lateral  and 
an  anterior. 

The  lateral  ligaments  are  triangular  in  form.  Each  is  connected  by  its 
apex  to  the  side  of  the  phalanx  near  the  anterior  part ;  and  by  its  base  to 
the  contiguous  phalanx  and  the  anterior  ligament. 

The  anterior  ligament  has  the  same  mode  of  attachment  between  the 
extremities  of  the  bones  as  in  the  metacarpo-phalangeal  joint,  but  it  is  not 
so  strong  ;  and  the  extensor  tendon  takes  the  place  of  a  posterior  band  as 
in  that  articulation. 

There  is  a  simple  synovial  membrane  present  in  the  joint. 

The  joint  of  the  second  with  the  last  phalanx  is  like  the  preceding  in 
the  number  and  disposition  of  its  ligaments ;  but  all  the  articular  bands 
are  much  less  strongly  marked. 

Articular  Surfaces.  The  anterior  end  of  each  phalanx  is  marked  by  a 
pulley-like  surface.  The  posterior  end  presents  a  transversely  hollowed 
fossa,  and  is  provided  with  a  crest  which  fits  into  the  central  depression  of 
the  opposed  articular  surface. 

Movements.  The  two  interphalangeal  joints  can  be  bent  and  straight- 
ened like  a  hinge. 

Flexion  and  extension.  In  flexion,  the  farther  phalanx  moves  under  the 
nearer  in  each  joint,  and  the  motion  is  checked  by  the  lateral  ligaments 
and  the  extensor  tendon  :  in  the  joint  between  the  middle  and  the  meta- 
carpal phalanx  this  movement  is  most  extensive.  In  extension  the  farther 
phalanx  comes  into  a  straight  line  with  the  nearer  one  and  the  motion  is 
stopped  by  tlie  anterior  ligament  and  the  flexor  tendons. 


CHIEF    ARTERIES    OF    THE    UPPER    LIMB 


303 


TABLE  OF  THE  CHIEF  ARTERIES  OF  THE  UPPER  LIMB. 

f  Superior  thoracic 


The  subclavian  is 
coatiuued  in  the 
arm  by  ...     . 


f  1.  Axillary 
artery. 


2.  brachial 
artery. 


3.  radial 
artery. 


4.  ulnar 
artery. 


acromial  thoracic      .     . 
long  thoracic 
alar  thoracic 
subscapular      .     .     .     . 
external  mammary 
anterior  circumflex 
^  posterior  circumflex. 

f  To  coraco-brachialis 

superior  profunda    . 

nutritious 

inferior  profunda  .     . 

anastomotic 
l^  muscular. 

f  Recurrent 

muscular 

superficial  volar 

posterior  carpal 

anterior  carpal 

metacarpal 

dorsal  of  the  thumb  of 
the  index  finger 

princeps  pollicis 

raJialis  indicis 


Muscular 
inferior  acromial 
humeral  thoracic. 


Dorsal  artery 
muscular 


(  Muscular  to  tt 
<  and  anconeus 
(   anastomotic. 


Muscular  to  ti'iceps 
anastomotic. 


Infrasca- 
pular 


r  Recurrent 
arch  J    perforating 


t  interosseous 
communicatinj 


Anterior  recurrent 
posterior  recurrent 

interosseous      .    . 

muscular 


dorsal  of  the  hand,  or 
metacarpal  .     .     . 


Anterior  . 
posterior. 


Nutritious 
muscular. 


Recnrrent 
muscular. 


Dorsal  carpal 
metacarpal  or  inter- 
osseous. 


anterior  carpal 
i^  superficial  arch 


f  Communicating 
•   four  digital  urauches 
I    cutaneous 
t  muscular. 


304 


SPINAL    NERVES    OF    THE    UPPER    LIMB, 


TABLE  OF  THE  SPINAL  NERVES  OF  THE  UPPER  LIMB, 
r  Anterior  thoracic    .  \  ^^7;;^"^*^ 


Beachiai. 
PLEXUSgives 
off  below  the 
clavicle     .    . 


subscapular    . 


circumflex . 


Superior 

iuferior 

long. 

Articular 

cutaneous 
to  teres  minor 
to  deltoid. 


nerve  of  Wrlsberg. 

C  Small  cutaneous 

internal  cutaneous  .  <  anterior  of  forearm 

(  posterior  of  forearm. 


musculo-cutaneous 


median 


ulnar. 


To  coraco-brachialis 
biceps  and 
brachialis  auticus 
cutaneous  external  of  forearm 
articular  to  carpus. 


To  pronator  teres 

to  muscles  of  forearm,  except  flexor 

ulnarus  and  part  of  profundus 
anterior  interosseous 
cutaneous  palmar 
to  mu<cles  of  thumb  in  part 
Ave  digital  branches. 


f  Articular  to  elbow 
to  flexor  carpi  ulnaris 
to  flexor  profundus  in  part 
cutaneous  branch  of  forearm  and 

palm 
dorsal  cutaneous  of  the  hand 


superficial  palmar  division 
L  deep  palmar  nerve. 


Communicating 
two  dit,atal 
branches. 


1^  musculo-spiral    .    . 


'  Internal  cutaneous 
to  triceps 
and  anconeus 
external  cutaneous 
to  supinator  and  extensor  radialia 
longus 

posterior  interosseous  .    . 


radial 


Muscular 
articular. 

Cutaneous  of  back  of 
thumb,  and  of  first 
two  Angers  and 
half  the  next. 


CAVITY    OF    THE    THORAX.  305 


CHAPTER  lY. 

DISSECTION  OF  THE  THORAX. 


Section  I. 

CAVITY  OF  THE  THORAX. 

The  cavity  of  the  thorax  is  the  space  included  by  the  spinal  column, 
the  sternum  and  ribs,  and  by  certain  muscles  in  the  intervals  of  the  bony 
framework.  In  it  the  organs  of  respiration,  and  the  heart  with  its  great 
vessels  are  lodged :  and  through  it  the  gullet,  and  some  vessels  and  nerves 
are  transmitted. 

Dissection.  When  the  soft  parts  covering  in  front  the  bony  parietes  of 
the  thorax  have  been  examined  and  taken  away,  the  cavity  is  to  be  opened 
by  removing  a  portion  of  the  anterior  boundary.  To  make  a  sufficient 
opening  in  the  thorax,  the  sternum  is  to  be  sawn  through  opposite  the  in- 
terval between  the  first  two  ribs,  and  again  between  the  cartilages  of  the 
fifth  and  sixth  ribs.  After  detaching  the  lining  membrane  (pleura)  from 
the  inner  surface  of  the  chest,  the  student  is  to  cut  through  the  true  ribs, 
except  the  first  and  seventh,^  as  far  back  as  he  can  conveniently  reach. 
The  loose  sternum  and  the  ribs  can  be  removed  by  dividing  the  internal 
mammary  vessels,  the  triangularis  sterni,  and  the  intercostal  muscles  in 
the  first  and  sixth  spaces.  Tlie  bag  of  the  pleura,  and  the  cavity  with  its 
contents  will  be  now  ready  for  examination. 

The  sternum  and  the  cartilages  of  the  ribs  will  be  required  hereafter  for 
the  dissection  of  the  ligaments. 

Form.  The  included  cavity  is  irregularly  conical,  with  the  apex  above 
and  the  base  down  ;  and  it  appears,  from  the  collapsed  state  of  the  lungs, 
to  be  only  partly  filled  by  the  contained  viscera,  but  during  life  the  whole 
of  the  now  vacant  space  is  occupied  by  the  expanded  lungs.  On  a  hori- 
zontal section  its  shape  would  appear  somewhat  cordiform  ;  for  the  cavity 
is  flattened  on  the  sides,  is  diminished  in  the  middle  line  by  the  prominent 
spinal  column,  and  is  projected  backwards  on  each  side  of  the  spine. 

Boundaries.  On  the  sides  are  the  ribs  witli  their  intercostal  muscles  ; 
whilst  in  front  is  tlie  sternum  ;  and  behind  is  the  spine. 

Tiie  base  is  constructed  at  the  circumference  by  the  last  dorsal  vertebra 
behind,  by  the  end  of  the  sternum  before,  and  by  the  ribs  on  the  side  ; 
whilst  the  space  included  by  the  bones  is  closed  by  the  diaphragm. 

The  base  is  widei  transversely  than  from  front  to  back,  and  is  convex 
towards  the  chest ;  though  at  certain  spots  it  projects  more  than  at  others. 

'  The  student  must  be  mindful  to  leave  those  ribs  uncut ;  the  division  of  thrm 
will  not  be  advantageous  to  him,  and  will  injure  the  dissection  of  the  neck  and 
abdomen. 
20 


306  DISSECTION    OF    THE    THORAX. 

Thus  in  the  centre  it  is  lower  than  at  the  sides,  and  is  on  a  level  with  the 
base  of"  the  xiphoid  cartilage.  On  the  right  side  it  rises  to  a  level  with 
the  upper  border  of  the  fifth  rib  near  the  sternum  ;  and  on  the  left  to  the 
corresponding  part  of  the  upper  border  of  the  sixth  rib.^  From  the  lateral 
projections,  the  diaphragm  slopes  suddenly  towards  its  attachment  to  the 
ribs,  but  more  behind  than  before,  so  as  to  leave  a  narrow  interval  be- 
tween it  and  the  wall  of  the  chest.  The  level  of  this  attached  part  will 
be  marked  by  an  oblique  line  over  the  side  of  the  chest  from  the  base  of 
the  xiphoid  cartilage  to  the  tenth  rib ;  but  it  difrers  slightly  on  the  two 
sides,  being  rather  lower  on  the  left  (fig.  97). 

The  apex  of  the  space  is  continued  higher  than  the  osseous  boundary, 
and  reaches  into  the  root  of  the  neck.  Its  highest  point  is  not  in  the 
middle  line,  for  there  the  windpipe,  bloodvessels,  &c.,  lie ;  but  it  is  pro- 
longed on  each  side  for  an  inch  or  an  inch  and  a  half  above  the  first  rib, 
so  that  the  apex  may  be  said  to  be  bifid.  Each  point  projects  between 
the  scaleni  muscles,  and  under  the  subclavian  bloodvessels ;  and  in  the 
interval  between  them  lie  the  several  parts  passing  between  the  neck  and 
the  thorax. 

Dimensions.  The  extent  of  the  thoracic  cavity  does  not  correspond 
with  the  apparent  size  externally ;  for  the  space  included  by  the  ribs  be- 
low is  occupied  by  the  abdominal  viscera,  and  the  cavity  reaches  above 
into  the  neck. 

In  consequence  of  the  arched  condition  of  the  diaphragm,  the  depth  of 
the  space  varies  greatly  at  different  points.  At  the  centre,  where  the 
depth  is  least,  it  measures  about  seven  inches,  but  at  the  back  as  much 
again ;  and  the  other  vertical  measurements  can  be  estimated  by  means  of 
the  data  given  of  the  level  of  the  base  on  the  wall  of  the  thorax. 

Alterations  in  capacity.  The  size  of  the  thoracic  cavity  is  constantly 
varying  during  life  with  the  condition  of  the  ribs  and  diaphragm  in 
breathing. 

The  liorizontal  measurements  are  increased  in  inspiration,  when  the  ribs 
are  raised  and  separated  from  one  another ;  and  are  diminished  in  expi- 
ration as  the  ribs  approach  and  the  sternum  sinks. 

An  alteration  in  depth  is  due  to  the  condition  of  the  diaphragm  in  res- 
piration ;  for  the  muscle  descends  when  air  is  taken  into  the  lungs,  in- 
creasing thus  the  cavity ;  and  ascends  when  the  air  is  expelled  from  those 
organs,  so  as  to  restore  the  previous  size  of  the  space,  or  to  diminish  it  in 
violent  efforts.  But  the  movement  of  the  diaphragm  is  not  equal  through- 
out, and  some  parts  of  the  cavity  will  be  increased  more  than  others.  For 
instance,  the  central  tendinous  piece,  which  is  joined  to  the  heart-case, 
moves  but  slightly  ;  but  the  lateral,  bulging,  fleshy  valves  descend  freely, 
and  add  greatly  to  the  size  of  the  lateral  part  of  the  chest  by  their  separa- 
tion from  the  thoracic  parietes. 

The  thoracic  cavity  may  be  diminished  by  the  diaphragm  being  pushed 
upwards  by  enlargement,  either  temporary  or  permanent,  of  tlie  viscera 
in  the  upper  part  of  the  abdomen  ;  or  by  the  existence  of  fluid  in  the 
latter  cavity. 

'  This  is  the  height  in  the  dead  body.  The  level  to  which  it  may  reach  in 
great  respiratory  efforts  during  life  will  be  stated  with  the  account  of  the  Dia- 
phragm. 


REFLECTIONS    OF    PLEURA.  307 


THE    PLEURA. 

The  pleurae  are  two  serous  membranes,  or  closed  sacs,  which  are  re- 
flected around  the  lungs  in  the  cavity  of  the  thorax.  One  occupies  the 
right,  and  the  other  the  left  half  of  the  cavity ;  they  approach  each  other 
along  the  middle  line  of  the  body,  forming  a  thoracic  partition  or  medias- 
tinum. 

Each  pleura  is  conical  in  shape ;  its  apex  projects  into  the  neck  above 
the  first  rib  (fig.  97),  and  its  base  is  in  contact  with  the  diaphragm.  The 
outer  surface  is  rough,  and  is  connected  to  the  lung  and  the  wall  of  the 
thorax  by  areolar  tissue,  but  the  inner  surface  is  smooth  and  secerning. 
Surrounding  the  lung,  and  lining  the  interior  of  one-half  of  the  chest,  the 
serous  membrane  consists  of  a  parietal  part — pleura  costalis,  and  of  a  vis- 
ceral part — pleura  pulmonalis. 

There  are  some  differences  in  the  shape  and  extent  of  the  two  pleural 
bags.  On  the  right  side  the  bag  is  wider  and  shorter  than  on  the  left ; 
and  on  the  latter  it  is  narroAved  by  the  projection  of  the  heart  to  that  side. 

The  continuity  of  the  bag  of  the  pleura  over  the  lung  and  the  wall  may 
be  traced  circularly  from  a  given  point  to  the  same,  in  the  following  man- 
ner:— Supposing  the  membrane  to  be  followed  outwards  from  the  sternum, 
it  may  be  traced  on  the  wall  of  the  cliest  as  far  as  the  spinal  column  ; 
here  it  is  directed  forwards  to  the  root  of  the  lung,  and  is  reflected  over 
the  viscus,  covering  its  surface,  and  connecting  together  its  different 
lobules.  From  the  front  of  the  root  the  pleura  may  be  followed  over  the 
side  of  the  pericardium  to  the  sternum.  Below  the  root  the  pleura  gives 
rise  to  a  thin  fold,  the  lignmentam  latum  pulmonis,  which  intervenes  be- 
tween the  inner  surface  of  the  lung  and  the  side  of  the  pericardium. 

If  the  serous  sac  be  traced  above  the  root  of  the  lung,  it  describes  a 
circle  without  deflection  over  a  viscus. 

The  mediastinum.  The  median  thoracic  partition,  or  the  mediastinum, 
is  formed  by  the  approximation  of  the  pleural  bags  along  the  middle  line, 
and  is  constructed  of  two  layers — one  being  derived  from  each  sac.  About 
midway  between  the  sternum  and  the  spine  the  contiguous  strata  of  the 
mediastinum  are  widely  separated  by  the  heart ;  but  in  front  of,  and  be- 
hind the  heart  they  approach  near  each  other.  To  the  parts  before  and 
behind  that  viscus  the  terms  "  anterior  and  posterior  mediastina"  are 
sometimes  applied. 

The  part  in  front  of  the  heart  (anterior  mediastinum)  extends  from  the 
back  of  the  sternum  to  the  pericardium.  Behind  the  second  piece  of  the 
sternum  the  pleural  bags  touch  each  other,  but  above  and  below  that  spot 
they  are  separated  by  an  interval ;  so  that  the  space  between  them  (inter- 
pleural) is  narrowed  at  the  centre,  and  is  inclined  below  to  the  left  of  the 
middle  line.  In  the  upper  part  of  the  space  are  the  remains  of  the  thymus 
gland,  and  the  origin  of  some  of  the  hyoid  and  thyroid  muscles ;  and  in 
the  lower  part  is  some  areolar  tissue,  together  with  the  triangularis  sterni 
muscle  of  the  left  side. 

The  part  behind  the  heart  (posterior  mediastinum)  intervenes  between 
the  back  of  the  pericardium  with  the  roots  of  the  lungs,  and  the  spinal 
column.  Its  lateral  boundaries  are  the  opposite  pleural  sacs,  which  are 
separated  here  by  a  larger  interpleural  interval  than  in  front  of  the  heart. 
If  the  pleura  be  divided  behind  the  lung  on  the  right  side,  the  extent  of 
the  space  and  its  contents  will  appear :  in  it  are  contained  the  different 
bodies  on  the  front  of  the  spine,  viz.,  the  aorta,  the  vena  azygos,  the  thoracic 


308  DISSECTION    OF    THE    THORAX. 

duct,  the  oesophagus  with  its  nerves,  the  trachea,  the  splanchnic  nerves  at 
the  lower  part,  and  some  lymphatic  glands. 

Dissection.  The  pleura  and  the  fat  are  now  to  be  cleaned  from  the  side 
of  the  pericardium. 

The  root  of  the  lung  is  to  be  dissected  out  by  taking  away  the  pleura 
and  the  areolar  tissue  from  the  front  and  back,  without  injuring  its  several 
component  vessels.  In  this  dissection  the  phrenic  artery  and  nerve  will 
be  found  in  front  of  the  root,  together  with  a  few  nerves  (anterior  pul- 
monary) ;  the  last  are  best  seen  on  the  left  side.  Behind  the  root  of  tlie 
lung  is  the  vagus  nerve,  dividing  into  branches;  and  arching  above  it  is 
the  large  azygos  vein. 

For  the  present,  the  arch  of  the  aorta  and  the  small  nerves  on  it  may 
be  left  untouched. 

Tlie  thymus  body  is  a  foetal  organ,  like  the  thyroid  body,  whose  use  is 
unknown.  It  occupies  chiefly  the  upper  part  of  the  thorax ;  and  it  may 
be  best  examined  in  a  full-grown  foetus. 

At  birth  it  is  about  two  inches  in  length,  and  is  of  a  grayish  color ;  it 
possesses  two  lobes  of  a  conical  form,  which  touch  each  other.  Its  upper 
end  is  pointed  and  extends  on  tlie  trachea  as  high  as  the  thyroid  body;  and 
the  lower  wider  part  reaches  as  far  as  the  fourth  rib.  In  the  tiiorax  it 
rests  on  the  aortic  arch  and  large  vessels,  on  the  left  innominate  vein,  and 
on  the  pericardium. 

In  the  adult  all  that  remains  of  the  thymus  is  a  brownish  rather  firm 
material  in  the  interpleural  space  beneath  the  upper  part  of  the  sternum. 

In  its  perfect  state  it  resembles  much  the  thyroid  body ;  and  a  whitish 
fluid,  containing  lymph-like  corpuscles,  escapes  from  it  when  it  is  cut. 

CONNECTIONS  OF  THE  LUNGS. 

The  lungs  are  two  in  number,  and  are  contained  in  the  cavity  of  the 
thorax,  one  on  each  side  of  the  spinal  column.  In  these  organs  the  blood 
is  changed  in  respiration. 

The  lung  is  of  a  somewhat  conical  form,  and  takes  its  shape  from  the 
space  in  which  it  is  lodged.  It  is  unattached,  except  at  the  inner  part 
where  the  vessels  enter ;  and  it  is  covered  by  the  bag  of  the  pleura.  Its 
base  and  apex,  borders  and  surfaces  can  be  distinguished  by  differences  in 
form  ;  it  is'  divided  also  into  lobes  by  fissures  ;  and  it  has  a  root  formed 
out  of  its  vessels  and  nerves. 

The  base  of  the  lung  is  hollow  in  the  centre  and  thin  at  the  circumfer- 
ence, and  fits  on  the  convexity  of  the  diaphragm.  Following  the  shape  of 
that  muscle,  it  is  sloped  obliquely  from  before  backwards,  and  reaches  in 
consequence  much  lower  posteriorly  than  anteriorly.  Its  position  with 
respect  to  the  wall  of  the  thorax  may  be  ascertained  externally  by  taking 
the  level  of  the  diaphragm  as  a  guide  (p.  306)  ;  and  it  will  be  a  rib's 
breadth  lower  in  front  on  the  left,  than  on  the  right  side  (Hg.  97).  The 
apex  is  rounded,  and  projects  an  inch  to  an  inch  and  a  half  above  the  first 
rib,  where  it  lies  beneath  the  clavicle,  the  anterior  scalenus  muscle,  and 
the  subclavian  artery. 

The  anterior  edge  or  border  is  thin,  and  overlays  in  part  the  pericar- 
dium. On  the  right  side  it  lies  along  the  middle  of  the  sternum  as  low  as 
the  sixth  costal  cartilage  (fig.  97).  On  the  left  side  it  reaches  the  mid- 
line of  the  chest  as  low  as  the  fourth  costal  cartilage  ;  but  below  that  spot 
it  presents  a  V-shaped  notch  (tig.  97),  whose  apex  is  opposite  the  outer 


CONNECTIONS    OF    THE    LUNGS 


309 


part  of  the  cartilage  of  the  fifth  rib.  Two  fissures  are  seen  in  the  border 
of  the  right  hing,  but  only  one  in  that  of  the  left.  The  posterior  border 
is  as  long  again  as  the  anterior,  and  projects  inferiorly  between  the  lower 
ribs  and  the  diaphragm  ;  it  is  thick  and  vertical,  and  is  received  into  the 
hollow  by  the  side  of  the  spinal  column. 

The  outer  surface  of  the  lung  is  convex,  and  is  in  contact  with  the  wall 
of  the  thorax :  a  large  cleft  divides  it  into  two  pieces  (lobes  of  the  lung), 
and  on  the  right  side  there  is  second  smaller  fissure.  The  inner  surface  is 
flat  when  compared  with  the  outer ;  altogether  in  front  is  the  hollow  cor- 
responding with  the  heart  and  its  large  vessels,  which  is  greatest  on  the 
left  lung ;  and  behind  this,  but  nearer  the  posterior  than  the  anterior 
border,  is  a  fissure  about  three  inches  long,  hilum  pulmonis,  which  receives 
the  vessels  forming  the  root  of  the  lung. 


Diagram  to  show  the  difference  ix  the  Anterior  Border  of  the  Rioht  and  Left  Ltno, 
the  edge  beiug  indicated  by  the  dark  line ;  and  to  mark  the  different  level  of  the  base  on  the 
two  sides. 


Each  lung  is  divided  incompletely  into  two  parts  or  lobes  by  an  oblique 
fissure,  which  begins  near  the  apex,  and  ends  in  the  anterior  border  near 
the  base  :  from  the  form  of  the  lung  and  the  direction  of  the  fissure  the 
lower  lobe  is  necessarily  tlie  largest.  In  the  right  lung  a  second  horizontal 
fissure  is  directed  forwards  from  the  middle  of  the  oblique  one  to  the  ante- 
rior border,  and  cuts  off  a  small  triangular  piece  from  the  upper  lobe  :  this 
is  the  third  lobe  of  the  lung.  Occasionally  there  may  be  a  trace  of  tlie 
third  lobe  in  the  left  lung. 

Besides  the  difference  in  the  number  of  the  lobes,  the  right  lung  is  larger 
and  heavier,  and  is  wider  and  more  hollowed  out  at  the  base  than  the  left ; 
it  is  also  shorter  by  an  inch.  The  increased  length  and  the  narrowness  of 
the  left  lung  are  due  to  the  absence  of  a  large  projecting  body  like  the 
liver  under  it,  and  to  the  direction  of  the  heart  to  the  left  side. 


310  DISSECTION    OF    THE    THORAX. 

The  root  of  the  lung  consists  of  the  vessels  entering  the  fissure  on  the 
inner  surface  ;  and  as  these  are  bound  together  by  the  pleura  and  some 
areolar  tissue  they  form  a  foot-stalk,  which  fixes  the  lung  to  the  heart  and 
the  windpipe.  The  root  is  situate  at  the  inner  surface,  about  midway  be- 
tween the  base  and  apex,  and  about  a  third  of  the  breadth  from  the  poste- 
rior border  of  the  lung. 

In  front  of  the  root  on  both  sides,  are  the  phrenic  and  the  anterior  pul- 
monary nerves,  the  former  being  at  some  little  distance  from  it ;  and  an- 
terior to  the  right  root  is  the  descending  cava.  Behind  on  both  sidc^s,  is 
the  posterior  pulmonic  plexus;  and  on  the  left  side  there  is,  in  addition, 
the  descending  aorta.  Above  on  the  right  side  is  the  vena  azygos  ;  and 
on  the  left  side,  the  arch  of  the  aorta.  Below  each  root  is  the  fold  of 
pleura  called  ligamentum  latum  pulmonis. 

In  the  root  of  the  lung  are  collected  a  branch  of  the  pulmonary  artery, 
two  pulmonary  veins,  and  a  division  of  the  air  tube  (bronchus) ;  small 
nutritive  bronchial  arteries  and  veins,  and  some  nerves  and  lymphatics. 
The  large  vessels  and  the  air  tube  have  the  following  position  to  one 
another : — 

On  both  sides  the  bronchus  is  most  posterior,  the  pulmonary  veins  most 
anterior,  and  the  pulmonary  artery  between  the  other  two.  In  the  direc- 
tion from  above  down  the  position  on  the  right  side  is,  bronclius,  pulmo- 
nary artery,  and  pulmonary  veins  ;  but  on  the  left  side  the  bronchus  and 
artery  have  changed  places,  consequently  the  relative  position  will  there 
be  artery,  bronchus,  and  veins.  This  difference  in  the  two  sides  may  be 
accounted  for  by  the  left  branch  of  the  air  tube  being  at  a  lower  level 
than  the  right. 

THE  PERICARDIUM. 

The  bag  containing  the  heart  is  named  the  pericardium.  It  is  situate 
in  the  middle  of  the  thorax,  in  the  interval  between  the  pleurae  of  opposite 
sides. 

Dissection.  Supposing  the  surface  of  the  pericardium  to  be  already 
cleaned,  the  student  should  next  dissect  out  the  large  vessels  connected 
with  the  heart,  and  the  nerves. 

The  large  artery  curving  to  the  left  above  the  heart  is  the  aorta,  which 
furnishes  three  trunks  to  the  head  and  the  upper  limbs,  viz.,  innominate 
to  the  right,  next  left  common  carotid,  and  left  subclavian.  On  its  left 
side  lies  the  pulmonary  artery. 

Above  the  arch  of  the  aorta  a  large  venous  trunk,  left  innominate, 
crosses  over  the  three  before  said  arteries,  and  ends  by  uniting  on  the  right 
side  with  the  right  innominate  vein  in  the  upper  cava.  Several  small 
veins,  which  may  be  mistaken  for  nerves,  ascend  over  the  aorta,  and  enter 
this  trunk.  Define  the  branches  of  this  vein,  and  especially  one  crossing 
the  aortic  arch  towards  the  left  side,  which  is  the  left  superior  intercostal 
vein. 

The  large  vein  by  tlie  side  of  the  aorta  which  enters  the  top  of  the  heart 
is  the  upper  cava :    look  for  the  azygos  vein  opening  into  it  behind. 

Seek  the  following  nerves  of  the  left  side  which  cross  the  arch  of  the 
aorta : — The  nerve  most  to  the  left,  and  the  largest,  is  the  vagus  ;  the 
next  largest  in  size  on  the  right  of  the  vagus  is  the  phrenic.  Between 
the  preceding  nerves,  and  close  to  the  coats  of  the  artery,  are  the  two 
following,  the  left  superficial  cardial  nerve  of  the  sympathetic,  and  the 


STRUCTURE    OF    PERICARDIUM.  311 

cardiac  branch  of  the  left  vagus  ;  of  the  two,  the  last  is  the  smaller,  and 
on  the  right  of  the  other. 

The  cardiac  nerves  from  the  left  vagus  and  sympathetic  are  to  be  pur- 
sued onwards  to  a  small  plexus  (superficial  cardiac)  in  the  concavity  of 
the  aorta.  An  offset  of  the  plexus  is  to  be  traced  downwards  between  the 
pulmonary  artery  and  the  aorta  towards  the  anterior  coronary  artery  of 
the  heart ;  and  another  prolongation  is  to  be  found  coming  forwards  from 
the  deep  cardiac  to  the  superficial  plexus :  this  dissection  is  difficult,  and 
will  require  care. 

When  the  pericardium  is  afterwards  opened  the  nerves  will  be  followed 
on  the  heart.  Oftentimes  these  small  nerves  are  destroyed  in  injecting 
the  body. 

The  pericardium  is  larger  than  the  viscus  it  contains.  Somewhat 
conical  in  form,  the  wider  part  of  the  bag  is  turned  towards  the 
diaphragm,  and  the  narrower  part  upwards  to  the  large  vessels  of  the 
heart. 

Occupying  the  interpleural  space,  it  is  situate  behind  the  sternum,  and 
projects  below  on  each  side  of  that  bone,  but  much  more  towards  the  left 
than  the  right  side.  Laterally  the  pericardium  is  covered  by  the  pleura, 
and  the  phrenic  nerve  and  vessels  lie  in  contact  with  it.  Its  anterior  and 
posterior  surfaces  correspond  with  the  objects  in  the  interpleural  space  ; 
and  on  the  anterior  aspect  the  bag  is  partly  covered  by  the  margin  of  the 
lungs,  especially  the  left. 

The  heart-case  consists  of  a  fibrous  structure,  which  is  lined  internally 
by  a  serous  membrane. 

The  fibrous  part  surrounds  the  heart  entirely,  and  is  pierced  by  the  dif- 
ferent vessels  of  that  organ  :  it  gives  prolongations  around  the  vessels,  and 
the  strongest  of  these  sheaths  is  on  the  aorta.  Inferiorly  it  is  united  by 
fibres  to  the  central  tendon  of  the  diaphragm. 

This  membrane  is  thickest  at  the  upper  part,  and  is  formed  of  fibres 
crossing  in  different  directions,  many  being  longitudinal.  When  the  peri- 
cardium has  been  cut  open,  the  serous  lining  will  be  discernible. 

The  serous  sac  lines  the  interior  of  the  fibrous  pericardium,  and  is  re- 
flected over  the  surface  of  the  heart.  Like  other  serous  membranes,  the 
arachnoid  for  example,  it  has  a  parietal  and  a  visceral  part.  After  lining 
the  interior  of  the  fibrous  case,  to  which  it  gives  the  shining  appearance, 
the  membrane  is  conducted  to  the  surface  of  the  heart  by  the  different 
vessels.  As  it  is  reflected  on  the  aorta  and  the  pulmonary  artery  it  con- 
tains those  vessels  in  one  tube,  not  passing  between  their  contiguous  sur- 
faces ;  and  at  the  posterior  part  of  the  pericardium  it  forms  a  pouch 
between  the  pulmonary  veins  of  opposite  sides. 

In  front  of  the  root  of  the  left  lung  the  serous  layer  forms  a  vertical 
band,  the  vestigial  fold  of  the  pericardium,  (Marshal),  which  includes  the 
remains  of  the  left  innominate  vein  of  the  foetus.  On  separating  the  [)ul- 
monary  artery  and  bronchus,  the  band  will  be  better  seen. 

The  vessels  of  the  pericardium  are  derived  from  the  aorta,  the  internal 
mammary,  the  bronchial,  the  oesophageal,  and  the  phrenic  arteries. 

Nerves.  According  to  Luschka  the  pericardium  receives  nerves  from 
the  phrenic,  sympathetic,  and  right  vagus. 


312  DISSECTION    OF    THE    THORAX. 


THE    HEART    AND    ITS    LARGE    VESSELS. 

The  heart  is  a  hollow  muscular  viscus,  and  is  tlie  agent  in  the  propul- 
sion of  the  blood  through  the  body.  Into  it,  as  the  centre  of  tlie  vascular 
system,  veins  enter ;  and  from  it  the  arteries  issue. 

Form.  AVhen  the  heart  is  distended,  its  form  is  conical,  but  it  is  rather 
flattened  from  before  backwards.  Its  surfaces  and  borders  have  the  fol- 
lowing differences  ;  the  anterior  surface  is  slightly  convex,  whilst  the  pos- 
terior is  nearly  flat :  the  left  border  is  thick  and  round,  but  the  right  is 
thin,  sharp,  and  less  firm. 

Size.  The  size  varies  greatly,  and  in  general  tlie  heart  of  the  woman 
is  smaller  than  that  of  the  man.  Its  average  weight  is  from  ten  to  twelve 
ounces  in  the  male,  and  from  eight  to  ten  in  the  female.  The  measure- 
ments may  be  said  to  be  about  four  inches  and  three-quarters  in  length, 
three  inches  and  a  half  in  width,  and  two  inches  and  a  half  in  thickness. 

Position  and  Direction.  Tlie  heart  lies  beneath  the  lower  two-thirds 
of  the  sternum,  and  projects  on  each  side,  but  more  on  the  left  than  tlie 
right.  Its  axis  is  not  parallel  to,  but  is  inclined  obliquely  across  that  of 
the  body  ;  and  its  position  is  almost  horizontal  with  the  base  directed 
backwards  and  to  the  right,  and  the  apex  forwards  and  to  the  left  side. 
The  left  margin  of  the  viscus  is  undermost,  whilst  the  right  is  foremost. 

In  consequence  of  the  direction  of  the  heart  in  the  thorax,  only  some 
parts  can  be  near,  or  in  contact  with  the  parietes  :  thus  the  right  half  and 
the  apex  will  correspond  with  the  thoracic  wall,  though  mostly  with  lung 
intervening,  whilst  the  base  is  directed  away  from  the  sternum  and  the 
costal  cartilages  :  and  the  left  half  will  be  undermost  and  deep  in  the 
cavity. 

Limits  (fig.  98.)  The  limits  of  the  whole  heart  are  the  following  : 
the  base  is  opposite  the  spinal  column,  and  corresponds  with  four  dorsal 
vertebrae  (5th  to  8th).  The  apex  strikes  the  wall  of  the  thorax  during 
life  just  below  the  fifth  rib,  near  the  junction  with  the  cartilage. 

The  upper  limit  would  be  shown  by  a  line  across  the  sternum  on  a  level 
with  the  upper  edge  of  the  third  costal  cartilage.  And  the  lower  limit 
would  be  marked  by  a  line  over  the  junction  of  the  sternum  with  the 
xiphoid  cartilage,  drawn  from  the  articulations  of  the  sixth  and  seventh 
cartilages  of  the  right  side  to  the  spot  where  the  apex  touches. 

Its  lateral  limits  are  the  following.  On  the  right  it  projects  from  one 
to  one  inch  and  a  half  beyond  the  middle  line  of  the  sternum,  and  its  in- 
crease in  this  direction  is  constantly  varying  with  the  degree  of  distension 
of  the  right  half  of  the  heart.  On  the  left  side  the  apex  projects  three 
inches  to  three  inches  and  a  half  from  the  centre  of  the  breast  bone. 

Component  parts.  The  heart  is  a  double  organ,  and  is  made  up  of  two 
similar  halves.  In  each  half  are  two  hollow  portions,  an  auricle  and  a 
ventricle  ;  these  on  the  same  side  communicate,  and  are  provided  with 
vessels  for  the  entrance  and  exit  of  the  blood.  On  the  surface  are  grooves 
indicatory  of  this  composition.  Thus,  passing  circularly  round  the  heart, 
nearer  the  base  than  the  apex,  is  a  groove  which  cuts  off  the  thin  auricular 
from  the  fleshy  ventricular  part.  A  longitudinal  sulcus  on  each  surface 
marks  the  situation  of  a  rqedian  partition  between  the  ventricles  :  this  sul- 
cus does  not  occupy  the  mid  space  either  on  the  anterior  or  the  posterior 
aspect,  but  it  is  nearer  the  left  border  of  the  heart  in  front,  and  the  right 
border  behind ;  so  that  most  of  the  anterior  suri'ace  is  formed  by  the  right, 
and  the  greater  part  of  the  posterior  surface  by  the  left  ventricle. 


COMPOSITION    OF    HEART. 


313 


The  auricles  are  two  (right  and  left)  and  receive  their  appellation  from 
the  resemblance  of  tlie  appendices  to  the  dog's  ears  :  they  are  placed  so 
deeply  at  the  base  of  the  heart,  that  only  the  tip  of  the  right  one  comes 
forwards  to  the  sternum.  The  auricles  are  much  thinner  than  the  ven- 
tricles. 


Diagram  showixo  the  Position  of  the  Heart  to  the  Ribs  and  Stkrncm,  the  soft  parts  being 
removed  from  the  exterior  of  the  thorax.    The  edge  of  each  luu^'  is  shown  by  a  dotted  line. 

The  ventricles  reach  unequal  distances  on  the  two  aspects  of  the  heart: 
thus  the  right  one  forms  the  thin  right  border  and  the  greater  part  of  the 
anterior  surface ;  but  the  left  enters  alone  into  the  apex,  and  constructs 
the  left  border,  and  most  of  the  posterior  surface  of  the  heart. 

Dissection.  Before  opening  the  heart  the  coronary  arteries  are  to  be  dis- 
sected on  the  surface,  with  the  small  nerves  and  veins  that  accompany 
them.  The  two  arteries  appear  on  the  sides  of  the  pulmonary  artery,  and 
occupy  the  grooves  on  the  surface  of  the  heart,  where  they  are  surrounded 
by  fat :  one  branches  over  the  right,  and  the  other  over  the  left  side.  With 
the  anterior  artery  is  a  plexus  of  nerves,  which  is  to  be  followed  upwards 
to  the  superficial  cardiac  plexus  ;  and  with  the  remaining  artery  another 
plexus  is  to  be  sought. 

In  the  groove  at  the  back  of  the  heart  between  the  auricles  and  ven- 
tricles, the  student  will  find  the  large  coronary  vein,  and  the  dilated  coro- 
nary sinus  in  which  it  ends  on  the  right:  the  last  should  be  defined  and 
followed  to  its  ending  in  the  right  auricle. 

The  coronary  arteries  are  two  small  vessels  which  are  so  named  from 
their  course  around  the  heart  :  they  are  the  first  branches  of  the  aorta. 
One  is  distributed  mostly  on  the  right,  and  the  other  on  the  left  side  of  the 
heart. 

The  right  coronary  brancli  appears  on  the  right  side  of  the  pulmonary 


314  DISSECTION    OF    THE    THORAX. 

artery,  and  is  directed  onwards  in  the  depression  between  the  right  auricle 
and  ventricle  to  end  in  the  left  half  of  the  heart  on  the  posterior  as[)ect. 
In  its  course  branches  are  distributed  upwards  and  downwards  to  the  right 
half  of  the  viscus.  Two  of  these  are  of  larger  size  than  the  rest :  one  runs 
on  the  anterior  as|)ect  of  the  right  ventricle  towards  the  free  margin  ;  the 
other  descends  on  the  back  of  the  heart  towards  the  apex,  along  the  septum 
between  the  ventricles. 

The  left  coronary  hr^iXich  is  inclined  behind  the  pulmonary  artery  to  the 
left  side  of  that  vessel,  and  in  the  groove  between  the  left  auricle  and  ven- 
tricle to  the  back  of  the  same  side  of  the  heart.  Like  the  preceding  artery, 
it  furnishes  offsets  to  the  substance  of  the  auricle  and  ventricle  of  its  side : 
the  largest  of  these  descends  in  the  anterior  sulcus  over  the  septum  ven- 
triculorum  towards  the  apex. 

The  veins  of  the  substance  of  the  heart  (cardiac)  are  not  the  same  in 
number,  nor  have  they  the  same  arrangement  as  the  arteries.  There  may 
be  said  to  be  three  sets,  but  for  the  most  part  they  are  collected  into  one 
large  trunk,  the  coronary  sinus,  which  opens  into  the  right  auricle. 

The  coronary  sinus  (fig.  99,  ^)  will  be  seen  on  raising  the  heart  to  be 
placed  in  the  sulcus  between  the  left  auricle  and  ventricle.  About  an  inch 
usually  in  extent,  it  is  joined  at  the  one  end  by  the  great  coronary  vein  (*) ; 
and  at  the  other  it  opens  into  the  right  auricle.  It  is  crossed  by  the  mus- 
cular fibres  of  the  left  auricle.  Inferiorly  and  at  its  right  end  it  receives 
some  branches  from  the  back  of  the  ventricles  (^  and  t) ;  and  nearly  at 
its  left  extremity  another  vein  (^), — the  oblique  vein  (Marshall),  which 
ascends  along  the  back  of  the  left  auricle. 

On  slitting  the  sinus  with  a  scissors  the  openings  of  its  different  veins 
will  be  seen  to  be  guarded  with  valves,  with  the  exception  of  the  oblique 
vein  ;  and  at  its  right  end  is  the  large  Thebesian  valve  of  the  right  auricle. 

The  great  cardiac  or  coronary  vein  begins  in  front  near  the  apex  of  the 
heart,  in  the  substance  of  the  ventricles.  The  vessel  turns  to  the  posterior 
surface  in  the  sulcus  between  the  left  auricle  and  ventricle,  and  opens  into 
the  coronary  sinus  (fig.  99,  *).  It  receives  collateral  branches  in  its  course, 
and  its  ending  in  the  sinus  is  marked  by  two  valves. 

Anterior  and  posterior  cardiac  veins.  Some  small  veins  on  the  ante- 
rior part  of  the  right  ventricle  open  separately,  by  one  or  more  trunks, 
into  the  lower  part  of  the  right  auricle.  Similar  small  veins  exist  over 
the  back  of  the  ventricles ;  and  one,  larger  than  the  rest,  lies  over  the 
septum  ventriculorum  :  they  enter  the  coronary  sinus  by  separate  valved 
openings. 

Smallest  cardiac.  A  third  set  of  veins  (venne  minima?)  lie  in  the  sub- 
stance of  the  heart,  and  are  noticed  in  the  description  of  the  right  auricle. 

Cardiac  nerves.  The  nerves  for  the  supply  of  the  iieart  are  derived  from 
a  large  plexus  (cardiac)  around  the  roots  of  the  aorta,  and  pulmonary  artery. 
Part  of  this  plexus  is  superficial  to  the  pulmonary  artery,  and  part  beneath  ; 
and  an  offset  is  sent  from  eacli  with  a  coronary  artery.  Only  the  superfi- 
cial part  of  the  plexus  can  now  be  seen. 

The  superficial  cardiac  plexus  is  placed  l)elow  the  arch  of  the  aorta, 
and  by  the  side  of  the  ductus  arteriosus.  The  nerves  joining  it  are  tiie 
left  superficial  cardiac  of  the  sympathetic,  the  lower  cardiac  of  the  left 
vagus  (p.  331),  and  a  considerable  bundle  from  the  deep  cardiac  plexus. 
A  small  ganglion  is  sometimes  seen  in  the  plexus.  Inferiorly  it  sends  off 
nerves  on  the  right  coronary  artery  to  the  heart.  A  few  filaments  pass  on 
the  left  division  of  the  pulmonary  artery  to  the  left  lung. 


NERVES    OF    HEART    SUBSTANCE. 


315 


The  right  coronary  nerves  pass  from  the  plexus  to  the  right  coronary- 
artery,  and  receive  near  the  heart  a  communicating  offset  from  the  deep 
cardiac  plexus. 

The  left  coronary  nerves  are  derived,  as  will  be  subsequently  seen  from 
the  deep  cardiac  plexus,  and  accompany  the  left  coronary  artery  to  the 
heart. 

At  first  the  nerves  surround  the  arteries,  but  they  soon  leave  the  vessels, 
and  becoming  smaller  by  subdivision,  are  lost  in  the  muscular  substance  of 

Fio:.  99. 


A,  Right  auricle. 

B.  Left  auricle,  with  the  auricula,  c. 

1.  Coronary  ainus. 

2,  Oblique  vein. 

.3.  Vein  from  the  right  side  of  the  heart. 
4.  Left  or  great  cardiac  vein, 
•f-f  Veins  joining  the  sinus  from  the  back  of  the 
ventricles. 


Back  of  the  Heart  with  the  Coronary  Sinus  and  its  Veins.     (Marshall.) 

the  ventricles.  On  and  in  the  substance  of  the  heart  the  nerves  are  marked 
by  small  ganglia. 

The  CAVITIES  OF  THE  HEART  may  be  examined  in  the  order  in  which 
the  current  of  the  blood  passes  through  them,  viz.,  right  auricle  and  ven- 
tricle, and  left  auricle  and  ventricle. 

Dissection.  In  the  examination  of  its  cavities  the  heart  is  not  to  be  re- 
moved from  the  body.  To  open  the  right  auricle,  an  incision  may  be  made 
in  it  near  the  right  or  free  border,  and  from  the  superior  cava  nearly  to  the 
inferior  cava;  from  tlie  centre  of  that  incision  the  knife  is  to  be  carried 
across  the  anterior  wall  to  the  auricula.  By  means  of  those  cuts  jin  open- 
ing will  be  made  of  sufficient  size  ;  and  on  removing  the  coagulated  blood, 
and  raising  the  flaps  with  hooks  or  pieces  of  string,  the  cavity  may  be  ex- 
amined. 

The  CAviTT  OF  THE  RIGHT  AURICLE  (fig.  100)  is  of  an  irregular  form, ^ 
though  when  seen  from  the  right  side,  with  the  flaps  held  up,  it  has  some- 
what the  appearance  of  a  cone,  with  the  base  to  the  right  and  the  apex 
below  and  to  the  left. 

The  base  or  wider  part  of  the  cavity  is  turned  towards  the  right  side, 

I  The  term  cavity  of  the  auricle  has  been  sometimes  applied  to  the  appendix,  and 
the  term  sinus  venosus  to  the  rest  of  the  space  here  named  auricle. 


316 


DISSECTION    OF    THE    THORAX 


and  its  extremities  are  the  openings  of  the  superior  and  inferior  cavre. 
Between  those  vessels  the  cavity  projects  a  little,  and  presents  a  sli^^ht 
elevation  in  some  bodies  (tubercle  of  Lower).  Tlie  apex  is  prolonged 
downwards  towards  the  junction  of  the  auricle  with  the  ventricle,  and  in 
it  is  the  opening  into  the  right  ventricular  cavity. 

The  anterior  wall  is  thin  and  loose.  Near  its  upper  part  is  an  opening 
leading  into  the  pouch  of  the  appendix  or  auricula  (//),  which  will  admit 
the  tip  of  the  little  finger.  Around  and  in  the  interior  of  the  ai)pendix, 
are  fleshy  bands,  named  musculi  pectinati,  which  run  mostly  in  a  ti-ans- 
verse  direction,  and  form  a  network  that  contrasts  with  the  general  smooth- 
ness of  the  auricle. 

Fig.  100. 


Upper  cava. 

Lower  cava. 

Right  auriculo-veutricular  opening. 

Fossa  ovalis. 

Opening  of  the  coronary  sinus. 

Foramina  Thebesii,  the  openings  of  veins. 

Aperture  of  the  pulmonary  artery. 


^       h.  Auricular  appendix. 


DlAQBAM  OF  THE  TWO  CAVITIES  OF  THE  RIGHT  SIDE  OF  THE  HEART. 


The  posterior  wall  corresponds  for  the  most  part  with  the  septum  be- 
tween the  auricles,  in  consequence  of  the  position  of  the  heart.  On  it, 
close  to  the  inferior  cava,  is  a  large  oval  depression,  tlie  fossa  ovalis  {d)^ 
which  is  the  remains  of  an  opening  between  the  auricles  in  the  foetus.  In- 
feriorly  it  merges  into  the  lower  cava.  A  thin  semi-transparent  structure 
forms  the  bottom  of  the  fossa  ;  and  there  is  oftentimes  a  small  oblique 
aperture  at  its  upper  part.  Around  the  upper  three-fourths  of  tliat  hollow 
is  an  elevated  band  of  muscular  fibre,  called  annulns  seu  isthmus  Vieus- 
senii,  wiiicli  is  most  prominent  above  and  on  the  left  side,  and  gradually 
subsides  inferiorly. 

Altogether  at  the  lower  part  of  the  posterior  wall  is  the  aperture  of  the 
coronary  sinus  (e).  Other  small  apertures  are  scattered  over  this  surface  : 
some  lead  only  into  depressions  ;  but  others  are  the  mouths  of  veins  of  the 
substance  of  the  heart  (venae  cordis  minimai),  and  are  named  foramina 
Tiiebesii  (/). 

Ti»e  chief  apertures  in  the  auricle  are  those  of  the  two  cavie,  coronary 
sinus,  and  ventricle.     The  opening  of  the  superior  cava  («),  is  in  the  front 


RIGHT    ATJRrCLE    OF    HEART.  817 

and  top  of  the  auricle,  and  its  direction  is  forwards.  The  inferior  cava  (b) 
enters  the  back  part  of  the  cavity  near  tlie  septum,  and  is  directed  back- 
wards to  the  fossa  ovalis  (d).  The  auriculo-ventricular  opening  (e)  is  the 
largest  of  all,  and  is  situate  at  the  lowest  part  of  the  cavity.  Between  this 
and  the  septum  is  placed  the  Opening  of  the  coronary  sinus  (e)  which  is 
about  as  large  as  a  turkey-quill. 

All  the  large  vessels,  except  the  superior  cava,  have  some  kind  of  valve. 
In  front  of  the  inferior  cava  is  a  thin  fold  of  the  lining  membrane  of  the 
cavity,  the  Eustachian  valve,  which  is  only  a  remnant  of  a  much  larger 
structure  in  the  foetus.  This  valve  in  its  perfect  state  is  semilunar  in  form, 
with  its  convex  margin  attached  to  the  anterior  wall  of  the  vein,  and  the 
other  free  in  the  cavity  of  the  auricle.  It  is  wider  than  the  vein  opening, 
and  its  surfaces  are  directed  forward  and  backwards  :  its  free  margin  is 
often  reticular.  The  aperture  of  the  coronary  sinus  is  closed  by  a  thin 
fold  of  the  lining  membrane — valve  of  Thebesius.  The  auriculo-ventricu- 
lar opening  will  be  seen,  in  examining  the  right  ventricle,  to  be  provided 
with  valves,  which  prevent  blood  running  back  into  the  auricular  cavity. 

In  the  adult  there  is  but  one  current  of  blood  in  the  right  auricle  towards 
the  ventricle.  But  in  the  foetus  there  are  two  streams  in  the  cavity  :  one 
of  pure,  and  the  other  of  impure  blood,  which  cross  one  another  in  early 
life,  but  become  more  commingled  as  birth  approaches.  The  placental  or 
pure  blood  entering  by  the  inferior  cava,  is  directed  by  the  Eustachian 
valve  chiefly  into  the  left  auricle,  through  the  foramen  ovale  in  the  sep- 
tum ;  whilst  the  current  of  systemic  or  impure  blood,  coming  in  by  the 
superior  cava,  flows  downwards  in  front  of  the  other  to  the  right  ventricle. 
Dissection.  To  see  the  cavity  of  the  right  ventricle,  the  student  should 
pierce  it  with  the  scalpel  below  the  opening  from  the  auricle,  and  cut  out 
interiorly  near  the  ai)ex  of  the  heart  without  injuring  the  septum  ventricu- 
lorum.  A  flap  is  thus  formed,  like  the  letter  V,  of  the  anterior  part  of  the 
ventricle.  In  the  examination  of  the  cavity  of  the  right  ventricle,  both 
the  flap  and  the  apex  of  the  heart  should  be  raised  with  hooks  or  string, 
so  that  the  space  may  be  looked  into  from  below. 

The  CAVITY  OF  THE  RiCrHT  VENTRICLE  (fig.  lOO)  is  triangular  in  form, 
and  has  the  base  turned  upwards  to  the  auricle  of  the  same  side.  On  a 
cross  section  the  cavity  would  appear  semilunar  in  shape,  with  the  sep- 
tum between  the  ventricles  convex  towards  the  cavity. 

The  apex  of  the  cavity  reaches  the  right  boi'der  of  the  heart  at  a  short 
distance  from  the  tip.  The  base  of  the  ventricle  is  sloped,  and  is  perfo- 
rated by  two  apertures  ;  one  of  these,  on  the  right,  leading  into  the  auri- 
cle, is  the  right  auriculo-ventricular  opening  (c)  ;  the  other  on  the  left, 
and  much  higher,  is  the  mouth  of  the  pulmonary  artery  (g).  The  part  of 
the  cavity  communicating  with  the  pulmonary  artery  is  funnel-shaped, 
and  is  named  infundibulum -or  conus  arteriosus. 

The  anterior  luall,  or  the  loose  part  of  the  ventricle,  is  comparatively 
thin,  and  forms  most  of  the  anterior  surface  of  the  ventricular  ijortion  of 
the  heart.  The  posterior  wall  corresponds  with  the  septum  between  the 
ventricles,  and  is  much  thicker. 

Over  the  greater  part  of  the  cavity  the  surface  is  irregular,  and  is  marked 
by  projecting  fleshy  bands  of  muscular  fibres,  the  coliimn(E  carnecB ;  but 
near  the  aperture  of  the  pulmonary  artery  the  wall  becomes  smooth.  The 
fleshy  columns  are  of  various  sizes,  and  of  three  different  kinds.  Some 
form  merely  a  prominence  in  the  ventricle,  as  on  the  septum.  Others  are 
attached  at  each  end,  but  free  in  the  middle  (trabeculae  carnea?).     And  a 


318  DISSECTION    OF    THE    THORAX. 

third  set,  which  are  fewer  in  number  and  much  the  largest,  project  into 
the  cavity,  and  form  rounded  bundles,  named  musculi  papiUares ;  these 
give  attachment  by  their  free  ends  to  the  little  tendinous  cords  of  the  valve 
of  the  auriculo- ventricular  opening. 

The  auriculo-ventricular  orifice  (c)  is  situate  in  the  base  of  the  ventri- 
cle, and  is  opposite  the  centre  of  the  sternum,  between  the  tliird  costal  car- 
tilages. It  is  slightly  larger  than  the  corresponding  aperture  of  the  left 
side  of  the  heart.  It  is  oval  from  side  to  side,  its  shape  being  maintained 
by  a  strong  fibrous  band  around  it ;  and  it  measures  one  inch  and  a  quar- 
ter in  diameter. 

Prolonged  from  the  circumference  of  the  opening  is  a  thin  membranous 
valve,  which  projects  into  the  cavity  of  the  ventricle.  Near  its  attach- 
ment to  the  heart  the  valve  is  undivided,  but  it  presents  three  chief  points 
at  its  lower  margin,  and  is  named  tricuspid ;  to  the  lower  margin  are 
attached  small  tendinous  cords  (chordae  tendineae),  which  unite  it  to  the 
muscular  bundles  of  th€  ventricle.  Its  three  slips  or  tongues  are  thus 
placed  : — one  touches  the  front  of  the  ventricle  ;  another  is  in  contact  with 
the  posterior  wall ;  and  the  remaining  slip,  the  largest  and  most  movable, 
is  interposed  between  the  aperture  into  tlie  auricle  and  pulmonary  artery. 

The  tricuspid  valve  is  constructed  by  the  lining  membrane  of  the  heart, 
which  incloses  fibrous  tissue.  The  central  part  of  each  tongue  is  strong, 
whilst  the  edges  are  thin  and  notched  ;  and  between  the  primary  pieces 
there  are  sometimes  secondary  points  (Kiirschner). 

The  chordce  tendince  which  keep  the  valve  in  position  ascend  from  the 
musculi  papillares  into  the  intervals  between  the  pieces  of  the  valve,  and 
are  connected  with  both.^  They  end  on  the  surface  of  the  valve  turned 
away  from  the  opening ; — some  reaching  the  attached  upper  margin  ; 
others  entering  the  central  thickened  part,  and  the  thin  edge  and  point 
of  the  tongue. 

As  the  blood  enters  the  cavity,  the  valve  is  raised  so  as  to  close  the 
opening  into  the  auricle ;  and  its  protrusion  into  the  other  cavity  during 
the  contraction  of  the  ventricle  is  arrested  by  the  small  tendinous  cords. 
The  valve  participates  in  the  production  of  the  first  sound  of  the  heart. 

The  mouth  of  the  pulmonary  artery  (ff)  will  be  seen  when  the  incision 
in  the  anterior  wall  of  the  .ventricle  is  prolonged  into  it.  Round  in  shape, 
it  is  situate  on  the  left  of  the  opening  into  the  auricle,  and  is  opposite  the 
inner  end  of  the  second  intercostal  space  of  the  left  side.  Its  diameter  is 
rather  less  than  an  inch.  Into  it  the  funnel-shaped  part  of  the  right  ventri- 
cle is  prolonged,  and  in  its  interior  are  tliree  semilunar  or  sigmoid  valves. 

Semilunar  valves.  Each  valve  is  attached  to  the  side  of  the  vessel  by 
its  convex  border ;  and  is  free  by  the  opposite  edge,  in  which  there  is  a 
slightly  thickened  nodule — the  corpus  Arantii.  In  the  wall  of  the  artery 
opposite  each  valve  is  a  slight  hollow,  the  sinus  of  Valsalva,  which  is 
better  marked  in  the  aorta. 

The  valves  resemble  the  tricuspid  in  structure,  for  they  are  formed  of 
fibrous  tissue  with  a  covering  of  the  lining  membrane.  In  each  valve  the 
fibres  have  this  arrangement :  there  is  one  band  along  the  attached  mar- 
gin ;  a  second  along  the  free  edge,  which  is  connected  with  the  projecting 
nodule  ;  and  a  third  set  of  fibres  is  directed  from  the  nodule  across  the 

'  The  papillary  muscles  are  collected  into  two  principal  groups,  whose  tendons 
enter  the  interval  on  each  side  of  the  anterior  tongue  of  the  valve.  In  the  inter- 
val between  the  left  and  posterior  segments  of  the  valve  the  tendinous  cords  are 
very  small,  and  are  connected  with  the  septum  ventriculorum. 


LEFT    VENTRICLE    OF    HEART. 


319 


Fig.  101. 


valve,  so  as  to  leave  a  semilunar  interval  on  each  side  near  the  free  edge, 
which  has  been  named  lunula. 

The  use  of  the  valves  is  obvious,  viz.,  to  give  free  passage  to  fluid  in 
one  direction,  and  to  prevent  its  return.  Whilst  the  blood  is  entering 
the  artery  the  valves  are  placed  against  the  wall ;  but  when  the  elasticity 
of  the  vessel  acts  on  the  contained  blood,  the  valves  are  thrown  towards 
the  centre  of  the  vessel,  and  arrest  the  flow  of  the  fluid  into  the  ven- 
tricle. They  are  concerned  also  in  giving  rise  to  the  second  sound  of  the 
heart. 

Dissection.  To  open  the  cavity  of  the  left  auricle  the  apex  of  the 
heart  is  to  be  raised,  and  a  cut  is  to  be  made  across  the  posterior  surface 
of  the  auricle  from  the  right  to  the  left  pulmonary  veins.  Another  short 
incision  should  be  made  downwards  at  right 
angles  to  the  first.  The  apex  of  the  heart 
must  necessarily  be  raised  during  the  exami- 
nation of  the  cavity. 

The  CAVITY  OF    THE    LEFT    AURICLE  (fig. 

101)  is  smaller  than  that  of  the  right  side. 
Irregularly  conical  in  shape,  the  wider  part 
is  turned  towards  the  spinal  column,  and  re- 
ceives the  pulmonary  veins ;  and  the  nar- 
rowed part  (l)  opens  inferiorly  into  the  left 
ventricle. 

On  the  left  side  towards  the  upper  part,  is 
the  aperture  of  the  pouch  of  the  auricula  (m), 
which  is  narrower  than  that  in  the  right  au- 
ricle. In  the  interior  of  the  pouch,  as  well 
as  around  the  entrance,  are  fleshy  fibres  (mus- 
culi  pectinati)  which  resemble  those  before 
seen  in  the  other  auricle. 

On  the  part  of  the  wall  corresponding  w^th 
the  septum  auricularum,  is  a  superficial  fossa 
(fig.  101,  o),  the  remains  of  the  oval  aperture 
through  that  partition ;  this  is  bounded  below 
by  a  projecting  ridge,  concave  upwards,  which 

valve  that 


is  the  edge  of  the   structure  or 

closed  the  opening  in  the  foetus.     This  im- 


DlAffRAM  OP  THB  TWO  CAVITIRS  OP 
THB  LEFT  SIDE  OP  THE  HeAET. 

Tt.  Left  pulmonary  veins. 
i.    Riffht  pulmonary  veins. 

0.  Remains  of  the  foramen  ovale. 

1.  Left  auriculo-ventriciilar  open- 
ing. 

m.  Auricular  appendix. 
n.  Aperture  of  the  aorta. 


pression  in  the  left  auricle  is  above  the  fossa 
ovalis  in  the  right  cavity,  because  the  aper- 
ture between  the  two  in  the  foetus  is  an  oblique 
canal  through  the  septum. 

The  apertures  in  this  auricle  are  those  of 
the  four  pulmonary  veins,  two  on  each  side, 

together  with  the  opening  of  communication  with  the  left  ventricle.  The 
mouths  of  each  pair  of  pulmonary  veins  are  close  to  one  another;  those  from 
the  right  lung  (^)  open  into  the  extreme  right  of  the  auricle  near  the  sep- 
tum, and  those  from  the  left  lung  {h)  enter  the  opposite  part  of  the  cavity, 
near  the  auricula. 

The  pulmonary  veins  are  not  provided  with  valves.  The  aperture  into 
the  ventricle  (/)  will  be  subsequently  seen  to  have  a  large  and  complicated 
valve  to  guard  it,  as  on  the  right  side. 

In  the  adult  the  blood  enters  this  cavity  from  the  lungs  by  the  pulmo- 
nary veins,  and  passes  to  the  left  ventricle  by  the  large  inferior  opening 


320  DISSECTION    OF    THE    THORAX. 

between  the  two.  In  the  foetus  the  lungs  are  impervious  to  the  air  and 
the  mass  of  the  circulating  fluid ;  and  the  left  auricle  receives  its  pure 
blood  at  once  from  the  right  auricle  through  the  aperture  in  the  se[)tum 
(foramen  ovale). 

Dissection.  The  left  ventricle  may  be  opened  by  an  incision  along 
both  the  anterior  and  the  posterior  surface,  near  the  septum  ;  these  are 
to  be  joined  to  the  apex,  but  are  not  to  be  extended  upwards  so  as  to 
reach  the  auricle.  On  raising  the  triangular  flap  the  interior  of  the  cavity 
will  be  visible. 

The  CAVITY  OF  THE  LEFT  VENTRICLE  (fig.  101)  is  longer,  and  more 
conical  in  shape  than  that  of  the  opposite  ventricle ;  and  is  over  or  almost 
circular,  on  a  transverse  section. 

The  apex  of  the  cavity  reaches  the  apex  of  the  heart.  The  hase  is 
turned  towards  the  auricle,  and  is  not  sloi)ed  like  that  of  the  right  ventri- 
cle; in  it  are  the  openings  into  the  aorta  (/*)  and  the  left  auricle  (/). 

The  walls  of  this  ventricle  are  thickest,  and  the  anterior  boundary  is 
formed  by  the  septum  ventriculorum. 

Its  surface  is  irregular,  like  that  of  the  right  ventricle,  in  consequence 
of  the  projections  of  the  fleshy  columns,  or  carneae  column:ie ;  but  near  the 
great  artery  (aorta)  the  surface  is  smoother.  There  are  three  sets  of 
fleshy  columns  ir  this  as  in  the  right  ventricle.  But  the  set  (musculi 
papillares),  whicli  project  into  the  cavity,  and  receive  the  small  tendinous 
threads  of  the  valve,  are  the  most  marked:  these  are  arranged  chiefly  in 
two  large  bundles,  and  spring  from  the  anterior  and  posterior  walls  of  the 
cavity. 

The  aperture  into  the  left  auricle  (I)  (auriculo-ventricular)  is  placed 
beneath  the  orifice  of  the  aorta,  but  close  to  it,  only  a  thin  fibrous  band 
intervening  between  the  two.  It  is  rather  smaller  than  the  corresponding 
aperture  of  the  right  side,  being  somewhat  more  than  an  inch  in  diameter, 
and  is  longest  in  the  transverse  direction.  Placed,  as  before  said,  beneath 
the  aortic  aperture,  it  extends  also  to  the  right,  so  as  to  lie  beneath  the 
left  extremity  of  the  right  auriculo-ventricular  opening.  It  is  furnished 
with  a  membranous  valve  (mitral)  which  projects  into  the  ventricle. 

The  mitral  valve  is  stronger  and  of  greater  length  than  the  tricuspid, 
and  has  also  firmer  and  more  tendinous  cords:  it  takes  its  name  from  a 
fancied  resemblance  to  a  mitre.  Attached  to  a  fibrous  ring  around  the 
aperture,  as  well  as  to  the  aortic  fibrous  ring,  it  is  divided  below  by  a 
notch  on  each  side  into  two  pieces.  Its  segments  lie  one  before  another, 
with  their  edges  directed  to  the  sides,  and  their  surfaces  towards  the 
front  and  back  of  the  cavity.  The  anterior  tongue  of  the  valve  intervenes 
between  the  auricular  and  aortic  openings,  and  is  larger  and  looser  than 
the  posterior  segment. 

The  mitral  resembles  the  tricuspid  valve  in  its  structure  and  oflice.  Its 
segments  consist  of  thicker  and  tiiinner  parts;  and  in  the  notches  at  the 
sides  there  are  also  secondary  pieces  between  the  two  primary  segments. 
The  tendinous  cords  ascend  to  be  attached  to  the  valve  in  the  notches 
between  the  tongues;  and  they  end  on  the  segments  in  the  same  way  as 
in  the  tricuspid  valve.  Piach  of  the  large  papillary  muscles  acts  on  both 
j)ortions  of  the  valve. 

When  the  blood  enters  the  cavity,  the  pieces  of  the  valve  are  raised  as 
on  the  right  side,  and  meet  to  close  the  passage  into  the  left  auricle.  In 
combination  with  the  tricusi)id  it  assists  in  producing  the  first  sound  of  the 
heart. 


STRUCTURE    OF    THE    HEART.  321 

The  opening  of  the  aorta^  anterior  to  that  of  the  auricle,  is  next  the 
septum  of  the  ventricles.  Its  aperture  is  round,  and  rather  smaller  than 
that  of  the  pulmonary  artery,  and  measures  about  three-quarters  of  an  inch 
in  diameter.  It  is  situate  opposite  the  inner  end  of  the  third  left  intercos- 
tal space. 

In  its  interior  are  three  semilunar  or  sigmoid  valves^  which  are  larger 
and  stronger  than  the  corresponding  parts  in  the  pulmonary  artery,  but 
have  a  like  structure  and  attachment.  The  projection  in  the  centre  of 
each  valve,  viz.,  the  corpus  Arantii,  is  better  marked.  Opposite  each 
valve  the  coat  of  the  aorta  is  bulged  as  in  the  pulmonary  artery,  though 
in  a  greater  degree,  and  presents  a  little  hollow  on  the  inner  side,  named 
sinus  of  Valsalva.  The  apertures  of  the  coronary  arteries  are  placed 
behind  two  of  the  valves. 

Like  the  valves  in  the  pulmonary  artery  these  meet  in  the  middle  line 
to  stop  the  blood  passing  back  into  the  ventricle,  and  combine  with  them 
in  causing  the  second  sound  of  the  heart. 

Position  of  the  ventricular  apertures.  Two  openings  have  been  seen 
in  each  ventricle — one  of  the  auricle  of  its  own  side  of  the  heart,  and  one 
of  an  artery. 

The  apertures  of  the  arteries  (aorta  and  pulmonary)  are  nearest  the 
septum ;  and  as  the  two  vessels  were  originally  formed  from  one  tube, 
they  are  close  together,  but  the  pulmonary  artery  is  the  more  anterior  of 
the  two.  The  aperture  of  communication  with  each  auricle  is  nearer  the 
circumference  of  the  heart,  and  is  posterior  to  the  artery  issuing  from  the 
fore  part  of  the  ventricle. 

The  position  of  tlie  openings  to  one  another  from  before  backwards  has 
been  before  referred  to,  viz.,  the  right  is  partly  before  the  left  auriculo- 
ventricular;  and  the  opening  of  the  pulmonary  artery  is  anterior  to  tliat 
of  the  aorta,  and  rather  higher  than  it. 

Structure.  The  heart  is  composed  of  strata  of  muscular  fibres,  and 
of  certain  fibrous  rings  with  a  fibro-cartilage. 

The  structure  may  be  studied  in  the  heart  of  the  sheep  or  ox,  in  which 
the  fibres  have  been  hardened  and  the  connective  tissue  destroyed  by  boil- 
ing, so  as  to  allow  of  the  fibres  being  separated.  The  description  of  the 
structure  of  the  heart  may  be  omitted  by  the  student  till  a  suitable  prepara- 
tion of  the  fibres  can  be  made. 

The  fibrous  structure  forms  rings  around  the  auriculo- ventricular  and 
arterial  orifices,  and  is  prolonged  into  the  valves  connected  with  those 
openings. 

The  auriculo-ventricular  rings  give  attachment  to  the  framework  of 
fibrous  tissue  in  the  tricuspid  and  mitral  valves.  They  are  distinct  from  the 
bands  encircling  the  mouths  of  the  arteries,  except  at  the  front  of  the  left 
auriculo-ventricular  opening,  where'the  auricular  and  arterial  circles  blend. 

An  arterial  ring  surrounds  each  large  artery  (aort  i  and  pulmonary), 
fixing  those  vessels,  and  giving  attachment  to  some  muscular  fibres.  It 
is  a  circular  band,  with  three  notches  in  the  margin  towards  the  artery; 
these  are  filled  by  corresponding  projections  of  the  artery,  and  give  attach- 
ment internally  to  the  sigmoid  valves  along  their  semilunar  edges. 

The  artery  is  connected  with  the  band  of  fibrous  tissue  in  the  following 
manner: — Its  middle  coat  presents  three  projections,  which  are  received 
into  the  notches  of  the  fibrous  ring,  being  joined  thereto  by  fibrous  tissue ; 
and  the  junction  between  the  two  is  strengthened  externally  by  the  outer 
arterial  coat  and  the  pericardium,  and  internally  by  the  endocardium. 
21 


322 


DISSECTION    OF    THE    THORAX. 


Fig.  102. 


Behind  the  aortic  aperture,  between  it  and  the  aiiriciilo-ventricnlar 
orifices,  is  a  piece  oi  Jibro-cartilage^  with  which  the  fibrous  rings  are 
united. 

The  muscular  fibres  belong  to  the  invohjntary  class,  though  marked 
with  transverse  stria?,  and  form  concentric  layers,  which  inclose  the 
cardiac  cavities.  In  the  auricles  the  fibres  are  separate  from  those  in  the 
ventricles. 

In  the  wall  of  the  auricles  the  fibres  are  mostly  transverse  (fig.  102,  a), 
and  are  best  marked  at  the  lower  part,  though  they  form  tliere  but  a  thin 
layer;  and  some  of  the  fibres  dip  into  tlie  septum  between  the  auricular 
cavities.  Besides  this  set  there  are  annular  fibres  around  the  appendages 
of  the  auricles,  and  the  endings  of  the  different  veins.  Lastly  a  few 
oblique  fibres  (c  and  d)  pass  upwards  over  the  auricles  both  in  front  and 
behind. 

Dissection.  The  auricles  having  been  learnt,  separate  them  from  tlie 
ventricles  by  dividing  the  fibrous  auriculo-ventricular  rings.     Next  clean 

the  fleshy  fibres  of  the  ventricles  by 
removing  all  the  fat  from  the  base  of 
tlie  heart  around  the  two  arteries 
(aorta  and  pulmonary),  and  from  the 
anterior  and  posterior  surfaces. 

Before  cutting  into  the  heart  let  the 
student  note  that  tlie  anterior  surface 
is  to  be  recognized  by  the  fibres  turning 
in  at  the  septum,  with  the  exception 
of  a  small  band  above  about  half  an  inch 
wide  ;  and  that  at  the  posterior  aspect 
the  fibres  are  continued  from  the  left 
to  the  right  ventricle  aross  the  septum. 
Separate  partly  the  ventricles  in  front 
along  the  septum  by  dividing  the  band 
near  the  base,  and  sinking  the  knife 
for  about  an  inch  into  the  groove  be- 
tween them.  Disjoin  then  the  aorta 
and  pulmonary  artery  along  the  mid- 
dle line,  so  as  to  leave  one  attached  to 
each  ventricle  as  in  fig.  103. 

To  show  the  laminar  composition  of 
the  left  ventricle  divide  its  fibres  in 
front  longitudinally  near  the  septum, 
and  transversely  about  half  an  inch 
below  the  left  auriculo-ventricular 
opening ;  but  the  cut  is  to  be  very 
shallow,  because  seven  layers,  each 
about  as  thick  as  the  thin  end  of  the 


Muscui.ATi  Fibres  of  the  Aukicles. 
Inferior  cava,  aud  e,  superior  cava  of  the 

right  auricle. 
Right,  and  /*,  left  pnlmonaiy  veins  of  the 

left  auricle. 
Transverse  fibres  of  the  right,  and  6, 

:transverse   fibres    of    the  left  auricle, 

entering  the  septum  auricularum. 
Oblique  fibres  of  the  left,  and  d,  of  the 

right  auricle.     Annular  fibres  surround 

the  auriculae  and  the  veins. 


scalpel,  are  to  be  demonstrated.  From 
the  lines  of  incision  reflect  the  different  layers  downwards  to  the  apex, 
upwards  to  the  auriculo-ventricular  aperture,  and  backwards  into  the 
septum.  As  the  layers  are  raised  the  fleshy  fibres  will  be  seen  to  change 
their  direction  ;  and  the  outer  three  to  be  thinner  than  the  three  internal. 
The  LEFT  VENTRICLE  is  a  hollow  cone,  and  its  wall  is  formed  of  layers 
of  fibres,  as  if  a  flat  muscle  had  been  rolled  up  into  a  conical  figure  (fig. 
103).     Seven  layers  enter  into  the  construction  of  the  wall ;  and  they  are 


VENTRICULAR    FIBRES    OF    HEART. 


323 


Fi?.  103. 


arranged  into  three  external  (1,  2,  3),  three  internal  (7,  6,  5),  and  a 
central  one  (4).  All  are  not  prolonged  equal  distances  on  the  ventricle, 
for  the  outermost  and  the  innermost  reach  fartliest  towards  apex  and  base  ; 
and  the  second  external  and  its  corresponding  inner  layer  (sixth)  extend 
farther  than  the  third  and  the  fifth. 
The  fourtJi  is  the  shortest  of  all. 
Consequently  the  wall  is  thickest 
about  the  middle  third  where  all  the 
layers  are  present,  and  gradually  be- 
comes thinner  upwards  and  down- 
w^ards,  until  there  is  only  the  outmost 
layer  at  the  a[)ex,  and  tlie  most  ex- 
ternal and  internal  (1st  and  7th)  at 
the  base.  (Dr.  Pettigrew,  Phil. 
Trans.  1864.) 

Direction  of  the  fibres.  Each 
stratum  is  formed  of  fleshy  fibres  with 
the  undermentioned  direction,  sup- 
posing the  ventricle  standing  on  the 
apex,  and  the  anterior  surface  towards 
.  the  dissector. 

In  the  three  external  strata  (1,  2, 
3)  the  fibres  are  inclined  dow^nwards 
from  the  base  and  septum  to  tiie  apex 
of  the  ventricle,  and  become  less 
vertical  in  each. 

The  fourth  or  mid  layer  (4)  pos- 
sesses transverse  fibres ;  and  it  is 
nearer  the  outer  than  the  inner  surface 
of  the  wall. 

In  the  three  inner  strata  the  fibres  change  their  direction,  as  is  shown 
by  5,  and  are  directed  upwards  from  the  apex  and  septum  to  tlie  base  of 
the  ventricle  ;  so  that  they  cross  the  fibres  of  the  outer  layers  like  the  legs 
of  the  letter  X,  and,  becoming  more  oblique  in  each  layer,  are  almost 
vertical  in  the  internal. 

Continuity  of  the  fibres.  With  a  piece  of  muscle  rolled  into  a  cone,  as 
before  said,  the  fibres  of  the  different  layers  would  be  necessarily  continu- 
ous at  the  apex  ;  but  in  the  heart  they  are  united  at  apex  and  base.  Thus 
the  outermost  layer  is  continuous  at  tlie  apex  and  base  with  the  innermost, 
the  fibres  being  curved  in  at  the  tip  and  out  at  the  base.  In  like  manner 
the  fibres  of  the  second  layer  are  unitel  with  those  of  the  sixth,  and  the 
third  stratum  with  the  fiftli.  From  the  three  outer  layers,  fibres  are  con- 
tinued to  the  right  ventricle  at  the  back  of  the  heart,  forming  the  "  com- 
mon fibres." 

Each  of  the  three  outer  layers  consists  of  two  sets  of  fibres,  which  occupy 
the  front  and  back  of  the  ventricle.  By  the  turning  inwards  of  the  two 
bundles  on  opposite  sides  of  the  apex,  the  wall  is  prevented  from  having 
a  slanting  side,  like  a  piece  of  paper  rolled  into  a  cone.  And  by  the  turn- 
ing outwards  of  two  sets  of  fibres  (anterior  and  posterior)  at  the  base  of 
the  ventricle  from  each  inner  layer,  the  sides  of  the  auriculo-ventricular 
opening  are  made  level  like  those  of  the  apex.  Many  of  the  fibres  of  the 
outer  layers  are  attached  to  the  fibrous  ring  around  the  aorta. 


A   Diagram  of  the  arrangement  of  the 
Fibres  in  Layers  in  the  Left  Vkntki- 

CLE. 

1.  First  or  external  layer. 

2.  Second  external. 

3.  Third  external. 

4.  Central  layer. 

6.  The  oiitermost  of  the  three  inner  strata. 


824  DISSECTION    OF    THE    THORAX. 

The  fibres  of  the  fourth  layer  are  continued  into  the  septum  ventri- 
culorum. 

Dissection.  To  display  the  layers  and  fibres  of  the  right  ventricle, 
great  care  will  le  needed  because  of  the  thinness  of  the  wall ;  but  the 
same  number  of  layers  exists   in  this,  as  on  the  other  side  of  the  heart. 

Make  a  vertical  cut  along  the  anterior  aspect  from  the  root  of  the  pul- 
monary artery  to  the  a|  ex  of  the  ventricle;  and  reflect  the  several  layers 
forwards  and  backwards  from  that  incision.  As  the  three  outer  are  raised 
let  them  be  traced  on  the  one  hand  into  the  part  of  the  septum  detached 
from  the  left  ventricle ;  and  on  the  other  into  the  left  ventricle  through 
the  continuity  of  the  common  fibres  behind. 

The  RIGHT  VENTRICLE  posscsscs  sevcu  layers  in  its  wall,  like  the  left, 
though  they  are  much  thinner.  They  are  arranged  as  in  the  other  ven- 
tricle into  three  external,  three  internal,  and  a  fourth  or  intermediate.  In 
like  manner  the  wall  decreases  from  the  centre  towards  the  base  and  apex, 
but  at  the  tip  it  is  thicker  than  the  apex  of  the  left  half  of  the  heart 
(Pettigrew). 

Directions  of  the  fibres.  In  this  as  in  the  other  ventricle,  the  fibres  of 
the  three  outer  layers  run  down  from  the  base  to  the  fore  part  of  the  sep- 
tum and  the  apex  of  the  heart :  the  outer  being  most  vertical.  In  the 
fourth  stratum  the  fibres  have  a  transverse  direction,  as  in  the  correspond- 
ing layer  of  the  left  ventricle.  And  in  the  three  inner  layers  they  are 
directed  upwards  from  the  apex  to  the  base  of  the  ventricle  across  the 
fibres  of  the  three  outer  strata,  the  deepest  being  the  most  vertical. 

Continuity  of  the  fibres.  The  fibres  are  not  distinct  from  those  of  the 
left  ventricle,  but  are  derived  in  the  three  outer  layers  from  the  "  common 
fibres"  and  the  septum,  and  from  the  auriculo-ventricular  opening.  They 
are  then  continued  forwards  to  the  front  of  the  septum  ventriculorum, 
where  they  leave  the  surface,  and  bending  back  construct  the  right  part  of 
the  septum  :  at  the  back  of  that  ])artition  they  blend  with  the  "  common 
fibres"  of  the  left  ventricle.  The  fourth  layer  fibres  are  continuous  for 
the  most  part  with  the  "  common  fibres"  crossing  the  posterior  groove. 
At  the  apex  the  three  cuter  layers  do  not  enter  in  a  whorl  as  in  the  left 
ventricle  ;  but  at  the  base  they  are  continuous  with  the  three  inner  as  on 
the  other  side  of  the  heart. 

Many  of  the  fibres  of  the  external  layer  are  attached  to  the  ring  of  the 
pulmonary  artery ;  and  the  narrow  slip  from  the  right  to  the  left  ventricle, 
near  the  base  in  front,  receives  its  fibres  from  the  two  outer  strata. 

In  this  ventricle  the  fibres  are  arranged  as  if  there  had  been  originally 
one  common  cavity  in  the  heart — the  leit  ventricle,  from  which  the  right 
had  been  detached  during  the  growth  by  a  pushing  inwards  of  a  partition 
from  the  fore  part. 

Septum  ventriculorum.  This  partition  between  the  two  cavities  has 
been  divided  anteriorly  into  right  and  left  jiarts  by  the  previous  dissection  ; 
and  the  layers  of  the  ventricles  may  be  traced  into  them. 

It  is  rather  thicker  than  the  wall  of  the  left  ventricle,  and  is  formed  by 
the  fibres  of  both  ventricles.  About  one-third  belongs  to  the  right,  and 
two-thirds  to  the  left  ventricle.  Where  the  two  portions  touch  the  fibres 
mingle,  and  altogether  behind  lie  the  "  common  fibres"  of  the  two  ven- 
tricles. 

Endocardium.  Lining  the  interior  of  the  cavities  of  the  heart  is  a  thin 
membrane,  which  is  named  endocardium.  It  is  continuous  on  the  one 
hand  with  the  lining  of  the  veins,  and  on  the  other  with  that  of  the  arteries. 


PULMONARY    ARTERY.  325 

Where  the  ni'^mbrane  passes  from  an  a'lriele  to  a  ventricle,  or  from  a  ven- 
tricle to  an  artery,  it  forms  duplicatures  or  valves,  in  which  fibrous  tissue 
is  inclosed  ;  and  in  the  ventricles  it  covers  the  tendinous  cords  of  the 
valves,  and  the  projecting;  muscular  bundles. 

The  thickness  of  the  membrane  is  greater  in  the  auricles  than  in  the 
ventricles,  and  in  the  left  than  in  the  right  half  of  the  heart.  In  its  struc- 
ture it  resembles  a  serous  membrane. 

Grea-T  Vessels  of  the  Heart.  The  arteries  which  take  origin  from 
the  heart  are  tlie  aorta  and  the  pulmonary.  The  large  veins  entering  the 
heart,  besides  the  coronary,  are  the  superior  and  inferior  cava,  and  the 
pulmonary. 

The  PULMONARY  ARTERY  is  a  short  thick  trunk,  which  conveys  the 
dark  or  impure  blood  from  the  right  side  of  the  heart  to  the  lungs.  From 
its  commencement  in  the  right  ventricle  the  vessel  is  directed  upwards  on 
the  left  of  the  aorta  ;  and  at  a  distance  of  an  inch  and  a  half  or  two  inches, 
it  divides  into  two  branches  of  nearly  equal  size  for  the  lungs.  The  trunk 
of  the  pulmonary  artery  is  contained  in  the  pericardium  ;  and  beneath  it 
is  the  beginning  of  the  aorta.  On  each  side  are  the  coronary  artery  and 
the  auricular  appendix. 

Fig.  104. 


The  Formation  of  the  Septum  Ventricclorum  by  the  Fibres  of  both  Vextricles 
IS  represented  in  this  cut. 

Near  the  bifurcation  of  the  artery  is  a  ligamentous  cord  about  as  large 
as  a  crow-quill,  the  remnant  of  the  arterial  duct,  which  passes  from  the 
left  branch  of  the  vessel  to  the  arch  of  the  aorta,  and  is  named  ligamentam 
ductus  arteriosi. 

The  right  branch  is  longer  than  the  left.  In  its  course  to  the  lung  it 
lies  beneath  the  aorta  and  the  vena  cava  superior,  and  rests  on  the  bron- 
chus or  piece  of  the  air  tube  :  and  as  it  passes  outwards  it  lies  above  the 
level  of  the  right  auricle  of  the  heart.  At  the  lung  the  artery  divides 
into  three  primary  branches,  one  for  each  lobe. 

The  left  branch  is  rather  smaller  than  the  right ;  it  is  directed  in  front 
of  the  descending  aorta  and  the  left  bronchus  to  the  fissure  of  the  root  of 
the  lung,  where  it  ends  in  two  branches  for  the  two  pulmonic  lobes. 


326 


DISSECTION    OF    THE    THORAX. 


As  the  riglit  and  left  branches  of  the  pulmonary  artery  pass  outwards, 
they  cross  the  air-tubes  resulting  from  the  division  of  the  trachea,  and 
inclose  with  them  a  lozenge-shaped  si)ace  which  contains  some  bronchial 
glands. 

Ductus  arteriosus.  The  ligamentous  structure  was  the  continuation  in 
the  fcctus  of  the  trunk  of  the  [)ulmonary  artery,  and  was  larger  than  either 
branch  to  the  lung.  At  that  period  the  vessel  receives  the  name  arterial 
canal  or  duct  (ductus  arteriosus,  Botalli),  and  opens  into  the  aorta  rather 
beyond  the  origin  of  the  last  great  vessel  of  the  head  and  neck  from  the 
arch. 

As  the  lungs  do  not  give  passage  to  the  circulating  fluid  before  birth, 
the  impure  blood  in  the  pulmonary  artery  passes  through  the  arterial  duct 
into  the  aorta  below  the  attachment  of  the  vessels  of  the  head  and  neck, 
in  order  that  it  may  be  transmitted  to  the  placenta  to  be  purified.  But 
after  birth,  when  the  function  of  the  lungs  is  established,  the  current  of 
blood  is  directed  along  the  branches  of  the  pulmonary  artery  instead  of 
through  the  arterial  duct  ;  and  this  tube  becoming  gradually  smaller,  is 
obliterated  before  the  eighth  or  tenth  day,  and  forms  finally  the  ligament 
of  the  arterial  duct. 

The  AORTA  is  the  great  systemic  vessel  which  conveys  the  blood  from 
the  heart  to  the  different  parts  of  the  body.  It  {irches  backwards  at  first 
to  reach  the  spinal  column,  and  is  continued  on  the  spine  through  the  chest 
and  abdomen.  In  the  thorax  the  vessel  is  divided  into  two  parts — arch 
of  the  aorta,  and  the  descending  or  thoracic  aorta. 

Arch  of  the  aorta  (fig.  105).  The  aorta  has  its  origin  in  the  left  ventri- 
cle, and  curving  backwards  over  the  windpipe  and  tlie  gullet,  forms  an 

Fig.  105. 


a.  Aortic  arch. 

b.  Innoiuinate  artery. 

c.  Left  common  carotid. 

d.  Lett  subclavian. 

e.  Ligameiitum  ductus  arteriosi. 
/.  Veua  cava  superior. 

g.  Left  innominate  vein. 

h.  Right  innominate  vein. 

i.  Left  upper  intercostal  vein. 

k.  Vena  azygos  major. 

I.  Left  subclavian  vein. 

n.  Thoracic  duct. 

o.  Coronary  artery. 


Arch  of  the  Aokta  and  its  Great  Vessels. 


arch  which  ceases  on  the  left  side  of  the  spinal  column,  at  the  lower  bor- 
der of  the  fifth  dorsal  vertebra.  The  arcli  has  its  convexity  upwards  and 
to  the  riglit,  and  its  concavity  to  the  root  of  the  left  lung ;  and  from  it  the 
large  vessels  for  the  sup[)ly  of  the  upper  part  of  the  body  take  their  origin. 
For  the  purpose  of  reducing  to  order  the  numerous  connections  of  this 


AORTIC    ARCH    AND    BRANCHES.  327 

portion  of  the  aorta,  it  is  divided  into  three  parts — ascending,  transverse, 
and  descending. 

The  Jirst  or  ascending  part  is  about  two  inches  in  length,  or  slightly- 
more,  and  is  directed  upwards  behind,  and  close  to  the  sternum  :  it  reaches 
as  high  as  the  upper  border  of  the  cartilage  of  the  second  rib  on  the  right 
side,  and  is  contained  nearly  altogether  in  the  pericardium.  At  first  the 
pulmonary  artery  is  superficial  to  it ;  but,  as  the  vessels  take  different 
directions,  the  aorta  is  soon  uncovered,  and  remains  so  to  its  termination. 
Behind  it  are  the  right  branches  of  the  pulmonary  vessels.  On  the  right 
side  is  the  descending  cava ;  and  on  the  left,  the  pulmonary  artery.  Near 
ttie  heart  the  vessel  bulges  opposite  the  semilunar  valves  (fig.  105).  There 
is  sometimes  another  dilatation  along  the  right  side,  which  is  named  the 
great  sinus  of  the  aorta. 

The  second  or  transverse  portion  recedes  from  the  sternum  and  reaches 
from  the  second  riglit  costal  cartilage  to  the  left  side  of  the  body  of  the 
fourth  dorsal  vertebra  (tlie  lower  border).  It  rests  upon  the  trachea  above 
the  bifurcation,  and  is  phiced  over  the  ojsophagus  and  the  thoracic  duct. 
Lying  in  front  of  this  part  of  the  artery  are  the  vagus,  phrenic,  and  super- 
ficial cardiac  nerves  of  the  left  side — the  first  nerve  sending  bacliwards  its 
recurrrent  branch  beneatii  tl»e  vessel.  Along  the  upper  border  is  the  left 
innominate  vein  ((/),  to  which  the  left  upper  intercostal  vein  (i)  is  directed 
over  the  left  part  of  the  arch  ;  and  to  the  lower  border  near  the  termina- 
tion, the  remnant  of  the  arterial  duct  (e)  is  attached.  From  tliis  part 
arise  the  three  great  vessels  of  the  head  and  upper  limbs. 

The  third  or  descending  part  of  the  arch  is  very  short,  extending  from 
the  lower  edge  of  the  fourth  to  tliat  of  the  fifth  dorsal  vertebra.'  It  lies 
against  the  fifth  vertebra,  and  the  fibro-cartilage  between  this  and  the 
fourth,  and  is  covered  by  the  pleura  of  the  left  side  of  the  chest. 

In  tlie  concavity  of  the  arch  of  the  aorta  are  contained  the  root  of  the 
left  lung,  the  branching  of  the  pulmonary  artery  with  its  arterial  duct,  and 
the  left  recurrent  nerve.  Deeper  than  those  parts,  the  cesophagus  and  the 
thoracic  duct,  with  some  lymphatic  glands,  may  be  recognized. 

Tlie  branches  of  the  arch  of  the  aorta  are  five  in  number;  two  come 
from  the  ascending,  and  three  from  the  transverse  part.  The  first  two 
are  the  coronary  arteries  of  the  heart  (o),  which  have  been  already  no- 
ticed (p.  313).  The  other  three  are  much  larger  in  size,  and  supply  the 
neck,  tiie  head,  and  the  upper  limbs.  First  on  the  right  is  the  large  trunk 
of  the  innominate  artery  (b)  ;  close  to  it  is  the  left  carotid  (c)  ;  and  last  of 
all  comes  the  left  subclavian  (d). 

The  INNOMINATE  ARTERY  (b)  (brachio-ccphalic),  the  first  and  largest 
of  the  three  branches,  measures  from  one  incli  and  a  half  to  two  inches  in 
length.  Ascending  to  the  right  beneath  the  sternum,  it  divides  opposite 
the  sterno-clavicular  articulation  into  the  right  common  carotid  and  the 
subclavian  artery. 

The  artery  is  crossed  by  the  left  innominate  vein  (-7),  and  li^s  beliind 
the  upper  piece  of  the  sternum,  and  the  origin  of  the  hyoid  and  tliyi'oid 
muscles.     At  first  it  rests  on  the  trachea,  but  as  it  ascends  it  is  placed  on 

I  It  is  usually  said  that  the  second  part  of  the  aortic  arch  ends  opposite  the  left 
side  of  the  body  of  the  second  dorsal  vertebra,  and  the  third  part,  opposite  the 
lower  edge  of  the  third  vertebra.  After  examination,  I  have  adopted  the  state- 
ment of  Mr.  Wood  respecting  the  position  of  the  aortic  arch  to  the  dorsal  vertebrre. 
(Journal  of  Anatomy  and  Physiology  for  1868.) 


328  DISSECTION    OF    THE    THORAX. 

the  right  side  of  the  air  tube.     On  its  right  is  the  innominate  vein  of  tlie 
same  side  (//).     Usually  no  lateral  branch  arises  from  tiie  artery. 

Left  Common  Carotid  Artery  (c).  The  common  carotid  artery  of 
the  left  side  of  the  neck  is  longer  tlian  the  right  by  the  distance  between 
the  jirch  and  the  top  of  the  sternum. 

In  the  thorax  the  artery  ascends  obliquely  to  the  left  sterno-davicuhir 
articulation,  but  not  close  to  the  first  piece  of  the  sternum  and  the  origin 
of  the  depressor  muscles  of  the  hyoid  bone  and  hirynx.  In  this  course  it 
passes  beneath  the  left  innominate  vein  (g),  and  the  remains  of  the  tliymus 
gland.  At  first  it  lies  on  the  trachea,  but  it  crosses  afterwards  to  the  left 
of  that  tube,  so  as  to  be  placed  over  the  oesophagus  and  the  thoracic  ducff. 
To  its  outer  side  is  the  left  vagus,  with  one  or  more  cardiac  branches  of 
the  sympathetic  nerve. 

In  the  neck  the  connections  of  the  vessels  of  opposite  sides  are  not  the 
same  (p.  120). 

The  LEFT  SUBCLAVIAN  ARTERY  (c?)  asccuds  to  the  neck  through  the 
upper  aperture  of  the  thorax.  Beyond  the  first  rib  the  vessels  of  opposite 
sides  are  alike  (p.  118). 

The  trunk  is  directed  almost  vertically  from  the  arch  of  the  aorta  to  the 
inner  margin  of  the  first  rib.  In  the  thorax  the  vessel  lies  deeply,  resting 
at  first  on  the  oesophagus,  and  afterwards  on  the  vertebral  column  and 
the  longus  colli  muscle.  It  is  invested  by  the  left  pleural  bag  in  all 
its  extent.  On  its  inner  side  is  the  trachea,  and  near  the  upper  opening 
of  the  thorax  the  o3sophagus  with  the  thoracic  duct  is  inside  it.  Some- 
what anterior  to  the  level  of  the  artery,  though  running  in  the  same  direc- 
tion, are  some  of  the  cardiac  nerves. 

Veins  of  the  Heart  (fig.  105).  In  addition  to  the  cardiac  veins  (p. 
314)  there  are  the  superior  and  inferior  cava,  and  the  pulmonary  veins  : 
the  former  are  the  great  systemic  vessels  which  return  impure  blood  to 
the  right  auricle  ;  and  the  latter  convey  pure  blood  from  the  lungs  into  the 
left  auricle. 

The  superior  or  descending  cava  (  /')  results  from  the  union  of  the 
right  and  left  innominate  veins,  and  brings  to  the  heart  the  blood  of  the 
head  and  neck,  upper  limbs,  and  thorax. 

Its  origin  is  placed  on  the  right  side  of  the  sternum,  opposite  the  interval 
between  the  cartilages  of  the  first  two  ribs.  From  that  spot  the  large  vein 
descends  to  the  pericardium,  perforates  the  fibrous  layer  of  that  bag  about 
one  inch  and  a  half  above  the  heart,  and  ends  in  the  right  auricle.  On 
its  outer  surface  the  vein  is  covered  by  the  pleura,  and  the  phrenic  nerve 
is  in  contact  with  it.  To  the  inner  side  is  tlie  ascending  part  of  the  arch 
of  the  aorta.     Behind  the  vein  is  the  root  of  the  right  lung. 

When  the  cava  is  about  to  perforate  the  pericardium  it  is  joined  by  the 
large  azygos  vein  of  the  thorax  (k) ;  and  higher  up  it  receives  small  veins 
from  the  pericardium,  and  the  parts  in  the  mediastinal  space. 

The  innominate  veins  are  united  inferiorly  in  the  trunk  of  the  descend- 
ing cava.  They  are  two  in  number,  right  and  left ;  and  each  is  formed 
near  the  inner  end  of  the  clavicle,  by  the  union  of  the  subclavian  and  in- 
ternal jugular  veins.  The  trunks  difier  in  length  and  direction,  and  in 
their  connections  with  the  surrounding  parts. 

The  right  vein  (//)  is  about  one  inch  and  a  half  long,  and  descends  ver- 
tically, on  the  right  side  of  the  innominate  artery,  to  its  junction  with  the 
vein  of  the  opposite  side.  On  the  outer  surface  the  pleura  covers  it,  and 
along  it  the  phrenic  nerve  is  placed. 


CAVA    AND    INNOMINATE    VEINS.  329 

The  left  vein  (g)  is  twice  as  long  as  the  right,  and  is  directed  obliquely 
downwards  above  the  level  of  the  arch  of  the  aorta.  It  crosses  behind  the 
sternum,  and  the  remains  of  tlie  thymus  gland ;  and  it  lies  on  the  three 
large  branches  of  the  aortic  arch,  as  well  as  on  the  several  nerves  descend- 
ing over  the  arch. 

The  branches  of  the  veins  are  nearly  alike  on  the  two  sides.  Each  re- 
ceives the  internal  mammary,  the  inferior  thyroid,  and  the  superior  inter- 
costal of  its  own  side  ;  and  the  left  vein  is  joined  in  addition  by  some 
small  thymic  and  pericardiac  veins. 

Sometimes  the  innominate  veins  are  not  united  in  the  vena  cava,  but 
descend  separately  to  the  heart,  where  each  has  a  distinct  opening  in  the 
right  auricle.  When  such  a  condition  exists,  the  right  vein  takes  the 
course  of  the  upper  cava  in  front  of  the  root  of  the  right  lung  ;  but  th(^  left 
vein  descends  in  front  of  the  root  of  the  left  lung,  and  turning  to  the  back 
of  the  heart,  receives  the  cardiac  veins,  before  it  opens  into  the  right 
auricle.     A  cross  branch  connects  the  two  above  the  heart. ^ 

This  occasional  condition  in  the  adult  is  a  regular  one  in  a  very  early 
period  of  the  growth  of  the  foetus ;  and  two  vessels  are  also  persistent  in 
some  mammalia. 

Change  of  the  two  veins  into  one.  The  changes  taking  place  in  the  veins  during 
the  growth  of  the  foetus,  to  produce  the  arrangement  common  in  the  adult,  con- 
cern the  trunk  on  the  left  side.  The  following  is  an  outline  of  them.  First  the 
cross  branch  between  the  two  trunks  enlarges,  and  forms  the  future  left  innomi- 
nate vein.  Next  the  left  trunk  below  the  cross  branch  disappears  at  its  middle, 
and  undergoes  transformations  at  each  end  : — At  the  upper  end  it  becomes  con- 
verted into  the  superior  intercostal  vein.  At  the  lower  part  it  remains  pervious 
for  a  short  distance  as  the  coronary  sinus  ;  and  even  the  small  oblique  vein  open- 
ing into  the  end  of  that  sinus  in  the  adult  (p.  314),  is  a  remnant  of  the  trunk  of 
the  vein  that  lay  beneath  the  heart. 

In  the  adult  there  is  a  vestige  of  the  occluded  vessel  in  the  form  of  a  fold  of  the 
serous  membrane  of  the  pericardium  in  front  of  the  root  of  the  left  lung  ;  this  Mr. 
Marshall  names  the  vestigial  fold  of  the  pericardium  (p.  311). 2 

The  INFERIOR  or  ascending  cava  enters  the  right  auricle  as  soon  as 
it  has  pierced  the  diaphragm.  No  branches  join  the  vein  in  the  thorax. 
The  anatomy  of  this  vein  will  be  given  with  the  vessels  of  the  abdomen. 

The  PULMONARY  VEINS  are  two  on  each  side.  They  issue  from  the 
fissure  of  the  root  of  the  lung,  and  end  in  the  left  auricle  :  their  position 
to  the  other  vessels  of  the  root  has  been  noticed  at  p.  310. 

The  right  veins  are  longer  than  the  left,  and  lie  beneath  the  aorta  and 
the  right  auricle  of  the  heart.  The  superior  receives  its  roots  from  the 
upper  and  middle  pulmonic  lobes,  and  the  inferior  vein  is  formed  by 
branches  of  the  lower  lobe. 

The  left  veins  cross  in  front  of  the  descending  aorta;  and  one  springs 
from  each  lobe  of  the  luns:. 


NERVES  OF  THE  THORAX. 

The  pneumogastric  and  the  sympathetic  nerves  supply  the  viscera  of  the 
thorax.     Through  the  cavity  courses  the  phrenic  nerve  to  the  diaphragm. 

'  An  example  of  tvvo  large  vessels,  '*  double  vena  cava,"  opening  into  the  right 
auricle  in  the  adult,  is  contained  in  the  Museum  of  University  College. 

2  See  a  paper  by  Mr.  Marshall  on  the  development  of  the  veins  of  the  neck 
(Philosoph.  Transac,  1850). 


830  DISSECTION    OF    THE    THORAX. 

Dissection.  The  phrenic  nerve  is  sufficiently  denuded  for  its  examina- 
tion ;  but  the  student  should  trace  the  vagus  nerves  through  the  thorax. 

The  vagus  is  to  be  followed,  on  both  sides,  behind  tlie  root  of  the  lung, 
and  its  large  plexus  in  that  position  is  to  be  dissected  out :  a  few  filaments 
of  the  gangliated  cord  of  the  sympathetic  coming  forwards  over  tlie  S[)inal 
column  to  the  plexus,  nuist  be  looked  for.  In  front  of  the  root  on  tlie  left 
side,  the  nerve  sup|)lies  a  few  pulmonary  filaments.  Beyond  the  root  tlie 
vagus  is  to  be  pursued  along  the  oesophagus  by  raising  the  lung  and  re- 
moving the  pleura. 

The  PHRENIC  NERVE  IS  a  branch  of  the  cervical  plexus  (p.  80).  In  its 
course  through  the  thorax  it  lies  along  the  side  of  the  pericardium,  and  at 
a  little  distance  in  front  of  the  root  of  the  lung,  with  a  small  companion 
artery.  When  near  the  diaphragm  it  is  divided  into  branches  ;  these  per- 
forate the  muscle,  and  are  distributed  on  the  under  surface.  The  nerves 
of  opposite  sides  differ  in  length,  and  in  their  connections  above  the  root 
of  the  lung. 

The  right  nerve  is  deeper  at  first,  and  is  also  shorter  and  straighter  than 
the  left.  In  entering  the  chest  it  crosses  behind  the  subclavian  vein,  but 
in  front  of  the  internal  mammary  artery  ;  and  it  lies  afterwards  along  the 
right  side  of  the  innominate  vein  and  superior  cava  till  it  reaches  the  root 
of  the  lung. 

The  left  nerve  crosses  the  subclavian  artery,  but  has  the  same  position 
as  the  right  to  the  mammary  vessels  when  entering  the  cavity.  In  the 
thorax  it  is  directed  in  front  of  the  arch  of  the  aorta  to  the  root  of  the 
lung,  and  makes  a  curve  lower  down  around  the  projecting  heart.  Before 
reaching  the  aorta  the  nerve  is  placed  external  to  the  left  common  carotid 
artery;  and  crosses  the  left  vagus  from  without  inwards,  so  as  to  be  inter- 
nal to  that  nerve  on  the  arch. 

Branches.  Some  small  filaments  are  said  to  be  furnished  from  the 
nerve  to  the  pleura  and  pericardium. 

Internal  mammary  artery.  A  small  part  of  this  artery,  which  lies  be- 
neath the  first  rib,  and  winds  round  the  phrenic  nerve  and  the  innominate 
vein  to  reach  the  side  of  the  sternum,  is  now  to  be  learnt.  It  gives  the 
following  offset : — 

The  superior  phrenic  branch  (comes  nervi  phrenici)  is  a  very  slender 
artery,  which  accompanies  the  phrenic  nerve  to  the  diaphragm,  and  is  dis- 
tributed to  that  muscle,  anastomosing  therein  with  other  branches  of  the 
aorta,  and  with  the  musculo-phrenic  branch  of  the  internal  mammary  (p.  239). 

Tlie  PNEUMOGASTRic  NERVE  (p.  181)  passcs  through  the  thorax  to  the 
abdomen.  In  the  lower  part  of  the  thorax  the  nerves  of  opposite  sides 
have  a  similar  {)osition,  for  they  pass  behind  the  root  of  the  lung,  each  on 
its  own  side,  and  along  the  oesophagus  to  the  stomach.  But  above  the 
root  of  the  lung,  the  right  and  left  nerves  differ  much.  Each  su[)plies 
branchvis  to  the  viscera,  viz.,  to  the  heart,  the  windpipe  and  lungs,  and 
the  gullet. 

The  right  vagus  is  posterior  to  the  left  in  position.  It  enters  the  tho- 
rax between  the  subclavian  artery  and  the  innominate  vein,  and  is  directed 
oblicjuely  backwards,  by  the  side  of  the  trachea,  and  between  this  tube 
and  the  oesophagus,  to  the  posterior  aspect  of  the  root  of  the  lung,  where  it 
gives  rise  to  the  posterior  pulmonary  plexus.  From  the  plexus  two  large 
offsets  are  continued  to  the  back  of  the  gullet,  and  unite  below  into  one 
trunk,  which  reaches  the  j)Osterior  surface  of  the  stomach. 

The  left  nerve  appears  in  the  thorax  on  the  outer  side  of  the  left  com- 


VAGUS  NERVE  AND  BRANCHES.  331 

mon  carotid  artery,  and  courses  over  the  arch  of  the  aorta,  and  beneath 
the  root  of  the  lung,  forming  there  a  larger  ph^xus  tlian  on  the  right  side. 
From  the  pulmonic  plexus  one  or  two  branches  pass  to  the  front  of  tiie 
cEsophagus,  and  join  with  offsets  of  the  right  nerve  in  a  plexus  ;  but  its 
piec(!S  are  collected  finally  into  one  trunk,  which  is  continued  on  the  front 
of  the  gullet  to  the  anterior  part  of  the  stomach. 

The  branches  of  the  pneumo-gastric  nerve  in  the  thorax  are  the  follow- 
ing :_ 

a.  The  recurrent  or  inferior  laryngeal  nerve,  arising  on  the  riglit  side 
on  a  level  with  the  subclavian  artery,  and  on  the  left,  at  the  lower  border 
of  tlie  arch  of  the  aorta,  bends  backwards  to  the  trachea,  along  which  it 
ascends  to  the  larynx.  On  each  side  this  branch  is  freely  connected  with 
the  cervical  cardiac  branches  of  the  sympathetic  nerve,  especially  on  the 
left  side  beneath  the  arch  of  the  aorta. 

b.  Cardiac  branches  (thoracic).  Besides  the  cardiac  branches  furnished 
by  the  vagus  in  the  neck,  other  offsets  pass  in  front  of  the  trachea  to  the 
cardiac  plexus.  On  the  right  side  they  come  from  the  trunk  of  the  vagus 
and  the  recurrent  branch,  but  they  are  supplied  by  the  recurrent  nerve 
alone  on  the  left  side. 

Ttie  termination  of  the  lower  cervical  cardiac  branch  of  each  vagus 
nerve  (p.  114)  may  be  now  seen.  The  branch  of  the  right  lies  by  the 
side  of  the  innominate  artery,  and  joins  a  cardiac  nerve  of  the  sympathetic 
of  the  same  side  ;  and  the  branch  of  the  left  vagus  crosses  over  the  arch 
of  the  aorta,  to  end  in  the  superficial  cardiac  plexus. 

c.  Pulmonary  branches.  There  are  two  sets  of  nerves  for  the  lung, 
one  on  the  anterior  and  the  other  on  the  posterior  aspect  of  the  root. 

The  anterior  branches  are  two  or  three  in  number,  and  small  in  size,  and 
communicate  with  filaments  of  the  sympathetic  on  the  pulmonary  artery  : 
these  nerves  are  best  seen  on  the  left  side. 

The  posterior  branches  are  the  largest  and  much  the  most  numerous. 
Forming  a  plexiform  arrangement  (posterior  pulmonary  plexus)  behind 
the  root  of  tlie  lung  by  the  flattening  and  splitting  of  tlie  trunk  of  the 
nerve,  they  are  joined  by  filaments  from  the  tliird  and  fourth  ganglia  of 
the  knotted  cord  of  the  sympathetic,  and  are  conveyed  into  the  lung  on 
the  divisions  of  the  air  tube. 

d.  (Esophageal  branches  are  furnislied  to  the  gullet,  but  in  greatest 
abundance  in  the  lower  half.  Below  the  root  of  the  lung  the  branches  of 
the  pneumo-gastric  nerves  surround  the  oesophagus  with  a  network  (j)lexus 
gulce). 

Sympathetic  Nerve.  In  the  thorax  the  sympathetic  nerve  consists 
of  a  knotted  cord  along  each  side  of  the  spinal  column,  which  communi- 
cates with  the  spinal  nerves  :  and  of  a  large  prevertebral  or  cardiac  plexus, 
which  distributes  branches  to  the  heart  and  the  lungs. 

The  gangliated  cord  will  be  seen  in  a  future  stage  of  the  dissection  after 
the  heart  and  the  lungs  have  been  removed. 

The  CARDIAC  PLEXUS  Hes  at  the  base  of  the  heart  around  the  great 
bloodvessels.  A  part  of  this  network,  the  superficial  cardiac  plexus,  has 
been  already  described  (p.  314).  The  remaining  part,  or  the  deep  cardiac 
plexus,  is  placed  beneath  the  arch  of  tlie  aorta. 

Dissections.  The  cardiac  plexus  has  been  injured  by  the  previous  ex- 
amination of  tlie  heart,  so  that  it  should  be  dissected  in  a  body  in  which 
the  heart  and  the  large  vessels  are  entire. 

Dissection.     The  arch  of  the  aorta  is  to  be  cut  across  near   the  lieart 


832  DISSECTION    OF    THE    THORAX. 

and  close  above  the  pulmonary  artery,  and  is  to  be  drawn  over  to  the  left 
side :  next  the  upper  cava  is  to  be  divided  above  the  entrance  of  the  vena 
azygos,  and  its  lower  part  is  to  be  thrown  down.  By  the  removal  of  some 
fibrous  and  fatty  tissues  and  lymphatic  glands,  tiie  rigiit  part  of  the  plexus, 
in  which  the  nerves  of  the  right  side  are  united,  will  be  seen  in  front  of  the 
trachea,  above  the  right  branch  of  the  pulmonary  artery.  The  offsets  to 
the  heart  should  be  followed  downwards  on  the  trunk  of  the  pulmonary 
artery  ;  and  those  to  the  lung  should  be  traced  along  the  right  branch  of 
that  vessel. 

To  lay  bare  the  part  of  the  plexus  into  which  the  nerves  of  the  left  side 
of  the  body  enter,  the  arch  is  to  be  cut  through  a  second  time,  to  the 
right  of  and  close  to  the  junction  of  the  ligamentum  arteriosum  with  it ; 
and  the  transverse  part  of  the  arch  is  to  be  turned  upwards  with  the  great 
vessels  attached.  The  lymphatic  glands  and  the  areolar  and  fatty  tissue 
being  cleared  away  from  the  plexus  as  on  the  opposite  side,  the  offsets  to 
the  posterior  coronary  plexus  of  the  heart  are  to  be  cleaned. 

Deej)  cardiac  plexus.  This  large  centre  is  situate  between  the  trachea 
and  the  arch  of  the  aorta,  above  the  branches  of  tlie  pulmonary  artery. 
In  it  are  united  the  cardiac  nerves  of  the  sympathetic  of  both  sides  of  the 
neck,  except  the  highest  nerve  of  the  left  side  :  and  the  cardiac  branches 
of  the  vagus  in  the  neck  and  chest,  with  the  exception  of  the  lowest 
cervical  branch  of  the  left  side.  From  it  nerves  are  furnished  to  the  heart 
and  lungs. 

The  several  nerves  entering  the  plexus  are  not  intermingled  in  a  plexi- 
form  mass  in  front  of  the  trachea  ;  but  those  of  the  right  side  unite 
together  on  the  right  of  the  air  tube,  and  those  of  the  left  have  a  like 
junction  on  their  side. 

The  right  part  of  the  plexus  is  placed  above  the  riglit  branch  of  the 
pulmonary  artery,  and  receives  the  nerves  of  the  right  side,  viz.,  the  car- 
diac nerves  of  the  sympathetic  in  the  neck  ;  the  cardiac  branches  of  the 
trunk  of  the  vagus,  in  both  the  neck  and  chest ;  and  the  cardiac  offsets  of 
the  recurrent  branch. 

The  branches  of  this  half  of  the  plexus  are  distributed  mostly  to  the 
right  side  of  the  heart,  and  pass  downwards  before  and  behind  the  right 
branch  of  the  pulmonary  artery  :  those  in  front  running  on  the  trunk  of 
the  pulmonary  artery  to  end  in  the  anterior  coronary  plexus  (p.  31o)  ;  and 
the  nerves  behind  supply  the  right  auricle  of  the  heart.  Offsets  are  sent 
laterally  on  the  branch  of  the  artery  to  the  root  of  the  lung. 

The  left  half  of  the  plexus  lies  close  to  the  ligamentum  arteriosum,  and 
rather  on  the  left  of  the  trachea.  In  it  are  collected  the  cardiac  nerves  of 
the  sympathetic  ganglia  of  the  left  side  of  the  neck,  except  the  highest ; 
and  numerous  and  large  branches  of  the  left  recurrent  nerve  of  the  vagus. 

Nerves  descend  from  it  to  the  heart  around  the  left  branch  and  trunk  of 
the  pulmonary  artery,  and  after  sup[)lying  branches  to  the  left  auricle,  ter- 
minate in  the  posterior  coronary  plexus  (p.  31.5).  A  considerable  offset  is 
directed  forwards  by  the  side  of  the  ligamentum  ductus  arteriosi  to  the 
su[)erficial  cardiac  plexus ;  and  some  nerves  reach  the  left  anterior  pulmo- 
nary plexus  by  [)assing  along  the  branch  of  the  pulmonary  artery. 

Termination  of  the  cardiac  branches  of  the  sympathetic  nerve  of  the 
neck  (p.  117). 

On  the  right  side  there  are  usually  only  two  cardiac  nerves  entering  the 
thorax,  for  the  highest  nerve  is  blended  commonly  with  one  of  the  others. 
The  middle  and  inferior  nerves  pass  beneath  the  subclavian  artery  to  the 


TRACHEA  AND  BRONCHI.  383 

riglit  half  of  the  deep  plexus  :  they  communicate  with  the  branches  of  the 
recurrent  laryngeal  nerve  of  the  vagus. 

On  the  left  side  the  highest  cardiac  nerve  lies  over  the  arch  of  the 
aorta,  and  ends  in  the  superficial  cardiac  plexus;  it  may  give  a  branch 
beneath  the  arch  to  the  deep  plexus.  Only  one  other  nerve,  the  lower 
cardiac,  may  be  seen  entering  the  left  side  of  the  deep  plexus,  as  the  mid- 
dle one  throws  itself  oftentimes  into  it. 


THE  TRACHEA  AND  THE  LUNG. 

Dissection.  To  see  the  pieces  of  the  air  tube  in  the  root  of  the  lung,  it 
will  be  necessary  to  remove  the  pu'monary  artery  with  its  branches,  and 
the  pulmonary  veins.  And  when  the  transverse  part  of  the  arch  of  the 
aorta,  which  has  been  already  cut  through,  is  turned  to  one  side,  the  dis- 
sector will  be  able  to  clear  away  the  bronchial  glands,  the  nerves,  and  the 
fibrous  tissue  from  the  part  of  the  trachea  in  the  thorax,  and  from  the 
branches  into  which  it  bifurcates. 

The  TRACHEA,  or  the  air  tube,  reaches  from  the  larynx  to  the  lungs, 
and  lies  on  the  front  of  tlie  spinal  column.  The  tube  begins  opposite  the 
fifth  cervical  vertebra  ;  and  it  ends  commonly  at  the  iburth  dorsal  vertebra 
by  dividing  into  two  pieces  (bronchi),  one  ibr  each  lung.  Its  point  of 
splitting  niiiy  be  a  vertebra  lower. 

Its  connections  in  the  neck  are  described  in  p.  121,  and  its  structure  in 
p.  162.     The  part  in  the  thorax  remains  to  be  studied. 

In  the  thorax  tlie  trachea  is  situate  witli  the  great  vessels  in  the  space 
between  the  pleural  bags.  Here  it  is  covered  by  the  arch  of  the  aorta,  by 
the  innominate  and  left  carotid  arteries,  and  by  the  cardiac  plexus  of 
nerves.  Behind  the  air  tube  is  the  oesophagus,  which  is  slightly  inclined 
to  the  left  near  the  arch  of  the  aorta.  On  the  right  side  are  the  vagus, 
and  the  innominate  artery,  for  a  short  distance,  alter  this  has  passed  over 
the  trachea ;  and  on  the  left  side  lie  the  left  subclavian  artery,  and  the 
vagus  with  its  recurrent  branch. 

The  bronchi^  or  the  branches  of  the  air  tube,  are  contained  in  the  roots 
of  the  lungs,  and  are  surrounded  by  vessels,  glands,  and  nerves.  Near  the 
lung  each  is  divided  into  as  many  primary  })ieces  as  there  are  lobes.  In 
their  structure  and  form  the  bronchi  resemble  the  windpipe,  for  they  are 
round  and  cartilaginous  in  front,  but  flat  and  muscular  find  membranous 
behind.  Their  position  behind  the  other  pulmonary  vessels  has  been  de- 
scribed at  p.  310  ;  but  the  characters  of  each  are  now  to  be  noticed. 

Tlie  right  branch  is  about  an  inch  in  length,  and  is  larger  than  the  left  ; 
it  passes  outwards,  on  a  level  with  the  fourth  dorsal  vertebra,  beneath  the 
arch  of  the  aorta  and  the  upper  cava,  and  above  the  right  pulmonary 
artery :  the  vena  azygos  arches  above  it. 

The  lejt  branch,  about  two  inches  long,  is  directed  obliquely  downwards 
through  the  arch  of  the  aorta,  and  joins  the  root  of  the  left  lung  a  vertebra 
lower  than  on  the  opposite  side.  Tlie  tube  lies  on  the  oesophagus  and 
thoracic  duct,  and  on  the  aorta ;  it  is  at  first  below  the  level  of  the  corre- 
sponding pulmonary  artery. 

Dissection.  The  lungs  are  to  be  removed  now  from  the  body  by  cutting 
through  the  vessels  of  the  root. 

The  remains  of  the  heart  and  pericardium  are  to  be  taken  away  after- 
wards. P'or  their  removal  the  inferior  cava  is  to  be  divided,  and  the  peri- 
cardium to  be  detached  from  the  surface  of  the  diaphragm  ;  in  removing 


834  DISSECTION    OF    THE    THORAX. 

the  pericardium,  the  dissector  should   be   careful  not  to   injure  the  parts 
contained  in  the  interpleural  space  in  front  of  the  spine. 

Physical  Characters  of  the  Lung.  The  surface  of  the  lung  is 
smooth  and  shining,  and  is  invested  by  the  pleura.  Through  the  serous 
covering  the  mass  of  the  lung  may  be  seen  to  be  divided  by  septa,  into 
small  irregularly-sized  pieces  or  lobules.  On  looking  closely  at  it,  espe- 
cially at  a  tliin  margin,  minute  cells  will  be  perceived  in  it. 

The  tint  of  the  lung  varies  with  age.  In  infancy  the  color  is  a  pale 
red;  but  in  the  adult  the  texture  becomes  grayish,  and  presents  here  and 
there  dark  gray  spots  or  lines  of  pigment,  whose  siiade  deepens  with  in- 
creasing age,  and  becomes  even  black  in  old  people.  After  death,  the 
color  of  the  posterior  border  may  be  bluish-black  from  the  accumulation  of 
blood. 

To  the  touch  the  lung  is  soft  and  yielding,  and  on  a  section  the  pulmo- 
nary substance  appears  porous  and  spongy  ;  but  the  lung  which  is  deprived 
of  air  by  pressure  has  a  tough  leathery  feel.  Slight  pressure  with  the 
thumb  and  finger  drives  the  air  from  the  containing  cells  through  the  pul- 
monary structure,  and  produces  tlie  noise  known  as  crepitation.  If  the 
lung  contains  serum,  a  frothy  red  fluid  will  run  out  when  it  is  cut. 

The  texture  of  the  lung  is  very  elastic ;  this  elasticity  causing  the  organ 
to  diminish  greatly  when  the  thorax  is  opened,  and  to  expel  air  that  may 
be  blown  into  it. 

The  specific  gravity  of  the  lung  varies  with  the  conditions  of  dilatation 
and  collapse,  or  of  infiltration  witii  fluid.  When  the  pulmonary  substance 
is  free  from  fluid,  and  filled  with  air,  it  floats  in  water;  but  when  it  is 
quite  deprived  of  air  it  is  slightly  heavier  than  water,  and  sinks  in  that 
fluid.  The  weight  of  the  lung  is  influenced  greatly  by  the  quantity  of 
other  material  contained  in  its  texture;  ordinarily  it  ranges  from  eighteen 
to  twenty-one  ounces,  and  the  right  lung  is  about  two  ounces  heavier  tlian 
the  left.  In  the  male  the  lungs  are  larger,  and  slightly  heavier  than  in 
the  female. 

Dissection.  By  tracing  the  large  branches  of  the  bronchi,  and  the 
bloodvessels  and  nerves  into  the  lung,  the  mode  of  branching  of  the  air 
tubes  will  be  apparent;  and  by  inflating  a  part  of  the  lung,  the  cellular 
structure  may  be  seen.  But  the  arrangement  of  the  small  air  cells  about 
their  tube,  and  the  disposition  of  the  different  vessels,  cannot  be  ascer- 
tained without  fine  injections  and  a  microscope. 

Structure  of  the  Lung.  The  spongy  pulmonary  tissue  consists  of 
minute  recesses  or  cells,  in  which  the  smallest  branches  of  the  air  tube 
terminate ;  and  the  mass  of  the  lung  is  formed  by  the  collection  of  those 
cells  into  small  groups  or  lobules,  and  by  the  aggregation  of  the  lobules 
into  larger  masses  or  lobes.  Each  lobule  is  distinct  from  its  fellows,  and 
is  furnished  witii  its  air  tube  and  nerves,  and  with  its  set  of  vessels  con- 
cerned in  the  function  and  nutrition. 

The  parts  of  the  lung  are  united  by  a  serous  covering,  prolonged  con- 
tinuously over  tlie  surface;  and  by  a  subserous  layer  of  areolar  tissue 
wliich  penetrates  into  the  anterior,  subdividing  it  into  pieces.  These 
several  parts  are  examined  more  in  detail  below. 

Serous  and  subserous  coverings.  The  casing  derived  from  the  pleura 
is  thin  and  transparent,  and  forms  an  entire  capsule  for  the  lung,  except 
at  the  root  where  the  vessels  enter.  The  subserous  areolar  layer  contains 
fibres  of  elastic  tissue,  and  not  only  covers  the  surface,  but  extends  in- 


STRUCTURE    OF    LUNG.  335 

wards,  establishing  tlie  division  of  the  mass  into  lobules:  where  it  sepa- 
rates the  lobules  it  is  named  interlobular  tissue,  and  is  free  from  fat. 

Bronchial  branches  in  the  lung.  When  a  bronchus  is  followed  into 
the  pulmonary  structure  it  is  found  to  divide  generally  in  a  binary  order, 
and  to  diminish  in  size  at  each  subdivision,  until  one  terminal  offset  ap- 
pertains to  a  lobule.  In  the  lobule  the  tube  has  a  diameter  of  g^^  to  -r^-^  of 
an  inch.  When  this  last  degree  of  diminution  is  reached,  the  tube  gives 
origin  to  the  air  cells. 

The  larger  bronchial  branches  have  the  same  composition  as  the  trachea, 
but  they  are  round  in  the  lung,  instead  of  being  semi-elliptical  as  in  the 
trachea.  The  smallest  branches  want  some  of  the  elements  found  in  the 
larger  bronchi ;  and  those  from  which  the  cells  spring  are  irregular  in 
shape,  appearing  to  be  spaces  amongst  the  cells  rather  than  tubes  with 
continuous  walls. 

Changes  in  the  bronchi.  The  modifications  of  the  component  parts  of 
the  bronchi  are  the  following: — The  pieces  of  cartilage  are  broken  up  in 
the  smaller  bronchial  tubes,  and  are  scattered  over  the  wall  as  irregular 
fragments.  Becoming  thinner  and  smaller  as  the  subdivision  of  the  air 
tube  proceeds,  they  at  last  disapi)ear,  -and  are  absent  from  the  terminal 
branches.  The  Jlbrotis  and  elastic  tissues  of  the  bronchial  tubes  are  con- 
tinued to  the  air  cells,  but  in  the  small  cell-bearing  branches,  the  bundles 
of  elastic  tissue  are  diffused,  and,  much  diminished  in  strength,  blend  with 
the  fibrous  or  areolar  tissue  to  form  the  wall.  The  muscular  fibres  are 
diffused  over  the  inner  surface  of  the  smaller  bronchi,  where  they  have  an 
annular  arrangement;  they  extend  beyond  the  limit  of  the  pieces  of  carti- 
lage, but  they  cease  where  the  cells  begin  to  be  formed.  The  mucous 
membrane  becomes  thinner  as  it  extends  onwards  in  the  bronchial  pieces, 
and  is  finally  continued  to  the  cells,  where  it  is  transparent.  Its  epithe- 
lium is  columnar  and  ciliated  in  the  bronchial  tubes,  but  is  changed  to 
squamous  or  laminar  in  the  air  cells. 

Lobules  and  lobes.  A  lobule  is  a  cluster  of  air  cells  around  a  terminal 
branch  of  the  air  tube.  Varying  in  size  and  shape,  each  lobule  is  invested 
by  areolar  tissue,  and  possesses  its  own  offset  of  the  air  tube,  as  well  as 
distinct  branches  of  vessels  and  nerves.  The  lobes  are  produced  by  the 
aggregation  of  the  lobules. 

The  air  cells  are  the  little  recesses  or  dilatations  connected  with  the 
smallest  branches  of  the  air  tube.  They  are  polyhedral  in  form,  except 
on  the  surface  of  tlie  lung,  and  are  distinct  one  from  another,  save  througli 
the  channel  of  the  air  passage.  The  cells  are  clustered  in  groups  around 
the  terminal  branches  of  the  air  tube,  with  which  they  communicate  by 
large  orifices.  These  small  spaces  are  about  yj^-  of  an  inch  across,  but 
they  are  larger  on  the  surface  and  at  the  edges  than  in  the  deeper  parts  of 
the  lung.  The  cell  wall  is  formed  by  areolar  and  elastic  tissue,  and  is 
lined  by  a  transparent  mucous  membrane  possessing  laminar  epithelium. 
Beneath  the  mucous  lining  is  a  network  of  capillaries  of  the  pulmonary 
vessels. 

Vessels  of  the  Lung.  Two  sets  of  vessels  are  furnished  to  the  lung, 
one  being  concerned  in  its  function,  the  other  in  the  nutrition.  The  ves- 
sels conveying  blood  to  the  lung  to  be  aerated,  and  carrying  that  fluid 
away  after  it  has  been  subjected  to  the  respiratory  process,  are  named 
pulmonary.  The  vessels  connected  with  the  nutrition  of  the  texture  are 
called  bronchial. 

The  pulmonary  artery  divides  like  the  bronchus,  which  it  accompanies 


386  DISSECTION    OF    THE    THORAX. 

to  the  lobule.  At  the  lobule  the  arterial  brunch  is  minutely  subdivided, 
and  its  ramifications  enter  the  interlobuhir  fissure  to  end  in  the  cell  wall 
in  the  following  way: — Over  the  bottom  of"  the  cell  they  form  a  very  fine 
caj)illary  network,  but  at  the  circumference  they  give  rise  to  a  circular 
vessel ;  and  the  circles  of  several  cells  communicate  with  each  other. 

The  'pulmonary  veins  begin  in  the  vascular  network  before  mentioned. 
The  twigs  issuing  from  the  several  lobules  are  destitute  of  valves,  and  are 
united  in  larger  tubes  which  course  to  the  root  of  the  lung.  Although  the 
small  lobular  branches  of  the  arteries  remain  separate  from  one  another, 
the  corresponding  veins  anastomose  together. 

The  bronchial  arteries  enter  the  lung  on  the  air  tube,  and  supply  deep 
branches  to  it  and  the  contiguous  glands,  to  the  large  bloodvessels,  and  to 
the  interlobular  areolar  tissue  of  the  lung.  On  the  smallest  air  tubes 
minute  branches  anastomose  with  offsets  of  the  pulmonary  arteries. 

Superficial  tortuous  offsets  of  the  artery  ramify  beneath  the  pleura,  form- 
ing a  capillary  network. 

The  bronchial  vein  begins  by  twigs  corresponding  with  the  superficial 
and  deep  branches  of  the  artery.  Leaving  the  lung  at  the  root,  the  vein 
ends  differently  on  opposite  sides  of  the  body  (p.  337). 

Nerves  and  lymphatics.  The  lung  receives  nerves  from  the  vagus  and 
the  sympathetic  ;  and  the  offsets  follow  the  branches  of  the  air  tube,  but 
their  ending  is  uncertain.  Remak  describes  small  ganglia  on  the  sympa- 
thetic filaments.  The  lymphatics  of  the  lung  are  both  supeificial  and  deep, 
and  enter  the  bronchial  glands  at  the  root  of  the  lung. 

PARTS  ON  THE  SPINE  AND  THE  SYMPATHETIC  CORD. 

In  front  of  the  spinal  column  are  the  several  parts  lying  in  the  inter- 
pleural space  of  the  posterior  half  of  the  mediastinum,  viz.,  the  aorta, 
iizygos  veins,  thoracic  duct,  cesophagus,  and  splanchnic  nerves. 

Dissection.  The  thoracic  duct  should  be  found  first  near  the  diaphragm 
by  removing  the  pleural ;  there  it  is  about  as  large  as  a  crow  quill,  and 
rests  against  the  right  side  of  the  aorta  :  this  slender  vessel  may  be  in- 
jected with  tallow. 

The  areolar  tissue  and  the  pleura  are  to  be  cleared  aAvay  from  the  dif- 
ferent parts  before  mentioned  ;  and  the  azygos  or  intercostal  veins,  one  on 
the  right  and  two  on  the  left  aorta,  should  be  dissected.  Next  follow  the 
thoracic  duct  upwards  beneath  the  arch  of  the  aorta,  and  along  the  oeso- 
phagus beneath  the  pleura,  till  it  leaves  the  upper  aperture  of  the  thorax. 

After  raising  the  pleura  also  from  the  inner  suH'ace  of  the  ciiest,  the 
ganglijited  cord  of  the  sympatlietic  nerve  will  be  seen  lying  over  the  heads 
of  the  ribs.  Branches  are  to  be  followed  outwards  from  the  ganglia  to  the 
intercostal  nerves  ;  and  others  inwards  over  the  bodies  of  tlie  vertebne, — 
the  lowest  and  largest  of  these  forming  the  three  trunks  of  the  splanchnic 
nerves. 

The  DESCENDING  THORACIC  AORTA  is  the  part  of  the  great  systemic 
vessel  above  the  diaphragm.  Its  extent  is  from  the  lower  border  of  the 
fifth  dorsal  vertebra  (the  left  side),  where  the  arch  ceases,  to  the  front  of 
the  last  dorsal  vertebra. 

Contained  in  the  interpleural  space  in  front  of  the  s[)ine,  the  vessel  is 
rather  curved,  lying  at  its  upper  part  on  the  left,  but  below  on  the  front 
of  the  spinal  column.  Beneath  it  are  the  vertebra?  and  the  smaller  azygos 
veins.     In  front  of  the  vessel  is  the  root  of  the  left  lung  with  the  pericar- 


INTERCOSTAL  ARTERIES.  337 

dinm.  On  its  left  side  it  is  covered  throughout  by  the  pleura;  and  on  its 
right  side  are  the  oesophagus  and  tlie  thoracic  duct,  though  near  the  dia- 
phragm the  gullet  is  placed  over  the  aorta. 

Tlie  branches  of  the  vessel  are  distributed  to  the  surrounding  parts,  and 
are  named  from  their  destination  bronchial,  pericardial,  oesophageal,  medi- 
astinal, and  intercostal. 

a.  The  bronchial  arteries  supply  the  structure  of  the  lungs,  and  adhere 
to  the  posterior  part  of  the  bronchial  tubes,  on  whicli  they  ramify  (p.  336)  ; 
they  give  some  twigs  to  the  bronchial  glands  and  the  oesophagus. 

For  the  left  lung  there  are  two  arteries  (superior  and  inferior),  which 
arise  from  the  front  of  the  aorta  at  a  distance  from  each  other. 

The  artery  of  the  right  lung  arises  in  common  with  one  of  the  left  bron- 
chial arteries  (superior),  or  from  the  first  intercostal  artery  of  the  right 
side. 

Bronchial  veins.  A  vein  issues  from  the  root  of  each  lung,  and  ends 
in  the  following  manner :  the  right  joins  the  larger  azygos  vein  ;  and  the 
left  ends  in  the  superior  intercostal  vein  of  its  own  side. 

b.  The  pericardial  branches  are  some  irregular  twigs,  which  are  fur- 
nished to  the  posterior  part  of  the  cardiac  bag. 

c.  (Esophageal  branches  arise  at  different  points  of  the  aorta,  and  are 
four  or  five  in  number.  Ramifying  in  the  gullet,  the  vessels  anastomose 
with  one  another;  above,  they  communicate  with  branches  of  the  inferior 
thyroid  artery  near  the  pharynx  ;  and  below,  with  twigs  of  the  coronary 
artery  of  the  stomach. 

d.  Small  mediastinal  branches  (posterior)  supply  the  areolar  tissue  and 
the  glands  in  the  interpleural  space. 

e.  The  intercostal  arteries  are  ten  on  each  side  ;  nine  are  furnished  to 
the  same  number  of  lower  intercostal  spaces,  whilst  the  last  lies  below  the 
twelfth  rib  :  to  the  upper  two  spaces  branches  are  supplied  from  the  inter- 
costal artery  of  the  subclavian  trunk. 

These  small  vessels  arise  from  the  posterior  part  of  the  aorta,  and  run 
outwards  on  the  bodies  of  the  vertebrae,  beneath  the  cord  of  the  sympathe- 
tic nerve,  to  the  intercostal  spaces,  where  each  divides  into  an  anterior  and 
a  [)Osterior  branch.  In  this  course  the  upper  arteries  have  a  somewhat 
oblique  direction  ;  and  as  the  aorta  lies  on  the  left  of  the  spine  the  right 
vessels  are  the  longest :  the  right  also  pass  beneath  the  oesophagus,  the 
thoracic  duct,  and  the  azygos  vein.  Many  twigs  are  supplied  to  the  bodies 
of  the  vertebrae. 

In  the  spaces  bounded  by  the  true  ribs,  the  anterior  branchy  the  larger 
of  the  two,  continues  onwards  between  the  muscular  strata  nearly  to  the 
anterior  third  of  the  intercostal  space,  where  it  ends  in  two  pieces,  which 
anastomose  with  the  intercostal  arteries  of  the  internal  mammary  (p.  239). 
At  first  the  artery  lies  in  the  middle  of  the  intercostal  space,  beneath  the 
pleura  and  a  fascia  from  the  internal  intercostal  muscle,  and  resting  on  the 
external  intercostal  layer ;  but  near  the  angle  of  the  rib  it  ascends  to  the 
upper  boundary.  Accompanying  the  artery  are  the  intercostal  vein  and 
nerve,  the  vein  being  commonly  above,  and  the  nerve  below  it ;  but  in 
the  upper  spaces  the  nerve  is,  at  first,  higher  than  the  artery. 

Below  the  true  ribs  the  vessels  are  contained  partly  in  the  thoracic  and 
partly  in  the  abdominal  wall.  Behind  they  have  the  same  course  and 
connections  as  the  higher  intercostals  ;  but  in  the  wall  of  the  abdomen 
they  lie  between  the  two  deep  muscles  ;  they  will  be  noticed  hereafter. 

Branches  are  furnished  to  the  intercostal  and  abdominal  muscles,  and 
22 


338  DISSECTION    OF    THE    THORAX. 

to  the  ribs.  About  the  centre  (from  front  to  back)  of  the  intercostal  space 
a  superficial  twig  arises,  which  accompanies  the  cutaneous  nerve. 

The  highest  artery  of  tlie  aortic  set  of  intercostuls  anastomoses  with  the 
superior  intercostal  branch  of  the  subclavian  artery;  and  the  lowest  (below 
tiie  true  ribs)  enters  the  abdominal  wall,  and  anastomoses  with  the  arteries 
of  that  part. 

The  posterior  branch  turns  backwards  between  a  vertebra  and  an  as- 
cending costo-transverse  ligament,  and  is  distributed  in  the  Back.  As  it 
passes  by  the  intervertebral  foramen  it  furnishes  a  small  spinal  branch  to 
the  vertebra}  and  the  spinal  cord.    (See  Vessels  of  the  Spinal  Cord.) 

The  intercostal  vein  resembles  closely  the  artery  in  its  course  and 
branching.  Near  the  head  of  the  rib  it  receives  a  contributing  dorsal 
branch,  and  then  joins  an  azygos  vein. 

Tlie  superior  intercostal  artery  of  the  subclavian  trunk  (p.  78)  descends 
over  the  neck  of  the  first  rib,  external  to  the  ganglion  of  the  sympathetic, 
and  supplies  a  branch  to  the  first  intercostal  space  :  continuing  to  tlie 
second  space,  which  it  supplies  in  like  manner,  it  anastomoses  with  the 
upper  aortic  branch. 

Its  intercostal  offsets  divide  into  an  anterior  and  a  posterior  branch,  like 
the  arteries  from  the  aorta. 

The  vein  accompanying  the  artery  opens  into  the  innominate  vein  of 
the  same  side.  The  left  superior  intercostal  vein  (fig.  105,  ^),  formed  by 
branches  from  the  two  or  three  highest  spaces,  is  joined  by  the  left  bron- 
chial vein,  and  ends  in  the  left  innominate  vein,  after  crossing  the  arch  of 
the  aorta. 

The  intercostal  or  azygos  veins  are  two  in  number  on  the  left,  and 
one  on  the  right  side,  and  receive  branches  corresponding  with  the  offsets 
furnished  by  the  thoracic  aorta. 

The  right  or  larger  azygos  (fig.  106,  ')  begins  in  the  lumbar  veins  on 
the  right  side  of  the  spine,  and  its  origin  is  discribed  with  the  vessels  of 
the  abdomen.  It  enters  the  thorax  through  the  aortic  opening  of  the 
diaphragm,  and  ascends  on  the  right  side  of  the  thoracic  duct,  over  the 
intercostal  arteries  and  the  bodies  of  the  vertebrae.  Opposite  the  fourth 
intercostal  space  the  vein  arches  forwards  above  the  root  of  the  right  lung, 
and  enters  the  superior  cava  as  this  vessel  pierces  the  pericardium.  Its 
valves  are  very  incomplete,  so  that  blood  may  flow  either  way  ;  and  the 
intraspinal  and  intercostal  veins  may  be  injected  through  it. 

Branches.  In  this  vein  are  collected  the  intercostals  of  the  right  side 
below  the  upper  two  sjiaces  ;  some  of  the  intercostals  of  the  left  side  of 
the  tliorax,  through  the  left  azygos  veins  ;  and  some  small  oesophageal,  me- 
diastinal, and  vertebral  veins,  with  the  right  bronchial  vein. 

By  means  of  the  right  vein  the  inferior  communicates  with  the  superior 
cava,  so  that  the  blood  may  reach  the  heart  from  the  lower  part  of  the 
body,  or  the  opposite,  if  one  of  the  cava?  should  be  obstructed. 

The  left  lower  azygos  vein  (fig.  100,  *)  begins  in  the  abdomen  in  the 
lumbar  veins  of  the  left  side  of  the  vertebral  column.  Entering  the  tliorax 
along  with  the  aorta,  or  through  the  crus  of  the  diaphragm,  the  vein  as- 
cends on  the  left  of  the  aorta  as  high  as  the  seventh  or  eighth  dorsal  ver- 
tebra, where  it  crosses  beneath  that  vessel  and  the  thoracic  duct  to  end  in 
the  right  azygos.  It  receives  the  four  or  five  lower  intercostal  veins  of  the 
left  side,  and  some  oesophageal  and  mediastinal  branches. 

The  left  upper  azygos  vein  (fig.  106,  ^)  is  formed  by  offsets  from  the 
space  between  the  superior  intercostal  and  the  preceding.     Receiving  three 


(ESOPHAGUS.  339 

or  four  branches,  the  trunk  either  joins  the  lower  azygos  of  its  own  side, 
or  crosses  the  spine  to  open  into  the  right  vein. 

The  (ESOPHAGUS  or  gullet  is  a  hollow  muscular  tube,  which  extends 
from  the  pharynx  to  the  stomach  :  the  cervical  portion  has  been  described 
at  p.  121,  and  the  thoracic  part  is  now  to  be  examined. 

Appearing  in  the  thorax  rather  to  the  left  of  the  middle  line,  the  gullet 
is  directed  beneath  the  arch  of  the  aorta,  and  reaches  the  middle  of  the 
spine  about  the  fifth  dorsal  vertebra.  From  that  spot  it  is  continued 
through  the  interpleural  space  on  the  right  of  the  aorta,  till  near  the 
diaphragm,  where  it  takes  a  position  over  the  aorta,  to  gain  the  oesopha- 
geal opening  of  that  muscle. 

As  far  as  the  aortic  arch  the  (esophagus  lies  beneath  the  trachea,  though 
it  is  inclined  somewhat  to  the  left  of  the  air  tube  ;  beyond  the  arch  it  is 
crossed  by  the  left  bronchus,  and  is  concealed  by  the  pericardium  as  far 
as  the  diaphragm.  At  the  upper  part  of  the  thorax  the  gullet  rests  on 
tiie  longus  colli  muscle  and  the  vertebrae ;  but  below  the  arch  of  the  aorta 
it  is  separated  from  the  spine  by  the  intercostal  vessels,  and  the  aorta. 
Laterally  it  touches  the  left  pleura  above  the  arch,  and  both  pleurae  be- 
low, but  more  of  the  right  than  the  left.  Below  the  bronchus  the  pneu- 
mogastric  nerves  surround  the  oesophagus  with  their  branches ;  and  above 
the  same  spot  the  thoracic  duct  is  in  contact  with  it  on  the  left. 

Structure.  If  a  piece  of  the  gullet  be  removed  and  distended  with  tow, 
it  will  be  easy  to  show  a  muscular,  fibrous,  and  mucous  coat,  one  within 
another. 

The  muscular  coat  is  thick  and  strong,  and  possesses  two  layers  of  fibres, 
of  which  the  external  is  longitudinal,  and  the  internal  circular  in  direc- 
tion, like  the  muscular  tunic  of  the  other  parts  of  the  alimentary  tube. 
In  the  upper  third  of  the  oesophagus  the  fibres  are  red,  but  below  that  spot 
the  color  becomes  paler. 

The  external  layer  is  formed  of  parallel  longitudinal  fibres,  which  form 
an  entire  covering,  and  end  below  on  the  stomach.  The  fibres  begin 
opposite  the  cricoid  cartilage  (p.  131)  ;  and  at  intervals  varying  from  half 
an  inch  to  an  inch  and  a  half,  they  are  connected  with  tendinous  points 
(uV  *^  iV  ^^  ^"  ^^^^^  l<^"g)  li'^G  the  fibres  of  the  rectus  abdominis  muscle. 

The  internal  layer  of  circular  fibres  is  continuous  above  with  the  fibres 
of  the  pharynx ;  they  are  more  oblique  at  the  middle  than  at  either  end 
of  the  oesophagus. 

The  Jibrous  layer  is  situate  between  the  muscular  and  mucous  coats, 
and  attaches  the  one  to  the  other  loosely. 

The  mucous  coat  will  be  seen  on  cutting  open  the  tube  :  it  is  reddish  in 
color  above  but  pale  below,  and  is  very  loosely  connected  with  the  muscu- 
lar coat,  so  that  it  is  thrown  into  longitudinal  folds  when  the  oesophagus  is 
contracted.  Lining  the  interior  is  a  thick  layer  of  scaly  epithelium  ;  and 
the  surface  is  studded  with  minute  papillae. 

Some  compouTtd  glands  (oesophageal)  are  scattered  along  the  tube ;  at 
the  lower  part  of  the  gullet  they  are  most  numerous,  and  form  a  ring 
(cardiac)  close  to  the  stomach. 

Lymphatics  of  the  Thorax.  In  the  thorax  are  lymphatic  vessels 
of  the  wall  and  the  viscera,  which  enter  collections  of  glands,  and  end  in 
one  or  other  of  the  two  lymphatic  ducts.  Besides  these,  the  large  thoracic 
duct  traverses  the  thorax  in  its  course  from  the  abdomen  to  tiie  neck. 

Lymphatic  glands.  Along  the  course  of  the  internal  mammary  artery 
lies  a  chain  of  sternal  or  mediastinal  glands,  which  receive  lymphatics 


340 


DTSSECTION    OF    THE    THORAX. 


Fig.  106. 


from  the  front  of  the  chest,  the  thymus  body,  the  pericardium,  and  the 
upper  surfaces  of  the  diaphragm  and  liver. 

On  each  side  of  the  spine,  near  the  heads  of  the  ribs,  as  well  as  between 
the  intercostal  muscles,  is  placed  a  group  of  intercostal  glands  for  the  re- 
ception of  the  lymphatics  of  the  posterior  wall  of 
the  thorax. 

Numerous  bronchial  glands  are  situate  at  the 
division  and  along  the  side  of  the  trachea,  through 
which  the  lymphatics  of  the  lung  pass  ;  and  be- 
neath the  arch  of  the  aorta  are  a  few  cardiac 
glands,  to  which  the  lymphatics  of  the  heart  are 
directed. 

Along  the  side  of  the  aorta  and  oesophagus  is  a 
chain  of  oesophageal  glands,  which  are  joined  by 
the  lymphatics  of  the  oesophagus,  and  communi- 
cate with  those  of  the  lungs. 

The  thoracic  duct  (fig.  106,^)  is  the  main 
channel  by  which  the  lymphatic  and  lacteal  fluid 
of  the  lower  half  of  the  body,  and  of  the  left  side 
of  the  upper  halt"  of  the  body,  is  conveyed  into  the 
blood.  The  duct  begins  in  the  abdomen  in  an 
enlargement  (chyli  receptaculum),  and  ends  in 
the  left  subclavian  vein  of  the  neck.  It  is  about 
eighteen  inches  in  length,  and  is  contained  in  the 
thorax,  except  at  its  origin  and  termination.  It 
has  the  undermentioned  connections  : — 

P^ntering  the  cavity  on  the  right  of  the  aorta 
and  through  the  same  opening,  the  duct  ascends 
on  the  riglit  side  of  that  vessel,  as  high  as  the 
arch.  Opposite  the  fifth  dorsal  vertebra  it  passed 
beneath  the  aortic  arch,  and  is  applied  to  the  left 
side  of  the  oesophagus,  on  which  it  is  conducted 
to  the  neck  under  the  left  subclavian  artery.  At 
the  lower  part  of  the  neck  the  duct  arches  out- 
wards, as  before  described  (p.  119),  to  open  into 
the  left  subclavian  vein. 

In  this  course  the  tube  is  oftentimes  divided 
in  two,  which  unite  again ;  or  its  divisions  niay 
even  form  a  plexus.  Near  its  termination  it  is 
frequently  branclied.  It  is  provided  with  valves 
at  intervals,  like  a  vein  ;  and  these  are  in  greatest 
number  at  the  upper  j)art. 

Branches.  In  tiie  thorax  the  duct  receives 
the  lym[)hatics  of  the  left  half  of  the  cavity,  viz., 
from  the  sternal  and  intercostal  glands ;  also  tlie 
lymphatics  of  the  left  lung,  the  left  side  of  the 
heart,  and  the  trachea  and  oesophagus. 

The  right  lymphatic  duct  (fig.  27)  receives 
large  branches  from  the  viscera  of  the  thorax.  It  is  a  short  trunk,  about 
half  an  inch  in  length,  and  opens  into  the  angle  of  union  of  the  subclavian 
and  jugular  veins  of  the  same  side  (p.  79)  :  its  opening  is  guarded  by 
valves. 

Branches.     Into  this  trunk  the  lymjdiatics  of  the  right  upper  limb,  and 


View  op  the  Thoracic 
Duct,  and  the  Inter- 
costal Veins. 

1.  Thoracic  duct. 

2.  Ending  of  the  duct  in  the 

left  subclavian  vein. 

3.  Large  or  right  azygos  vein. 
A.  Left  lower  azygos  or  in- 
tercostal vein. 

6.  Left  upper  azygos  or  inter- 
costal. 

6.  Vena  cava  superior. 

7.  Left  internal  jugular  vein, 

cut  through. 


SYMPATHETIC    NERVE    AND    OFFSETS 


341 


right  side  of  the  head  and  neck  pour  their  contents.  In  addition,  the 
lym{)hatics  of  the  right  side  of  the  chest,  right  lung  and  right  half  of  the 
heart,  and  some  from  the  right  lobe  of  the  liver,  after  passing  through  their 
respective  glands,  unite  into  a  few  large  trunks,  which  ascend  beneath  the 
innominate  vein  to  reach  the  duct  in  the  neck. 

Structure  of  the  ducts.  The  wall  of  the  tube  resembles  that  of  the 
bloodvessels  in  structure  (p.  119). 

Cord  of  the  Sympathetic  Nerve.  The  thoracic  part  of  the  gan- 
gliated  cord  of  the  sympathetic  nerve  is  covered  by  the  pleura,  and  is  placed 
over  the  heads  of  tlie  ribs,  and  the  intercostal  vessels.  The  ganglia  on  it 
are  usually  twelve,  one  being  opposite  each  dorsal  nerve,  but  this  number 
varies  much.  The  upper  ganglion  is  the  largest ;  and  the  last  two  are 
rather  anterior  to  the  line  of  the  others,  being  situate  on  the  side  of  the 
bodies  of  the  corresponding  vertebrje. 

P^ach  ganglion  furnishes  external  branches  to  communicate  with  the 
spinal  n  Tves,  and  internal  for  the  supply  of  the  viscera. 

External  or  connecting  branches  (fig.  107).  Two  offsets  pass  outwards 
from  each  ganglion  to  join  a  spinal  nerve  (intercostal).     In  the  branches 


Fig.  107. 


a.  Posterior  root  of  a  sp'nal  nerve,  with  a 
ganglion,  c. 

6.  Anterior  root. 

d.  Posterior  primary  branch. 

6.  Anterior  primary  branch  of  the  spinal  nerve. 

/.  Knotted  cord  of  the  sympathetic. 

g.  Ganglia  on  the  cord, 

h.  White  oflfset  from  the  spinal  to  the  sympa- 
thetic nerve. 

i.  Gray  offset  from  the  sympa  hetic  to  the 
spinal  nerve. 


Scheme  to  Illustrate  the  connection  between  the  Spinal  and  Sympathktic  Nerves. 

(Todd  and  Bowman.) 

of  communication  both  spinal  and  sympathetic  nerve  fibrils  are  combined : 
but  one  {h)  consists  almost  entirely  of  spinal,  and  the  other  {i)  nearly  al- 
together of  sympathetic  nerve  fibres. 

The  internal  or  visceral  branches  differ  in  size  and  distribution,  accord- 
ing as  they  are  derived  from  the  upper  or  lower  six  ganglia. 

The  offsets  of  the  upper  six  are  very  small,  and  are  distributed  to  the 
aorta,  and  the  vertebrae  with  the  ligaments.  Mr.  Swan  describes  a  plexus 
in  front  of  the  spine,  from  the  union   of  the  branches  of  opposite  sides. 


342  DISSECTION    OF    THE    THORAX. 

From  the  third  and  fourth  ganglia  offsets  are  sent  to  the  posterior  pulmo- 
nary plexus. 

The  branches  of  the  loiver  six  are  larger  and  much  whiter  than  the 
others,  and  are  united  to  form  visceral  or  splanchnic  nerves  of  the  abdo- 
men :  these  are  three  in  number  (large,  small,  and  smallest),  and  pierce 
the  diaphragm  to  end  in  the  solar  and  renal  plexuses. 

The  great  splanchnic  nerve  is  a  large  white  cord,  which  receives  roots 
apparently  from  only  four  or  five  g*anglia  (sixth  to  the  tenth),  but  its  fibres 
may  be  traced  upwards  on  the  knotted  cord  as  high  as  the  third  ganglion. 
Descending  on  the  bodies  of  the  vertebra?,  it  pierces  the  fibres  of  the  crus 
of  the  diaphragm,  and  ends  in  the  semilunar  ganglion  of  the  abdomen. 
At  the  lower  part  of  the  thorax  the  nerve  may  present  a  ganglion. 

The  small  splanchnic  nerve  begins  in  the  tenth  and  eleventh  ganglia, 
or  in  the  intervening  cord.  It  is  transmitted  interiorly  through  the  crus 
of  the  diaphragm,  and  enters  the  part  of  the  solar  plexus  by  the  side  of 
the  coeliac  artery. 

The  smallest  splanchnic  nerve  springs  from  the  last  ganglion,  and  ac- 
companies the  other  nerves  through  the  diaphragm  :  in  the  abdomen  it 
ends  in  the  renal  plexus.  This  nerve  may  be  absent,  and  its  place  may 
be  taken  by  an  offset  of  the  preceding. 

PARIETES    OF    THE    THORAX. 

Between  the  ribs  are  lodged  the  two  layers  of  intercostal  muscles,  with  the 
intervening  nerves  and  arteries  ;  and  inside  them  lies  a  thin  fleshy  layer 
behind, — the  infracostals.     At  the  base  of  the  thorax  is  the  diaphragm. 

The  INFRACOSTAL  MUSCLES  are  small  slips  of  fleshy  fibres,  which  are 
situate  on  the  inner  surface  of  the  ribs,  where  the  internal  inrtercostals 
cease.  Apparently  part  of  the  inner  intercostals,  they  arise  from  the 
inner  surface  of  one  rib,  and  are  attached  to  the  like  surface  of  the  rib 
next  succeeding. 

They  are  uncertain  in  number,  but  there  may  be  ten  :  they  are  smaller 
above  than  below,  and  the  upper  and  lower  may  pass  over  more  than  one 
space. 

Action.  These  thin  muscles  approach  the  ribs  to  one  another,  dimin- 
ishing the  size  of  the  thoracic  cavity,  and  act  thus  as  expiratory  muscles. 

Intercostal  Muscles.  The  anterior  part  of  the  muscles  has  been 
described  (p.  237)  ;  and  the  posterior  part  may  be  now  examined  from 
the  inner  side. 

The  inner  muscle  begins  at  the  sternum,  and  reaches  backwards  to  the 
angle  of  the  ribs  in  the  middle  spaces,  but,  higher  and  lower,  the  muscu- 
lar fibres  approach  nearer  the  spine.  Where  the  fibres  cease,  a  thin  fascia 
is  continued  backwards  over  the  outer  muscle.  The  inner  surface  is  lined 
by  the  pleura,  and  the  oi)posite  surface  is  in  contact  with  the  intercostal 
nerve  and  vessels. 

External  muscle.  When  the  fascia  and  the  infracostal  muscles  have 
been  removed,  the  external  intercostal  will  be  seen  between  the  posterior 
border  of  the  internal  muscle  and  the  spine.  Its  fibres  cross  those  of  the 
inner  intercostal  layer.  Whilst  this  muscle  extends  backwards  to  the 
tubercle  of  the  rib,  it  does  not  reacli  further  forwards  than  the  rib  carti- 
lages, as  before  said. 

Action.  The  use  of  the  intercostal  muscles  in  respiration  is  given  in 
p.  238. 


INTERCOSTAL    NERVES.  343 

Dissection.  In  a  few  spaces  the  internal  intercostal  muscle  may  be  cut 
through,  and  the  intercostal  nerve  and  artery  traced  outwards. 

The  INTERCOSTAL  NERVES  are  the  anterior  primary  branches  of  the 
dorsal  nerves.  Twelve  in  number,  they  occupy  the  intercostal  spaces, 
without  communicating  in  a  plexus ;  and  the  last  is  placed  below  the 
twelfth  rib.  Tlie  upper  six  lie  between  the  ribs,  and  are  confined  to  the 
wall  of  the  thorax ;  whilst  the  lower  six  are  prolonged  into  the  abdominal 
wall,  where  the  ribs  cease  in  front. 

Upper  SIX.  At  first  the  nerves  lie  between  the  pleura  and  subjacent 
fascia  and  the  external  intercostal  muscle,  with  an  artery  and  vein  ;  but 
they  enter  soon  between  the  intercostals  and  extend  forwards  to  the  middle 
line  of  the  body.  Near  the  head  of  the  rib  each  is  joined  by  filaments 
from  the  sympatlietic.  In  its  course  each  supplies  branches  to  the  inter- 
costal muscles  and  tlie  ribs,  and  cutaneous  offsets  to  the  surface  ;  these  are 
described  in  the  dissections  of  the  upper  limb  and  wall  of  the  abdomen. 

There  are  some  deviations  in  the  first  and  second  nerves  from  the  ar- 
rangement above  specified. 

The^^rs^  nerve  ascends  in  front  of  the  neck  of  the  highest  rib,  and  ends 
in  the  brachial  plexus.  Before  it  leaves  the  chest  it  supplies  to  the  first 
intercostal  space  a  branch,  which  furnishes  muscular  offsets,  and  becomes 
cutaneous  by  the  side  of  the  sternum.  There  is  not  any  lateral  cutaneous 
offset  from  this  branch,  except  in  those  cases  in  which  the  second  nerve  is 
not  as  large  as  usual. 

The  second  nerve  may  extend  a  considerable  way  on  the  wall  of  the 
chest  before  entering  between  the  intercostal  muscles,  and  may  ascend 
even  to  the  first  space.  It  is  remarkable  in  having  a  very  large  lateral 
cutaneous  branch  (p.  225).     In  front  it  ends  like  the  others. 

Upper  surface  of  the  diaphragm.  The  centre  of  the  muscle  is  tendinous, 
and  the  sides  are  fleshy.  In  contact  with  the  upper  surface  are  the  lungs 
laterally,  and  the  pericardium  in  the  middle :  the  phrenic  vessels  and 
nerves  pierce  this  surface,  external  to  the  pericardium.  In  the  diaphragm 
are  the  following  apertures  :  one  for  the  oesophagus  and  the  pneumogastric 
nerves,  a  second  for  the  vena  cava,  a  third  for  the  aorta  with  the  thoracic 
duct  and  the  vena  azygos,  and  a  fourth  on  each  side  for  the  splanchnic 
nerves.     Beneath  it  the  sympathetic  passes  into  the  abdomen. 

The  arch  of  the  diaphragm  towards  the  thorax  has  been  before  referred 
to  (p.  306). 

Directions.  The  dissector  of  the  thorax  now  waits  while  the  examina- 
tion of  the  Back  is  made.  Afterwards  lie  is  to  learn  the  ligaments  of  the 
ribs  and  spine  :  a  notice  of  these  will  be  found  in  the  following  Section. 


Section  II. 

LIGAMENTS  OF  THE  TRUNK. 


The  ligaments  of  the  vertebrse,  ribs,  and  sternum,  are  included  in  this 
Section. 

Articulation  of  the  Ribs.  The  osseous  part  of  each  rib  is  united  to 
the  spinal  column  on  the  one  side,  and  the  rib  cartilage  on  the  other,  by 
three  sets  of  ligaments,  viz.,  one  between  the  head  of  the  bone  and  the 


344 


DISSECTION    OF    THE    THORAX 


Fig.  108. 


bodies  of  the  vertebrae;  a  second  from  tlie  neck  and  tubercle  to  the  trans- 
verse processes  of  tlie  vertebne  ;  and  a  third  between  it  and  tlie  cartihige. 

Dissection.  For  tlie  purpose  of  examining  the  ligaments  between  the 
rib  and  the  vertebrae,  take  a  piece  of  the  spinal  column  with  three  or  four 
ribs  attached.  After  removing  the  intercostal  and  other  muscles,  and  the 
loose  tissue  from  the  surface  of  the  bones,  the  student  will  be  able  to  define, 
as  below,  the  ligaments  passing  from  the  head  and  neck  of  the  rib  to  the 
bodies  and  transverse  processes  of  the  vertebrae. 

The  ligaments  attaching  the  costal  cartilage  to  the  rib  and  sternum  are 
to  be  dissected  on  the  part  of  the  thorax  which  was  removed  in  opening 
the  cavity. 

Ligaments  of  the  Head  of  the  Rib.  Where  the  head  of  the  rib  is 

received  into  a  hollow  in  the  bodies  of  two 
continuous  vertebrae,  the  articulation  is  pro- 
vided with  two  retaining  ligaments — costo- 
vertebral and  interarticular,  with  two  syno- 
vial sacs. 

The  costo-vertehral  ligament  (fig.  108,  '), 
named  stellate  from  its  form,  is  composed  of 
radiating  fibres,  and  is  placed  in  front  of  the 
joint.  Attached  by  one  end  to  the  rib,  it  is 
divided  at  the  other  into  three  sets  of  fibres: 
The  upper,  the  largest,  ascends  to  the  body 
of  the  vertebra  above  the  rib  head ;  the 
lower  descends  to  the  vertebra  below  the 
head;  and  the  central  part  is  united  with  the 
fibro-cartilage  between  the  vertebrae. 

Where  the  rib  is  in  contact  with  only  one 
vertebra,  as  in  the  first,  eleventh,  and  twelfth, 
the  ligament  has  but  two  sets  of  fibres.  The 
chief  fibres  in  those  three  joints  are  fixed 
into  the  body  of  that  vertebra  which  is 
touched  by  the  costal  head ;  whilst  the  as- 
cend'ng  band  is  attached  to  the  body  of  the 
vertebra  immediately  above.  In  tlie  first 
rib-jont  the  ascending  band  is  continued  to 
the  last  cervical  vertebra. 

The  interarticular  ligament  will  be  seen 
when  the  stellate  is  divided.  It  is  a  short 
thin  band  of  fibro-cartilage,  which  is  attached 
on  one  side-  to  the  ridge  separating  tlie  articu- 
lar surfaces  on  the  head  of  the  rib,  and  on 
the  other  to  the  fibro-cartilage  between  the 
vertebrae.  In  the  joints  of  the  first,  eleventh, 
and  twelfth  ribs,  where  the  head  is  not  in  contact  with  the  intervertebral 
substance,  the  ligament  is  absent. 

Synovial  sacs.  There  are  two  sacs  in  the  articulation,  one  on  each 
side  of  the  interarticular  ligament.  In  the  three  joints  before  mentioned 
(1st,  11th,  and  12th)  there  is  but  one  sac. 

Movements.  In  the  costo-vertebral  articulation  there  is  a  gliding  of  the 
rib  up  and  down,  and  forwards  and  backwards.  The  movement  of  the 
head  is  more  limited  in  the  first  seven  ribs  which  are  fixed  to  the  sternum 
than  in  the  others ;  and  is  greatest  in  the  last  two,  in  consequence  of  the 


LlGAMBNTS   OF   THE   RiBS   AND  VER- 
TEBRA (Bourgery). 

1 .  Anterior  ligament  of  the  bodies  of 

the  vertebrse. 

2.  Lateral  part  of  the  anterior  liga- 

ment of  the  spine. 

3.  Ligament  (stellate)  between  the 

vertebrae  and  head  of  the  rib. 

4.  Ascending  costo-trans verse  liga- 

ment. 
6.   Interspinous  ligament. 


LIGAMENTS    OF    THE    RIB.  345 

ribs  being  free  anteriorly,  and  not  fixed  behind  by  a  joint  to  the  transverse 
process. 

During  the  increase  and  decrease  of  the  chest  the  body  of  the  rib  is 
rotated  out  and  in,  around  a  line  subtending  the  arc  of  the  circle  of  which 
its  fore  part  is  a  segment.  The  degree  of  motion  is  greatest  in  the  long- 
est ribs. 

Ligaments  of  the  Neck  and  Tubercle.  Three  ligaments  (costo- 
transverse) pass  from  the  neck  and  tubercle  of  the  rib  to  two  transverse 
processes.  And  there  is  a  synovial  sac  between  the  rib  and  its  transverse 
process. 

The  anterior  costo  transverse  ligament  (fig.  108,  *)  is  larger  and  longer 
than  the  others.  It  ascends  from  the  upper  edge  of  the  neck  to  the  trans- 
verse process  of  the  upper  of  the  two  vertebrae  with  which  the  head  articu- 
lates: it  is  wanting  to  the  first  rib.  Between  this  ligament  and  the  verte- 
bra the  posterior  branches  of  the  intercostal  vessels  and  dorsal  nerve  pass ; 
and  externally  it  is  joined  by  the  fibrous  membrane  between  the  strata  of 
the  intercostal  muscles. 

The  posterior  costo-transverse  (fig.  115,  ^)  is  placed  at  the  posterior 
aspect  of  the  rib.  It  is  a  short  band  of  fibres  between  the  rough  part  of 
the  tubercle  and  the  tip  of  the  transverse  process  of  the  lower  of  the  two 
vertebrse  touched  by  the  rib  head.  This  band  is  longest  in  the  lowest 
tw'o  articulations. 

The  middle  or  interosseous  costo-transverse  is  placed  horizontally  be- 
tween the  neck  of  the  rib  and  the  transverse  process  with  which  the 
tubercle  articulates.  It  will  be  best  seen  by  sawing  horizontally  through 
the  rib  and  the  transverse  process.  Its  fibres  are  mixed  with  reddish 
areolar  tissue. 

In  the  lowest  two  ribs  the  interosseous  costo-transverse  blends  in  one 
band  with  the  posterior  costo-transverse  ligament. 

Synovial  sac.  If  the  posterior  ligament  is  divided,  a  synovial  mem- 
brane will  be  exposed  in  the  joint  between  the  tubercle  of  the  rib  and  the 
transverse  process. 

In  the  lowest  tw^o  ribs,  wliich  do  not  touch  transverse  processes,  the 
synovial  sac  is  absent. 

Movement.  In  the  motion  of  the  rib,  the  bone  glides  upwards  and 
downwards  on  the  articular  facet  of  the  transverse  process ;  and  the  degree 
will  be  limited  by  the  surrounding  costo-transverse  ligaments. 

Ligaments  of  the  Steknal  Cartilages.  The  cartilages  of  the 
true  ribs  except  the  first  are  united  to  the  sternum  by  a  fibrous  capsule, 
which  covers  a  synovial  membrane;  and  externally  they  are  joined  to  tlie 
osseous  part  of  the  rib.  The  first  is  generally  ossified  to  the  sternum ; 
and  some  of  the  lower  cartilages  touch  each  other,  and  are  connected  to- 
gether by  fibrous  bands  with  synovial  membranes. 

In  the  chondro-sternal  articulation  (fig.  51,  *),  the  cartilages  are  re- 
ceived into  the  depressions  on  the  side  of  the  sternum,  and  are  fixed  in 
their  position  by  a  capsule  of  surrounding  fibres.  In  front  and  behind 
the  capsule  are  thickened  bands,  which  have  been  described  as  anterior 
and  posterior  ligaments. 

Between  the  cartilage  and  the  bone  is  a  synovial  membrane. 

In  the  joint  of  the  second  cartilage  there  is  an  interarticular  ligament 
(fig.  51,  «),  as  in  the  head  of  the  rib,  which  joins  the  cartilage  between 
the  pieces  of  the  sternum.  A  synovial  sac  exists  on  each  side  of  the 
interarticular  lijrament. 


346  DISSECTION    OF    THE    THORAX. 

A  separate  band  of  fibres  joins  the  cartilage  of  the  seventh  rib  to  the 
xiphoid  cartilage,  and  is  named  costo-xiphoid  ligament. 

Costal  cartilage  with  the  rib.  The  bony  part  of  the  rib  is  hollowed  to 
receive  the  costal  cartilage,  and  the  posterium  of  the  rib  is  the  investing 
membrane  between  the  two. 

Costal  Cartilages  to  one  Another.  The  contiguous  surfaces  of 
the  costal  cartilages  from  the  sixth  to  the  ninth  are  flattened,  and  are  con- 
nected by  ligamentous  fibres ;  each  articulation  is  provided  with  a  synovial 
membrane. 

Movement.  There  is  only  a  limited  gliding  motion  in  the  chondro- 
sternal  and  the  interchondral  articulations.  The  second  rib-cartilage  joint 
is  the. most  movable. 

Asternal  Cartilages.  The  cartilages  of  the  three  first  false  ribs 
are  united  only  by  end-bands  of  fibrous  tissue,  and  are  freer  to  move  than 
those  which  are  attached  to  the  sternum.  The  lowest  two,  which  are 
separate  from  one  another,  are  the  least  fixed  of  all. 

Articulation  of  the  Sternum  (fig.  51).  As  the  two  pieces  of  the 
bone  are  united  by  cartilage  without  any  synovial  membrane,  the  kind  of 
articulation  is  sometimes  named  synchondrosis.  The  articulation  is 
strengthened  by  anterior  and  posterior  longitudinal  fibres. 

Movement.  In  articulations  through  the  medium  of  cartilage,  as  here 
and  in  the  pelvis,  there  is  very  little  motion  to  be  perceived,  even  when 
the  osseous  pieces  are  forcibly  pulled  by  the  hands. 

Articulation  of  the  Vertebra.  The  vertebrae  of  the  spinal  col- 
umn are  united  together  by  two  sets  of  ligaments — one  for  the  bodies,  and 
the  other  for  the  arch  and  processes. 

Along  the  spinal  column  the  ligaments  have  a  general  resemblance,  and 
one  description  will  suffice  except  for  those  between  the  first  two  vertebrae 
and  the  head,  and  in  the  pelvis. 

Dissection.  After  the  articulations  of  the  ribs  have  been  examined, 
the  same  piece  of  the  spinal  column  will  serve  for  the  preparation  of  the 
ligaments  of  the  bodies  of  the  vertebrae.  The  anterior  ligament  of  the 
bodies  will  be  defined  with  very  little  trouble,  by  removing  the  areolar 
tissue. 

It  is  supposed  that  the  spinal  canal  has  been  opened  to  examine  the 
spinal  cord,  and  that  the  posterior  ligament  of  the  bodies  of  the  vertebrae 
is  laid  bare ;  but  if  the  canal  should  not  be  open,  the  neural  arches  of  the 
vertebrae  are  to  be  removed  by  sawing  through  the  pedicles. 

The  remaining  ligaments  between  the  neural  arches,  spines,  and  articular 
processes  of  the  bones,  may  be  dissected  on  the  piece  taken  away  in  open- 
ing the  spinal  canal. 

Ligaments  of  the  Bodies.  The  bodies  of  the  vertebrae  are  united  by 
an  anterior  and  a  posterior  common  ligament,  with  an  intervening  piece  of 
fibro-cartilage. 

The  anterior  common  ligament  (fig.  109,  a)  reaches  from  the  atlas  to 
the  sacrum :  it  is  widest  opposite  the  lumbar  vertebrae,  and  is  narrowed 
upwards.  It  consists  of  a  central  wide  and  thick  part  (a),  and  of  a  thinner 
portion  (6),  on  each  side  of  the  body  of  the  vertebrai.  If  the  central  piece 
be  cut  across  at  intervals  it  will  be  seen  to  be  thickest  opposite  the  hollow 
of  the  bodies. 

The  fibres  of  the  middle  part  are  longitudinal  in  direction.  By  detach- 
ing parts  of  the  ligament,  the  supei'ficial  fibres  will  be  seen  to  reach  three 
or  more  vertebrae,  whilst  the  deep  extend  from  bone  to  bone.     A  greater 


LIGAMENTS    OF    VERTEBRA, 


347 


Fig.  109. 


number  of  the  fibres  are  attaclied  to  the  intervertebral  fibro-cartilages  than 
to  the  bones  ;  and  more  are  fixed  to  the  margins  than  the  centre  of  the 
body. 

The  posterior  common  ligament  (fig.  110),  much  thinner  than  the 
anterior,  is  contained  in  the  spinal  canal,  lying  on  the  posterior  surface  of 
the  vertebrae,  and  extends  from  the  sacrum 
to  the  occipital  bone.  This  ligament  is 
wide  above,  and  diminishes  in  size  down- 
wards, just  the  opposite  of  the  anterior. 
In  the  neck.  A,  it  is  loose,  and  extends 
across  the  bodies.  In  the  back  and  loins 
it  is  a  narrow  band,  b,  which  sends  off 
on  each  side  a  pointed  process  to  be  at- 
tached to  the  pedicle  of  the  neural  arch ; 
and  it  is  wider  opposite  the  intervertebral 
disks  than  on  the  bodies,  so  that  the 
margins  are  dentate.  One  surface  of  the 
ligament  is  in  contact  with  the  dura 
mater ;  and  between  the  band  and  the 
vertebrae  are  the  intraspinal  vessels. 

Its  fibres  are  superficial  and  deep  as  in 
the  anterior  ligament,  and  are  more 
closely  united  with  the  intervertebral  sub- 
stance than  with  the  bone. 

Dissection.  To  see  the  intervertebral 
substance,  the  anterior  and  posterior  com- 
mon ligaments  must  be  taken  away.  One 
vertebra    should    be    detached   from    the 

fibro-cartilage  to  obtain  a  horizontal  view  of  this  structure ;  and  two  other 
vertebrae  should  be  sawn  vertically  to  see  the  difference  in  the  consistence 
and  arrangement  of  the  laminae. 


Anterior  Common  Ligament  of  the 

Bodies  of  the  Vertebra. 

a.  Middle   strong    part,  and  &,  lateral 

thin  part  of  the  ligament. 


Fiff.  110a. 


Fig.  110b. 


Two  Views  op  the  Posterior  Common  Ligament,  c,  of  the  Bodies  of  the  VERTEBRiE,  to 

Show  the  Difference  in  Shape. 

A,  refers  to  its  form  in  the  neck,  and  b,  to  its  shape  in  the  loins. 


The  intervertebral  substance  (fig.  Ill)  is  placed  between  the  contiguous 
surfaces  of  the  bodies  of  the  vertebrae,  from  the  axis  to  the  sacrum.     It 


348 


DISSECTION    OF    THE    THORAX 


forms  a  flattened  disk  between  each  pair  of  the  vertebrse,  and  its  width  is 
determined  by  the  size  of  the  bones.  It  is  connected  in  front  and  behind 
with  the  anterior  and  posterior  common  ligaments,  and  on  the  sides  with 
the  stellate  ligament  of  the  head  of  the  rib. 

By  means  of  the  dissection  before  made,  the  intervertebral  substance 
may  be  observed  to  consist  of  two  distinct  parts ;  an  external,  tirm  and 
laminar,  and  an  internal,  soft  and  elastic  (fig.  112). 

The  outer  laminar  part  (fig.  113,  a)  forms  more  than  half  of  the  disk, 
and  is  composed  of  pieces  of  fibro-cartilage  with  layers  of  fibrous  tissue. 
All  the  strata  are  arranged  one  within  another,  like  the  scales  of  an  onion, 
and  are  connected  by  their  edges  to  the  bodies  of  the  vertebrae ;  but  all 
have  not  a  vertical  direction,  for  whilst  the  outer  pieces  are  straight,  the 
inner  are  bent  with  the  convexity  outwards  (fig.  112)  (Humphry).  The 
laminae  do  not  form  complete  rings,  but  those  composed  of  fibrous  tissue 
reach  farther  than  those  of  fibro-cartilage  :  the  free  ends  of  both  layers 
overlap. 

Each  layer  is  constructed  of  oblique  fibres  ;  and  the  fibres  of  one  layer 
are  directed  across  those  of  another  like  the  parts  of  the  letter  X  (fig.  111). 
This  disposition  of  the  fibres  will  be  best  seen  on  the  disks  between  the 
lumbar  vertebrae  ;  and  it  may  be  rendered  evident  by  dissecting  layer  after 
layer. 


Fig.  111. 


Fig.  112. 


iNTEBVERTEBRAli  SPBSTANCE  IN  THK  LUM-  VeKTICAL  SECTION  OF  THE  INTERVERTEBRAL  SUB- 

BAE  Rkoion,  with  its  laminse  difiplayed.  stance,  to  show  the  direction  of  the  layers. 

a.  Superficial,  and  b,  deeper  layer,  the  fibres  a.  Circumferential  layers  bent  outwards, 

in  each  taking  a  difi'erent  direction.  b.  Central  pulpy  part. 


The  central  or  pulpy  portion  of  the  disk  (fig.  113,  b)  is  very  soft  and 
elastic,  and  projects  when  two  vertebrae  and  the  interposed  mass  are  sawn 
through.  Placed  nearer  the  back  than  the  front  of  the  disk,  it  is  more 
marked  in  the  loins  and  neck  than  in  the  dorsal  region.  It  has  a  yellow- 
ish color,  and  is  deficient  in  the  stratiform  arrangement  so  conspicuous 
at  the  circumference. 

Towards  the  confines  of  the  two  portions  of  the  intervertebral  substance, 
there  is  an  alternating  arrangement  of  fibrous  tissue  and  fibro-cartilage, 
though  the  former  is  gradually  diminishing;  but  towards  the  centre  a  loose 
fibro-cartilaginous  material  with  large  cells  preponderates. 


LIGAMENTS    OF    VERTEBRA. 


349 


Fig.  1]3. 


A    HORTZOJirAL     CCT    THROUGH     AN     In- 
TtRVKRTEBUAL  FlBitO-CARILAO E. 

a.  Laminar  external  part. 
6.  Pulpy  central  part  of  the  fibro-carti- 
lage. 


The  surfaces  of  the  vertebroe  in  contact  with  the  disk  have  a  cartilajrin- 
ous  covering;  this  may  be  seen  by  cutting  tlie  intervertebral  substance 
from  the  bone.      Over   the  centre   of  the 
osseous  surface  it  forms  a  continuous  layer, 
but  towards  the  circumference  it  consists  of 
separate  pieces. 

The  disks  are  thicker  between  the  lum- 
bar and  cervical,  than  between  the  upper 
and  middle  dorsal  vertebrae;  and  where  the 
spinal  column  is  arched  forwards,  as  in  the 
loins  and  neck,  they  are  deepest  at  the  an- 
terior edge,  being  wedge-shaped.  The  thin- 
nest piece  is  situate  between  the  second  and 
third  cervical  vertebrae,  and  the  thickest 
between  the  fifth  lumbar  and  the  sacrum. 

Use.  The  intervertebral  substance  unites 
together  the  vertebrjie  so  firmly  as  to  pre- 
vent displacement  of  those  bones  without 
rupture  of  it. 

By  means  of  the  central  elastic  part  the 
revolving  motion  of  one  bone  on  another  is 
produced ;  and  the  degree  of  the  movement  is  limited  by  the  circumferen- 
tial laminar  portion. 

Through  its  wedge-shaped  form  the  disk  is  chiefly  instrumental  in  giving 
rise  to  the  convexity  of  the  spinal  column  in  the  loins  and  neck  ;  and 
through  its  elasticity  it  moderates  the  effect  of  jars  or  shocks  transmitted 
from  bone  to  bone. 

The  depth  of  its  several  pieces  amounts  to  about  a  fourth  of  the  length 
of  the  movable  part  of  the  spinal  column  ;  but  as  it  yields  under  pressure, 
the  height  of  the  body  will  be  shorter  from  half  an  inch  to  an  inch  in  the 
course  of  the  day,  according  to  the  fatigue  undergone. 

Ligaments  of  the  Neural  Arch  and  Processes.  The  several  pro- 
cesses of  the  vertebrae  have  special  uniting  ligaments  :  thus  the  articular 
processes  are  joined  by  a  capsule  and  a  synovial  membrane  ;  the  neural 
arches  are  connected  by  yellow  ligaments ;  the  spinous  processes  have  one 
band  along  the  tip  and  another  between  them  ;  and  the  transverse  pro- 
cesses are  provided  with  intervening  bands  of  fibres. 

Ligaments  of  Articulattn;/  processes.  Between  the  articulating  processes 
there  is  a  movable  joint,  in  which  the  bones  are  covered  witli  cartilage, 
and  are  surrounded  by  a  loose  capsular  ligament  of  scattered  fibres,  en- 
closiug  a  synovial  membrane.  In  the  cervical  part  of  the  spine  the  cap- 
sular ligaments  are  looser  than  in  the  dorsal  or  lumbar  region. 

Movement.  With  flattened  articular  surfaces  is  combined  a  gliding  of 
one  bone  upon  another.  This  movement  is  least  limited  in  the  neck,  tlie 
loins,  and  the  lower  dorsal  vertebr;^. 

By  the  difference  in  the  shape  of  the  articulating  processes,  the  kind  of 
motion  in  the  spine  is  determined  ;  and  by  tiieir  arrangement  tlie  degree 
is  limited,  and  the  vertebrae  are  partly  maintained  in  situ.  In  dislocation 
of  the  spinal  column  they  are  generally  broken  before  a  vertebra  can  be 
dislodged  from  its  imbricated  position. 

Ligaments  of  the  arches.  The  ligamenta  siihflava  (fig.  114,'*)  so  named 
from  their  color,  are  situate  between  the  neural  arches  of  the  vertebme, 
and  close  the  spinal  canal  behind.     Between  each  pair  of  arches  are  two 


350 


DISSECTION    OF    THE    THORAX. 


ligaments,  one  for  each  half  of  the  arch,  wliich  approach  one  another  along 
the  middle  line,  and  reach  on  each  side  from  the  pedicle  of  the  arch  to  the 
root  of  the  spinous  process. 

Eacli  consists  of  elastic  yellow  tissue.  It  is  attached  above  to  the  inner 
surface  of  the  one,  but  below  to  the  upper  border  and  outer  surface  of  the 
other  neural  arch. 

Between  the  first  two  vertebra?  and  the  skull  there  are  special  fibrous 
ligaments  in  the  corresponding  situation  (see  p.  1  66). 

Ligaments  of  the  spities.  Along  the  tips  of  the  spinous  processes  of  the 
dorsal  lumbar  vertebrae  is  a  longitudinal  band  of  fibres  (fig.  115,  ^) — the 


Fig.  114. 


Fig.  115. 


An  Inner  View  of  the  Neural  Arches 
OP  THE  Vertebra,  with  their  Inter- 
posed LlQAMKNTS. 

1  aud  2.  Ligameata  subflava.  (Bourgery 
and  Jacob.) 


LiaAMENTS  OF  THE  PROCESSES  OF  THE  VERTEBRAE, 

AND  OF  THE  Ribs.     (Bourgery.) 

1.  Supraspinous  band  of  ligament. 

2.  Ligamentum  subflavuni. 

3.  Posterior  costo-transverse  ligament :  on  the  op- 

posite side  the  band  has   been  removed  aud 
the  joint  opened. 

4.  Intertransverse  ligament. 


supraspinous  ligament.  It  is  thickest  in  the  lumbar  region  of  the  spine, 
and  is  formed  by  the  superficial  and  deep  fibres ;  the  former  reach  over 
three  or  more  spines,  whilst  the  latter  pass  from  bone  to  bone.  It  is  closely 
united  with  the  tendons  of  the  muscles. 

The  band  of  the  ligamentum  nucha?,  which  is  composed  of  fibrous  tissue, 
takes  its  place  in  the  neck. 

Along  the  spinal  column  there  are  also  thin  membranous  interspinous 
ligaments  (fig.  108,  '^},  which  reach  from  the  root  to  the  tip  of  the  spinous 
processes.  The  strength  of  these  bands  is  dependent  upon  the  interval 
they  fill ;  they  are  more  marked  in  the  lumbar  than  the  other  vertebra?, 
and  they  are  least  strong  in  the  cervical  region. 

Ligaments  of  the  transverse  process.    In  the  loins  the  inter-transverse 


MOTION    OF    SPINAL    COLUMN.  351 

ligaments  are  thin  membranous  bands  in  the  intervals  between  the  pro- 
cesses. In  the  dorsal  vertebrae  they  are  round  bundles  of  fibres  (fig.  115,  *). 
And  in  the  neck  the  fibres  exist  only  at  the  apex  of  the  processes,  or  they 
may  be  wanting  here  and  there. 

Ligaments  of  Special  Vertebra.  The  ligaments  of  the  first  two 
cervical,  and  the  sacral  and  coccygeal  vertebrae,  will  be  given  with  the 
dissection  of  the  neck  (pp.  166,  167)  and  of  the  pelvis  (Section  vii.). 

Movements  of  Spinal  Column.  The  spinal  column  can  be  bent  for- 
wards, backwards,  and  to  each  side ;  and  can  be  rotated. 

In  Jiexion  the  vertebrae  between  the  axis  and  sacrum  are  bowed  for- 
wards. The  greatest  movement  takes  place  between  the  last  two  lumbar 
vertebrae  and  the  sacrum  (Humphry) ;  there  is  an  intermediate  degree 
in  the  neck  ;  and  the  least  is  in  the  upper  half  of  the  dorsal  region,  where 
the  ribs  are  united  to  the  sternum. 

The  bodies  of  the  bones  are  brought  nearer  together  in  front,  whilst 
they  are  separated  behind.  The  inferior  pair  of  articular  processes  of  the 
second  vertebra  glide  upwards  on  the  upper  articular  of  the  third  vertebra  ; 
the  inferior  of  the  third  bone  move  in  like  manner  on  the  upper  processes 
of  the  fourth  ;  and  so  on  throughout  the  movable  column. 

The  ligament  in  front  of  the  bodies  is  loose,  but  the  posterior,  and  those 
uniting  the  neural  arches  and  processes,  are  stretched.  The  fore  part  of 
each  intervertebral  disk  is  squeezed  and  thinner,  and  the  back  is  elongated. 

In  extension^  the  vertebrae  are  arched  backwards,  but  not  to  so  great  a 
degree  as  when  the  spine  is  bent  forwards.  The  motion  is  most  in  the 
neck  ;  and  is  least  in  the  dorsal  vertebrae,  which  are  fixed  by  the  true  ribs 
and  the  sternum,  and  are  impeded  in  their  movement  by  the  overlapping 
spinous  processes. 

The  posterior  parts  of  the  vertebrae  are  approximated,  whilst  the  ante- 
rior are  separated  ;  and  the  inferior  articular  processes  of  each  (from  the 
second  cervical  to  the  sacrum)  glide  downwards,  on  the  upper  articular 
processes  of  the  next  succeeding  bone. 

The  condition  of  the  ligaments  is  the  opposite  to  that  in  flexion.  Thus, 
the  intervertebral  disks  are  compressed  behind  and  widened  before  ;  the 
spinous  and  subflaval  are  relaxed  ;  the  anterior  common  of  the  bodies  is 
tightened,  and  the  hinder  band  is  slackened. 

Lateral  inclination.  The  spine  can  be  curved  to  the  right  or  the  left 
side.  Like  the  other  movements,  this  is  least  in  the  more  fixed  upper 
dorsal  vertebrte,  and  is  greatest  in  the  neck. 

On  the  concave  side  of  the  curve,  say  the  right,  the  bodies  are  brought 
nearer  together ;  and  are  carri(;d  away  from  each  other  on  the  opposite 
aspect.  The  right  inferior  articular  surface  glides  down,  and  the  left  up, 
in  the  joints  wiih  the  vertebra  beneath. 

On  the  right  side  the  ligaments  will  be  relaxed  and  the  intervertebral 
substance  compressed ;  and  on  the  left  those  structures  will  be  tightened 
so  as  to  check  the  movement. 

Rotation  is  the  twisting  of  the  bodies  of  the  vertebrae  around  a  line 
through  their  centres,  the  fore  part  being  turned  to  the  rigiit  and  to  the 
left.  Its  degree  is  greatest  in  the  cervical  and  the  upper  dorsal  vertebrae, 
but  is  absent  in  the  lumbar  part  of  the  column. 

The  vertebral  bodies  are  directed  horizontally,  and  the  articular  pro- 
cesses move  diflTerently  on  the  two  sides.  Supposing  the  face  turned  to 
the  right,  the  processes  of  the  right  side  glide  inWards  towards,  and  those 
of  the  left  side  outwards  from  the  spinal  canal. 


862  DISSECTION    OF    THE    THORAX. 

The  flat  ligaments  and  tlie  intervertebral  disks  of  the  bodies,  and  the 
ligaments  of  the  neural  arches,  will  be  less  tight  on  the  side  to  which  the 
face  is  directed  than  on  the  other. 

Dislocation  of  one  vertebra  from  another  without  fracture  seldom  occurs, 
in  consequence  of  the  way  in  whicli  the  inferior  pair  of  articular  processes 
are  placed  behind  the  superior  of  the  next  following  bone,  like  scales.  In 
tlie  cervical  region,  where  the  articuUir  surfaces  are  more  horizontal,  sim- 
ple displacement  may  occasionally  take  place. 


DISSECTION    OF    THE    BACK.  353 


CHAPTER  Y. 

DISSECTION  OF  THE  BACK. 

Directions.  The  dissection  of  the  Back  may  be  undertaken  by  one  stu- 
dent ;  or  conjointly  by  the  dissectors  of  the  head  and  upper  limbs — the 
former  preparing  the  neck,  and  the  latter  making  ready  the  parts  in  the 
dorsal  and  himbar  regions. 

If  the  Back  should  be  allotted  to  more  than  one  student,  the  dissector 
of  the  upper  limb  may  attend  chiefly  to  the  paragraphs  marked  with  an 
asterisk  ;  and  the  dissector  of  the  neck  may  study  specially  the  paragraphs 
which  are  not  so  marked.  But  as  many  of  the  dissections  in  the  earlier 
stages  require  the  co-operation  of  the  students  employed  on  the  same  side 
of  the  body,  a  general  attention  may  be  given  to  the  whole  by  each. 

The  dissector  of  the  abdomen  is  to  examine  the  arrangement  of  the  fas- 
cia lumborum,  after  the  first  layer  of  muscles  has  been  learnt. 

Position.  The  body  lies  with  the  face  downwards  ;  and  the  trunk  is  to 
be  raised  by  blocks  beneath  the  chest  and  the  pelvis,  so  that  the  limbs 
may  hang  over  the  end  and  sides  of  the  dissecting  table.  To  make  tense 
the  neck,  the  head  is  to  be  depressed  and  fastened  with  hooks. 

In  this  region  there  are  five  successive  strata  of  muscles,  amongst  which 
vessels  and  nerves  are  interspersed. 

Dissection.  Tiie  first  step  is  to  raise  the  skin  in  two  flaps,  by  means  of 
the  following  incisions  : — One  cut  is  to  be  made  along  the  middle  of  the 
body  from  the  occipital  protuberance  to  the  back  of  the  sacrum.  Another 
is  to  be  carried  from  the  last  dorsal  vertebra  to  the  acromion  process  of 
the  scapula.  The  flap  of  skin  above  the  last  cut  is  to  be  turned  outwards 
by  the  dissectors  of  the  head  and  upper  limb. 

By  anotlier  transverse  incision  opposite  the  iliac  crest,  the  remaining 
piece  of  integument  may  be  detached,  and  reflected  by  the  dissector  of  the 
upper  limb  in  tlie  same  direction  as  the  other  flap. 

Under  the  upper  flap  of  skin  is  placed  the  trapezius,  and  underneath  the 
lower  one  the  latissimus  dorsi  muscle. 

The  cutaneous  nerves  may  now  be  sought  in  the  superficial  fatty  layer : 
they  are  accompanied  by  small  cutaneous  arteries  which  will  guide  the 
student  to  their  position.  The  nerves  vary  much  in  size  in  the  different 
parts  of  the  Back,  and  their  number  is  also  irregular ;  as  a  general  rule, 
there  is  one  opposite  each  vertebra  except  in  the  neck. 

To  find  them  in  the  cervical  region  look  near  the  middle  line,  from  the 
3d  to  the  6th  vertebra,  and  trace  an  ofl^set  from  the  third  nerve  upwards 
to  the  head  :  the  branch  of  the  second  nerve  (large  occi{)ital)  has  been 
laid  bare  at  the  back  of  the  head  (p.  20). 

Opposite  the  upper  part  of  tlie  thorax,  they  will  be  best  found  near  the 
spines  of  the  vertebrae,  where  they  lie  at  first  beneath  the  fat ;  but  at  the 
lower  part,  and  in  the  loins,  they  issue  in  a  line  with  the  angles  of  the  ribs. 

The  cutaneous  branches  of  the  sacral  nerves  are  included  in  the  dissec- 
tion of  the  lower  limb. 
23 


354  DISSECTION    OF    THE    BACK. 

Cutaneous  Nerves.  The  tegumentary  nerves  are  derived  from  the 
posterior  primary  branches  of  the  spinal  nerves,  which  subdivide  amongst 
the  deep  muscles  into  two  pieces,  inner  and  outer.  Arteries  accompany- 
ing the  greater  number  of  the  nerves,  bifurcate  like  them,  and  furnish 
cutaneous  offsets. 

Cervical  nerves.  In  tlie  neck  the  nerves  are  derived  from  the  inner  of 
the  two  pieces  into  which  the  posterior  trunks  bifurcate  :  tliey  perforate 
the  trapezius,  and  supply  the  neck  and  the  back  of  the  head.  They  are 
four  in  number,  viz.,  one  from  each,  except  the  first  and  the  tliree  last. 

The  branch  of  the  second  nerve  is  named  large  occipital,  and  accom- 
panies the  occipital  artery  to  the  back  of  the  head  (p.  23). 

The  branch  of  the  third  cervical  nerve  supplies  a  transverse  offset  to 
the  neck,  and  then  ascends  to  the  lower  part  of  the  head,  where  it  is  dis- 
tributed near  the  middle  line,  uniting  with  the  great  occipital  nerve 

*  Dorsal  nerves.  These  are  obtained  from  both  the  inner  and  outer 
pieces — the  upper  six  from  the  inner,  and  the  lower  six  from  the  outer. 
On  the  surface  they  are  directed  outwards  in  the  integument  over  the 
trapezius  and  latissimus  dorsi  muscles. 

The  upper  six  perforate  the  trapezius  near  the  spines  of  the  vertebra? ; 
and  the  branch  of  the  second,  which  is  larger  than  the  rest,  readies  as 
far  as  the  scapula.  The  lower  six  pierce  the  latissimus  dorsi  mostly  in  a 
line  with  the  angles  of  the  ribs ;  they  are  oftentimes  uncertain  in  number. 

*  Lumbar  nerves.  In  the  loins  the  nerves  are  derived  from  the  outer 
pieces  of  the  first  three ;  they  perforate  the  latissimus  dorsi  muscle  at  the 
outer  border  of  the  erector  spinae,  and  crossing  the  iliac  crest  of  the  in- 
nominate bone,  are  distributed  in  the  integuments  of  the  buttock. 

*  First  Layer  of  Muscles  (fig.  116).  Two  muscles,  the  trapezius 
and  the  latissimus  dorsi,  are  included  in  this  layer. 

Dissection.  The  superficial  fatty  layer  is  to  be  taken  from  the  trape- 
zius and  latissimus  dorsi  in  the  direction  of  the  fibres  of  each,  viz.,  from 
the  shoulder  to  the  spinal  column  ;  and  the  upper  limb  is  to  be  carried 
backw^ards  or  forwards  according  as  it  may  be  necessary  to  put  on  the 
stretch  different  portions  of  the  muscles. 

Some  of  the  cutaneous  nerves  and  vessels  may  be  left,  in  order  that 
they  may  be  traced  afterwards  through  the  muscles  to  their  origin. 

*  The  TRAPEZIUS  MUSCLE  (fig.  IIG,  ^)  is  triangular  in  shape,  with 
the  base  towards  the  spine,  but  the  two  have  a  trapezoid  form.  The 
muscle  has  an  extensive  aponeurotic  origin  along  the  middle  line  from 
the  spines  of  all  the  dorsal  vertebra?  and  their  supraspinous  ligament ;  from 
the  spinous  process  of  the  seventh  cervical  vertebra  ;  from  the  ligamentum 
nucha;  between  the  last  point  and  the  head  ;  and  lastly  from  the  inner  third 
of  the  superior  transverse  ridge  of  the  occipital  bone.  From  this  origin  tlie 
fibres  are  directed  outwards,  converging  to  the  shoulder,  and  are  inserted 
into  the  outer  third  of  the  clavicle,  at  its  posterior  aspect  ;  into  the  pos- 
terior border  of  the  acromion  ;  and  into  the  upper  edge  of  the  spine  of 
the  scapula  as  far  as  an  incli  from  the  root  of  that  process,  as  well  as  into 
a  rough  impression  on  the  surface  of  the  spine  near  the  hinder  part. 

The  muscle  is  subcutaneous.  At  the  outer  side  the  lowest  fleshy  fibres 
end  in  a  small  triangular  tendon,  which  glides  over  tlie  smooth  surface  at 
the  root  of  the  spine  of  the  scapula.  The  anterior  border  bounds  behind 
the  posterior  triangular  space  of  the  neck.  By  its  insertion  the  trapezius 
corresponds  with  the  origin  of  the  deltoid  muscle. 

Action.     If  all  the  fibres  of  the  muscle  act,  the  scapula  gliding  on  the 


TRAPEZIUS    MUSCLE. 


355 


ribs  is  moved  upwards  and  towards  the  spinal  column  ;  but  the  upper  fibres 
can  assist  other  muscles  in  elevating,  and  the  lower  fibres  will  help  in 
depressing  that  bone. 

When  the  scapula  is  prevented  from  gliding  on  the  ribs,  the  trapezius 
imparts  a  rotatory  movement  to  it,  and  raises  the  acromion. 


Fiff.  116. 


Muscles  of  the  Back.     On  the  left  side  the  first  layer  is  shown,  and  on  the  right  side  the  second 
layer,  with  part  of  the  third. 

A.  Trapezius.  b.  Rhomboideus  major. 

B.  Latissimus  dorsi.  F.  Splenius. 

c.  Levator  Hnguli  scapulae.  G.  Serratus  posticus  inferior. 

D    Rhomboideus  minor. 


Dissection.  The  fibres  of  the  trapezius  are  to  be  divided  near  the  sca- 
pula, over  the  situation  of  the  spinal  accessory  nerve,  so  that  the  ramifica- 
tions of  that  nerve  in  the  muscle,  and  its  junction  with  the  branches  of  the 
cervical  plexus  may  be  observed.  A  small  artery  to  the  trapezius  (art. 
superficialis  colli)  accompanies  the  nerve. 


356  DISSECTION    OF    THE    BACK. 

The  spinal  accessory  cranial  nerve  (p.  114),  having  crossed  the  poste- 
rior triangle  of  the  neck,  passes  beneath  the  trapezius,  and  forms  a  plexi- 
form  union  with  branches  of  the  third  and  fourth  nerves  of  the  cervical 
plexus.     The  nerve  is  distributed  nearly  to  the  loAver  border  of  the  muscle. 

Dissection.  To  see  the  parts  covered  by  the  trapezius,  the  pieces  of 
the  divided  muscle  are  to  be  thrown  inwards  and  outwards. 

The  dissector  of  the  neck  should  now  clean  the  splenius,  and  define  the 
parts  beneath  the  clavicle,  viz.  the  posterior  belly  of  the  omo-hyoid  mus- 
cle with  the  suprascapular  nerve  and  vessels  ;  the  transverse  cervical  ves- 
sels ;  and  the  small  branches  of  nerves  to  the  levator  anguli  scapula3,  and 
rhomboid  muscles.  If  the  trapezius  be  detached  along  the  middle  line,  the 
ligamentum  nuchse,  from  which  it  takes  origin,  will  be  brought  into  view. 

*  The  dissector  of  the  upper  limb  should  clean  the  fibres  of  the  rhom- 
boidei  and  levator  anguli  scapulae  muscles,  which  are  fixed  to  the  base  of 
the  scapula ;  and  whilst  this  is  being  done,  the  scapula  is  to  be  drawn 
away  from  the  trunk  to  make  tense  the  fleshy  fibres. 

*  Parts  covered  by  the  trapezi'ts.  The  trapezius  conceals  in  the  neck 
the  splenius,  a  small  part  of  the  complexus,  and  the  levator  anguli  scapu- 
lae ;  in  the  dorsal  region  it  covers  the  following  muscles,  the  rhomboidei, 
the  erector  spinse,  and  the  latissimus  dorsi.  Near  the  insertion  it  lies  over 
the  supraspinatus  muscle. 

The  ligamentum  nuchce  is  a  narrow  fibrous  band,  which  extends  from  the 
spinous  process  of  the  seventh  cervical  vertebra  to  the  occipital  protuber- 
ance. From  its  nnder  part  processes  are  attached  to  the  spines  of  the 
six  lower  cervical  vertebrae,  so  that  it  serves  as  a  partition  between  the 
muscles  of  the  opposite  sides  of  the  neck.  In  man  it  is  not  formed  of  elas- 
tic tissue. 

*  The  LATISSIMUS  DORSI  (fig.  116,^)  is  the  widest  muscle  in  the  back, 
and  is  thin  and  aponeurotic  at  its  inner  attachment.  It  arises  along  the 
middle  line  from  the  spinous  processes  of  the  six  lower  dorsal,  all  the  lum- 
bar, and  the  upper  two  sacral  vertebrae,  as  well  as  from  the  supraspinous 
ligament.  On  the  outer  side  it  arises  by  an  aponeurosis  from  the  outer 
edge  of  the  posterior  half  of  the  iliac  crest ;  and  by  three  or  four  fleshy 
processes  from  as  many  of  the  lower  ribs,  which  digitate  with  pieces  of  the 
external  oblique  muscle  of  the  abdomen.  And  between  the  outer  and 
inner  attachments  it  is  inseparably  blended  below  with  the  subjacent  ten- 
don of  the  multifidus  spinas.  All  the  fibres  converge  to  the  inferior  angle 
of  the  scapula,  and  after  crossing  that  point  of  bone,  are  continued  for- 
wards to  be  inserted  by  tendon  into  the  bottom  of  the  bicipital  groove  of 
the  humerus  (p.  236). 

The  muscle  is  subcutaneous,  except  a  smjdl  part  of  the  upper  border 
which  is  covered  by  the  tra[)ezius.  Near  the  scapula  there  is  a  space  be- 
tween the  two,  in  which  the  rhomboid  muscles  appear.  The  lower  or 
anterior  overlays  the  edge  of  the  external  oblique  muscle  of  the  abdominal 
wall  in  the  interval  between  the  last  rib  and  the  iliac  crest,  with  the  ex- 
ception of  a  small  part  below.  Frequently  the  latissimus  has  a  distinct 
fleshy  slip  from  the  inferior  angle  of  the  scapula. 

Action.  If  the  arm  is  hanging  loose  the  muscle  can  move  it  behind  the 
back,  rotating  it  in  at  the  same  time.  If  the  limb  is  raised,  the  latissimus, 
combining  with  the  })ectoralis  and  teres,  will  depress  the  humerus.  From 
its  attachment  to  the  sca[)ula  this  bone  can  be  depressed  with  the  arm. 

Supposing  the  arm  fixed,  the  fibres  may  elevate  the  ribs  as  an  inspira- 


FASCIA    LUMBORUM.  357 

tory  muscle ;    or    they  may  assist  the   pectoralis  major  in  drawing  the 
movable  trunk  towards  the  humerus,  as  in  the  act  of  climbing. 

*  Dissection.  The  latissimus  is  to  be  divided  about  midway  between 
the  spines  of  the  vertebrae  aud  the  angle  of  the  scapula,  and  the  pieces  are 
to  be  reflected  inwards  and  outwards.  In  raising  the  inner  part  of  the 
muscle,  care  must  be  taken  not  to  destroy  either  the  thin  lower  serratus 
with  which  it  is  united,  or  the  aponeurosis  continued  upwards  from  the 
serratus.  In  the  interval  between  the  last  rib  and  the  iliac  crest  the  latis- 
simus is  adherent  to  the  aponeurosis  of  the  transversalis  abdominis  muscle, 
and  should  not  be  detached  from  it. 

*  Parts  covered  by  the  latissimus.  The  latissimus  dorsi  lies  on  the 
erector  spinas,  the  serratus  posticus  inferior,  and  the  lower  ribs  with  their 
intercostal  muscles.  As  it  rests  on  the  angle  of  the  sca|)ula,  it  conceals 
the  teres  major,  and  part  of  the  rhomboid  muscle.  Its  position  to  the 
teres  is  worthy  of  note  : — at  the  angle  of  the  scapula  it  covers  the  posterior 
surface  of  the  teres,  but  nearer  the  humerus  it  turns  round  the  lower  bor- 
der, and  is  inserted  in  front  of  that  muscle.  Between  the  angle  of  the 
scapula  and  the  humerus  the  latissimus  forms  part  of  the  posterior  boundary 
of  the  axilla. 

Dissection  of  fascia  lumboram.  After  the  latissimus  dorsi  has  been 
reflected,  the  dissector  of  the  abdomen  can  look  to  the  disposition  of  the 
posterior  tendon  of  the  transversalis  abdominis  (fascia  lumborum)  between 
the  last  rib  and  the  innominate  bone. 

In  the  spot  referred  to  are  portions  of  the  external  and  internal  oblique 
muscles,  left  in  the  dissection  of  the  wall  of  the  abdomen.  After  the 
removal  of  those  muscles  the  aponeurosis  of  the  transversalis  muscle  (fas- 
cia lumborum)  appears,  and  perforating  it  are  two  nerves — one,  the  last 
dorsal  with  an  artery  near  the  last  rib:  and  the  other,  the  ilio-hypogastric 
with  its  vessels,  close  to  the  iliac  crest. 

Two  offsets  are  prolonged  backwards  from  this  fascia  to  the  transverse 
processes.  To  see  the  more  superficial  layer  which  passes  beneath  the 
erector  spinae  to  the  apices  of  the  processes,  the  latissimus  dorsi  is  to  be 
cut  through  (both  its  aponeurosis  and  fleshy  part)  by  a  horizontal  incision 
directed  outwards  from  the  spinous  processes,  on  a  level  with  the  third 
lumbar  vertebra.  On  raising  the  outer  border  of  the  erector  spinas 
muscle  which  comes  into  view,  the  strong  process  of  the  fascia  will  be 
apparent. 

After  dividing  transversely  this  first  prolongation,  another  muscle  (quad- 
ratus  lumborum)  will  be  seen;  and  on  raising  its  outer  border  the  second 
thin  offset  of  the  fascia  will  be  ev^ident  on  the  abdominal  aspect  of  that 
muscle. 

Tha  fascia  lumhorum  (fig.  136,  ^)  is  the  posterior  aponeurosis  or  tendon 
of  the  transversalis  abdominis  muscle,  and  occupies  the  interval  between 
the  last  two  ribs  and  the  crest  of  the  hip-bone.  By  its  cutaneous  surface 
it  gives  attachment  to  the  internal  oblique  muscle,  and  sometimes  to  the 
external  oblique.  The  last  dorsal  Q)  and  ilio-hypogastric  Q)  nerves,  ac- 
companied by  vessels,  pierce  it  in  their  course  from  the  abdomen.  From 
the  inner  part  of  the  aponeurosis  two  offsets  are  prolonged  to  the  trans- 
verse processes  of  the  lumbar  vertebrae,  and  inclose  the  quadratus  lum- 
borum in  a  sheath. 

Tiie  more  superficial  of  the  two  is  the  strongest ;  it  lies  beneath  the 
erector  spina?  in  this  position  of  the  body,  and  is  connected  to  the  apices 
of  the  transverse  processes,  but  it  also  fills  the  intervals  between  tiiem  :  at 


358  DISSECTION    OF    THE    BACK. 

the  outer  border  of  the  erector  spinae  it  blends  with  the  aponeurosis  of  the 
latissimus  dorsi  and  inferior  serratus. 

The  deeper  or  anterior  prolongation  passes  on  the  abdominal  surface  of 
the  quadratus  lumborum,  and  is  fixed  to  the  tips  and  borders  of  the  trans- 
verse processes. 

In  like  manner  the  erector  spinae  lies  in  another  sheath,  which  is  formed 
by  the  vertebral  aponeurosis  and  the  tendons  of  the  latissimus  and  serratus 
on  the  one  side,  and  by  the  superficial  of  the  two  prolongations  of  the  fascia 
lumborum  on  the  other. 

*  Second  Layer  of  Muscles  (fig.  116).  This  stratum  contains  the 
elevator  of  the  angle  of  the  scapula,  and  the  large  and  small  rhomboid 
muscles ;  besides  these,  the  posterior  belly  of  the  omo-hyoid  muscle,  and 
some  vessels  and  nerves  turning  backwards  towards  the  scapula  are 
included. 

Dissection.  By  the  reflection  of  the  trapezius  and  latissimus,  and  by 
the  dissection  made  subsequently  (p.  3oo),  the  several  parts  in  this  layer 
will  have  been  sufficiently  prepared  for  learning. 

*  The  LEVATOR  ANGULi  SCAPULA:  (fig.  116,  ^)  ariscs  by  tendinous 
slips  from  the  posterior  transverse  processes  of  the  upper  three  or  four 
cervical  vertebrae.  The  fibres  form  rather  a  roundish  muscle,  and  are 
inserted  into  the  base  of  the  scapula  between  the  spine  and  the  superior 
angle. 

At  its  origin  the  muscle  lies  beneath  the  sterno-mastoideus,  and  at  its 
insertion  beneath  the  trapezius,  where  it  touches  the  serratus  magnus  mus- 
cle ;  the  rest  of  the  muscle  appears  in  the  posterior  triangular  s})ace  of  the 
neck.  Beneath  it  are  some  of  the  other  cervical  muscles,  viz.,  splenius 
colli  and  cervicalis  ascendens. 

Action.  The  muscle  raises  the  angle  and  hinder  part  of  the  scapula, 
and  depresses  the  acromion;  but  united  with  the  upper  part  of  the  trape- 
zius, which  prevents  the  rotation  down  of  the  acromion,  it  shrugs  the 
shoulder. 

When  the  shoulder  is  fixed,  the  neck  can  be  bent  laterally  to  the  same 
side. 

*  RiiOMBOiDEi  Muscles.  The  thin  muscular  layer  of  the  rhomboidei 
is  attaclied  to  the  base  of  the  scaj)ula,  and  consists  of  two  pieces,  large  and 
small,  which  are  separated  by  a  slight  interval. 

*  The  rhomhoidevs  minor  (fig.  116,  ^)  is  a  thin  narrow  band,  which 
arises  from  the  spines  of  the  seventh  cervical  and  first  dorsal  vertebrae,  and 
the  ligamentum  nuchae;  it  is  inserted  into  the  base  of  the  scapula,  opposite 
the  smootli  surface  at  the  root  of  the  spine. 

*  The  rliomhoideus  major' (fig.  116,  ^)  is  larger  than  the  preceding  by 
the  width  of  tliree  or  more  spinous  processes.  It  arises  from  the  S[)ines  of 
four  or  five  dorsal  vertebrrf?  below  tlie  rhomboideus  minor,  and  from  the 
supraspinous  ligament;  and  its  fibres  are  directed  outwards  and  downwards 
to  be  fixed  to  tlie  base  of  the  scapula  between  the  spine  and  the  lower 
angle.  Sometimes  all  the  fibres  do  not  reach  the  scapula  directly,  some 
ending  on  a  tendinous  arch  near  the  bone. 

The  rhomboidei  muscles  are  covered  chiefly  by  the  trapezius  and  latis- 
simus; but  a  portion  of  the  larger  rhomboid  is  subcutaneous  near  the 
angle  of  the  scapula. 

Action.  From  tlie  direction  of  their  fibres  both  rhomboidei  will  draw 
the  base  of  the  scapula  upwards  and  backwards,  so  as  to  de{)ress  the  acro- 
mion.    In  combination  with   the  trapezius   they  will  carry  the  scapula 


SCAPULAR    VESSELS.  359 

directly  back  ;  for  as  one  tends  to  raise,  and  the  other  to  depress  the  acro- 
mion, the  bone  will  be  moved  in  a  direction  between  the  two  forces.  By 
their  united  action  the  muscles  help  to  fix  the  scapula. 

The  OMO-iiYOiD  MUSCLE  consists  of  two  fl<ishy  bellies,  anterior  and 
posterior,  which  are  united  by  an  intervening  tendon.  Only  the  posterior 
half  is  now  seen. 

The  muscle  ai'ises  from  the  upper  border  of  the  scapula  behind  the 
notch,  and  from  the  ligament  converting  the  notch  into  a  foramen.  The 
fibres  form  a  thin,  riband-like  muscle,  which  is  directed  forwards  across 
the  lower  part  of  the  neck,  and  ends  anteriorly  in  a  tendon  beneath  the 
sterno-mastoideus  (p.  72).  The  fleshy  belly  of  the  muscle  is  placed  partly 
beneath  the  trapezius ;  and  is  partly  superficial  in  the  posterior  triangular 
space  of  the  neck,  where  it  lies  above  the  clavicle  and  tlie  subclavian 
artery.  It  crosses  the  suprascapular  vessels  and  nerve,  and  the  brachial 
plexus  near  the  scapula. 

Action.  For  the  supposed  use  of  the  posterior  belly  of  the  omo-hyoideus, 
see  page  72. 

The  suprascapnlar  artery^  a  branch  of  the  subclavian  (p.  78),  is  directed 
outwards  across  the  lower  part  of  the  neck  to  the  dorsum  of  the  scapula. 
The  vessel  courses  behind  the  clavicle  with  the  suprascapular  nerve,  but 
beneath  the  trapezius  and  omo-hyoid  muscles  to  the  supraspinal  fossa. 
Before  entering  the  fossa  it  furnishes  a  small  branch  (supra-acromial)  to 
the  upper  surface  of  the  acromion. 

The  suprascapular  nerve^  an  offset  of  the  brachial  plexus  (p.  79),  is 
inclined  backwards  to  the  superior  border  of  the  scapula.  It  passes  through 
the  notch  in  the  upper  costa  of  the  bone,  and  terminates  beneath  the  supra- 
spinatus  in  the  muscles  of  the  dorsum  of  the  .scapula  (p.  248). 

The  transverse  cervical  artery,  also  a  branch  of  the  subclavian  (p.  78), 
has  the  same  direction  as  the  suprascapular,  towards  the  upper  part  of  the 
scapula,  but  it  is  higher  than  the  clavicle.  Crossing  the  u{)per  part  of  the 
space  in  which  the  subclavian  artery  lies,  it  passes  beneath  the  trapezius, 
and  divides  into  the  two  following  branches — superficial  cervical  and  pos- 
terior scapular : — 

a.  The  superficial  cervical  branch  is  distributed  chiefly  to  the  under 
surface  of  the  trapezius,  though  it  furnishes  offsets  to  the  levator  anguli 
scapula  and  the  cervical  glands. 

b.  The  posterior  scapular  branch  crosses  beneath  the  elevator  of  the 
angle  of  the  scapula,  and  turns  along  the  base  of  the  scapula  beneath  the 
rhomboid  muscles.  If  the  rhomboid  muscles  are  divided,  the  artery  will 
be  seen  to  furnish  branches  to  them  ;  and  to  give  small  anastomotic  twigs 
to  both  surfaces  of  the  scapula.  This  branch  arises  very  frequently  from 
the  third  part  of  the  subclavian  trunk. 

The  suprascapular  and  transverse  cervical  veins  have  the  same  course 
and  branches  as  the  arteries  above  described ;  they  open  into  the  external 
jugular,  near  its  junction  with  the  subclavian  vein. 

Nerve  to  the  rhomboid  muscles.  This  slender  nerve  of  the  brachial  plexus 
(p.  79)  courses  beneath  the  elevator  of  the  angle  of  the  scapula,  and  is 
distributed  to  the  rhomboidei  on  the  under  surface.  Before  its  termination 
it  supplies  one  or  two  twigs  to  the  elevator  of  the  scapula. 

*  Third  Layer  (fig.  1 17).  In  this  stratum  are  the  following  muscles  : — 
the  serratus  posticus  superior  and  inferior,  with  the  splenius. 

*  Dissection.  By  reflecting  the  rhomboidei  muscles  towards  the  spinous 


360 


DISSECTION    OF    THE    BACK 


processes,  and  removing  loose  areolar  tissue,  the  thin  upper  serratus  muscle 
beneath  them  will  be  laid  bare. 

The  splenius  and  the  inferior  serratus  have  been  previously  exposed  by 

the  reflection  of  the  trapezius  and 


Fig.  117. 


latissimus. 

*  The    SERRATi    muscles   are 

fvT — r'^^^^'}'^ — ^""^iIMli  very  thin,  and  receive  their  name 

"  ^^^  -„  ;;_1'%,     -'flHI  from  their  toothed  attacliment  to 

SUfli^  ^^^^Jlmmm  *^'^  ^^^^*     '^^^^Y  ^^^  ^^^'^  ^"  num- 

ber,   superior   and   inferior,    and 

have  aponeurotic  origins  from  the 
spines  of  the  vertebrae. 

*  The  serratus  posticus  supe- 
rior (fig.  117,  ^)  arises  from  the 
ligamentum  nuclide,  and  from  the 
spinous  processes  of  the  last  cer- 
vical, and  two  or  three  upper 
dorsal  vertebras.  The  fleshy 
fibres  are  inclined  down  and  out, 
and  are  inserted  by  slips  into  the 
second,  third,  and  fourth  ribs, 
external  to  their  angles. 

The  muscle  rests  on  the  sple- 
nius, and  is  covered  by  the  rhom- 
boideus  major. 

*  Tlie  serratus  posticus  infe- 
rior (fig.  116,  ®)  occupies  the 
lumbar  region,  and  is  wider  than 
the  preceding  muscle.  Its  apo- 
neurosis of  origin  is  inseparably 
united  with  that  of  the  latissimus 
dorsi,  and  with  the  fascia  lumbo- 
rum,  and  is  connected  to  the 
spinous  processes  of  the  last  two 
dorsal  and  first  three  lumbar  ver- 
tebrae. The  fleshy  fibres  ascend 
to  be  inserted  into  tlie  last  four 
ribs  in  fiont  of  their  angles,  each 
successive  piece  extending  further 
forwards  than  the  one  below. 

This  muscle  lies  on  the  mass  of  the  erector  spina? ;  and  with  its  tendon 
the  vertebral  aponeurosis  is  united. 

Action.  The  superior  serratus  raises  the  upper  ribs,  and  ofllciates  as  an 
inspiratory  muscle  ;  and  the  inferior,  de])ressing  the  lower  ribs,  becomes  an 
expiratory  muscle.  Theile  supposes  tlie  inferior  to  act  indirectly  as  a 
muscle  of  inspiration,  because,  by  fixing  the  lower  ribs,  it  enables  the  dia- 
phragm to  contract  more  effectively. 

*  The  vertebral  aponeurosis  is  a  fibrous  expansion,  which  is  spread  over 
the  fourth  layer  of  muscles,  and  confines  the  erector  spina3  in  the  vertebral 
groove. 

Inferiorly  it  is  thickened  by  the  tendons  of  the  latissimus  and  lower 
serratus;  but  it  is  continued  above  beneath  the  splenius,  without  joining 
the  upper  serratus,  and  blends  with  the  deep  fascia  of  the  neck. 


Part  of  the  Third  Layer  of  the  Back- 
Muscles. 

A.  Serratns  posticus  superior. 

B.  Splenius  capitis, 
c.  Splenius  colli. 

D.  Ilio-costalis, 

E.  Longissimus  dorsi. 

F.  Spinalis  dorsi. 


SERRATI    AND    SPLENIUS    MUSCLES.  361 

Internally  it  is  attaclied  to  the  spinous  processes.  Externally  it  is  con- 
nected to  the  posterior  third  of  the  iliac  crest,  uniting  with  tlie  tendon  of 
the  latissimus  ;  between  the  hip-bone  and  the  ribs,  to  the  fascia  lumborum  ; 
and  in  the  dorsal  region  to  the  ribs  and  a  fascia  over  the  intercostal  mus- 
cles. Below,  between  the  pelvic  and  vertebral  attachments,  it  blends  with 
the  underlying  tendon  of  the  erector  spinae  and  multifidus. 

*  Dissectio7i.  The  up[)er  serratus  is  to  be  cut  through,  and  the  subja- 
cent vertebral  aponeurosis  to  be  taken  away ;  and  the  part  of  the  splenius 
muscle  under  the  serratus  should  be  cleaned. 

The  SPLENIUS  muscle  (fig.  117)  is  thin  and  elongated;  it  is  undivided 
internally,  but  is  split  externally  into  two  parts.  It  takes  origin  along  the 
middle  line  from  the  six  upper  dorsal  spines,  from  the  seventh  cervical, 
and  from  the  ligamentum  nucliae  as  high  as  the  third  cervical  vertebra. 
Some  fibres  ascend  to  the  head  (splenius  capitis),  and  others  to  the  neck 
(splenius  colli). 

The  splenius  colli^  c,  is  inserted  by  tendinous  slips  into  the  posterior 
transverse  processes  of  the  u|)per  three  cervical  vertebrae  w^ith,  but  behind 
the  attachment  of  the  elevator  of  the  angle  of  the  scapula. 

The  splenius  capitis,  b,  much  the  largest,  is  inserted  by  a  thin  tendon 
into  the  aj)ex  and  hinder  border  of  the  mastoid  process,  and  into  the  bone 
behind  it  for  about  an  inch  and  a  half. 

Tliis  muscle  is  situate  beneath  the  trapezius,  the  rhomboidei,  and  the 
serratus  superior;  and  the  insertion  into  the  occipital  bone  is  beneath  the 
sterno-mastoideus.  The  complexus  muscle  projects  above  the  upper  border 
of  the  splenius  capitis. 

Action.  The  cranial  parts  of  both  muscles  will  carry  the  head  directly 
back ;  and  one  will  turn  the  face  to  the  same  side. 

The  splenius  colli  of  botii  sides  will  bend  back  the  upper  cervical  verte- 
brae ;  but  one  muscle  will  turn  the  face  to  the  same  side,  being  able  to 
rotate  the  head  by  its  attachment  to  the  transverse  process  of  the  atlas. 

*  Fourth  Layer.  In  this  layer  are  included  the  spinalis  dorsi ;  the 
erector  spin^e,  with  its  divisions,  and  accessory  muscles  to  the  neck  ;  and 
the  complexus  muscle.  Most  of  the  vessels  and  nerves  of  the  Back  are  to 
be  learnt  with  tliis  layer  of  muscles. 

Dissection  (fig.  118).  To  lay  bare  the  complexus  muscle  in  the  neck, 
the  s{)lenii  must  be  detached  from  the  spinous  processes,  and  thrown  out- 
wards. 

And  whilst  the  large  erector  spin;i?  is  being  displayed  in  the  dorsal  and 
lumbar  regions  by  the  dissector  of  the  upper  limb,  two  prolongations  from 
it  to  the  cervical  vertebrae  and  the  head  are  to  be  defined  by  the  dissector 
of  the  neck  :  One,  a  thin  narrow  muscle,  the  cervicalis  ascendens,  is  con- 
tinued beyond  the  ribs  from  the  outer  piece  of  the  erector  (ilio-costalis), 
and  is  to  be  separated  from  the  muscles  around.  The  otlier  is  a  larger 
offset  of  the  inner  piece  of  the  erector  (longissimus  dorsi) ;  blended  at  first 
with  the  fibres  of  the  longissimus,  it  is  divided  afterwards,  like  the  sple- 
nius, into  a  cranial  part  (trachelo-mastoid)  and  a  cervical  part  (transversalis 
colli). 

*  The  serratus  inferior  is  to  be  detached  with  the  vertebral  aponeurosis 
from  the  spines  in  th(^  dorsal  region,  and  the  areolar  tissue  is  to  be  cleaned 
from  the  surface  of  the  large  mass  of  the  erector  spinas  whicli  now  comes 
into  view.  Opposite  the  last  rib  is  the  beginning  of  an  intermuscular  in- 
terval, which  divides  tlie  erector  spinas  into  an  outer  piece  (sacro-lumbalis), 
and  an  inner  (longissimus  dorsi).     By  sinking  the  knife  into  this  interval 


362  DISSECTION    OF    THE    BACK. 

the  sacro-lumbalis  may  be  turned  outwards,  so  as  to  uncover  tlie  fleshy 
slips  of  its  accessory  muscle,  which  are  fixed  to  the  angles  of  the  ribs :  a 
muscular  slip  (cervicalis  ascendens)  is  prolonged  from  this  to  the  neck. 

*  In  preparing  the  sacro-lumbalis  muscle,  the  external  pieces  of  the  dor- 
sal nerves  with  their  accompanying  arteries  will  appear. 

*  Before  the  longissimus  can  be  displayed,  it  will  be  needful  to  detach, 
and  raise  towards  the  spinous  processes  the  thin  muscular  fasciculus  of  the 
spinalis  dorsi,  which  lies  between  that  muscle  and  the  spines  of  the  verte- 
bras in  the  dorsal  region.  Then  the  attachments  of  the  longissimus  dorsi 
are  to  be  traced  out.  Externally  it  has  thin  muscular  processes  of  insertion 
into  about  the  eight  lower  ribs.  Internally  it  is  inserted  into  the  trans- 
verse processes  of  the  lumbar  and  dorsal  vertebrae  by  rounded  tendons ; 
and  for  the  purpose  of  seeing  these  tendons,  the  longissimus  should  be 
drawn  away  from  the  spinous  processes,  and  its  superficial  aponeurosis 
should  be  cut  through  below  the  ribs,  along  the  line  of  separation  between 
the  muscle  and  the  fleshy  multifidus  spinae  on  the  inner  side.  From  this 
muscle,  as  from  the  sacro-lumbalis,  a  fleshy  piece  (transversalis  colli  and 
trachelo-mastoid)  is  continued  into  the  neck. 

*  Between  the  longissimus  and  the  multifidus  spinas  are  the  internal 
pieces  of  the  dorsal  and  lumbar  nerves,  and  of  the  intercostal  and  lumbar 
arteries  and  veins. 

*  The  SPINALIS  DORSI  is  placed  on  tlie  side  of  the  spines  of  the  dorsal 
vertebrje,  and  is  united  with  the  longissimus  dorsi.  Inferiorly  it  arises  by 
tendinous  processes  from  the  spines  of  the  last  two  dorsal  and  first  two 
lumbar  vertebrae,  and  by  fleshy  fibres  from  the  contiguous  tendon  of  the 
longissimus.  From  this  origin  the  fibres  ascend,  forming  arches,  whose 
concavity  looks  inwards,  and  are  connected  by  tendinous  processes  to  the 
spines  of  the  dorsal  vertebra?  as  low  as  the  eighth  or  ninth,  or  only  for  half 
that  extent. 

Action.  Both  muscles  contracting  will  extend  the  dorsal  region  of  the 
spine.  Perhaps  the  muscle  of  one  side  may  tend  to  incline  the  spine 
laterally. 

*  The  ERECTOR  SPixiE  is  the  muscular  mass  on  the  side  of  the  spine  in 
the  lumbar  region.  It  is  single  and  pointed  below  ;  and  its  cutaneous  sur- 
face is  covered  near  the  sacrum  by  a  wide  and  strong  tendon,  which  is 
common  to  it  and  the  multifidus  spinae.  The  muscle  arises  at  the  pelvis 
from  the  posterior  fifth  of  the  crest  of  tlie  hip-bone  at  the  inner  aspect, 
except  opposite  the  upper  spinous  process  :  in  the  lumbar  region  it  is  at- 
tached by  fleshy  and  tendinous  pieces  to  the  transverse  processes,  to  the 
tubercle  (process,  accessorius)  at  the  root,  and  to  the  layer  of  the  fascia 
lumborum  external  to  each.  0{)posite  the  last  rib  it  divides  into  ilio-cos- 
talis  and  longissimus  dorsi. 

*  The  iLio-cosTALis  (sacro-lumbalis)  is  the  smallest  of  the  two 
pieces  resulting  from  the  division  of  the  erector  spinae.  Its  fibres  end  in 
six  or  seven  flat  tendons,  which  are  connected  together  by  their  mjirgins, 
and  are  inserted  into  tlie  angles  of  as  many  of  the  lower  ribs.  Tlie  muscle 
is  continued  onwards  to  the  other  ribs  and  the  neck  by  a  fleshy  part,  which 
constitutes  the  two  under-mentioned  muscles: — 

*  The  mysrulus  accessorius  ad  sacro-lamhalum  begins  by  a  series  of 
tendinous  and  fleshy  bundles  on  the  angles  of  the  lower  six  ribs,  internal 
to  the  insertion  of  the  ilio-costalis  ;  and  it  ends  in  tendons,  which  are  in- 
serted into  the  remaining  ribs  (upper  six),  in  a  line  with  the  ilio-costalis, 
and  into  the  posterior  transverse  process  of  the  seventh  cervical  vertebra. 


LONGISSIMUS    DORSI.  363 

Tlie  cervicalis  ascendens  is  a  muscular  slip  prolonging  the  accessorius 
into  the  neck  :  this  muscle  is  attached  to  four  ribs  (third,  fourth,  fifth,  and 
sixth),  and  is  inserted  into  the  posterior  transverse  processes  of  three  cer- 
vical vertebrne,  viz.,  sixth,  fifth,  fourth. 

*  The  LONGISSIMUS  DORSI  gradually  decreases  in  size  as  it  ascends 
along  the  thorax.  Internally  the  muscle  is  inserted  into  the  transverse 
processes  of  all  the  dorsal  vertebrae  by  a  series  of  tendinous  and  fleshy  bun- 
dles ;  and  externally  it  is  attached  to  the  ribs,  except  the  first  two  or 
three,  by  thin  fleshy  processes  between  the  tubercle  and  angle.  Its  mus- 
cular prolongation  to  the  neck  is  united  with  the  upper  fleshy  fibres,  and 
splits  into  the  two  following  pieces: — 

The  transversalis  colli  (fig.  118,  ^)  arises  from  the  transverse  pro- 
cesses of  the  upper  six  dorsal  vertebrae,  and  is  inserted  into  the  posterior 
transverse  processes  of  the  certical  vertebrae,  except  the  first  two  and  the 
last. 

The  trachelo-mastoid  muscle  (fig.  118,  ^)  (transversalis  capitis?)  arises 
in  common  with  the  preceding,  and  is  attached,  besides,  by  distinct  ten- 
dons to  the  articular  processes  of  the  last  three  or  ibur  cervical  vertebrte. 
The  muscle  is  thin,  and  is  inserted  beneath  the  splenius  into  the  upper 
half  of  the  posterior  part  of  the  mastoid  process  :  its  insertion  is  about 
three-quarters  of  an  inch  wide.^ 

*  Connections  of  the  erector  spince.  The  erector  spinae  and  its  prolonga- 
tions occupy  the  lumbar,  thoracic,  and  cervical  parts  of  the  Back. 

In  the  loins  the  muscle  is  contained  in  an  aponeurotic  sheath  (p.  358), 
and  has  the  multifidus  spinte  on  its  inner  side  :  its  attachment  on  the  in- 
ner surface  of  the  innominate  bone  corresponds  in  part  with  the  origin  of 
the  gluteus  maximus  on  the  outer  side.  The  superficial  tendon,  which  is 
common  to  it  and  the  multifidus,  will  be  described  with  the  last-mentioned 
muscle  (p.  371). 

Opposite  the  ribs  the  ilio-costalis  and  longissimus  dorsi  are  concealed  by 
the  muscles  of  the  other  layers  already  examined. 

In  the  neck  its  accessory  small  muscles  lie  underneath  the  splenius  and 
the  trapezius  ; — the  cervicalis  ascendens  is  attached  in  a  line  with,  but 
below  the  splenius  colli  ;  and  the  transversalis  colli  and  trachelo-mastoid 
are  more  internal,  or  between  the  splenius  and  cervicalis  and  the  com- 
plexus. 

Action.  Taking  their  fixed  point  at  the  pelvis,  both  erectors  will  keep 
the  spine  straight  in  sitting  and  standing ;  and,  in  rising  from  stooping  to 
the  ground,  they  will  bring  the  trunk  into  the  erect  posture.  In  laborious 
respiration,  the  spine  being  fixed,  the  muscles  are  able  to  depress  the  ribs, 
and  assist  in  the  expulsion  of  the  air  from  the  thorax. 

One  muscle  will  incline  the  spinal  column  laterally  and  to  its  own  side. 

The  cervical  prolongations  of  the  erector  act  on  the  neck  and  head,  as 
below  : — 

The  cervicalis  ascendens.  Taking  tlieir  fixed  point  below,  both  mus- 
cles will  extend  the  cervical  i)art  of  tlie  spine  :  and  acting  from  the  trans- 
verse processes  they  will  elevate  the  ribs.  One  muscle  will  give  a  lateral 
movement  to  the  neck. 

1  The  anatomy  of  the  prolongation  from  the  longissimus  might  be  simplified  by 
describing  it  as  the  transversalis  muscle  with  a  double  insertion,  like  the  splenius, 
into  the  head  and  neck.  In  accordance  with  the  nomenclature  of  the  splenius  the 
part  to  the  head  might  be  named  transversalis  capitis,  and  the  part  to  the  neck 
transversalis  colli,  as  at  present. 


364 


DISSECTION    OF    THE    BACK. 


The  transversalis  co//f  bends  back  the  neck  if  the  muscles  of  both  sides 
contract  together;  or  laterally  towards  its  own  side,  if  only  one  is  used. 

The  tracheh-mastoldevs  will  extend  the  head  in  concert  with  its  fell6w ; 
or  by  itself  will  turn  the  face  to  its  own  side,  and  then  help  to  approximate 
the  head  to  the  shoulder. 

The  cOMPLExus  (fig.  118,  ^)  is  internal  to  the  prolongations  from  the 
longissimus  dorsi,  and  converges  towards  its  fellow  of  the  opposite  side  at 

Fig.  118. 


DiRSECTION  OF  THE  MCSCLES  UNDERNEATH  THK  SPLKNIUS. 

A.  Longus  colli.  H.  Semispinali.s  dorsi. 

B.  Transversalis  colli.  a.  Occipital  artery. 

c    Trachelo-mastoid.  1.  Great  occipital  nerve. 

D.  Complexus.  2.  External  piece  of  the  second  nerve. 

F.  Splenins  capitis,  cut.  3.  Outer  piece  of  the  third  nerve. 

G.  Splenius  colli,  cut. 

the  occipital  bone.  Narrow  at  its  lower  end,  the  muscle  arises  by  ten- 
dinous pieces  from  the  transverse  processes  of  the  up|)er  six  dorsal  verte- 
brre,  from  the  spine  of  the  last  cervical,  and  from  the  articular  processes 
of  the  cervical  vertebrjB  as  high  as  the  third.  Tlie  fleshy  fibres  pass  up- 
wards to  be  inserted  into  an  impression  between  the  curved  lines  of  the  os 
occipitis,  which  reaches  outwards  nearly  two  inches  from  the  occipital 
crest  towards  the  trachelo-mastoidcus. 

The  inner  part  of  the  complexus  having  two  fleshy  bellies  with  an  in- 
tervening tendon,  is  described  often  as  a  separate  muscle  with  the  name 
hiventer  cervicis. 


POSTERIOR  CERVICAL  NERVES.  365 

The  complexus  is  concealed  by  the  splenis  and  trapezius  :  and  the  cuta- 
neous surface  is  marked  by  a  tendinous  cross  intersection  towards  the 
upper  end.  Two  or  three  of  the  cervical  nerves  perforate  it.  Along  the 
inner  side  is  the  semispinalis  muscle,  with  tiie  ligamentum  nuchse.  Be- 
neath it  are  the  small  recti  and  obliqui  muscles,  the  semispinalis,  and  the 
cervical  nerves  and  vessels. 

Action.  Both  muscles  will  move  the  head  directly  back.  One  will 
draw  the  occiput  down  and  back  towards  its  own  side. 

Dissection  of  vessels  and  nerves  (fig.  119).  In  the  neck  the  nerves  and 
vessels  will  be  brought  into  view  by  detaching  the  complexus  from  the 
occipital  bone  and  the  spine  of  the  seventh  vertebra,  and  throwing  it  out- 
wards carefully  from  the  subjacent  parts.  Beneath  the  muscle  is  a  dense 
fascia,  in  which  are  contained  the  ramifications  of  the  cervical  nerves,  and 
the  deep  cervical  and  other  vessels. 

Each  nerve  except  the  first  divides  into  an  inner  and  an  outer  piece. 
Dissect  out  first  the  inner  pieces  of  the  seven  lowest,  which  lie  partly  over 
and  partly  beneath  the  fibres  of  the  semispinalis  muscle  (g).  The  exter- 
nal pieces  (^)  are  very  small ;  they  are  given  off  between  the  transverse 
processes  close  to  where  the  trunks  appear ;  they  are  to  be  looked  for  outside 
the  complexus,  and  enter  the  muscles  prolonged  from  the  erector  spinie. 

The  first  or  suboccipital  is  the  most  difficult  of  the  set  to  find  :  this  little 
nerve  is  a  short  trunk,  whicli  is  contained  in  the  interval  between  the 
small  recti  and  obliqui  muscles  near  the  head ;  it  will  be  best  found  by 
looking  for  the  small  twigs  furnished  by  it  to  the  muscles  around. 

The  deep  cervical  artery  is  met  with  on  the  semispinalis  muscle  ;  a  part 
of  the  vertebral  artery  will  be  found  in  contact  with  the  suboccipital 
nerve ;  and  the  occipital  artery  will  be  seen  crossing  the  occipital  bone. 

*  Opposite  the  thorax  the  dorsal  nerves  and  vessels  will  be  readily  dis- 
played on  the  inner  side  of  the  longissimus  dorsi  muscle,  on  the  removal 
of  a  little  fatty  tissue  from  between  the  transverse  processes.  External 
and  internal  pieces  are  to  be  traced  from  each  nerve  and  vessel  into  the 
muscles  ;  some  of  the  former  have  been  seen  in  the  interval  between  the 
ilio-costalis  and  the  longissimus  dorsi. 

*  The  two  pieces  of  the  lumbar  nerves  and  vessels  will  be  found  in  the 
same  line  as  the  dorsal ;  but  the  inner  set  are  the  most  difficult  to  be  dis- 
covered. 

*  The  small  sacral  nerves  are  placed  beneath  the  multifidus  spinas,  and 
will  be  dissected  after  the  examination  of  that  muscle  (p.  372). 

*  Posterior  Primary  Branches  of  the  Spinal  Nerves.  The 
spinal  nerves,  with  a  few  exceptions  in  the  cervical  and  sacral  groups, 
bifurcate  in  the  intervertebral  foramina  into  anterior  and  posterior  primary 
branches  (p.  165).  The  posterior  supply  the  integuments  and  the  muscles 
of  the  back,  and  are  now  to  be  learnt. 

In  the  neck.  The  posterior  primary  branches  of  the  cervical  nerves  are 
eight  in  number,  and  issue  between  the  transverse  processes ;  but  those  of 
the  first  and  second,  which  begin  on  the  neural  arches  of  the  atlas  and 
axis,  cross  those  arches.  All,  except  the  first,  divide  into  internal  and 
external  pieces. 

The  external  pieces  (fig.  118)  are  very  inconsiderable  in  size,  and  end 
in  the  splenius,  and  in  the  muscles  prolonged  from  the  erector  spinre. 

The  internal  pieces  (fig.  119)  are  larger  than  the  external;  they  are 
directed  towards  the  spinous  processes,  the  three  lowest  nerves  passing 
beneath  the  semispinalis,  and  the  four  next  over  that  muscle,    ^y  the  side 


866 


DISSECTION    OF    THE    BACK. 


of  the  spine  cutaneous  branches  are  furnished  to  the  neck  and  the  head  by 
the  nerves  that  are  superficial  to  tlie  semispinalis  ;  these  cutaneous  offsets 
ascend  to  the  surface  through  the  splenius,  the  complexus,  and  tra))ezius 
muscles,  and  are  distributed  as  before  seen  (p.  354).     In  their  course   to 


Fiff.  319. 


Deep  Dissection  of  thk  Back  of  the  Neck 
Muscles  : 

A.  Rectus  posticus  major. 

B.  Rpctus  posticus  minor. 
c.  Obliquus  inferior. 
D.  Obliqnus  superior, 
B.  Splenius  capitis. 

F.  Complexus,  cut  across. 

G.  Semispinalis  colli. 
Arteries  : 

a.  Occipital,  and  h,  its  cervical  branch. 

c.  Vertebral  artery,  and  d,  its  cervical  branch. 

e.  Deep  cervical  artery  of  the  subclavian. 


(Illustrations  of  Dissections.) 
Nerves  : 

1.  Suboccipital  nerve  (posterior  branch). 

2,  Inner  piece  of  the  posterior  primary  branch 
of  the  second  nerve. 

3,  Inner  piece  of  the  third  nerve. 

4.  Inner  piece  of  the  fourth. 
And  the  remaining  figures  point  to  the  inner 

pieces  of  the  respective  nerves. 


the  spine  the  nerves  supply  the  surrounding  muscles,  viz.,  complexus, 
semispinalis,  multifidus  spince,  and  interspinales. 

The  cutaneous  branches  of  the  second  and  third  nerves  reach  the  head, 
and  require  a  separate  notice. 

That  of  the  second  nerve  (fig.  119,  ^),  named  great  occipital,  appearing 


POSTERIOR  CERVICAL  NERVES.  867 

beneath  the  inferior  oblique  muscle  to  which  it  gives  offsets,  is  directed 
upwards  througli  the  complexus  and  trapezius  to  end  on  the  occiput  (p.  23). 

The  branch  of  the  third  nerve  (fig.  119,  ^)  supplies  an  offset  to  the  in- 
teguments of  the  neck  ;  and  ascending  to  tlie  head  througli  the  trapezius, 
is  distributed  to  the  lower  part  of  the  occiput,  internal  to  the  great  occi- 
pital nerve.  Usually  tins  nerve  joins  the  preceding  both  beneath,  and 
superficial  to  the  trapezius. 

The  posterior  primary  branch  of  the  suboccipital  or  first  spinal  nerve 
(fig.  119,  ^)  is  very  short,  and  appears  in  the  interval  between  the  recti 
and  obliqui  muscles.  In  passing  from  the  spinal  canal  it  is  placed  between 
the  arch  of  the  atlas  and  the  vertebral  artery.  The  following  branches 
radiate  from  its  extremity: — 

One  enters  the  under  surface  of  the  complexus  near  the  cranial  attach- 
ment. A  slender  branch  is  furnished  to  each  of  the  small  muscles  bound- 
ing the  space  in  which  the  nerve  is  contained,  viz.,  the  rectus  major  and 
minor,  and  the  superior  and  inferior  oblique :  the  offset  to  the  last  muscle 
joins  the  inner  branch  of  the  second  cervical  nerve.  Occasionally  this 
nerve  gives  a  cutaneous  branch  to  the  occiput. 

Posterior  cervical  plexus.  Sometimes  there  is  an  intercommunication 
between  the  suboccipital  nerve  and  the  internal  pieces  of  the  next  two 
cervical  nerves  beneath  the  complexus  ;  this  forms  the  posterior  cervical 
plexus  of  M.  Cruveilhier. 

*  In  the  dorsal  region.  The  posterior  primary  branches  of  the  dorsal 
nerves  are  twelve  in  number,  and  appear  between  the  transverse  processes. 
Each  divides  into  an  internal  and  an  external  piece ;  and  these  are  distri- 
buted after  the  same  plan  as  in  the  neck. 

*  The  external  pieces  increase  in  size  from  the  first  to  the  last,  and  are 
differently  distributed  above  and  below.  The  tipper  six  or  eight  pass  be- 
neath the  longissimus  and  its  cervical  prolongation,  as  far  as  the  interval 
between  the  longissimus  and  the  ilio-costalis,  and  end  by  supplying  these 
muscles  and  the  levatores  costarum.  The  lower  six  or  four  have  a  similar 
arrangement  and  distribution  with  respect  to  muscles  ;  but,  after  reaching 
the  interval  between  the  ilio-costalis  and  the  longissimus  dorsi,  they  are 
continued  to  the  surface  through  the  serratus  and  latissimus  muscles,  nearly 
in  a  line  with  the  angles  of  the  ribs. 

*  The  internal  pieces  decrease  in  size  from  above  downwards,  and  are 
directed  inwards  between  the  semispinalis  dorsi  and  multifidus  spina?  mus- 
cles ;  offsets  are  supplied  to  the  muscles  between  which  they  are  placed. 
The  upper  six  become  cutaneous  along  the  sides  of  the  spinous  processes 
by  perlbrating  the  seratus,  rhomboideus,  and  trapezius.  The  lower  six 
are  small  in  size,  and  end  in  the  multifidus  spinas  muscle. 

*  In  the  loins.  The  posterior  primary  branches  of  the  lumbar  nerves, 
five  in  number,  appear  between  the  erector  and  multifidus  spiniij.  In  their 
mode  of  dividing  and  general  arrangement  they  resemble  the  dorsal  nerves. 
Cutaneous  offsets  are  furnished  by  the  external  set  of  branches. 

'^  The  external  pieces  enter  the  erector  spina?,  and  supply  it  and  the 
small  intertransverse  muscles.  The  first  three  pierce  the  erector  spinse, 
and  become  cutaneous  after  perforating  the  aponeurosis  of  the  latissimus. 
The  branch  of  the  last  nerve  is  connected  with  the  corresponding  part  of 
the  first  sacral  nerve  by  an  offset  near  the  bones. 

*  The  internal  pieces  are  furnished  to  the  multifidus  spinae  muscle. 
Near  their  origin  they  are  difficult  to  find,  in  consequence  of  being  con- 
tained in  grooves  on  the  articular  processes. 


368  DISSECTION    OF    THE    BACK. 

*  Vessels  in  the  back.  The  vessels  now  dissected  are  the  occipital 
and  the  deep  cervical ;  part  of  the  vertebral ;  and  the  posterior  branches 
of  the  intercostal  and  the  lumbar  arteries  of  the  aorta.  Veins  accompany 
the  arteries  for  the  most  part. 

In  the  neck.  Tiie  vessels  in  the  neck  are  the  occipital,  the  vertebral, 
and  the  deep  cervical. 

The  occipital  artery  (fig.  119,  «)  courses  along  the  occipital  bone.  Ap- 
pearing from  beneath  the  digastric  muscle,  the  vessel  is  directed  back- 
wards beneath  the  sterno-mastoideus,  the  splenius,  and  sometimes  the 
trachelo-mastoideus,  but  over  theobliquus  superior  and  complexus  muscles. 
Near  the  middle  line  it  perforates  the  trapezius,  and  ascends  to  the  occi- 
put, on  which  it  is  distributed  (p.  21).  It  su[)plies  the  surrounding  muscles, 
and  furnishes  the  following  branch  to  the  neck  : — 

The  cervical  branch  (b)  (ram.  princeps  cervicalis)  distributes  twigs  to 
the  under  part  of  the  trapezius,  and  passing  beneath  the  complexus,  anas- 
tomoses with  the  vertebral  and  deep  cervicjil  arteries. 

The  vertebral  artery  (fig.  119,  c)  lies  on  the  neural  arch  of  the  first 
vertebra,  behind  the  articulating  process,  and  appears  in  the  interval  be- 
tween the  straight  and  oblique  muscles.  Beneath  it  is  the  suboccipital 
nerve.  Small  brandies  are  given  to  the  surrounding  parts,  and  to  anasto- 
mose with  the  contiguous  arteries. 

The  deep  cervical  artery  (fig.  119,  e)  is  a  branch  of  the  superior  inter- 
costal (p.  78),  and  resembles  the  posterior  branches  of  the  other  inter- 
costal arteries.  Passing  back  between  the  transverse  process  of  the  last 
cervical  vertebra  and  the  neck  of  the  first  rib,  it  ascends  between  the  com- 
plexus and  semispinalis  muscles,  as  high  as  the  upper  border  of  the  latter, 
and  anastomoses  with  the  cervical  branch  of  the  occipital  artery.  The 
contiguous  muscles  receive  branches  from  it,  and  anastomoses  are  formed 
between  its  offsets  and  those  of  the  vertebral. 

*  In  the  dorsal  region.  The  postei'ior  branches  of  the  intercostal  ves- 
sels (p.  337)  pass  back  between  the  vertebra)  and  the  anterior  costo-trans- 
verse  ligament,  and  are  divided  like  the  nerves  into  inner  and  outer 
pieces. 

*  The  {n?ier  branches  end  in  the  fleshy  mass  of  the  multifidus  spinte  and 
semispinalis,  and  furnish  small  cutaneous  offsets  with  the  nerves. 

*  The  external  branches  cross  beneath  the  longissimus  dorsi,  and  supply 
it  and  the  ilio-costalis.  Like  the  nerves,  the  lowest  branches  of  this  set 
are  the  largest  and  extend  to  the  surface. 

As  the  dorsal  branch  of  the  intercostal  artery  passes  by  the  interverte- 
bral foramen,  it  furnishes  a  small  intraspinal  artery  to  the  spinal  canal. 

*  In  the  loins.  Tlie  posterior  branches  of  the  lumbar  arteries  divide, 
like  the  intercostal,  into  internal  and  external  pieces,  as  soon  as  they  reach 
the  interval  between  the  longissimus  dorsi  and  multifidus  spinas.  Each 
gives  also  a  spinal  branch  to  the  spinal  canal. 

*  The  internal  branches  are  small,  and  end  in  the  multifidus  spinas 
muscle. 

*  The  external  branches  supply  the  erector  spinas;  and  offsets  are  con- 
tinued onwards  to  the  integuments  with  the  superficial  nerves. 

Veins.  With  the  deep  cervical  artery  is  a  large  vein,  vena  profunda 
cervicis,  which  communicates  with  the  occijntal  and  other  deep  veins  in 
this  region,  forming  the  posterior  plexus  of  the  neck,  and  passes  forwards 
with  its  artery,  between  the  transverse  processes,  to  join  the  vertebral 
vein. 


RECTI    AND    OBLIQUI.  369 

The  occipital  vein  lies  with  its  artery,  and  communicates  sometimes 
with  the  lateral  sinus  oK  the  skull  through  the  mastoid  foramen. 

The  dorsal  and  himhar  veins  correspond  in  their  branching  and  distri- 
bution with  tlie  arteries  they  accompany,  and  end  in  the  intercostal  veins 
and  the  vena  cava. 

In  contact  with  the  spinous  processes  and  plates  of  the  vertebrae  is  a 
deeper  set  of  veins  {dorsi  spirial),  which  anastomose  freely  together,  and 
open  into  the  veins  in  the  interior  of  the  spinal  canal. 

*  Fifth  Layer.  In  this  layer  are  the  following  small  muscles:  the 
recti  and  obliqui,  semispinalis,  interspinales,  multifidus  spina?,  and  inter- 
transversales. 

Dissection.  Most  of  the  remaining  muscles  of  the  Back  are  uncovered 
by  tlie  previous  dissection.  Between  the  Hrst  two  vertebrae  and  the  occi- 
pital bone  the  small  straight  and  oblique  muscles  extend. 

*  In  the  cervical  and  dorsal  regions  the  semispinalis  muscle  appears, 
with  the  small  interspinales  internal  to  it  ;  and  occupying  a  corresponding 
position  in  the  loins,  is  the  multifidus  spinre. 

*  The  small  intertransverse  muscles  of  the  lumbar  region  will  be  found 
by  removing  the  erector  spinte. 

The  RECTUS  CAPITIS  POSTICUS  MAJOR  (fig.  119,  a)  is  the  largest  of 
the  muscles  between  the  occipital  bone  and  the  first  two  vertebrae,  and 
arises  from  the  side  of  the  spinous  process  of  the  axis.  It  is  inserted  into 
the  outer  part  of  the  inferior  curved  line  of  the  occipital  bone  for  about  an 
inch,  as  well  as  into  the  surface  below  it. 

The  muscle  is  directed  outwards  very  obliquely,  and  forms  one  side  of 
the  triangular  space  which  contains  the  suboccipital  nerve  and  the  verte- 
bral artery.  Its  upper  attachment  lies  beneath  the  superior  oblique 
muscle. 

Action.  By  the  action  of  both  muscles  the  head  will  be  put  backwards. 
By  one  rectus  the  face  will  be  turned  to  the  same  side ;  and  after  the  head 
has  been  so  rotated,  the  muscle  will  assist  in  extending  the  head. 

The  RECTUS  CAPITIS  POSTICUS  MINOR  (fig.  119,  b)  is  internal  to  the 
preceding,  and  is  shorter  than  it.  Arising  from  the  neural  arch  of  the 
atlas,  the  muscle  is  inserted,  close  to  the  middle  line,  into  the  inferior 
curved  ridge  of  the  occipital  bone,  and  between  this  and  the  foramen 
magnum. 

This  small  muscle  is  fan-shaped,  and  is  deeper  than  the  rectus  major : 
it  covers  the  ligament  between  the  atlas  and  the  occipital  bone.  The  two 
small  recti  muscles  correspond  with  the  inter-spinales  between  the  other 
vertebrae. 

Action.  Both  muscles,  or  one,  will  have  the  same  use,  viz.,  to  approach 
the  occiput  to  the  atlas. 

The  OBLiQuus  INFERIOR  (fig.  119,  c)  slauts  between  the  first  two 
vertebrje.  It  arises  from  the  spinous  process  of  the  axis,  external  to  the 
rectus  major  muscle,  and  is  inserted  into  the  tip  of  the  transverse  pro- 
cesses of  the  atlas. 

Action.  One  muscle  turns  the  face  to  the  same  side  by  rotating  the 
atlas  on  the  axis.  If  both  muscles  act  at  the  same  time  they  will  assist  in 
keeping  the  head  straight. 

The  OBLIQUUS  SUPERIOR  (fig.  119,  d)  takes  origin  from  the  upper  part 
of  the  transverse  process  of  the  atlas,  where  the  preceding  muscle  termi- 
nates ;  and  is  directed  inwards  to  be  inserted  between  the  curved  lines  of 
the  occipital  bone,  near  the  mastoid  process. 
24 


370  DISSECTION    OF    THE    BACK. 

This  muscle  is  concealed  by  the  complexus  and  trachelo-mastoideus,  and 
crosses  the  vertebral  artery.  Its  insertion  is  beneath  the  splenius  (e),  but 
above  the  rectus  major  muscle. 

Action.  With  its  fellow  the  upper  oblique  will  assist  in  carrying  back- 
wards the  head.  By  the  action  of  one  muscle  the  occiput  will  be  inclined 
backwards  to  the  same  side. 

The  SEMispiNALis  (fig.  119,  g)  occupies  the  vertebral  groove  in  the 
dorsal  and  cervical  regions,  and  extends  from  the  transverse  and  articular 
processes  to  the  spines  of  the  vertebrae  ;  it  is  undivided  at  the  outer,  but 
bifurcated  at  the  inner  attachment.  It  arises  externally  from  the  trans- 
verse processes  of  the  ten  upper  dorsal  vertebra,  and  from  the  articular 
processes  of  the  four  lower  cervical ;  and  it  is  inserted  by  two  [)ieces,  as 
below  : — 

The  lower  piece,  semispinaNs  dorsi,  is  inserted  into  the  spinous  processes 
of  the  upper  four  dorsal  and  the  last  two  cervical  vertebrae. 

The  upper  piece,  semispinalis  colli^  is  inserted  into  tlie  spines  of  the 
cervical  vertebrse  above  the  attachment  of  the  semispinalis  dorsi,  the  atlas 
not  receiving  any  slip. 

The  semispinalis  muscle  is  covered  by  the  complexus,  and  the  deep  cer- 
vical artery.  Some  of  the  cervical  nerves  are  superficial,  and  others 
beneath  it.     To  its  inner  side  is  the  multifidus  spinae  muscle. 

Action.  The  muscles  of  both  sides  acting  together  will  extend  the  spine. 
One  muscle  will  rotate  the  cervical  and  dorsal  parts  of  the  spine,  so  as  to 
turn  the  face  to  the  opposite  side. 

*  The  INTERSPINAL  MUSCLES  are  placed,  as  their  name  expresses  :  they 
are  arranged  in  pairs,  one  on  each  side  of  the  interspinous  ligament ;  and 
they  are  best  seen  in  the  neck  and  loins. 

In  the  cervical  region  the  muscles  are  absent  from  the  interval  between 
the  first  two  vertebrae.  They  are  small  round  bundles,  and  are  attached 
above  and  below  to  the  bifurcated  apices  of  the  spines. 

*  In  the  dorsal  region  the  muscles  are  rudimentary  ;  they  exist  between 
the  first  two,  and  the  lowest  two  pair  of  spinous  processes,  and  between 
the  last  dorsal  and  the  first  lumbar  vertebra. 

*  In  the  lumbar  region  they  are  thin  flat  muscles,  Avhich  reach  the 
length  of  the  spines. 

Action.  By  the  approximation  of  the  spinous  processes  these  small 
muscles  will  help  in  extending  the  spine.  Necessarily  the  movement  of 
each  pair  is  very  slight,  but  the  aggregate  of  all  would  amount  to  percep- 
tible motion. 

*  The  INTERTRANSVERSE  MUSCLES  lie  between  the  transverse  pro- 
cesses of  the  vertebriE ;  but  only  those  in  the  loins  and  the  back  are  now 
dissected. 

In  the  neck  they  are  double,  like  the  interspinal  muscles  of  the  same 
vertebrae  (p.  165). 

*  In  the  dorsal  region  they  are  single  rounded  bundles,  and  are  found 
only  between  the  lower  processes  :  their  number  varies  from  three  to  six. 

*  In  the  lumbar  region  the  anterior  set  are  four  thin  and  fleshy  planes. 
The  posterior  set  are  rounded  bundles,  which  are  attached  to  the  accessory 
points  at  the  roots  of  the  transverse  processes  :  these  have  been  named 
interaccessorii. 

Action.  The  small  intertransversales  help  to  incline  laterally  the  spine 
by  approximating  the  transverse  processes ;  the  motion  between  a  single 


MULTIFIDUS    SPIN^..  3Y1 

pair  of  bones  would  be  scarcely  appreciable,  as  in  the  case  of  the  inter- 
spin  ales. 

Dissection.  The  multifidus  spinas  muscle,  which  fills  the  hollow  by  the 
side  of  the  spinous  processes,  may  be  now  dissected.  The  upper  part  of 
the  muscle  is  to  be  prepared  and  learnt  by  the  dissector  of  the  head  and 
neck.  It  will  be  laid  bare  by  cutting  through  the  insertion  of  the  semi- 
spinalis,  and  everting  this. 

*  Over  the  sacrum  the  thick  aponeurosis  covering  the  multifidus  and  the 
erector  spinas  must  be  turned  aside.  In  the  dorsal  region  the  muscle  will 
appear  on  detaching,  and  drawing  the  semispinals  from  the  spines. 

*  The  MULTIFIDUS  SPiN^  muscle  extends  from  the  sacrum  to  the  second 
vertebra,  and  is  much  larger  towards  the  pelvis  than  in  the  neck. 

On  the  back  of  the  sacrum  it  takes  origin  between  the  central  and  ex- 
ternal row  of  processes,  as  low  as  the  fourth  aperture ;  from  the  inner 
surface  of  the  iliac  spine  (posterior  superior)  of  the  hip  bone ;  and  from 
the  ligaments  connecting  this  bone  to  the  sacrum.  It  is  attached  differ- 
ently along  its  outer  edge  (origin)  in  the  several  regions  of  the  spine  : — 
In  the  loins  it  arises  by  large  fasciculi  from  the  accessory  and  the  articular 
processes.  In  the  dorsal  region,  from  the  transverse  processes.  And  in 
the  neck,  from  the  articular  processes  of  the  five  lower  vertebrae.  From 
these  attachments  the  fibres  are  directed  obliquely  inwards,  some  extend- 
ing more  than  tlie  length  of  one  vertebra  to  be  inserted  into  the  spines 
and  the  neural  arches  of  the  vertebrse  from  the  second  cervical  to  the  third 
sacral. 

This  muscle  fills  chiefly  the  vertebral  groove,  and  is  concealed  by  the 
erector  spinoe  and  the  semispinalis.  The  internal  branches  of  the  vessels 
and  nerves  in  the  back  lie  along  its  outer  border.  The  small  muscles  de- 
scribed below  may  be  said  to  be  parts  of  the  multifidus.    ' 

Action.  By  the  use  of  the  muscle  of  both  sides,  the  spinal  column  can 
be  extended  ;  and  by  the  contraction  of  one,  the  spine  will  be  rotated  in 
the  dorsal  region  and  the  neck,  the  face  being  turned  to  the  opposite  side. 

*  Rotatores  dorsi  (Theile).  These  are  eleven  small  muscles  beneath  the 
multifidus  spinae  in  the  dorsal  region,  and  are  separated  from  that  muscle 
by  fine  areolar  tissue.  Each  is  attached  inferiorly  to  the  tip  and  upper 
edge  of  a  transverse  process,  and  superiorly  to  tlie  lower  border  of  the 
neural  arch  of  the  vertebra  next  above.  The  first  springs  from  the  trans- 
verse process  of  the  second  vertebra. 

Action.  These  small  rotators  will  assist  the  larger  muscle  (multifidus) 
in  turning  the  trunk  to  the  opposite  side. 

*  The  aponeurosis  common  to  the  multifidus  and  erector  spina?  is  fixed 
firmly  to  the  surrounding  bones,  and  furnishes  attachment  to  the  muscu- 
lar fibres.  In  the  middle  line  it  is  united  witii  the  spines  of  the  lower 
lumbar  vertebrae  and  sacrum.  On  the  outer  side  it  is  attaciied  to  the  pos- 
terior part  of  the  iliac  crest,  and  to  the  outer  row  of  tubercles  on  the  back 
of  the  sacrum,  being  connected  at  tlie  last  spot  with  the  great  sacro-sciatic 
ligament.  Above,  it  is  continued  some  way  on  the  surface  of  the  erector 
spina.%  but  further  on  the  longissimus  dorsi  than  the  ilio-costalis.  Below, 
the  latissimus  dorsi  and  the  vertebral  aponeurosis  blend  with  its  cutaneous 
surfjxce  (p.  3G0). 

*  Dissection  (fig.  120).  To  find  the  branches  of  the  sacral  nerves,  it 
will  be  necessary  to  remove  tlie  part  of  the  multifidus  spiniB  wiiich  covers 
the  sacrum.  The  first  three  are  split  into  two  each  :  their  external  pieces 
will  be  found  readily  on  the  great  sacro-sciatic  ligament,  from  which  they 


872 


DISSECTION    OF    THE    BACK. 


may  be  traced  inwards ;  the  inner  branches  are  very  slender  and  difficult 
to  be  recognized. 

The  lowest  two  nerves  are  very  small,  and  are  to  be  sought  on  the  back 
of  the  sacrum,  below  the  attachment  of  the  multifidus  spinse.  They  are 
not  bifurcfited  like  the  others,  but  unite  together,  and  with  the  coccygeal 
nerve  in  loops.  The  fourth  comes  through  a  sacral  a[)erture,  the  lifth 
between  the  sacrum  and  coccyx  ;  and  the  coccygeal  is  still  lower. 

Sacral  Nerves  (fig.  120) The  posterior  primary  branches  of  the 

sacral  nerves  are  five  in  number.  Four  issue  from  the  spinal  canal  by  the 
apertures  in  the  back  of  the  sacrum,  and  the  fifth  between  the  sacrum  and 
the  coccyx.  The  first  three  have  the  common  division  into  inner  and 
outer  pieces,  like  the  other  spinal  nerves  ;  but  the  last  two  are  undivided. 

*  The  Jirst  three  nerves  are  covered  by  the  multifidus  spince;  and  divide 
regularly. 

The  inner  pieces  {^)  are  distributed  to  the  multifidus ;  and  the  last  of 
this  set  is  very  fine. 

The  outer  pieces  (^)  are  larger,  and  have  communicating  offsets  from  one 
to  another  on  the  back  of  the  sacrum  :  further,  the  branch  of  tlie  first 

Fig.  120. 


Muscles  .* 

A.  Multifidus  spinse,  and 

B.  Erector  spinae  :  both  cut. 

c.  Gluteus  maximus  detached  from  its  origin,  and 

thrown  down. 
D.  Great  sacro-sciatic  ligament. 
Nerves  : 
5  I.  Last  lumbar. 
1  S  to  5  S,  the  five  sacral  nerves  issuing  from  the 

sacrum. 
1  c.  The  coccygeal  nerve,  escaping  by  the  opening 

of  the  sacral  canal. 

1.  Internal  offsets  of  the  last  lumbar  and  first  three 

sacral  (these  are  too  large  in  the  cut)  :  and 

2.  External  offsets  of  the  same  nerves. 

3.  Anterior  primary  branch,  and 

4.  Posterior  of  the  coccygeal  uerve. 

5.  The    nerve   derived  from    the    anterior   primary 

branches   of    the   lower   sacral    nerves,  which 
pierces  the  sacro-sciatic  ligament. 


Dissection  of  the  Sacral  Nerves  (Lond.  Med.  Gazette,  18-tr?). 


nerve  is  connected  with  the  corresponding  part  of  the  last  lumbar ;  and 
the  branch  of  the  third  joins  in  a  similar  manner  the  sacral  nerve  next 
below.  After  this  looping  they  pass  outwards  to  the  surface  of  the  great 
sacro-sciatic  ligament,  where  they  join  a  second  time,  and  become  cuta- 
neous.    (Dissection  of  the  Buttock.) 

*  Last  two  nerves  (4  S  and  5  S).  These  nerves,  which  are  below  the 
multifidus,  are  much  smaller  than  the  preceding,  and  want  the  regular 
branching  of  the  others :  they  are  connected  with  each  other  and  the  coc- 


LEVATORES    COSTARUM    MUSCLES.  873 

cygeal  nerve  by  loops  on  the  back  of  the  sacrum.     A  i'ew  filaments  are 
distributed  to  the  back  of  the  sacrum  and  the  coccyx. 

Coccygeal  nerve  (1  c).  Its  posterior  primary  branch  issues  through  the 
lower  aperture  of  the  spinal  canal,  and  appears  by  the  side  of  the  coccyx. 
It  is  joined  by  a  loop  from  the  last  sacral  nerve,  and  ends  on  the  posterior 
surface  of  the  coccyx. 

*  Sacral  Arteries.  Small  branches  leave  the  spinal  canal  with  the 
sacral  nerves  ;  they  supply  the  muscular  mass  of  the  erector  spinae,  and 
anastomose  with  branches  on  the  back  of  the  sacrum  from  the  gluteal  and 
sciatic  arteries. 

*  Dissection.  The  examination  of  the  posterior  part  of  the  wall  of  the 
thorax  may  be  made  before  the  body  is  again  turned.  By  removing,  oppo- 
site the  ribs,  the  ilio  costalis  and  longissimusdorsi,  the  small  levatores  cos- 
tarum  will  be  uncovered.  The  hinder  part  of  the  external  intercostal 
muscle  will  be  denuded  at  the  same  time. 

*  The  LEVATORES  COSTARUM  are  twelve  small  fan-shaped  muscles, 
which  are  connected  with  the  hinder  part  of  the  ribs.  Each,  except  the 
first,  arises  from  the  apex  and  lower  border  of  the  transverse  process  of  a 
dorsal  vertebra  ;  and  is  inserted,  the  fibres  spreading  out,  into  the  upper 
border  of  the  rib  beneath,  from  the  tubercle  to  the  angle.  The  muscles 
increase  in  size  from  above  down,  and  their  fibres  have  the  same  direction 
as  the  external  intercostal  layer. 

The  first  is  fixied  above  to  the  transverse  process  of  the  last  cervical 
vertebra,  and  below  to  the  outer  border  of  the  first  rib.  Some  of  the  four 
lower  muscles  are  continued  beyond  one  rib  to  that  next  succeeding :  these 
-  longer  slips  have  been  named  levatores  longiores  costarum. 

Action.  The  muscles  raise  the  hinder  part  of  the  ribs,  as  the  name  sig- 
nifies, and  the  lowermost  draw  the  bones  somewhat  back. 

*  The  external  intercostal  muscle  is  continued  backwards  along  the  ribs 
as  far  as  the  tubercle,  and  is  overlaid  by  the  elevator  muscle.  Beneath 
the  muscle  are  the  intercostal  nerve  and  artery. 

Dissection.  To  trace  the  anterior  and  posterior  primary  branches  of  the 
dorsal  nerves  to  their  common  trunk,  the  elevator  of  the  rib  and  the  ex- 
ternal intercostal  muscle  are  to  be  cut  through  in  one  or  more  spaces.  The 
intercostal  artery  with  its  posterior  branch  is  laid  bare  by  this  proceeding. 

*  The  dorsal  nerves  split  in  the  intervertebral  foramina  into  anterior 
and  posterior  primary  branches. 

*  The  posterior  branches  are  directed  backwards,  internal  to  the  anterior 
costo-transverse  ligament,  and  have  been  examined  (p.  3(57). 

The  anterior,  named  intercostal,  is  continued  between  the  ribs  to  the 
front  of  the  chest :  its  anatomy  is  learnt  in  the  dissection  of  the  thorax 
(p.  343). 

*  The  intercostal  artery  has  an  almost  exact  correspondence  with  the 
dorsal  nerve  in  its  branchin«c  and  distribution. 


374  DISSECTION    OF    THE    SPINAL    CORD, 


CHAPTER  YI. 

THE  SPINAL  CORD  AND  ITS  MEMBRANES. 

The  spinal  cord  (medulla  spinalis)  gives  ori«;in  to  the  spinal  nerves, 
and  is  lodged  in  the  osseous  canal  formed  by  the  bodies  and  neural  arches 
of  the  vertebrae.  It  is  invested  by  prolongations  of  the  membranes  of  the 
brain,  which  form  sheaths  around  and  support  it. 

Dissection.  After  all  the  muscles  have  been  taken  from  the  arches  and 
spines  of  the  vertebri»,  the  spinal  canal  is  to  be  opened  by  sawing  through 
the  neural  arches,  on  each  side,  close  to  the  articular  processes  ;  and  the 
cuts  of  the  saw  should  extend  to  the  lower  end  of  the  sacrum,  but  not 
higher  in  the  neck  than  the  fourth  cervical  vertebra.  As  it  is  difficult  to 
use  the  saw  in  the  hollow  of  the  lumbar  region,  a  chisel  and  a  mallet  will 
be  found  useful  to  com[)lete  the  division  of  the  vertebral  arclies. 

The  tube  of  the  dura  mater  is  covered  by  some  veins  and  fat ;  and  by  a 
loose  areolar  tissue  containing  fluid  sometimes,  especially  at  tlie  lower  part. 
The  fat  may  be  scraped  away  with  tlie  handle  of  tlie  scalpel ;  and  the 
lateral  prolongations  of  the  membrane  through  the  intervertebral  foramina 
are  to  be  defined. 

Membranes  of  the  Cord  (fig.  122).  Three  membranes,  like  those  on 
the  brain,  surround  tlie  cord,  viz.,  an  external  tube  of  dura  mater,  an 
internal  sheath  of  pia  mater,  and  an  intervening  arachnoid  or  serous 
covering. 

The  dura  mater  (a)  forms  a  strong  tube,  and  is  continuous  with  the 
membrane  lining  the  interior  of  the  skull.  It  forms  a  loose  sheath  along 
the  spinal  canal,  as  far  as  the  second  or  third  piece  of  the  sacrum  (fig.  121)  ; 
but  beyond  that  point  it  is  continued  by  a  slender  impervious  cord  to  the 
back  of  the  coccyx  (fig.  121,  h).  The  capacity  of  tlie  sheath  is  greater 
than  is  needed  for  the  contents ;  and  its  size  is  larger  in  the  neck  and 
loins  than  in  the  back. 

On  the  outer  aspect  the  dura  mater  is  smooth,  when  a  comparison  is 
made  between  it  and  the  part  in  the  skull,  for  it  does  not  act  as  a  perios- 
teum to  the  bones.  Between  it  and  the  osseous  surfaces  are  some  vessels 
and  fat ;  and  it  is  connected  to  the  posterior  common  ligament  of  the  ver- 
tebrae by  a  few  fibrous  bands. 

On  each  side  the  dura  mater  sends  offsets  along  the  spinal  nerves  in  the 
intervertebral  foramina  ;  and  these  several  offsets  become  gradually  longer 
inferiorly  (fig.  121),  wiiere  they  form  tubes  which  enclose  the  sacral  nerves, 
and  lie  for  some  distance  within  the  spinal  canal.  In  the  midst  of  the 
tubes,  below,  is  the  slender  impervious  cord  (h),  which  blends  with  the 
periosteum  covering  the  back  of  tiie  coccyx. 

Dissection.  To  remove  the  spinal  cord  with  the  sheath  of  the  dura 
mater  from  the  body,  the  lateral  processes  in  the  intervertebral  apertures 
are  to  be  cut ;  and  one  or  two  of  them  in  the  dorsal  region  should  be  fol- 
lowed outwards  beyond  the  intervertebral  foramen  by  cutting  away  the 
surrounding  bone.     The  central  prolongation  may  be  now  detached  from 


SPINAL    DURA    MATER. 


375 


the  coccyx  ;  and  the  cord  and  its  membranes  are  to  be  divided  opposite 
the  lower  cervical  vertebrne,  and  to  be  removed  by  cutting  the  bands  tliat 
attacii  the  dura  mater  to  the  posterior  ligament  of  the  bodies  of  the  ver- 
tebrse. 

When  the  cord  is  taken  out,  place  the  anterior  surface  uppermost  with 
the  lateral  offsets  widely  separated.  To  show  the  arachnoid  covering,  the 
dura  mater  is  to  be  slit  along  the  middle  as  far  as  the  small  terminal 
fibrous  cord  before  referred  to ;  but  the  membrane  is  to  be  raised  whilst  it 
is  being  cut  through,  so  that  the  loose  arachnoid  on  the  cord  may  not  be 
injured.     Lastly,  fasten  back  the  dura  mater  with  pins. 


Fip;.  121. 


Fig.  122. 


LowRR  End  of  the  Dura  Mater,  with  its 
Central  and  Lateral  Processes.  (Mu- 
senm  University  College,  Loudon.) 

a.  Large  sheath  of  the  dura  mater. 

h.  Central  fibrous  band  fixing  it  to  the  coc- 
cyx. The  lateral  ofi'sets  encasing  the 
last  two  lumbar,  and  the  five  sacral 
nerves,  with  the  coccygeal  nerve,  are 
also  shown.  Each  nerve  is  marked  by 
the  numeral,  and  the  first  letter  of  its 


View  op  the  Membranes  of  the  Spinal 
Cord. 

a.  Dura  mater  cut  open  and  reflected. 

6.  Small  part  of  the  translucent  arachnoid,  left. 

h.  Pia  mater  closely  investing  the  spinal  cord. 

c.  Ligamentum  dentlculatura  on  the  side  of  the 
cord,  shown  by  cutting  through  the  ante- 
rior roots  of  the  nerves. 

d.  Processes  joining  it  to  the  dura  mater. 

g.  Anterior  spinal  artery  and  the  fibrous  band 
(linea  splendens)  on  the  cord. 

e.  Anterior  roots  of  the  nerves,  cut. 

/.  Posterior,  each  entering  a  separate  hole  in 
the  dura  mater. 


The  arachnoid  membrane  (fig.  122,  b)  is  the  thin  serous  covering  of  the 
cord  which  is  immediately  beneath  the  dura  mater.  Like  the  correspond- 
ing membrane  in  the  skull,  it  invests  the  spinal  cord  and  lines  the  dura 
mater,  and  consists  thus  of  a  visceral  and  a  parietal  part. 


876  DISSECTION  OF  THE  SPINAL  CORD. 

The  outer  or  parietal  part  is  inseparably  joined  to  the  inner  surface  of 
the  dura  mater,  and  gives  to  that  membrane  a  sliining  appearance.^ 

The  inner  or  visceral  layer  surrounds  the  cord  loosely,  so  as  to  leave  a 
considerable  interval  between  the  two  (sub-arachnoid  space).  At  the 
lower  part  of  the  spinal  canal  the  loose  sheath  is  largest,  and  envelops  the 
mass  of  nerves  forming  the  cauda  equina.  As  the  different  spinal  nerves 
extend  to  the  intervertebral  foramina,  they  receive  loose  tubes  from  the 
arachnoid,  but  lose  the  same  when  they  perforate  the  dura  mater. 

Dissection,  The  sub-arachnoid  space  may  be  made  evident  by  placing 
the  handle  of  the  scalpel  beneath  the  visceral  layer ;  or  by  putting  a  piece 
of  the  cord  in  water,  with  the  posterior  aspect  uppermost,  and  blowing  air 
beneath  the  serous  membrane. 

The  suh-arachnoid  space  separates  the  loose  or  visceral  part  of  the 
arachnoid  membrane,  from  the  spinal  cord  invested  by  pia  mater.  Larger 
at  the  lower  than  the  upper  part  of  the  spinal  canal  it  contains  a  special 
fluid — cerebrospinal;  and  it  communicates  with  the  cavity  in  the  interior 
of  the  brain  by  an  aperture  in  the  fourth  ventricle.  Crossing  the  space, 
at  the  posterior  part  of  the  cord,  are  bundles  of  fibrous  tissue,  whicli  are 
most  marked  in  the  neck.  In  the  space  are  contained  the  serrations  of 
the  ligamentum  denticulatum,  and  the  roots  of  the  spinal  nerves,  with 
some  vessels. 

Dissection.  For  the  purpose  of  seeing  the  next  covering  of  the  cord 
with  the  ligamentum  denticulatum,  tlie  arachnoid  membrane  is  to  be  taken 
away ;  and  two  or  three  of  the  anterior  roots  of  the  upper  dorsal  nerves 
may  be  cut  through  and  reflected,  as  in  the  wood-cut  122. 

The  pia  mater  (fig.  122,  h)  is  much  less  vascular  on  the  spinal  cord 
than  on  the  brain.  Thicker  and  more  fibrous  in  its  nature,  the  membrane 
closely  surrounds  the  cord  with  a  sheath,  and  sends  a  thin  prolongation 
into  the  anterior  median  fissure ;  it  furnishes  coverings  to  the  roots  of  the 
spinal  nerves. 

The  outer  surface  of  the  pia  mater  is  rough.  Along  the  front  is  a  cen- 
tral, anterior  fibrous  band  (linea  splendens,  Haller)  ;  and  on  each  side 
another  fibrous  band,  the  ligamentum  denticulatum,  is  attached  to  it. 
Scattered  through  the  membrane  are  branched  pigment  cells,  which  give  a 
dark  appearance  in  the  cervical  region. 

Where  the  medulla  s])inalis  ceases,  viz.,  about  the  lower  part  of  the 
body  of  the  first  lumbar  vertebra,  the  tube  of  the  pia  mater  is  suddenly 
reduced  in  size,  and  has  the  appearance  of  a  round  fibrous  cord  (fig.  124, 
h).  This  cord-like  part  (filum  terminale)  is  provided  with  nervous  sub- 
stance above ;  and  blends,  below,  Mith  the  central  impervious  prolongation 
of  the  dura  mater.  It  serves  to  fix  the  lower  end  of  the  medulla  spinalis, 
and  has  been  named,  from  that  circumstance,  the  central  ligament  of  the 
cord.  A  vein  and  artery  accompany  this  fibrous  piece,  and  distinguish  it 
from  the  surrounding  nerves. 

The  ligamentum,  denticulatum  (fig.  122,  c)  is  the  white,  fibrous  toothed 
band,  on  each  side  of  the  spinal  cord.  It  is  named  from  its  serrated  ap- 
pearance ;  and  it  has  the  same  structure  as  the  dura  mater,  except  that  it 
wants  an  epithelial  covering. 

Situate  betw(^en  the  anterior  and  posterior  roots  of  the  nerves,  the  band 
reaches  upwards  to  the  medulla  oblongata,  and  ends  inferiorly  on  the 

'  According  to  the  opinion  of  Kolliker,  the  arachnoid  membrane  is  a  simple 
tube  corresponding  with  the  visceral  layer  in  the  text. 


SPINAL    NERVES.  377 

lower  pointed  extremity  of  the  cord.  Internally  it  is  united  to  the  pia 
mater.  Externally  it  ends  in  a  series  of  triangular  or  tooth-like  projec- 
tions (rf),  which  are  fixed  at  intervals  into  the  dura  mater,  each  being 
about  midway  between  the  apertures  of  the  roots  of  the  spinal  nerves. 
There  are  twenty  or  twenty-one  denticulations  ;  of  which  the  first  is  at- 
tached to  the  dura  mater  opposite  the  margin  of  the  occipital  foramen,  and 
the  last,  opposite  the  twelfth  dorsal,  or  the  first  lumbar  vertebra. 

This  fibrous  band  supports  the  spinal  cord,  and  has  been  called  a  liga- 
ment from  that  circumstance. 

Vessels  and  nerves  of  the  membranes.  The  dura  mater  of  the  cord  has 
but  few  vessels  in  comparison  with  that  in  the  skull,  for  its  office  is  differ- 
ent. Nerves  are  said  to  be  furnished  to  it  from  offsets  on  the  vessels  sup- 
plying the  cord. 

The  arachnoid  is  sparingly  supplied  with  vessels  like  serous  membranes 
in  general ;  and  proof  of  its  containing  nerves,  in  man,  is  yet  wanting. 

The  pta  mater  has  a  network  of  vessels  in  its  substance,  though  this  is 
less  marked  than  in  the  part  on  the  brain  ;  and  from  them  offsets  enter 
the  cord.  In  the  membrane  are  many  nerves,  derived  from  the  sympa- 
thetic. 

Dissection.  The  arachnoid  membrane  is  to  be  taken  from  the  fibrils 
of  the  roots  of  the  nerves  on  one  side  ;  and  the  roots  are  to  be  traced  out- 
wards to  their  transmission  through  two  apertures  in  the  dura  mater  for 
each  nerve. 

One  of  the  offsets  of  the  dura  mater,  which  has  been  cut  of  some 
length,  is  to  be  laid  open  to  show  the  contained  ganglion.  The  student 
should  define  one  grano-lion,  showing^  its  bifid  condition  at  the  inner  end 
(fig.  123,  °),  and  should  trace  a  bundle  of  threads  of  the  posterior  root  into 
each  point.  The  anterior  root,  consisting  of  two  bundles  of  threads,  is 
to  be  followed  over  the  ganglion  to  its  union  with  the  posterior  beyond  the 
ganglion. 

Spinal  Nerves.  There  are  thirty-one  pairs  of  spinal  nerves  ;  and 
each  nerve  is  constructed  by  the  blending  of  two  roots  (anterior  and  pos- 
terior) in  the  intervertebral  foramen  (fig.  123). 

They  are  divided  into  groups  corresponding  with  the  regional  subdi- 
visions of  the  spinal  column,  viz.,  cervical,  dorsal,  lumbar,  sacral,  and 
coccygeal.  In  each  group  the  nerves  are  the  same  in  number  as  the  ver- 
tebrae, except  in  the  cervical  region  of  the  spine  where  they  are  eight,  and 
in  the  coccygeal  region  where  there  is  only  one.  In  consequence  of  the 
number  of  nerves  in  the  neck,  exceeding  that  of  the  vertebra?,  the  last  is 
placed  below  the  seventh  vertebra  ;  and  the  lowest  nerve  of  each  group, 
except  the  coccygeal,  will  be  below  its  corresponding  vertebra. 

Each  nerve  divides  into  two  primary  branches,  anterior  and  posterior, 
the  former  of  these  is  distributed  to  the  front  of  the  body  and  the  limbs, 
and  the  latter  is  confined  to  the  hinder  part  of  the  trunk. 

Roots  of  the  Nerves  (fig.  123).  Two  roots  (anterior  and  posterior) 
attach  the  nerve  to  the  spinal  cord ;  and  these  unite  together  to  form  a 
common  trunk  in  the  intervertebral  foramen.  The  posterior  root  is 
marked  by  a  ganglion,  but  the  anterior  root  is  aganglionic. 

The  posterior  or  ganglionic  roots  (fig.  123,  h)  surpass  in  size  the  an- 
terior, and  are  formed  by  larger  and  more  numerous  fibrils.  They  are 
attached  to  the  side  of  the  cord  between  the  posterior  and  lateral  columns 
in  a  straight  line,  which  they  keep  even  to  the  last  nerve. 

In  their  course  to  the  trunk  of  the  nerve  the  fibrils  converge  to  an  aper- 


378 


DISSECTION    OF    THE    SPINAL    CORD 


ture  in  the  dura  mater,  opposite  the  intervertebral  foramen  ;  as  they  ap- 
proach tliat  aperture  tliey  are  collected  into  two  bundles  (fig.  123  b,  b) 
which,  lying  side  by  side,  receive  a  sheath  from  the  dura  mater,  and  enter 
the  two  points  of  the  intervertebral  ganglion. 

Vis.  123. 


A.  Plan  of  the  origiu  of  a  spinal  nerve  from  the  spinal 

cord. 

a.  Anterior  root. 

b.  Posterior  root. 

c.  Ganglion  on  the  posterior  root. 

d.  Anterior  primary  banch. 

e.  Posterior  primary  branch  of  the  nerve  truuk. 

B.  A  drawing  to  show  the  arrangement  of  tbe  nerve-roots, 

and  the  form  of  the  ganglion  in  a  lumbar  nerve. 
6.  Posterior  root  gathered  into  two  bundles  of  threads, 
c.  The  ganglion,  bifid  at  the  inner  end. 
a.  Threads  of  the  anterior  root,  also  gathered  into  two 

bundles. 


The  intervertebral  ganglion  (fig.  123).  Each  posterior  root  is  provided 
with  a  ganglion  (c).  The  ganglia  are  reddish  in  color,  and  oval  in  shape 
whilst  they  are  surrounded  by  the  dura  mater  ;  and  their  size  is  propor- 
tioned to  that  of  the  root.  By  means  of  the  previous  dissection,  the  gan- 
glion may  be  seen  to  be  bifid  at  the  inner  end  (fig.  123  b),  where  it  is 
joined  by  the  bundles  of  fibrils  of  the  root  (b)  ;  it  might  be  said  to  possess 
two  small  ganglia,  one  for  each  bundle  of  fibrils,  which  are  blended  at 
their  outer  ends. 

Sometimes  the  first  or  suboccipital  nerve  is  without  a  ganglion. 

The  anterior  or  aganglionic  roots  (fig.  123  a)  arise  from  the  side  of  the 
spinal  cord  by  filaments  which  are  attached  irregularly — not  in  a  straight 
line,  and  approach  near  the  middle  fissure  at  the  lower  end  of  the  cord. 

Taking  the  same  direction  as  the  posterior  root  to  the  intervertebral 
foramen,  the  fibrils  enter  a  distinct  opening  in,  and  have  a  separate  sheath 
of  the  dura  mater.  In  their  further  course  to  the  trunk  of  the  nerve  they 
are  gathered  into  two  bundles  (fig.  123,  b,  (/),  and  pass  over  the  ganglion 
without  joining  it.  Finally  the  antej-ior  root  blends  with  the  posterior 
beyond  the  ganglion,  to  form  the  trunk. 

Characters  of  the  roots.  Besides  variations  in  the  relative  size  of  the 
two  roots,  the  following  characters  are  to  be  noted  : — 

Union  of  the  fibrils.  The  fibrils  of  contiguous  anterior  roots  may  be 
intermingled,  and  the  fibrils  of  the  neighboring  po.sterior  roots  may  be 
connected  in  a  like  manner  ;  but  the  anterior  is  never  mixed  with  the 
posterior  root. 


VESSELS    OF    THE    SPINAL    CORD.  379 

Size  of  the  roots  to  each  other.  The  posterior  root  is  larger  than  the  an- 
terior, except  in  the  suboccipital  nerve  ;  and  the  number  of  the  fibrils  is 
also  greater.  Further,  the  posterior  is  proportionally  larger  in  the  cervical 
than  in  any  other  group ;  in  the  dorsal  nerves  there  is  but  a  very  slight 
difference  in  favor  of  the  hinder  root. 

Size  of  both  roots  along  the  cord.  Both  roots  are  larger  where  the  nerves 
for  the  limbs  arise,  than  at  any  other  part  of  the  cord  ;  and  they  are 
greater  in  the  nerves  to  the  lower  than  in  those  to  the  upper  limbs.  They 
are  smallest  at  the  lower  extremity  of  tlie  cord. 

Direction  and  length  of  the  roots.  As  the  apertures  of  transmission  from 
the  spinal  canal  are  not  opposite  the  place  of  origin  of  the  nerves,  the  rools 
must  be  directed  more  or  less  obliquely.  This  obliquity  increases  from 
above  down  ;  for  in  the  upper  cervical  nerves  the  roots  are  horizontal,  but 
in  the  lumbar  and  sacral  nerves  they  have  a  vertical  direction  around  the 
end  of  the  medulla  spinalis.  The  appearance  of  tlie  long  fibrils  around  the 
end  of  the  cord  (fig.  124)  resembles  the  extremity  of  a  horse's  tail,  and 
bears  appropriately  the  term  cauda  equina. 

The  length  of  the  roots  increases  in  proportion  to  their  obliquity.  Be- 
tween the  origin  and  the  place  of  exit  of  the  roots  of  the  lower  cervical 
nerve  the  increase  amounts  to  the  depth  of  one  vertebra :  in  the  lower 
dorsal  nerve  it  equals  the  depth  of  two  vertebrae  ;  and  in  the  lumbar  and 
sacral  nerves  each  succeeding  root  becomes  a  vertebra  longer,  for  the  cord 
does  not  reach  beyond  the  first  lumbar  vertebra. 

Place  of  union  of  the  roots.  Commonly  the  roots  unite  as  before  state 
in  the  intervertebral  foramina  ;  and  the  trunk  of  the  nerve  bifurcates  at 
the  same  spot  into  anterior  and  posterior  primary  branches  (fig.  123,  d 
and  e).  But  deviations  from  this  arrangement  are  found  at  the  upper  and 
lower  ends  of  the  spinal  column  in  the  following  nerves. 

The  roots  of  the  first  two  cervical  nerves  join  on  the  neural  arches  of 
the  corresponding  vertebrae ;  and  the  anterior  and  posterior  primary 
branches  diverge  from  the  trunks  in  that  situation. 

In  the  sacral  nerves  the  union  of  the  roots  takes  place  within  the  spinal 
canal ;  and  the  primary  branches  of  the  nerves  issue  by  the  apertures  in 
the  front  and  back  of  tlie  sacrum. 

The  roots  of  the  coccygeal  nerve  are  also  united  in  the  spinal  canal ;  and 
the  anterior  and  posterior  branches  of  its  trunk  escape  by  the  lower  ajjcr- 
ture  of  that  canal. 

Situation  of  the  ganglia.  The  ganglia  are  placed  commonly  in  the  in- 
tervertebral foramina,  but  where  the  position  of  those  apertures  is  irregu- 
lar, as  at  the  upper  and  lower  extremities  of  the  spinal  column,  they  have 
the  following  situation  :  In  the  first  two  nerves  they  lie  on  the  neural 
arches  of  the  atlas  and  axis.  In  the  sacral  nerves  they  are  contained  in 
the  spinal  canal.  In  the  coccygeal  nerve  the  ganglion  is  also  within  the 
canal,  and  about  the  middle  of  the  long  posterior  root  (wSchlemm). 

Vessels  of  the  Spinal  Cord.  The  arteries  on  the  surface  of  tlie 
cord  are  anterior  and  posterior  spinal. 

The  anterior  spinal  ar/^^ry  occupies  the  middle  line  of  the  cord  beneath 
the  fibrous  band  before  alluded  to  in  that  position.  It  begins  by  the  union 
of  two  small  branches  of  the  vertebral  artery  (p.  174)  ;  and  it  is  continued 
to  the  lower  part  of  the  cord  by  a  series  of  anastomotic  branches,  which 
are  derived  from  the  vertebral  and  ascending  cervical  arteries  in  the  neck, 
and  from  the  intercostal  arteries  in  the  Back.  Inferiorly  it  supplies  the 
roots  of  the  nerves  forming  the  cauda  equina,  and  ends  on   the  central 


380 


DISSECTION    OF    THE    SPINAL    CORD. 


Fig.  124. 


c 


fibrous  prolongation  of  tlie  cord.     The  branches  of  this  artery  ramify  in 
the  f)ia  mater,  some  entering  the  median  fissure. 

The  posterior  spinal  arteries^  one  on  each  side,  are  continued  from  the 
upper  to  the  lower  part  of  the  cord,  behind 
the  roots  of  the  nerves.  These  vessels  are 
furnished  from  the  same  source  as  the  ante- 
rior, and  their  continuity  is  maintained  by  a 
series  of  anostomotic  branches,  which  enter 
the  canal  along  the  spinal  nerves.  Dividing 
into  small  branches,  the  vessels  of  opposite 
sides  form  a  free  anostomosis  around  the  pos- 
terior roots,  and  some  offsets  enter  the  poste- 
rior fissure  of  the  cord. 

The  veins  of  the  spinal  cord  are  very  tor- 
tuous and  form  a  plexus  on  the  surface.  At 
intervals  larger  trunks  arise,  which  accompany 
the  spinal  nerves  to  the  intervertebral  fora- 
mina, and  end  in  the  veins  outside  the  spinal 
canal.  Near  the  top  of  the  cord  the  veins  are 
united  into  two  or  more  small  branches ;  after 
communicating  with  the  intraspinal  veins, 
these  join  in  the  skull  the  inferior  cerebellar 
veins,  or  the  inferior  petrosal  sinuses. 

The  SPINAL  CORD  (medulla  spinalis). is  the 
cylindrical  elongated  part  of  the  cerebro- 
spinal centre,  wiiich  is  inclosed  within  the 
spinal  canal.  Invested  by  the  membranes 
before  examined,  the  medulla  occupies  about 
two-thirds  of  the  length  of  the  vertebral  canal, 
and  is  much  smaller  than  the  bony  case  sur- 
rounding it. 

The  extent  of  the  spinal  cord  is  from  the 
upper  border  of  the  atlas  to  the  lower  border 
of  the  first  lumbar  vertebra,  but  its  termina- 
tion inferiorly  may  be  a  little  higher  or  lower 
than  that  spot.  In  the  embryo  before  the 
third  month  the  medulla  reaches  throughout 
the  spinal  canal,  but  it  gradually  recedes  as 
the  surrounding  bones  enlarge  faster  than  it, 
until  it  takes  the  position  it  has  in  the  adult. 
Its  length  is  usually  from  fifteen  to  eighteen 
inches. 

Superiorly  the  cord  joins  the  medulla  ob- 
longata ;  and  inferiorly  it  becomes  pointed, 
being  sometimes  marked  by  one  or  two  swell- 
ings, and  ends  in  the  fibrous  prolongation, 
named  the  central  ligament  of  the  cord  or 
filum  terminale  (fig.  124,  d). 

The  size  of  the  spinal  cord  is  much  in- 
creased where  the  nerves  of  the  limbs  are 
attached.  There  are  therefore  two  enlarge- 
ments on  it,  viz.,  cervical  and  dorsal:  the 
one  in  the  neck  reaches  from   the  tiiird  cer- 


Mrmbranes  op  thr  Spinai-  Cord 
LAID  OPEM,  to  show  the  lower 
end  of  the  cord  with  the  filum 
termiaale. 

a.  Dura  rnater,  and  h,  the  fibrous 
baud  fixiu!,'  It  to  the  coccyx. 

c.  Pointed  lower  end  of  the  cord. 

d.  Filum  terminale  of  the  cord. 


FISSURES    OF    THE    CORD. 


381 


vical  to  the  first  dorsal  vertebra  ;  the  other  in  the  Back  is  smaller,  and  is 
on  a  level  with  the  last  dorsal  vertebra.  In  the  upper  enlargement  the 
greatest  thickness  is  from  side  to  side ;  but  in  the  lower  swelling  the 
measurement  from  before  back  rather  exceeds  the  other. 

Whilst  the  pia  mater  remains  on  the  cord,  the  anterior  surface  is  dis- 
tinguished from  the  posterior  by  a  central  fibrous  band  and  the  anterior 
spinal  artery  ;  and  by  the  irregular  line  of  the  anterior  nerve-roots,  which 
approach  the  middle  towards  the  lower  end. 

Dissection.  For  tlie  examination  of  the  structure  the  student  should 
possess  a  piece  of  the  medulla  which  has  been  hardened  in  spirit,  for  the 
cord  which  is  obtained  from  the  spinal  canal  at  this  period,  is  not  fitted  for 
the  purpose  of  dissection.  Supposing  the  pia  mater  removed  from  the 
surface,  with  the  roots  of  the  nerves  left  on  one  side,  the  student  will  be 
able  to  observe  the  following  divisions  of  the  medulla. 

Fissures  of  the  Cord  (fig.  125).  On  the  anterior  and  posterior 
aspects  of  the  cord  is  a  median  longitudinal  cleft — the  anterior  and  poste- 
rior median  fissures,  which  mark  its  division  into  halves  ;  and  along  the 
line  of  the  posterior  roots  of  the  nerves,  in  each  half,  is  another  slit — the 
lateral  fissure. 


Fig.  125. 


A  Skction  of  the  Spinal  Cord, 
TO  SHOW  ITS  Composition,  and 
ITS  Divisions.    Fissures  in  the 

MIDDLE  LINE    ARE  THE   ANTERIOR 

AND    Posterior    Median  — the 
Anterior  being  thk  wider. 


d.  The  lateral  fissure. 

e.  The  slight  groove  between  the  lateral  and  the  posterior 

median  fissure,  which  mai'lis  the  limit  of  the  posterior 
median  column. 

Columns  : 
a.  Antero-lateral. 
6.  Posterior, 
c.  Posterior  median. 

Composition  : 
g.  Gray  crescent,  surrounded  by  white  fibres. 
h.  Gray  transverse  commissure,  and 

in  It. 
j.  Posterior,  and  k,  anterior  root  of  a  nerve  entering  the 
gray  crescent. 


canal  of  the  cord 


The  anterior  median  fissure  (fig.  125)  is  wider  than  the  posterior,  and 
penetrates  about  one-third  of  the  thickness  of  the  medulla :  it  is  lined  by 
a  piece  of  the  pia  mater,  and  is  deepest  towards  the  lower  end  of  the  cord. 
White  medullary  substance  lines  the  fissure;  and  in  the  bottom  of  it  the 
white  fibres  are  transverse,  and  are  separated  by  apertures  for  blood- 
vessels. 

The  posterior  median  fissure  (fig.  125)  is  not  so  wide,  or  so  well  marked 
as  the  anterior;  but  it  is  best  seen  at  tlie  upper  part  of  the  neck,  and  in 
the  lower  or  dorsal  enlargement.  Vessels  of  tlie  posterior  surface  of  the 
cord  enter  it. 

The  lateral  fissure  is  situate  along  the  line  of  attachment  of  the  fibrils 
of  the  posterior  roots  (fig.  125,  d). 

Between  the  lateral  and  posterior  median  fissures  is  a  slight  groove  on 
the  surface  (fig.  125,  e). 

Sometimes  a  lateral  fissure  is  described  along  the  line  of  origin  of  the 
anterior  roots  (k),  but  there  is  not  any  cleft  in  that  situation. 


382  DISSECTION    OF    THE    SPINAL    CORD. 

Segments  of  the  Cord.  Each  half  of  the  cord  between  the  median 
fissures  is  divided  into  two  parts  by  the  lateral  sulcus  (fig.  125,  d):  the 
piece  in  front  of  that  slit  and  the  posterior  roots  of  the  nerves  is  called 
the  antero-lateral  column  («) ;  and  the  piece  behind,  the  posterior  col- 
umn (6). 

The  antero-lateral  column  (fig.  125,  a)  includes  rather  more  than  two- 
thirds  of  the  half  of  the  cord,  extending  backwards  to  the  posterior  roots 
of  the  nerves,  and  gives  attachment  to  the  anterior  roots. 

The  posterior  column  (fig.  125,  b)  is  situate  between  the  lateral  fissure 
(c?),  with  the  posterior  roots  of  the  nerves,  and  the  central  median  fissure. 
Near  the  median  fissure  is  a  slight  groove  («?),  which  marks  ofi'  a  slender 
piece,  the  posterior  median  column  (c) :  this  portion  is  best  seen  in  tiie 
cervical  part  of  the  cord. 

A  central  piece,  or  the  commissure  of  the  cord,  connects  the  halves  of 
the  medulla,  and  limits  the  depth  of  the  median  fissures. 

Different  division  of  the  cord.  Each  half  of  the  cord  is  sometimes  di- 
vided into  three  columns — anterior,  lateral,  and  posterior,  whose  limits 
are  the  following : — The  anterior  reaches  from  the  anterior  roots  of  the 
nerves  to  the  median  fissure  in  front.  The  lateral  column  is  limited  be- 
fore and  behind  by  the  roots  of  the  nerves.  The  posterior  with  its  small 
posterior  median  segment,  is  placed  between  the  posterior  roots  and  the 
median  fissure  behind. 

Composition  op  the  Cord  (fig.  125).  A  horizontal  section  of  the 
medulla  shows  more  distinctly  its  division  into  halves,  with  the  commis- 
sural or  connecting  piece  between  them.  The  same  cut  demonstrates  the 
existence  of  a  mass  of  gray  matter  in  the  interior,  which  is  arranged  in 
the  form  of  two  crescents  (one  in  each  half)  united  by  a  cross  piece,  and 
surrounded  by  white  substance. 

The  commissure  (fig.  125,  h)  consists  of  two  parts,  viz.,  a  transverse 
band  of  gray  matter,  with  a  white  stratum  in  front. 

The  gray  transverse  band  {gray  commissure)  connects  the  opposite 
crescents,  and  consists  of  nerve  cells,  and  of  transverse  nerve  fibres  de- 
rived from  the  halves  of  the  cord  and  the  roots  of  the  nerves. 

In  its  centre  is  the  shrunken  canal  of  the  spinal  cord  (fig.  125,  ^), 
which  is  best  seen  in  the  foetus.  It  reaches  the  whole  length  of  the  me- 
dulla, and  a  cross  section  of  the  cord  shows  it  as  a  round  spot.  Above,  it 
opens  on  the  fioor  of  the  fourth  ventricle,  and  below  it  is  continued  into 
the  filum  terminale.  It  is  lined  by  a  columnar  ciliated  epithelium,  and  is 
obstructed  by  a  granular  material  near  the  upper  opening  (Clarke). 

The  white  piece  of  the  commissure  is  formed  partly  by  fibres  of  the  an- 
terior column  ;  and  partly  by  fibrils  of  the  anterior  roots  of  the  nerves, 
which  here  decussate  as  they  cross  from  the  one  half  to  the  other.  It  is 
best  marked  opposite  the  enlargements  on  the  cord,  and  is  least  developed 
in  the  dorsal  region. 

The  half  of  the  medulla.  In  the  half  of  the  cord  as  in  the  commissure, 
gray  and  wiiite  portions  exist;  tiie  former  is  elongated  from  before  back, 
being  crescentic  in  shape  as  before  said,  and  is  quite  surrounded  by  the 
latter. 

The  gray  crescent  (g)  is  semilunar  in  form,  with  the  horns  or  cornua  of 
the  crescent  directed  towards  the  roots  of  the  nerves,  and  the  convexity  to 
the  middle  line  (fig.  125).  The  crescentic  masses  in  the  opposite  halves 
of  the  cord  are  united  by  the  gray  commissure. 

The  posterior  cornu  is  long  and  slender  (fig.  126,  ^)  and  reaches  near 


ORIGIN    OF    THE    NERVES.  383 

the  fissure  along  the  attachment  of  the  posterior  nerve-roots.  At  its  ex- 
tremity, where  it  is  slightly  enlarged,  it  is  incased  with  a  rather  transpa- 
rent stratum  of  small  nerve  cells,  which  has  been  named  substantia  gelati- 
nosa  (fig.  126,  ^). 

The  anterior  cornu  (fig.  126,  ^)  is  shorter  and  thicker  than  the  other, 
and  projects  towards  the  anterior  roots  without  reaching  the  surface.  Its 
end  lias  an  irregular  or  zigzag  outline. 

Mr.  Clarke  describes  two  special  collections  of  cells,  one  on  the  outer 
and  the  other  on  the  inner  side  of  the  gray  crescent,  which  extend  through 
the  cord  below  the  cervical  swelling,  and  with  which  the  roots  of  the 
nerves  are  connected.^ 

The  inner  group,  or  the  posterior  vesicular  column  (fig.  126,  ®)  is  close 
behind  the  transverse  commissure  (^)  ;  whilst  the  outer  group,  or  the  inter- 

Fig.  126. 

1.  Posterior  cornu  (captit  cornu,  Clarke)  of  the  crescent. 

V*V  i.^^^  ^*  Anterior  cornu. 

^*.   1  m^^r^  ^"  Casing  of  the  substantia  gelatinosa. 

4  1^,    I      -^X^  ■*•  Central  canal  of  the  cord. 

J  _j^  ^^y^^^^S^i^  ^'  Transverse  commissure. 

^^       /^*"  ■■ *^^^  "  6-  Tractus  intermedio-lateralis. 

I      F  t(~^'^  ^  ^"  Cervix  cornu  of  Clarke,  reaching  from  the  anterior  points  of 
■V-/        I    "J^f/s-^  the  substantia  gelatinosa  to  the  level  of  the  canal. 

^»  S.  Posterior  vesicular  column. 

A  Represkntation  of  the  Gray  Substance  in  the  Interior  op  the  Spinal  Cord,  near  the 
Middle  OF  THE  Dorsal  Region  (Clarke). 

mediate  tract  (^),  is  placed  outside  the  crescent,  about  midway  from  front 
to  back.  The  first  is  best  marked  in  the  dorsal  enlargement,  and  the  last 
in  the  upper  part  of  the  dorsal  region.  Above  the  cervical  swelling  of  the 
cord  only  rudiments  of  those  tracts  i-emain  ;  and  the  cells  in  a  line  with 
the  intermediate  tract  are  traversed  by  the  roots  of  the  spinal  accessory 
nerVe. 

The  white  substance  of  the  cord  is  composed  chiefly  of  nerve  fibres  dis- 
posed longitudinally  in  bundles,  so  as  to  give  passage  to  intermediate 
vessels. 

A  framework  of  very  fine  areolar  tissue  extends  through  the  substance 
of  the  spinal  cord,  supporting  the  fibres  and  cells  :  this  is  continuous  with 
the  pia  mater  on  the  surface. 

Modifications  of  the  grai/  and  white  substance.  The  white  substance 
exceeds  the  gray  in  quantity  in  the  neck  and  back  ;  but  it  is  less  abundant 
in  proportion  to  the  gray  matter  in  the  lumbar  region. 

The  cornua  of  the  gray  crescents  decrease  in  length  from  above  down, 
especially  the  posterior,  and  towards  the  end  of  the  cord  they  blend  in  one 
indented  or  cruciform  mass. 

Origin  of  the  Nerves.  The  deep  origin  of  the  spinal  nerves  is  un- 
certain, like  that  of  the  cranial  nerves,  but  the  fibrils  in  each  root  enter 
the  gray  matter  of  the  cord  (fig.  125). 

The  anterior  root  (k)  traverses  the  longitudinal  fibres  of  the  antero- 
lateral column  in  distinct  bundles  ;  and  entering  the  anterior  cornu  of  the 

'  Further  researches  on  the  gray  substance  of  the  spinal  cord.  By  J.  Lockhart 
Clarke,  F.R.S.,  Philosoph.  Trans,  of  the  Royal  Society  for  1859.     Part  i. 


384 


DISSECTION    OF    THE    SPINAL    CORD. 


gray  crescent,  it  is  resolved  into  three  sets  of  fibres,  external,  internal, 
and  middle. 

The  outer  set  penetrate  into  the  antero  lateral  column. 

The  inner  set  pass  through  the  anterior  column  and  across  the  median 
fissure  to  the  opposite  half  of  the  cord,  decussating  with  like  fibres  of  the 
opposite  side. 

The  middle  set  enter  the  substance  of  the  crescent,  and  are  lost  in  it 
and  in  the  cells  of  the  intermediate  tract. 

The  posterior  root  (j)  pierces  chiefly  the  posterior  column  of  the  cord, 
and  enters  the  posterior  cornu  of  the  crescent :  but  a  few  fibres  penetrate 
by  the  lateral  fissure.     It  terminates  in  two  bundles  of  fibres. 

One  bundle  courses  round  the  outer  side  of  the  vesicular  column,  some 
fibres  enclosing,  and  others  entering  it ;  and  a  few  fibrils  escape  into  the 
posterior  column  of  the  cord,  becoming  longitudinal. 

The  second  bundle  is  prolonged  into  the  crescent  and  the  intermediate 
tract,  as  well  as  into  the  transverse  commissure  behind  the  central  canal 
of  the  cord. 

Intraspinal  Vessels  (fig.  127).    Arteries  supply  the  cord  and  its 


Fig.  127. 


Fig.  128. 


Intraspinal  Arteries  in  the  Loins  (Museum 
of  University  College,  London). 
a.  Branch  of  the  lumbar  artery. 
5.  Ascending,  and  c,  its  descending  offset. 

d.  Offsets  to  the  body  of  the  vertebra  on  each 

side. 

e.  Central  artery  formed  by  offsets  from  the 

lateral  loops. 


Intraspinal  Veins  in  thk  Loins. 

a.  Branch  to  join  a  lumbar  vein. 

I.  Anterior  longitudinal  vein,  one  on  each 

side. 
c.  Veins  from  the  bodies  of  the  vertebra;. 


membranes,  and  the  bodies  of  the  vertebroe.  The  veins  form  a  remark- 
able plexus  within  the  canal,  but  this  will  not  be  seen  unless  the  veins  have 
been  specially  injected. 

The  intraspinal  arteries  (a)  are  derived  from  the  vessels  along  the  sides 
and  front  of  the  spinal  column,  viz.,  from  the  vertebral  and  ascending 
cervical  in  tlie  neck,  from  the  intercostal  in  the  Back,  and  from  the  lum- 
bar and  lateral  sacral  below.  They  are  distributed  after  the  following 
plan  : — 

As  each  artery  enters  the  spinal  canal  by  the  intervertebral  foramen, 
it  divides  into  two  branches,  ui)per  and  lower.  From  the  point  of  division 
the  branches  are  directed,  one  (6)  upwards  and  the  other  (c)  downward?, 


INTRASPINAL    VESSELS.  385 

behind  the  bodies  oP  the  two  contiguous  vertebrae,  and  join  in  anastomotic 
loops  with  an  offset  of  the  intraspinal  artery  above  and  below.  And  from 
the  loops  offsets  (rf)  are  furnished  to  the  periosteum  and  the  bodies  of  the 
vertebras.     Anastomotic  twigs  connect  the  arches  across  the  vertebrae. 

The  intraspinal  vessels  produce  also  a  central  longitudinal  artery  {e)^ 
like  that  on  the  front  of  the  spinal  cord,  which  lies  on  the  bodies  of  the 
vertebrae,  and  is  reinforced  at  intervals  by  offsets  from  the  loops. 

The  intraspinal  veins  (fig.  128)  consist  of  two  anterior  longitudinal 
vessels,  which  extend  the  whole  length  of  the  spinal  canal  ;  of  veins  inside 
the  bodies  of  the  vertebrae  ;  and  of  a  plexus  of  veins  beneath  the  neural 
arches. 

The  anterior  longitudinal  (a)  are  close  to  the  bodies  of  the  vertebrae, 
one  on  each  side  of  the  posterior  common  ligament ;  and  they  are  irregu- 
lar in  outline,  owing  to  certain  constrictions  near  the  intervertebral  fora- 
mina. They  receive  opposite  the  body  of  each  vertebra  the  veins  {c)  from 
that  bone  ;  and  through  the  intervertebral  foramina  they  have  branches  of 
communication  (a)  with  the  veins  outside  the  spine  in  the  neck,  the  dorsal 
region,  the  loins,  and  the  pelvis. 

Veins  of  the  bodies  of  the  vertebrce.  Within  the  canals  in  the  bodies  of 
the  vertebrae  are  large  veins,  which  join  on  the  front  of  the  bone  with 
veins  in  that  situation.  Towards  the  back  of  the  body  they  are  united  in 
an  arch,  from  which  two  trunks  issue  by  the  large  apertures  on  the  poste- 
rior surface.  Escaped  from  the  bone,  the  trunks  diverge  to  the  right  and 
left,  and  open  into  the  longitudinal  veins. 

The  posterior  spinal  veins  form  a  plexus  between  the  dura  mater  and 
the  arches  of  tlie  vertebrae.  A  large  vein  may  be  said  to  lie  on  each  side 
of  the  middle  line,  which  joins  freely  with  its  fellow,  and  with  the  ante- 
rior longitudinal  vein  by  lateral  branches.  Offsets  from  these  vessels  are 
directed  through  the  intervertebral  foramina,  to  end  in  the  veins  (a)  at  the 
roots  of  the  transverse  processes. 


25 


386  DISSECTION    OF    THE    PERINiEUM. 


CHAPTEE  YII. 

DISSECTION  OF  THE  PERINEUM. 


Section  I. 

PERINiEUM  OF  THE  MALE. 

Directions.  The  perinseum  may  be  allotted  with  greatest  advantage 
to  the  dissector  of  the  abdomen  ;  and  its  examination  should  be  made  first, 
as  the  distinctness  of  many  of  the  parts  is  destroyed  soon  after  death. 
Before  the  body  is  placed  in  the  position  suited  for  the  dissection,  the 
student  may  practise  passing  the  catheter  along  the  urethra. 

Position  of  the  body.  Whilst  the  body  lies  on  the  Back  it  is  to  be 
drawn  to  the  end  of  the  dissecting  table,  till  the  buttocks  project  sliglitly 
over  the  edge  ;  and  a  moderately-sized  block  is  to  be  placed  beneath  the 
pelvis,  to  raise  the  perinaium  to  a  convenient  height.  The  legs  are  to  be 
raised  and  kept  out  of  the  way  by  the  following  means  :  After  the  knees 
have  been  bent,  and  the  thighs  bent  upon  the  trunk,  the  limbs  are  to  be 
fastened  with  a  cord  in  their  raised  position.  For  this  purpose  make  one 
or  two  turns  of  the  cord  around  one  bent  knee  (say  the  right)  ;  carry  the 
cord  beneath  the  table,  and,  encircling  tlie  opposite  limb  in  the  same  man- 
ner, fasten  it  finally  round  the  right  knee.  When  the  position  has  been 
arranged,  let  the  student  raise  the  scrotum,  and  place  a  small  piece  of 
cotton  wool  or  tow  within  the  anus,  but  let  him  avoid  distending  the 
rectum. 

Superficial  limits  and  marking.  The  perinatal  space  in  the  male  is 
limited,  on  the  surface  of  the  body,  by  the  scrotum  in  front,  and  by  the 
thighs  and  buttocks  on  the  sides  and  behind. 

Tliis  region  is  of  a  dark  color,  and  is  covered  with  hairs.  In  the  middle 
line  is  the  aperture  of  the  anus,  which  is  posterior  to  a  line  extended  from 
the  anterior  part  of  the  one  ischial  tuberosity  to  the  other.  In  front  of 
the  anus  the  surface  is  slightly  convex  over  the  urethra,  and  presents  a 
longitudinal  prominent  line  or  raphe,  which  divides  this  part  of  the  space 
into  two  halves.  Between  the  anus  and  the  tuberosity  of  the  hip  bone  the 
surface  is  somewhat  depressed  over  the  hollow  of  the  subjacent  ischio-rectal 
fossa,  especially  in  emaciated  bodies. 

The  margin  of  the  anal  aperture  possesses  numerous  converging  folds, 
but  these  are  more  or  less  obliterated  by  the  position  of  the  body  and  the 
distension  of  the  rectum  ;  and  projecting  oftentimes  through  and  around 
the  opening  are  some  dihited  veins  (huimorrlioids). 

Deep  boundaries.  The  deep  boundaries  of  the  perinaeal  space  will  be 
ascertained,  in  the  progress  of  the  dissection,  to  correspond  with  the  infe- 
rior aperture  or  the  outlet  of  the  pelvis.    The  limits  may  be  seen  on  a  dry 


POSTERIOR    HALF    OF    THE    SPACE.  387 

or  prepared  pelvis,  on  which  the  ligaments  remain  entire ;  and  the  student 
should  trace  on  the  body  the  individual  boundaries  with  his  finger.  In 
front  is  the  arch  of  the  pubes  ;  and  at  the  posterior  part  is  the  tip  of  the 
coccyx,  with  the  great  gluteal  muscles.  On  each  side  in  front  is  the  por- 
tion of  the  innominate  bone  which  forms  the  pubic  arch,  viz.,  from  the 
pubes  to  the  ischial  tuberosity ;  and  still  further  back  is  the  great  sacro- 
sciatic  ligament  extending  from  the  tuber  ischii  to  the  tip  of  the  coccyx. 
This  region  sinks  into  the  outlet  of  the  pelvis  as  far  as  the  recto- vesical 
fascia,  which  forms  its  floor. 

Form  and  size.  The  interval  included  within  the  boundaries  above  said 
has  the  form  of  a  lozenge,  and  measures  about  four  inches  from  before 
backwards,  and  three  inches  between  the  ischial  tuberosities. 

Depth.  The  depth  of  the  perinaeum  from  the  surface  to  the  floor  may 
be  said  to  be  generally  about  three  inches  at  the  anus,  but  this  measure- 
ment varies  in  different  bodies  ;  and  it  amounts  to  about  an  inch  near  the 
pubes. 

Division.  A  line  from  the  front  of  the  tuberosity  of  one  side  to  the 
corresponding  point  on  the  other,  will  divide  the  perinoeal  space  into  two 
triangular  parts.  Tiie  anterior  half  (urethral)  contains  the  penis  and  the 
urethra,  with  their  muscles  and  vessels  and  nerves.  The  posterior  half 
(rectal)  is  occupied  by  the  lower  end  of  the  large  intestine,  with  its  mus- 
cles, etc. 

POSTERIOR  HALF  OF  THE  SPACE. 

This  portion  of  the  perinoeal  space  contains  the  lower  end  of  the  rectum, 
surrounded  by  its  elevator  muscle  and  the  muscles  acting  on  the  anus.  The 
gut  does  not  occupy  however  the  whole  of  the  interval  between  the  pelvic 
bones ;  for  on  each  side  is  a  space,  the  ischio-rectal  fossa,  in  which  is  con- 
tained much  loose  fat,  with  the  vessels  and  nerves  for  the  supply  of  the 
end  of  the  gut. 

Dissection  (fig.  129).  The  skin  is  to  be  raised  from  this  part  of  the 
perinii3um  by  the  employment  of  the  following  cuts :  One  is  to  be  made 
across  the  perinajum  at  the  front  of  the  anus,  and  is  to  be  extended  rather 
beyond  the  ischial  tuberosity  on  each  side.  A  second  is  to  be  carried  a 
little  behind  the  tip  of  the  coccyx  in  the  same  direction,  and  for  the  same 
distance.  The  two  transverse  cuts  are  to  be  connected  by  carrying  the 
knife  along  the  middle  and  around  the  anus.  The  flaps  of  skin  thus  marked 
out,  are  to  be  raisediind  thrown  outwards  from  the  middle  line  :  in  detach- 
ing the  skin  from  the  margin  of  the  anus,  the  superficial  subcutaneous 
sphincter  muscles  may  be  injured  without  care,  for  they  are  close  to  the 
skin,  without  the  intervention  of  fat.  The  dissector  should  trace  the 
sphincter  back  to  the  coccyx,  and  forwards  for  a  short  distance  beneath 
the  skin  ;  and  define  a  fleshy  slip  at  each  side  in  front  and  behind  to  the 
subcutaneous  fatty  layer. 

The  next  step  is  to  bring  into  view  the  ischio-rectal  hollow  between  the 
side  of  the  rectum  and  the  tuberosity  of  the  hip  bone.  On  the  left  side 
the  fat  is  to  be  cleaned  out  of  it  without  reference  to  the  vessels  and 
nerves,  but  on  the  opposite  side  a  special  dissection  is  to  be  made  of  them. 
To  take  out  the  fat  from  the  left  fossa,  besrin  at  the  outer  margin  of  the 
sphincter  ani,  and  proceed  forwards  and  backwards.  In  front  tlie  dissec- 
tion should  not  extend  farther  than  the  anus,  whilst  behind  it  should  lay 
bare  the  margin  of  the  gluteus  maxim  us.  On  the  inner  side  of  the  hollow 
the  levator  ani  (sometimes  very  pale)  is  to  be  dissected.     On  the  outer 


388 


DISSECTION    OF    THE    PERINiEUM, 


boundary  the  pudic  vessels  and  nerve  should  be  denuded:  they  lie  in  a 
canal  formed  by  fascia,  and  at  some  distance  from  the  surface. 

On  the  right  side  it  is  not  necessary  to  clean  the  muscular  fibres,  when 
following  the  vessels  and  nerves.  If  the  student  begins  at  the  outer  bor- 
der of  the  sphincter,  he  will  find  tlie  inferior  hiemorrhoidal  vessels  and 
nerve,  which  he  may  trace  outwards  to  the  pudic  trunks:  some  of  the 
branches,  which  join  the  superficial  perinneal  and  inferior  pudendal  nerves, 
are  to  be  followed  forwards.  In  the  posterior  angle  of  the  space  seek  a 
small  offset  of  the  fourth  sacral  ne^'ve ;  and  external  to  it,  one  or  more 
branches  of  the  sciatic  nerve  and  vessels  turning  round  the  border  of  the 
gluteus.  Near  tiie  front  of  the  fossa  is  a  superficial  perinatal  artery  and 
nerve  (of  the  pudic) ;  and  the  last,  after  communicating  with  the  hiemor- 
rhoidal nerve,  leaves  the  fossa.  A  second  perinaeal  nerve  with  a  deeper 
position  may  be  found  at  the  front  of  the  hollow. 

The  isCHio-RECTAL  FOSSA  (fig.  129)  is  the  space  intervening  between 
the  rectum  and  the  ischial  part  of  the  innominate  bone.     It  is  a  somewhat 


Fig.  129. 


A  View  op  the  Dissection  of  the  Rfctal  half  of  the  Perin;e[jm.     (Illustrations  of* 

Dissections.) 


Muscles  : 

A.  External  sphincter. 

B.  Corrugator  cutis,  only  part  left, 
c.  Internal  sphincter. 

D.  Levator  ani. 

E.  Gluteus  maximus. 


Arteries  : 

a.  Trunk  of  the  pudic  artery. 

6.  Inferior  hiemorrhoidal. 

c.  Branches  of  the  sciatic. 
Nerves  : 

1.  Inferior  hsemorrholdal. 

2.  Superficial  perinseal. 

3.  Perinaal  branch  of  the  fourth  sacral. 

4.  Small  sciatic. 


conical  interval,  uncovered  by  muscle,  which  is  larger  behind  than  before, 
and  diminishes  in  width  as  it  sinks  into  the  pelvis.  Its  width  is  about 
one  inch  at  the  surface;  and  its  depth  about  two  inches  at  the  outer  part. 
It  is  filled  by  a  soft  granular  fat. 


MUSCLES    OF    ANUS.  889 

The  inner  or  longest  side  of  the  space  is  very  oblique,  and  is  bounded 
by  the  levator  ani  (d),  together  with  the  coccygeus  muscle  posteriorly; 
but  the  outer  side  is  vertical,  and  is  formed  by  the  obturator  muscle  and 
the  fascia  covering  it.  In  front  it  is  limited  by  the  triangular  ligament 
(to  be  afterwards  seen) ;  and  behind  are  the  great  sacro-sciatic  ligament, 
and  the  largest  gluteal  muscle.  Towards  the  surface  it  is  covered  by  the 
teguments,  and  is  overlaid  in  part  by  the  gluteus  e  and  the  sphincter 
externus  A. 

Position  of  vessels.  Along  the  outer  wall  lie  the  pudic  vessels  and 
nerve  («),  which  are  contained  in  a  tube  of  fascia;  opposite  the  ischial 
tuberosity,  they  are  situate  an  inch  and  a  half  from  the  surface,  but  to- 
wards the  front  of  the  space  they  approach  to  about  half  an  inch  from  the 
edge  of  the  pubic  arch.  Crossing  the  centre  of  the  hollow  are  the  inferior 
haemorrhoidal  vessels  and  nerves  (h) — branches  of  the  pudic.  At  the  an- 
terior part,  for  a  short  distance,  are  two  superficial  perinaeal  nerves  (^)  (of 
the  pudic) ;  and  at  the  posterior  part  is  a  small  branch  of  the  fourth  sacral 
nerve  (^),  with  cutaneous  offsets  of  the  sciatic  vessels  (c)  and  nerve  (*) 
bending  round  the  gluteus. 

Into  this  space  the  surgeon  sinks  his  knife  in  the  first  incisions  in  the 
lateral  operation  of  lithotomy ;  and  as  he  carries  it  from  before  backwards, 
he  will  divide  the  superficial  haRmorrhoidal  vessels  and  nerve. 

Muscles.  Connected  with  the  lower  end  of  the  rectum  are  four  mus- 
cles, viz.,  a  fine  cuticular  muscle,  and  two  sphincters  (external  and  inter- 
nal) with  the  levator  ani. 

Corrugator  cutis  ani^  (fig.  129,  ^).  This  thin  subcutaneous  layer  of 
involuntary  muscle  surrounds  the  anus  with  radiating  fibres.  Externally 
it  blends  with  the  subdermic  tissue  outside  the  internal  sphincter;  and  in- 
ternally it  enters  the  anus  and  ends  in  the  submucous  tissue  within  the 
sphincter. 

Action.  By  the  contraction  of  the  fibres  the  skin  is  raised  into  ridges 
radiating  from  the  anus,  such  as  may  be  seen  when  that  aperture  is  firmly 
closed. 

The  EXTERNAL  SPHINCTER  (fig.  129,  ^)  (sphincter  ani  externus)  is  a 
flat,  thin,  orbicular  muscle,  which  surrounds  the  lower  part  of  the  rectum. 
The  fibres  form  ellipses  around  a  central  aperture,  as  in  other  orbicular 
muscles.  It  arises  posteriorly  by  a  fibrous  band  from  the  back  of  the 
coccyx  near  the  tip,  and  by  fleshy  fibres  on  each  side  from  the  subcuta- 
neous fatty  layer.  Its  fibres  pass  Ibrwards  to  the  anus,  where  they  sepa- 
rate to  encircle  that  aperture  ;  and  in  front  they  are  inserted  into  tlie 
central  point  of  the  perinoeum,  and  into  the  superficial  fascia  by  a  rather 
wide  fleshy  slip  on  each  side. 

The  sphincter  is  close  beneath  the  skin,  and  conceals  partly  the  levator 
ani.  The  outer  border  projects  over  the  ischio-rectal  fossa,  and  the  inner 
is  contiguous  to  the  internal  sphincter. 

Action.  The  muscle  gathers  into  a  roll  the  skin  around  the  anus,  and 
occludes  the  anal  aperture  :  by  its  contraction  it  makes  tense  also  the  cen- 
tral point  of  the  perinseum. 

Commonly  the  fibres  are  in  a  state  of  involuntary  slight  contraction, 
but  they  may  be  firmly  contracted  under  the  influence  of  the  will. 

The  INTERNAL  SPHINCTER  (fig.  129,  °)  (sphincter  ani  internus)  is 
situate  around  the  extremity  of  the  intestine,  internal  to   the  preceding 

*  Illustrations  of  Dissections,  p.  243.     Lond.  1865. 


390  DISSECTION    OF    THE    PERINEUM. 

muscle,  and  its  edge  will  be  seen  by  removing  the  corrugator  and  the 
mucous  membrane.  The  fibres  of  the  muscle  are  pale,  fine  in  texture, 
quite  separate  from  the  surrounding  external  sphincter,  and  encircle  the 
lower  part  of  the  rectum  in  the  form  of  a  ring  about  half  an  inch  in  depth. 
The  muscle  is  a  thickened  band  of  the  involuntary  circular  fibres  of  the 
large  intestines,  which  is  not  attached  to  the  bone. 

Action.  This  sphincter  assists  the  external  in  closing  the  anus  ;  and  its 
contraction  is  altogether  involuntary. 

The  LEVATOR  ANi  musclc  (fig.  129,  ^)  can  be  seen  only  in  part;  and 
the  external  sphincter  may  be  detached  from  the  coccyx,  in  order  that  its 
insertion  may  be  more  apparent.  The  muscle  descends  from  its  origin  at 
the  inner  aspect  of  the  hip  bone,  and  is  inserted  along  the  middle  line  from 
the  coccyx  to  the  central  point  of  the  perinaeum  : — The  most  posterior 
fibres  are  attached  to  the  side  of  the  coccyx ;  and  between  that  bone  and 
the  rectum  tlie  muscles  of  opposite  sides  are  united  in  a  median  tendinous 
line.  The  middle  fibres  are  blended  with  the  side  of  the  intestine  (rec- 
tum). And  the  anterior  are  joined  with  the  opposite  muscle,  in  front  of 
the  rectum,  in  the  central  point  of  the  perinaeum. 

This  muscle  bounds  the  ischio-rectal  fossa  on  the  inner  side,  and  unites 
with  its  fellow  to  form  a  fleshy  layer,  convex  downwards,  through  which 
the  rectum  is  transmitted.  Deeper  than  the  muscle  is  the  recto-vesical 
fascia.     Along  the  hinder  border  is  placed  the  coccygeus. 

Action.  Its  action  on  the  rectum  is  to  elevate  and  invert  the  lower  end 
of  the  gut  after  this  has  been  protruded  and  everted  in  the  passage  of  the 
feces. 

With  the  description  of  the  muscle  in  the  pelvis  its  action  on  the  urethra 
will  be  referred  to. 

Arteries  (fig.  129).  The  pudic  artery,  with  its  inferior  haemorrhoidal 
branch,  and  other  small  offsets  of  it  and  the  sciatic,  are  now  visible. 

The  pudic  artery  (a)  is  derived  from  the  internal  iliac  in  the  pelvis,  and 
ascending  to  the  genital  organs,  distributes  offsets  to  the  perinaeum ;  one 
portion  will  be  laid  bare  in  the  hinder,  and  the  other  in  the  anterior  half 
of  the  perinaeum. 

As  now  seen,  the  vessel  enters  the  posterior  part  of  the  ischio-rectal 
fossa,  and  courses  forwards  along  the  outer  wall  at  the  depth  of  one  inch 
and  a  half  behind,  but  of  only  half  an  inch  at  the  fore  part.  It  is  con- 
tained in  an  aponeurotic  sheath  which  attaches  it  to  the  obturator  fascia. 
The  usual  companion  veins  lie  by  its  side  ;  and  two  nerves  accompany  it, 
viz.,  the  trunk  of  the  pudic,  and  the  perinaeal  branch  of  the  same  nerve 
which  is  nearer  the  surface.  Its  offsets  in  the  posterior  half  of  its  course 
are  the  following  : — 

The  injerior  hcemorrhoidal  branch  (b)  arises  internal  to  the  ischial 
tuberosity ;  it  sends  offsets  inwards  across  the  ischio-rectal  fossa  to  the 
teguments,  and  the  sphincter  and  levator  ani  muscles.  On  the  rectum  it 
anastomoses  with  the  upper  haemorrhoidal  branch,  and  with  the  artery  of 
the  o[)posite  side.  In  a  well  injected  body  cutaneous  branches  may  be 
seen  to  run  forwards  to  the  anterior  part  of  the  perinaeum,  and  to  commu- 
nicate with  the  superficial  perinaeal  branch. 

Small  muscular  branches  cross  tlie  front  of  the  ischio-rectal  fossa,  and 
supply  the  anterior  part  of  the  levator  ani  muscle. 

The  branches  of  the  sciatic  artery  (c)  appear  on  the  inner  aspect  of  the 
gluteus  maximus  at  the  back  of  tlie  fossa;  some  end  in  that  muscle,  and 
others  are  continued  round  its  border  to  the  fat. 


URETHRAL    HALF    OF    THE    REGION.  391 

Veins  accompany  the  different  arteries,  and  have  a  like  course  and 
ramification  :    the  pudic  end  in  the  internal  iliac. 

Nerves  (fig.  129).  The  nerves  to  be  learned  in  thi«  part  of  the  peri- 
naeum  are,  the  trunk  of  the  pudic  and  its  inferior  h£emorrhoidal  and  peri- 
naeal  branches  ;  an  offset  of  the  fourth  sacral ;  and  some  branches  of  the 
small  sciatic. 

The  pudic  nerve  comes  from  the  sacral  plexus,  and  accompanies  the 
artery  to  the  genitals.  In  the  anal  half  of  the  perinaeum  it  is  placed  deeper 
than  the  artery,  and  furnishes  the  two  subjoined  branches. 

The  inferior  hcemorrhoidal  branch  (1)  crosses  the  ischio-rectal  fossa, 
and  reaches  the  margin  of  the  anus,  where  it  terminates  in  offsets  to  the 
integument  and  the  sphincter  muscle.  Other  cutaneous  offsets  of  the  nerve 
turn  forwards  over  the  fossa,  and  communicate  with  one  of  the  superficial 
perinjeal  nerves,  and  with  the  inferior  pudendal  (of  the  small  sciatic)  on 
the  margin  of  the  thigh. 

The  perinceal  branch  arises  about  half  way  along  the  fossa,  and  becomes 
superficial  to  the  bloodvessels.  It  is  larger  in  size  than  the  continuation 
of  the  nerve  to  the  penis,  and  divides  into  cutaneous,  muscular,  and  geni- 
tal offsets.  Its  two  cutaneous  offsets  (superficial  perinaeal)  may  be  seen 
on  the  right  side,  where  they  lie  for  a  short  distance  in  the  ischio-rectal 
fossa. 

The  hcBmorrhoidal  branch  of  the  fourth  sacral  nerve  (')  reaches  the 
ischio-rectal  fossa  by  piercing  the  fibres  of  the  levator  ani.  Appearing  in 
the  posterior  part  of  the  fossa,  near  the  coccyx,  the  nerve  ends  by  supply- 
ing the  external  sphincter,  and  the  integuments  behind  the  anus. 

One  or  two  cutaneous  branches  of  the  small  sciatic  nerve  (*)  turn  round 
the  lower  border  of  the  gluteus,  in  their  course  to  the  integuments  on  its 
surface. 

ANTERIOR  HALF  OF  THE  PERINEAL  SPACE. 

In  the  anterior  part  of  the  perinaeal  space  are  lodged  the  crura  of  the 
penis,  and  the  tube  of  the  urethra  as  it  courses  from  the  interior  of  the 
pelvis  to  the  surface  of  the  body.  Placed  about  midway  between  the 
bones,  the  urethra  is  supported  by  the  triangular  ligament  of  the  perinaeum, 
and  by  its  union  with  the  penis. 

Muscles  are  collected  around  the  urethra  to  aid  in  the  expulsion  of  the 
contents  of  that  tube  :  some  of  these  are  superficial  to,  and  some  within 
the  triangular  ligament. 

The  vessels  and  nerve  lie  along  the  outer  side,  as  in  the  posterior  half, 
and  send  inwards  offsets. 

Dissection  (fig.  130).  To  raise  the  skin  from  the  anterior  part  of  the 
perinaeum,  a  transverse  cut  is  to  be  made  at  the  back  of  the  scrotum,  and 
is  to  be  continued  for  a  short  distance  (two  inches)  on  each  thigh.  A 
second  incision  along  the  middle  line  will  allow  the  fiaps  of  skin  to  be  re- 
flected outwards.  After  the  removal  of  the  skin  the  subcutaneous  fat 
(superficial  fascia)  which  covers  the  front  of  the  perinaeal  space,  is  to  be 
blown  up  by  means  of  a  pipe  introduced  beneath  it  posteriorly.  Each 
side  is  to  be  inflated  to  demonstrate  a  partition  along  the  middle  line,  and 
a  septum  between  the  perinseal  space  and  the  thigh  which  prevents  the  air 
passing  to  the  limb. 

The  student  is  next  to  cut  through  the  superficial  fascia  on  the  left  side 
from  the  scrotum  to  the   ischio-rectal  fossa  ;  and  after  reflecting  it,  and 


392 


DISSECTION    OF    THE    PERINEUM. 


removing  loose  fatty  tissue,  its  line  of  attachment  to  the  bones  externally, 
and  to  the  triangular  ligament  posteriorly,  will  be  brought  into  view. 
The  septum  along  the  middle  line  should  be  also  defined.  To  demonstrate 
more  completely  the  attachment  of  this  subcutaneous  layer  to  the  pubic 
arch  between  the  perina?al  space  and  the  thigh,  it  will  be  necessary  to  take 
away  from  the  left  limb  the  fat  on  the  fascia  lata,  external  to  the  line  of 
the  bone. 

In  the  fat  of  the  thigh  on  the  right  side  the  student  should  seek  the  in- 
ferior pudendal  nerve,  which  pierces  the  fascia  lata  one  inch  anterior  to 
the  tuber  ischii,  and  about  the  same  distance  from  the  margin  of  the  pubic 
arch  ;  and  should  trace  its  junction  in  the  fat  with  the  inferior  haimor- 
rhoidal  nerve.  Afterwards  the  nerve  is  to  be  followed  forwards  to  where 
it  enters  beneath  the  superficial  fascia  in  the  middle  line. 

Fiff.  130. 


Superficial  Dissection  of  the  Antekior  Half  of  the  PERiNiECM. 
(Illustratious  of  Dissectioa.s.) 
Muscles  :  Arteries  : 

A.  Ejaculator  urinae.  a.  Transverse  perinseal. 

B.  Erector  penis.  b.  Superficial  periiiseal. 
c.  Transversalis  perlnsel.  c.  Brauch  of  sciatic. 

D.  Levator  ani.  Nerves: 

K.  Gluteus  maximus.  1.  Inferior  hsemorrhoidal. 

a.  Crus  peuis.  2  and  3.  Superficial  periuaeal. 

H.  Urethra.  4.  Inferior  pudendal. 


The  suh cutaneous  fatty  layer  or  the  svperjicial  fascia  of  the  anterior 
half  of  the  perinaeum  is  continuous  with  that  cf  the  adjoining  regions; 
and  its  depth,  and  the  quantity  of  fat  in  it,  will  vary  with  the  condition  of 
the  body.  It  resembles  the  corresponding  stratum  of  the  groin  and  upper 
part  of  tlie  thigh,  in  consisting  of  two  different  portions. 

One,  a  subcutaneous  fatty  part,  continuous  with  that  of  the  rest  of  the 
body,  which  loses  its  fat  towards  the  scrotum,  and  obtains  there  involun- 
tary  muscular  fibres. 


PERINiEAL    ARTERY    AND    NERVES.  393 

The  other  deeper,  but  more  membranous  part,  is  of  limited  extent,  and 
is  connected  with  the  firm  subjacent  structures.  Externally  it  is  fixed  to 
the  pubic  arch  of  tlie  hip-bone,  outside  the  line  of  the  crus  penis  and  its 
muscle,  extending  as  low  as  the  ischial  tuberosity.  Posteriorly  the  stratum 
bends  down  to  join  tlie  triangular  ligament  of  the  urethra  ;  but  in  front  it 
is  unattached,  and  is  continued  to  the  scrotum  and  penis.  By  means  of 
similar  connections  of  the  membrane  on  both  sides,  a  space  is  enclosed 
over  the  anterior  half  of  the  perinjeum.  From  its  under  surface  a  septum 
dips  downwards  in  the  middle  line,  and  divides  posteriorly  the  subjacent 
space  into  two  ;  but  anteriorly  this  partition  is  less  perfect,  or  may  disap- 
pear. 

Air  blown  beneath  the  fascia  passes  forwards  to  the  scrotum  ;  and  this 
direction  is  given  to  it  by  the  deep  connections  of  that  membrane  with 
parts  around.  Should  urine  be  effused  beneatli  the  superficial  fascia,  the 
fluid  will  necessarily  be  directed  forwards,  like  the  air,  through  the  scrotum 
to  the  penis  and  the  front  of  the  abdomen. 

Dissection.  The  superficial  vessels  and  nerves  are  to  be  dissected  on  the 
right  side  of  the  perinaeum,  by  cutting  through  the  superficial  fascia  in  tho. 
same  manner  as  on  the  left  side.  The  long  slender  artery  then  visible  is 
the  superficial  perinaeal,  which  gives  a  transverse  branch  near  its  com- 
mencement. Two  superficial  perinaeal  nerves  accompany  the  artery ;  and 
the  inferior  pudendal  nerve  is  to  be  traced  forwards  to  tiie  scrotum.  Com- 
munications are  to  be  sought  between  these  nerves  anteriorly,  and  between 
one  of  the  peringeal  and  the  inferior  haemorrhoidal  posteriorly  ;  and  all  the 
nerves  are  to  be  followed  backwards. 

Arteries  (fig.  130).  The  superficial  and  transverse  perinaeal  arteries 
beneath  the  fascia  are  branches  of  the  pudic,  and  are  two  or  three  in 
number. 

The  superficial  'perinceal  branch  (fig.  130,  6),  arising  at  the  fore  part 
of  the  ischio-rectal  fossa,  runs  over  or  under  the  transverse  muscle,  and 
beneath  the  superficial  fascia  to  the  back  of  the  scrotum,  where  it  ends  in 
flexuous  branches.  As  the  vessel  lies  internal  to  the  pubic  arch,  it  sup- 
plies offsets  to  the  muscles  beneath  ;  and  in  front  it  anastomoses  with  the 
external  or  superficial  pudic  branches  of  the  femoral  artery.  Sometimes 
there  is  a  second  perinaeal  branch. 

The  transverse  artery  o^  the  perinaeum  (fig.  130,  a)  arises  from  the 
preceding,  and  is  directed  transversely  to  the  middle  of  the  perinatal  space, 
where  it  is  distributed  to  the  integuments  and  the  muscles  between  the 
urethra  and  the  rectum.     It  anastomoses  with  the  one  of  the  opposite  side. 

Branches  of  veins  accompany  the  arteries,  and  open  into  the  trunk  of 
the  pudic  vein  ;  those  with  the  superficial  perinaeal  artery  are  plexiform  at 
the  scrotum. 

Nerves  (fig.  130).  There  are  tliree  cutaneous  nerves  of  the  scrotomon 
each  side,  viz.,  inferior  pudendal  of  the  small  sciatic,  and  tAvo  superficial 
perinaeal  branches  of  the  pudic  nerve. 

The  superficial  perinceal  nerves,  two  in  number,  are  named  anterior 
and  posterior  from  their  relative  position  :  both  arise  in  the  ischio-rectal 
fossa  from  the  perinaeal  branch  of  the  pudic  nerve  (p.  391). 

T\\Q  posterior  branch  (^)  is  continued  forwards,  beneath  the  superficial 
fascia,  with  the  artery  of  the  same  name  to  the  back  of  the  scrotum. 
Whilst  in  the  fossa  the  nerve  gives  inwards  an  offset  to  the  integuments 
in  front  of  the  anus  ;  and  this  communicates  with  the  inferior  haemorrhoidal 
nerve. 


394  DISSECTION    OF    THE    PERINEUM. 

The  anterior  branch  (')  passes  under  the  transverse  muscle,  and  accom- 
panies tlie  other  to  tlie  scrotum.  Muscular  otfsets  are  furnished  by  it  to 
the  levator  ani  and  the  other  superficial  muscles. 

The  superficial  perinteal  branches  communicate  with  one  another,  and 
the  posterior  is  joined  by  the  inferior  pudendal  nerve.  At  the  scrotum 
they  are  distributed  by  long  slender  filaments,  which  reach  as  far  as  the 
under  surface  of  the  penis.  In  the  female  these  nerves  supply  the  labia 
pudendi. 

Other  muscular  branches  of  the  pudic  will  be  afterwards  examined  (p. 
399). 

The  inferior  pudendal  nerve  (*)  is  a  branch  of  the  small  sciatic.  It 
pierces  the  fascia  lata  about  one  inch  in  front  of  the  ischial  tuberosity,  and 
enters  beneath  the  superficial  fascia  of  the  perinseum,  to  end  in  the  outer 
and  fore  parts  of  the  scrotum.  Communications  take  place  between  this 
nerve,  the  inferior  hsRmorrhoidal,  and  the  posterior  of  the  two  superficial 
perinfeal  branches.  In  the  female  the  inferior  pudendal  nerve  is  distri- 
buted to  the  labium. 

Dissection.  F'or  the  display  of  the  muscles,  the  fatty  layer,  as  well  as 
the  vessels  and  nerves  of  the  left  side,  must  be  taken  away  from  the  ante- 
rior half  of  the  perinaeal  space.  Afterwards  a  thin  subjacent  aponeurotic 
layer  is  to  be  removed  from  the  muscles.  Along  the  middle  line  lies  the 
ejaculator  urinse ;  and  in  cleaning  it  the  student  is  to  follow  two  fasciculi 
of  fibres  from  it  on  the  same  side — one  in  front,  the  other  behind.  On  the 
outer  part  of  the  space  is  the  erector  penis.  And  behind,  passing  obliquely 
between  the  other  two,  is  the  transverse  muscle. 

The  student  should  seek,  on  the  right  side,  the  branches  of  the  two 
superficial  perinaeal  nerves  to  the  underlying  muscles  ;  and  beneath  the 
transversalis,  an  offset  of  the  perinceal  branch  which  supplies  the  deep 
muscles  and  the  ur'ethra. 

Muscles  (fig.  130).  Superficial  to  the  triangular  ligament  in  the  ante- 
rior half  of  the  perinatal  space,  are  three  muscles,  viz.,  the  erector  penis, 
the  ejaculator  urinae,  and  the  transversalis  perintei.  Other  muscles  of  the 
urethra  are  contained  between  the  layers  of  the  triangular  ligament,  and 
will  be  subsequently  seen. 

Central  point  of  the  perinceum.  Between  the  urethra  and  the  rectum  is 
a  white  fibrous  spot,  to  which  this  term  has  been  applied.  It  occupies  the 
middle  line,  half  an  inch  in  front  of  the  anus.  In  it  the  muscles  acting  on 
the  rectum  and  the  urethra  are  united ;  and  it  serves  as  a  common  point 
of  support  to  the  space. 

The  ERECTOR  PENIS  (fig.  130,  ^)  is  the  most  external  of  the  three  mus- 
cles, and  is  narrower  at  each  end  than  in  the  middle.  It  covers  the  crus 
penis;  and  its  fibres  arise  from  the  ischial  tuberosity  farther  back  than  the 
attachment  of  the  penis,  and  from  the  bone  on  each  side  of  the  crus.  Su- 
periorly the  muscle  is  inserted  into  the  inner  and  outer  surfaces  of  the  crus 
penis.     It  rests  on  the  root  of  the  penis  and  the  bone. 

Action.  The  muscle  compresses  the  crus  penis  against  the  subjacent 
bone,  and  retards  the  escape  of  the  blood  from  that  organ  by  the  veins :  in 
that  way  it  will  contribute  to  the  continuance  of  distension. 

The  EJACULATOR  URiN^  musclc  (fig.  130,  ^)  lies  on  the  urethra.  The 
muscles  of  opposite  sides  unite  by  a  median  tendon  along  the  middle  line 
and  in  the  central  point  of  the  perina^um  (origin).  The  fibres  are  directed 
outwards,  curving  around  the  convexity  of  the  urethra,  and  give  rise  to  a 
thin  muscle,  which  has  the  following  insertion: — The  most  posterior  fibres 


SUPERFICIAL    MUSCLES    OF    URETHRA.  395 

are  lost  on  the  front  of  the  triangular  ligament.  The  anterior  fibres,  which 
are  the  longest  and  best  marked,  are  inserted  into  the  penis  on  its  outer 
aspect  before  the  erector  ;  and,  according  to  Kobelt,^  they  send  a  tendinous 
expansion  over  the  dorsal  vessels  of  the  penis.  Whilst  the  middle  or  in- 
tervening fibres  turn  round  the  urethra,  surrounding  it  for  two  inches,  and 
join  its  fellow  by  a  tendon. 

The  ejaculator  muscle  covers  the  bulb  and  the  urethra  for  three  inches 
in  front  of  the  triangular  ligament.^  If  the  muscle  be  cut  through  on  the 
right  side,  and  turned  off  the  urethra,  the  junction  with  its  fellow  above 
that  tube  will  be  apparent. 

Action.  The  two  halves,  actino;  as  one  muscle,  can  diminish  the  urethra, 
and  eject  forcibly  its  contents.  During  the  flow  of  fluid  in  micturition  the 
fibres  are  relaxed,  but  tliey  come  into  use  at  the  end  of  the  process,  when 
the  passage  has  to  be  cleared.  The  action  is  involuntary  in  the  emission 
of  the  semen. 

The  TRANSVERSALS  PERiN^i  (fig.  130,  °)  is  a  small  thin  muscle,  which 
lies  across  the  perinteum  opposite  the  base  of  the  triangular  ligament. 
Arising  ^Yoxn  the  inner  surface  of  the  pubic  arch  near  the  ischial  tuberosity, 
it  is  inserted  into  tiie  central  point  of  the  perinteum  with  the  muscle  of  the 
opposite  side,  and  with  the  sphincter  ani  and  the  ejaculator  urinse.  Be- 
hind this  muscle  the  superficial  fascia  bends  down  to  join  the  triangular 
ligament. 

Sometimes  there  is  a  second  small  fleshy  slip,  anterior  to  the  transver- 
salis,  which  has  been  named  transversalis  alter  ;  this  throws  itself  into  the 
ejaculator  muscle. 

Action.  From  the  direction  of  the  fibres  the  muscle  will  draw  back- 
wards the  central  point  of  the  perinaeum,  and  help  to  fix  it,  preparatory  to 
the  contraction  of  the  ejaculator. 

The  three  muscles  above  described,  when  separated  from  each  other  by 
the  dissection,  limit  a  triangular  space,  of  which  the  ejaculator  urin?e 
forms  the  inner  boundary,  the  erector  penis  the  outer  side,  and  the  trans- 
versalis perinasi  muscle  the  base.  In  the  area  of  this  interval  is  the  trian- 
gular ligament  of  the  urethra,  with  the  superficial  perinaeal  vessels  and 
nerves.  Should  the  knife  enter  the  posterior  part  of  this  space  during  the 
deeper  incisions  in  the  lateral  operation  of  lithotomy,  it  will  divide  the 
transverse  muscle  and  artery,  and  probably  the  superficial  perinaeal  vessels 
and  nerves. 

Dissection  (fig.  131).  For  the  display  of  the  triangular  ligament,  the 
muscles  and  the  crus  penis,  which  are  superficial  to  it,  are  to  be  detached 
in  the  following  way: — On  the  left  side  the  ejaculator  urina3  is  to  be  re- 
moved completely  from  the  front  of  the  ligament,  and  the  erector  muscle 
from  the  crus  of  the  penis.  Next,  the  crus  penis  is  to  be  detached  from 
the  bone ;  but  this  must  be  done  with  care  so  as  not  to  cut  the  triangular 
■  ligament,  nor  to  injure,  near  the  pubes,  the  terminal  branches  of  the  pudic 
artery  and  nerve  to  the  penis. 

On  the  right  side  the  dissector  should  trace  out  beneath  the  transversalis 

*  Die  Mannlichen  und  Weibliclien  WoUust-Organe,  von  G.  L.  Kobelt,  1844. 

*  Some  of  the  deeper  fibres  which  immediately  surround  the  bulb,  have  been 
described  as  a  separate  stratum  by  Kobelt.  These  are  separated  from  the  super- 
ficial layer  by  thin  areolar  tissue,  and  join  the  corresponding  part  of  the  other 
muscle  by  a  small  tendon  above  the  urethra.  The  name  compressor  Jmnisp/icErium 
bulbi  has  been  proposed  for  it  by  that  anatomist. 


896 


DISSECTION    OF    THE    PERINJEUM 


the  offsets  of  the  perinatal  nerve  to  tlie  deep  muscles  and  the  urethra,  with 
the  vessels  accompanying  them. 

The  TRIANGULAR  LIGAMENT  OF  th£  URETHRA  (fig.  131,  ^)  (perinatal 
aponeurosis)  occupies  the  anterior  part  of  the  pubic  arch,  and  supports  the 
urethral  canal.  The  ligament  is  triangular  in  form,  with  its  base  below ; 
and  it  is  about  one  inch  and  a  half  in  depth. 


Fig.  131. 


Deep  Dissection  or  the  Perineum.    (Illustrations  of  Dissections.) 


Muscles  : 
A.  Erector  penis. 

Ejaculatorurinae,  cut. 

Triangular  ligament. 

External  sphincter. 

Bulbous  part  of  the  urethra. 

Levator  ani. 
H.  Deep  transverse. 
I.  Constrictor  urethrse. 
K.  Cms  penis,  cut. 


Arteries  : 
a.  Pudic,  in  the  triangular  ligament. 
&.  Dorsal  of  penis. 

c.  Cavernous. 

d.  Deep  muscular  and  urethral  branch. 
Nerves  : 

1.  Pudic  trunk. 

2.  Deep  perinajal  or  muscular  branch. 

3.  Dorsal  of  the  penis. 


On  each  side  it  is  fixed  to  the  pubic  arch  beneath  the  crus  penis.  Its 
apex  is  connected  with  tlie  symphysis  pubis.  Its  base  is  turned  towards 
the  rectum,  and  is  partly  attached  and  partly  free;  in  the  middle  line  it  is 
connected  with  the  central  ])oint  of  the  perinaeum,  whilst  laterally  it  is 
s'oped  towards  the  bone,  so  that  it  is  less  deep  at  the  centre  than  at  the' 
sides:  connected  with  tlie  lower  border  is  a  thin  fascia  which  covers  the 
surface  of  the  levator  ani  muscle  in  the  ischio-rectal  fossa.  Superficial  to 
it  are  the  muscles  in  the  anterior  half  of  the  perinaeal  space ;  and  the  super- 
ficial fascia  is  united  to  it  near  the  lower  border. 

The  ligament  is  comjiosed  of  two  layers  of  membrane  (anterior  and  pos- 
terior) which  are  united  below.  The  posterior  layer  is  derived  from  tlie 
recto-vesical  fascia.  The  anterior  is  a  separate  membrane,  formed  chiefiy 
of  transverse  fibres,  but  it  is  so  thin  as  to  allow  the  vessels  and  the  mus- 
cular fibres  to  be  seen  through  it. 


DEEP    MUSCLES    OF    URETHRA.  597 

Perforating  the  fore  part  of  the  ligament,  about  one  incli  below  the 
symphysis  pubis,  is  the  canal  of  the  urethra,  f  ;  but  the  margin  of  the 
opening  giving  passage  to  that  tube  is  blended  with  the  tissue  of  the  cor- 
pus spongiosum  urethras.  About  midway  between  the  preceding  opening 
and  the  symphysis  pubis  is  the  aperture  for  the  dorsal  vein  of  the  penis ; 
and  external  to  this,  near  the  bone  on  each  side,  the  terminal  parts  of  the 
pudic  artery  and  nerve  to  the  penis  (b  and  3)  perforate  the  ligament  by 
separate  apei'tures. 

Between  the  layers  of  the  ligament  are  contained  tlie  membranous  part 
of  the  urethra,  with  its  muscles,  vessels,  and  glands ;  and  the  bloodvessels 
and  nerves  of  the  penis. 

Dissection.  The  muscles  between  the  layers  of  the  ligament  will  be 
reached  by  cutting  tlirough  with  care,  on  the  left  side,  the  superficial 
stratum  near  its  attachment  to  the  bone,  and  raising  and  turning  inwards 
that  piece  of  membrane.  By  a  little  cautious  dissection,  and  the  removal 
of  some  veins,  the  following  objects  will  come  into  view  with  the  under- 
mentioned position  : — 

Parts  between  the  layers  of  the  ligament.  Near  the  base  is  a  narrow 
transverse  muscle,  h,  which  is  directed  to  the  bulb  of  the  urethra. 
Higher  up,  and  crossing  inwards  from  behind  the  pubic  arch,  is  the  fasci- 
culus of  fibres  of  the  constrictor  urethra  muscle,  i,  which  surrounds  the 
membranous  part  of  the  urethra.  And  below  the  urethra  are  the  glands 
of  Cowper.  Beneath  the  bone  are  the  pudic  vessels  {a)  and  nerve,  the 
former  giving  its  branch  to  the  bulb,  and  the  latter  being  deeper  in  posi- 
tion ;  and  below  the  pubes  is  the  sub-pubic  ligament.  Deeper  than  all, 
the  student  will  recognize  the  posterior  layer  of  the  ligament,  continuous 
with  the  recto-vesical  fascia,  which  separates  those  parts  from  the  cavity 
of  the  pelvis. 

Muscles.  The  two  muscles  connected  with  the  membranous  part  of 
the  urethra  are,  deep  transverse,  and  constrictor  of  the  urethral  passage. 

The  DEEP  TRANSVERSE  MUSCLE  (fig.  131,  h)  (elevator  urethra  Santo- 
rini)  is  a  thin  flat  band  on  a  level  with  the  base  of  the  triangular  ligament. 
It  arises  externally  from  the  pubic  arch  of  the  innominate  bone,  and  is 
directed  below  the  tip  of  the  bulb  and  the  membranous  part  of  the  urethra 
to  the  middle  line,  where  it  joins  the  muscle  of  the  opposite  side,  and  is 
inserted  into  the  central  point  of  the  perinaeum. 

The  muscle  conceals  Cow[)er's  gland,  and  is  frequently  placed  over  the 
artery  of  the  bulb.  The  transverse  muscle  is  not  always  separate  from 
the  following. 

Action.  Like  the  superficial  muscle  it  will  fix  the  central  point  of  the 
perinaeum. 

The  CONSTRICTOR  MUSCLE  (fig.  131,  ')  (constrictor  isthmi  urethralis) 
incloses  the  membranous  part  of  the  urethra,  and  consists  of  transverse 
fibres  above  and  below  that  tube. 

The  muscle  arises  by  aponeurotic  fibres  from  the  pubic  arch  above  the 
preceding,  and  from  the  [)Osterior  layer  of  the  triangular  ligament,  but 
this  attachment  is  not  evident  unless  it  has  been  dissected  from  behind. 
The  fibres  pass  inwards,  and  separate  near  the  urethra  into  two  layers 
(fig.  132),  of  which  one  {c)  passes  over,  the  other  (d)  under  that  canal; 
in  the  middle  line  they  unite  (sometimes  by  tendon)  with  the  like  parts 
of  the  muscle  of  the  opposite  side. 

It  may  be  considered  a  single  muscle  extending  across  the  perinaeum 


398 


DISSECTION    OF    THE    PERINiEUM 


Fig.  132. 


from  one  lateral  attachment  to  the  other,  and  inclosing  the  urethra,  like 
the  sphincter  ani  encircles  tlie  rectum. 

Action.  The  muscles  of  both  sides  act  as  a  single  sphincter  in  dimin- 
ishing the  membranous  part  of  the  urethra,  and  ejecting  the  contents  of 

the  tube.  Like  the  ejaculator,  they  are 
relaxed  whilst  the  urine  is  passing,  but 
the  two  contract  forcibly  in  expelling 
the  last  of  that  fluid. 

Involuntary  circular  Jihres  within 
the  constrictor  muscle  surround  the 
urethra  from  the  bulb  to  the  prostate, 
and  form  a  layer  about  ^^gth  of  an  inch 
thick  ;  they  are  not  fixed  to  bone,  and 
are  continuous  behind  with  the  circular 
fibres  of  the  prostate.  This  layer  is  a 
portion  of  the  large  involuntary  muscle, 
of  which  the  prostate  is  chief  part, 
surrounding  the  beginning  of  the 
urethra.^ 

Action.  This  involuntary  layer  as- 
sists in  moving  forwards  the  urine  and 
the  semen. 

The  glands  of  Cowper  will  be  found 
by  cutting  through  the  transverse  mus- 
cle. They  are  situate  below  the  mem- 
branous part  of  the  urethra,  one  on 
each  side  of  the  middle  line,  and  close 
behind  the  bulb.  Each  gUmd  is  about 
the  size  of  a  pea,  and  is  made  up  of 
lobules;  and  the  lobules  are  composed 
of  small  vesicles,  which  are  lined  by  flattened  epithelium. 

Connected  with  each  is  a  minute  duct,  nearly  an  inch  in  length,  wdiich 
perforates  obliquely  the  wall  of  the  urethra  (corpus  spongiosum),  and 
opens  into  the  urethral  canal  about  half  an  inch  in  front  of  the  triangular 
ligament.  Its  aperture  in  the  ordinary  state  does  not  admit  a  bristle.  In 
the  wall  of  the  duct  are  unstriated  muscular  fibres ;  and  the  interior  is 
lined  by  a  columnar  epithelium.  The  nature  of  the  secretion  of  the  gland 
is  not  known. 

These  bodies  are  sometimes  so  small  as  to  escape  detection,  and  they 
appear  to  decrease  in  size  with  advancing  age. 

Dissection.  The  student  may  complete  the  examination  of  the  perinaeum 
by  tracing  out  the  pudic  vessels  and  nerve,  and  their  remaining  branches. 
From  the  point  of  its  division  beneath  the  crus  into  two  branches  (dorsal 
of  the  penis,  and  cavernous),  the  artery  is  to  be  followed  backwards,  along 
the  pubic  arch  of  the  left  side.  The  pudic  nerve  will  be  by  tlie  side  of, 
but  deeper  than  the  artery. 

Pudic  Artkky  (a).  The  posterior  half  of  this  artery  has  been  already 
dissected  (p.  390).  In  the  anterior  half  of  the  ])erina^um  it  ascends  be- 
tween tlie  layers  of  the  triangular  ligament,  and  along  the  pubic  arch 
nearly  to  the  pubes  ;    there  it  perforates  the  superficial  part  of  the  liga- 


The  Symphysis  Pubis  seen  from  behind 
with  part  of  the  urinary  bladder 
ANDTHE  Prostate,  and  with  thk  Tube 
OF  the  Urethra  surrounded  by  the 
Constrictor  Muscle  (Santorini). 

a.  Bladder  cut  open:  tlie  swelling  of  the 
prostate  surrounds  it  in  front. 

6.  Constrictor  urethra:— 

c.  Part  of  the  muscle  above,  and 

d.  Part  underneath  the  urethra. 


'  See  a  paper  on  the  Arrangement  of  tlie  Muscular  Fibres  of  the  Urethra,  in  vol. 
xxxix.  1850,  of  the  Trans,  of  the  Med.-Chir.  Society. 


PUDIC    ARTERY    AND    NERVE.  399 

itient,  and  divides  into  the  arteries  of  the  cavernous  structure  and  dorsum 
of  the  penis.  In  this  course  it  is  placed  beneath  the  constrictor  urethras, 
and  is  accompanied  by  venae  comites  and  the  pudic  nerve.  Its  offsets  are 
subjoined : — 

a.  The  artery  of  the  hulb  of  the  urethra  is  a  branch  of  considerable 
size,  and  arises  near  the  base  of  the  triangular  ligament.  Passing  almost 
transversely  inwards  between  the  layers  of  that  ligament,  about  half  an 
inch  from  the  base,  the  artery  reaches  the  back  of  the  bulb,  and  enters  the 
spongy  structure.  Near  the  urethra  it  furnishes  a  small  branch  to  Cow- 
per's  gland. 

The  distance  of  this  branch  from  the  base  of  the  ligament  will  be  in- 
fluenced by  its  origin  near  the  front  or  back  of  the  perinatal  space.  If  the 
vessel  arises  farther  behind  than  usual,  it  may  be  altogether  below  the 
ligament,  and  may  cross  the  front  of  the  ischio-rectal  fossa,  so  as  to  be 
liable  to  be  cut  in  the  operation  of  lithotomy. 

h.  Deep  muscular  branches  (d).  As  the  artery  is  about  to  enter  between 
the  layers  of  the  triangular  ligament  it  furnishes  one  or  more  branches  to 
the  levator  ani  and  sphincter,  and  fine  twigs  through  the  ligament  to  the 
constrictor  and  the  urethra. 

c.  The  artery  of  the  cavernous  structure  of  the  penis  (c)  (art.  corporis 
cavernosi)  is  one  of  the  terminal  branches  of  the  pudic.  At  first  this  small 
vessel  lies  between  the  crus  penis  and  the  bone,  but  it  soon  enters  the  crus, 
and  ramifies  in  the  cavernous  structure  of  the  penis. 

d.  The  dorsal  artery  of  the  penis  (^)  is  in  direction  and  size  the  con- 
tinuation of  the  pudic  ;  it  runs  upwards  between  the  crus  and  the  bone, 
and  reaches  the  dorsum  of  the  penis  by  passing  through  the  suspensory 
ligament.  Its  distribution  with  the  accompanying  nerve  is  noticed  at  page 
408.     It  is  much  smaller  in  the  female  than  in  the  male. 

Accessory  pudic  artery.  In  some  cases  the  pudic  artery  is  not  large 
enough  to  supply  the  branches  above  described  to  the  penis  and  the  ure- 
thra. One  or  more  offsets  will  be  then  contributed  by  an  accessory  vessel, 
which  leaves  the  pelvis  in  front  by  piercing  the  triangular  ligament.  The 
source  of  this  accessory  artery  is  the  internal  iliac. 

The  pudic  veins,  two  in  number,  have  the  same  connections  as  the 
artery ;  they  receive  similar  branches,  except  that  the  dorsal  vein  of  the 
penis  does  not  join  them. 

The  PUDIC  NERVE  has  been  examined  in  the  ischio-rectal  fossa  (p.  391). 
In  the  anterior  half  of  the  perina3um  it  is  much  diminished  in  size,  in  con- 
sequence of  the  emission  of  the  large  perinteal  branch,  and  courses  with 
the  artery  between  the  layers  of  the  triangular  ligament ;  near  the  pubes 
it  pierces  the  ligament  (fig.  131,  ^),  and  is  continued  to  the  dorsum  of  the 
penis  with  the  dorsal  branch  of  tlie  pudic  artery  ;  its  termination  is  de- 
scribed at  page  408.  The  deep  muscles  and  the  corpus  spongiosum  are 
supplied  by  the  following  branch. 

Perinceal  branch  (p.  391).  Arising  in  the  ischio-rectal  fossa  it  supplies 
superficial  nerves,  and  ends  near  the  base  of  the  triangular  ligament  in 
deep  muscular  offsets:  some  of  these  (fig.  131,  '^)  pass  beneath  the  trans- 
versalis,  and  piercing  the  triangular  ligament,  sup])ly  the  muscles  within 
it.  A  long  slender  branch,  nerve  of  the  bulb,  is  distributed  like  the  artery 
to  the  spongy  structure  investing  the  urethra :  its  filaments  reach  some 
way  on  the  surface  before  disappearing  in  the  cor{)us  spongiosum  ui-ethne. 

Parts  cut  in  the  lateral  operation  of  lithotomy.  This  operation  for  stone 
in  the  bladder  may  be  divided  into  three  stages,  viz.,  cutting  down  to  the 


400  DISSECTION    OF    THE    PERINiEUM. 

urethra,  opening  the  canal,  and  slitting  that  tube  and  the  neck  of  the 
bladder.  In  the  external  incisions  the  knife  is  entered  in  the  middle 
line  of  the  perinaiuni,  half  an  inch  in  front  of  the  anus,  and  is  drawn  back- 
wards on  the  left  side  as  far  as  midway  between  the  ischial  tuberosity  and 
the  anus.  The  skin  and  superficial  fascia,  and  the  inferior  hemorrhoidal 
vessels  and  nerve  lyinj?  across  the  ischio-rectal  fossa,  will  be  cut  in  this 
first  stage  of  the  operation  ;  and  the  transverse  perinaeal  muscle  and  artery, 
and,  possibly,  tlie  superficial  perinaeal  vessels  and  nerves,  may  be  divided, 
if  the  first  incision  is  begun  farther  forwards. 

In  the  subsequent  attempt  to  reach  the  staff,  when  the  knife  is  intro- 
duced into  the  anterior  part  of  the  wound,  the  lower  part  of  the  triangular 
ligament,  the  deep  transverse  urethral  muscle,  and  the  fore  part  of  the 
levator  ani  will  be  divided  ;  and  when  the  knife  is  placed  within  the  groove 
of  the  staff,  the  membranous  part  of  the  urethra  will  be  cut,  with  the 
muscular  fibre  about  it. 

Lastly,  as  the  knife  is  pushed  along  the  staff  into  the  bladder,  it  incises 
in  its  progress  the  membranous  portion  of  the  urethra,  part  of  tlie  prostate 
with  large  veins  around  it,  and  the  neck  of  the  bladder.  When  the  last 
two  parts  are  being  cut,  the  handle  of  the  knife  is  to  be  raised,  and  the  blade 
depressed;  and  the  incision  is  to  be  made  downwards  and  outwards  in  tlie 
direction  of  a  line  from  the  urethra  through  the  left  lateral  lobe  of  the 
prostate,  above  the  level  of  the  ejaculatory  duct. 

Parts  to  be  avoided.  In  the  first  incjsions  in  the  ischio-rectal  fossa, 
the  rectum  may  be  cut  if  the  knife  is  turned  inwards  across  the  intestine, 
instead  of  being  kept  parallel  with  it ;  and  if  the  gut  is  not  kept  out  of  the 
way  with  the  fore  finger  of  the  left  hand.  The  pudic  vessels  on  the  outer 
wall  of  the  ischio-rectal  fossa  can  be  wounded  near  the  anterior  part  of  the 
hollow,  where  they  approach  the  margin  of  the  triangular  ligament ;  but,  pos- 
teriorly, they  are  securely  lodged  inside  the  projection  of  the  tuber  ischii. 

Whilst  making  the  deeper  incisions  to  reach  the  staff,  the  artery  of  the 
bulb  lies  immediately  in  front  of  the  knife,  and  will  be  wounded  if  the  in- 
cisions are  made  too  far  forwards ;  but  the  vessel  must  almost  necessarily 
be  cut,  when  it  arises  farther  back  than  usual,  and  crosses  the  front  of  the 
ischio-rectal  fossa  in  its  course  to  the  bulb  of  the  urethra. 

In  the  last  stage  of  the  operation  the  neck  of  the  bladder  should  not  be 
cut  to  a  greater  extent  than  is  necessary  for  the  extraction  of  the  stone, 
lest  the  recto-vesical  fascia  separating  the  perinaeum  from  the  pelvis  should 
be  divided,  and  the  abdominal  cavity  opened.  Too  large  an  incision 
through  the  prostate  may  wound  also  an  unusual  accessory  pudic  artery 
on  the  side  of  that  body. 

Directions.  When  the  dissection  of  the  perinaeum  is  completed,  the 
flaps  of  skin  are  to  be  fastened  together,  after  salt  has  been  used,  and  the 
limbs  are  to  be  put  down  for  the  examination  of  the  abdomen. 


Section  II. 

PERINiEUM  OF  THE  FEMALE. 


The  perinaeum  in  the  female  differs  from  that  in  the  male  more  in  the 
external  form  than  the  internal  anatomy.  On  the  surface  it  has  special 
parts  distinguishing  it,  viz.,  the  aperture  of  the  vagina,  and  the  opening  of 
the  vulva  with  the  labia. 


PERINiEUM    OF    THE    FEMALE. 


401 


Surface-marking.  In  the  middle  line,  there  are  the  two  apertures  of 
the  anus  and  vulva,  which  are  separated  from  one  another  by  an  interval 
of  about  an  inch.  The  anus  is  situate  rather  farther  back  than  in  the 
male.  And  the  vulva  with  the  labia  majora  on  the  sides  is  placed  in  the 
situation  of  the  scrotum  oF  the  other  sex. 

Within  the  vulva  at  the  upper  part,  is  the  clitoris,  and  two  small  mem- 
branous folds,  labia  minora,  extend  downwards  from  it.  Below  the  clitoris 
is  the  small  aperture  of  the  urethra  ;  and  still  lower  down  is  the  vagina, 
whose  opening  is  sometimes  partly  closed  by  a  thin  piece  of  membrane, 
the  hymen. 

Dee'p  houndarus.  The  deep  boundaries  of  the  perinseum  are  alike  in 
both  sexes;  but  in  the  female  the  outlet  of  the  pelvis  is  larger  than  in  the 
male. 

Fig.  133. 


The  Female  Perin;e0M  (from  Dr. 

1.  Pudic  artery. 

2.  Branch  to  levator  ani. 

3.  Inferior  hseinorrhoidal  artery. 
4    Transverse  artery. 

5.  Great  labial  (superficial  perineal)  artery. 

7.  Dorsal  artery  of  clitoris. 

8.  Artery  of  bulb 

9.  Artery  to  cms  clitoridis. 

10.  Inferior  haemorrhoidal  nerve. 

11.  Pudic  nerve. 

12.  Muscular  branch. 

13.  Internal  superficial  perinasil  nerve. 

14.  External  superficial  perinseal  nerve. 
\o.  Its  junction  with — 

16.  Inferior  pudendal  nerve. 

17.  Small  sciatic  nerve. 

18.  IS.  Dorsal  nerve  of  clitoris. 


Savage's  "Illustrations''). 
19.  Ilio-ingainal  nerve. 
A.  Anus. 
C.  Clitoris. 
M.  Meatus  urinarius. 
L.  Great  sacro-sciatic  ligament. 

Vagina. 

Coccyx. 

Tuberosity  of  ischium. 

Gluteus  miximus 

Levator  ani. 

Superficial  transverse  muscle. 

Compressor  bulbi. 

Erector  clitoridis. 

Triangular  ligament  (cut). 

Biceps  and  semi-tendinosus. 

Adductor  magHus. 

Gracilis. 


Dissection.  T!ie  steps  of  the  dissection  are  much  the  same  In  both 
sexes,  and  the  same  description  will  serve,  generally,  for  the  male  and 
female  perina^um. 

First,  the  dissection  of  the  ischio-rectal  fossa  is  to  be  made.  After- 
26 


402 


DISSECTION    OF    THE    PERINiEUM. 


wards  the  muscles,  vessels,  and  nerves  of  the  posterior  half  of  the  perinagal 
space  are  to  be  examined.  (See  description  of  the  male  perinseum,  p.  386 
to  392.) 

Next  the  skin  is  to  be  taken  from  the  interior  half  of  the  perina?al 
space,  as  in  the  male;  and  tlie  transverse  incision  in  front  is  to  be  made 
at  the  anterior  part  of  the  vulva.  The  attachments  of  the  superficial  fascia 
are  then  to  be  looked  to,  and  the  cutaneous  vessels  and  nerves  are  to  be 
traced  beneath  it  (p.  392  to  394). 

Superficial  fascia.  The  description  of  this  fascia  in  the  male  will 
serve  for  the  like  part  in  the  female,  with  these  modifications :  that  in  the 
female  it  is  interrupted  in  the  middle  line,  and  is  of  less  extent,  in  conse- 
quence of  the  aperture  of  the  vulva ;  and  that  it  is  continued  forwards 
through  the  labia  majora  (the  representative  of  the  scrotum)  to  the  in- 
guinal region. 

Fig.  134. 


The  Muscles  op  the  Female  Perinjepm,  Superficial  on  Right,  and  Deep  on  Lkft  Side 
(from  Savage  and  Luschka). 

1.  Clitoris.  9.  Deep  transversus  perinsei. 

2.  Erector  clitoridis,  10.  Superficial  transversus  perinsei. 

3.  Jarjavay's  muscle,  11.  Posterior  layer  of  triangular  ligameat. 

4.  Bulb  of  vagina.  12.  Sphincter  ani. 

5.  Transversus  perinaei  (reflected).  13.  Triangular  ligament. 

6.  Compressor  bulbi  (sphincter).  14.  Levator  ani. 

7.  Constrictor  vaginae  15.  Ischio-perineal  ligament. 

8.  Gland  of  Bartholin. 


Dissection.  The  labia  and  the  superficial  fascia  are  to  be  removed,  to 
follow  the  sphincter  muscle  around  tlie  opening  of  the  vagina.  Two  other 
muscles  are  exposed  at  the  same  time,  viz.,  the  erector  clitoridis  on  the 
pubic  arch,  and  the  transversalis  perinjei  passing  across  the  periniuum  to 
the  central  point. 

The  SPiiiNCTKR  VAGINA  is  an  orbicular  muscle  around  the  orifice  of 
the  vagina,  and  corresponds  with  the  ejaculator  urin^e  in  the  mule.  Pos- 
teriorly it  is  attached  to  the  central  point  of  the  perinijcum,  where  it  mixes 
with  the  sphincter  ani  and  transversalis  muscles ;  and  its  fibres  are  directed 


DEEP    URETHRAL    MUSCLES.  403 

forwards  on  each  side  of  the  vagina,  to  be  inserted  into  the  body  of  the 
clitoris,  and  front  of  the  triangular  ligament. 

Action.  Like  the  other  orbicular  muscles  the  sphincter  diminishes 
that  part  of  the  vagina  which  it  encircles;  and  it  assists  in  fixing  the  cen- 
tral point  of  the  perinaeum. 

The  ERECTOR  CLiTORiDis  Tcsembles  the  erector  of  the  penis  in  the 
male,  though  it  is  much  smaller  (p.  394). 

The  TRANSVERSALis  is  similar  to  the  muscle  of  the  same  name  in  the 
male.  The  one  description  will  suffice  for  those  muscles  in  both  sexes 
(p.  395). 

Dissection.  To  see  the  triangular  ligament  of  the  urethra,  the  erector 
and  the  crus  clitoridis  are  to  be  detached  from  the  bone,  and  the  outer 
fibres  of  the  sphincter  vaginae  are  to  be  removed. 

The  triangular  ligament  transmits  the  urethra,  but  is  not  quite  so 
strongly  marked  as  in  the  male  (p.  396) ;  its  extent  is  partly  interrupted 
behind  by  the  large  aperture  of  the  vagina. 

Dissection.  By  cutting  through  the  superficial  layer  of  the  ligament  in 
the  same  way  as  in  the  male  (p.  397),  the  deep  muscles,  with  the  pudic 
vessels  and  nerve  and  their  branches,  will  be  arrived  at. 

The  DEEP  TRANSVERSE  MUSCLE  (dcprcssor  urethras,  Santorini)  lias  the 
same  origin  externally  as  in  the  male  (p.  397) ;  and  it  meets  its  fellow  at 
the  middle  line,  like  the  muscle  answering  to  it  in  the  other  sex.  Santo- 
rini described  the  muscle  as  passing  over,  instead  of  below  the  urethra ; 
hence  the  name  given  to  it  by  its  discoverer. 

The  CONSTRICTOR  MUSCLE  of  the  urethra  resembles  that  of  the  male  in 
its  origin  from  the  pubes,  and  its  disposition  around  the  urethra  (p.  397). 
Within  it  is  a  circular  layer  of  involuntary  fibres,  as  in  the  other  sex. 

The  description  of  the  pudic  artery  (p.  398)  will  serve  for  both  sexes, 
except  that  the  branch  in  the  female,  which  is  the  representative  of  the 
artery  of  the  bulb  in  the  male,  is  furnished  to  the  vagina.  The  terminal 
branches  are  much  smaller  in  the  female. 

The  pudic  nerve  has  the  same  peculiarity  as  the  artery  with  respect  to 
the  branch  to  the  vagina,  and  the  smaller  size  of  the  terminal  part  of  the 
nerve  on  the  clitoris. 


404  DISSECTION    OF    THE    ABDOMEN 


CHAPTER  VIII. 

DISSECTION  OF  THE  ABDOMEN. 


Section  I. 

WALL   OF   THE  ABDOMEN. 

The  examination  of  the  abdomen  is  to  proceed  as  far  as  the  end  of 
Section  III.  before  the  body  is  turned  for  tlie  dissection  of  the  Back. 

Position.  The  body  will  be  sufficiently  raised  by  blocks  beneath  the 
thorax  and  head  for  the  dissection  of  the  upper  limbs  and  neck,  but  the 
dissector  should  see  that  the  chest  is  higher  than  the  pelvis.  If  the  ab- 
domen is  flaccid,  let  it  be  inflated  by  an  aperture  through  the  umbilicus, 
but  if  it  is  firm,  proceed  with  the  dissection  without  blowing  it  up. 

Surface-ynarhing.  On  its  anterior  aspect  the  abdomen  is  for  the  most 
part  convex,  especially  in  fat  bodies  ;  but  on  the  sides,  betw^een  the  ribs 
and  the  crista  ilii,  the  surface  is  somewhat  depressed.  Along  the  middle 
line  is  a  slight  groove  over  the  linea  alba,  which  presents  txbout  its  centre 
the  hollow  of  the  umbilicus.  Inferiorly  the  groove  ceases  a  little  above 
the  pelvis  in  the  prominence  of  the  pubes ;  and  superiorly  it  subsides 
below  the  ensiform  cartilage  in  a  hollow  named  the  epigastric  fossa.  On 
each  side  of  the  middle  line  is  the  projection  of  the  rectus  muscle,  and 
this  is  intersected  in  adult  well-formed  bodies  by  two  or  three  transverse 
lines 

Underneath  the  eminence  of  the  pubes  the  student  w^ill  be  able  to  recog- 
nize with  his  flnger  the  symphysis  pubis,  and  to  trace  outwards  from  it 
the  osseous  pubic  crest  which  leads  to  the  pubic  spinous  process.  Eather 
above  and  to  the  outside  of  the  pubes,  the  opening  of  the  external  abdomi- 
nal ring  may  be  felt ;  and  the  prominence  of  the  spermatic  cord  descend- 
ing through  it  to  the  testicle  may  be  detected.  The  internal  abdominal 
ring  is  still  to  the  outer  side,  though  it  cannot  be  recognized  on  the  sur- 
face with  the  finger ;  but  its  position  may  be  ascertained  by  taking  a  point 
midway  between  the  symphysis  pubis  and  the  crest  of  the  innominate 
bone,  and  a  little  above  Poupart's  ligament. 

If  the  finger  is  carried  upwards  and  outwards  between  the  abdomen 
and  the  thigh,  it  will  detect  the  firm  band  of  Poupart's  ligament,  and 
sometimes  one  or  two  inguinal  glands. 

Dissection.  The  requisite  incisions  for  raising  the  skin  from  the  sides 
and  front  of  the  belly  are  the  following  :  One  cut  is  to  extend  outwards 
over  the  side  of  the  cliest  from  the  ensiform  cartilage  to  about  midway 
between  the  sternum  and  the  spine.  A  second  incision  is  to  be  begun  in 
the  middle  line  midway  between  the  umbilicus  and  the  pubes,  and  to  be 
carried  outwards  to  tlie  iliac  crest,  and  along  the  crest  till  it  ends  opposite 
the  first  cut.     Lastly,  the  hinder  extremities  of  the  two  incisions  are   to 


HOW    SHOWN.  405 

be  connected  along  the  side  of  the  chest  and  the  belly.  The  piece  of  skin 
thus  marked  out  is  to  be  raised  towards  the  middle  line,  but  is  not  to  be 
taken  away ;  and  the  cutaneous  vessels  and  nerves  are  to  be  sought  in  the 
fat  at  the  side  and  middle  line  of  the  abdomen. 

Along  the  side  of  the  abdomen  look  for  the  lateral  cutaneous  nerves, 
five  or  six  in  number,  which  issue  in  a  line  with  the  corresponding  nerves 
of  the  thorax.  At  first  they  lie  beneath  the  fat,  and  divide  into  two  :  one 
ofiset  is  to  be  traced  forwards,  and  the  other  backwards,  with  small  cuta- 
neous arteries.  On  the  iliac  crest,  near  the  front,  is  a  large  branch  from 
the  last  dorsal  nerve  ;  and  usually  farther  back  on  the  crest,  and  deeper, 
is  a  small  branch  of  the  iliohypogastric  nerve.  Near  the  middle  line  the 
small  anterior  cutaneous  nerves  will  be  recognized  with  small  arteries; 
these  are  uncertain  in  number  and  size,  and  are  to  followed  outwards  in 
the  integuments. 

The  piece  of  skin  covering  the  lower  part  of  the  abdomen  or  the  groin 
is  next  to  be  thrown  downwards,  on  both  sides,  by  an  incision  along  the 
middle  line  to  the  root  of  the  penis.  After  its  reflection  the  cutaneous 
vessels  and  nerves  are  to  .be  dissected  on  the  right  side,  and  the  superfi- 
cial fascia  on  the  left. 

To  make  the  necessary  dissection  on  the  right  side,  all  the  fascia  super- 
ficial to  the  vessels  is  to  be  raised  in  the  same  manner  as  the  piece  of  skin. 
The  vessels  which  will  then  appear  are  the  superficial  pudic  internally, 
the  superficial  epigastric  in  the  centre,  and  an  offset  of  the  superficial 
circumflex  iliac  artery  externally.  Some  inguinal  glands  lie  along  the 
line  of  the  reflected  fascia.  Two  cutaneous  nerves  are  to  be  sought :  one, 
the  ilio-inguinal,  comes  through  the  abdominal  ring,  and  descends  to  the 
thigh  and  scrotum  ;  the  other,  ilio-hypogastric,  appears  in  the  superficial 
fascia  above,  and  rather  outside  the  abdominal  ring. 

In  the  examination  of  the  fatty  layer  on  the  left  side  two  strata  are  to 
be  made  out,  one  over  and  one  beneath  the  vessels.  The  layer  that  is 
superficial  to  the  vessels  is  to  be  reflected  by  means  of  a  transverse  cut 
from  the  front  of  the  iliac  crest,  about  two  inches  above  Poupart's  liga- 
ment ;  and  by  a  vertical  one  near  the  middle  line  to  the  pubes.  The  sub- 
jacent vessels  mark  the  depth  of  this  layer ;  and  when  these  are  reached, 
a  flap  of  the  fascia,  like  that  of  the  skin,  is  to  be  thrown  towards  the 
thigh.  To  define  the  thinner  under  stratum,  cut  it  across  in  the  same 
manner  as  the  other  layer,  and  detach  it  with  the  vessels  from  the  tendon 
of  the  external  oblique  muscle.  This  stratum,  like  the  preceding,  is  to 
be  traced  around  the  cord  to  the  scrotum  ;  and  as  the  student  follows  it 
downwards,  he  will  find  it  connected  with  Poupart's  ligament,  and  blended 
with  the  fascia  lata  close  below  that  structure. 

The  subcutaneous  fat,  or  the  superficial  fascia,  is  a  single  layer  over 
the  greater  part  of  the  abdomen  ;  but  in  the  groin  it  is  divided  into  a  sub- 
cutaneous and  a  deeper  stratum  by  the  vessels  and  the  glands. 

The  subcutaneous  layer  contains  fat,  and  varies  therefore  in  appear- 
ance and  thickness  in  different  bodies  ;  for  it  is  sometimes  divisible  into 
strata,  whilst  at  others  it  is  very  thin,  and  somewhat  membranous  near 
the  thigh.  It  is  continuous  with  the  fatty  covering  of  the  thigh  and  ab- 
domen ;  and  when  traced  to  the  limb,  it  is  separated  from  Poupart's  liga- 
ment beneath  by  the  superficial  vessels  and  glands.  Internally  it  is  con- 
tinued to  the  penis  and  scrotum,  where  it  changes  its  adipose  tissue  for 
involuntary  muscular  fibre  ;  and  after  investing  the  testicle,  it  is  prolonged 
to  the  perinseum. 


406  DISSECTION    OF    THE    ABDOMEN. 

The  deejyer  layer  (aponeurosis  of  the  fascia  lata,  Scarpa)  is  thinner  and 
more  membranous  than  the  other,  and  is  closely  united  to  the  tendon  of 
the  external  oblique  by  fibrous  bands,  especially  towards  the  linea  alba. 
Like  the  subcutaneous  part,  this  layer  is  continued  upwards  on  the  abdo- 
men, and  inwards  to  the  penis  and  the  scrotum  :  here  it  becomes  very 
thin,  and  reaches  the  perinaeum,  where  it  has  attachments  to  the  subjacent 
parts,  as  before  specified  (p.  393).  Towards  the  limb,  it  ends  a  little  be- 
low Poupart's  ligament  in  the  fascia  lata  across  the  front  of  the  thigh  ;  as 
it  passes  over  the  ligament  it  is  closely  joined  to  that  band  by  fibrous 
tissue. 

Urine  effused  in  the  perinaeum  from  rupture  of  the  urethra  will  be 
directed  through  the  scrotum  and  along  the  spermatic  cord  to  the  abdo- 
men (p.  393).  From  the  arrangement  of  the  deeper  layer  of  the  fascia 
across  the  thigh,  it  is  evident  that  the  fluid  cannot  pass  down  the  limb, 
though  its  progress  over  the  front  of  the  abdomen  is  uninterrupted. 

In  the  female  the  fatty  layer  of  the  groin  is  separable  into  two  layers, 
and  the  disposition  of  each  is  nearly  the  same  as  in  the  male  ;  but  the 
part  that  is  continued  to  the  scrotum  in  the  one  sex  enters  the  labium  in 
the  other.     In  the  female  the  round  ligament  of  the  uterus  is  lost  in  it. 

Cutaneous  Nerves.  The  nerves  in  the  teguments  are  derived  from 
the  trunks  of  the  lower  intercostal  nerves  ;  thus  the  cutaneous  branches, 
along  the  side  of  the  belly,  are  offsets  from  five  or  six  of  those  nerves  ; 
and  the  cutaneous  branches,  along  the  front,  are  the  terminal  parts  of  the 
same  trunks.  Two  other  cutaneous  offsets  from  the  lumbar  plexus,  viz., 
ilio-hypogastric  and  ilio-inguinal,  appear  at  the  lower  part  of  the  ab- 
domen. 

The  lateral  cutaneous  nerves  of  the  abdomen  emerge  between  the  digi- 
tations  of  the  external  oblique  muscle,  in  a  line  with  the  same  set  of  nerves 
on  the  thorax  ;  and  the  lowest  are  the  most  posterior.  As  soon  as  they 
reach  the  surface  they  divide,  with  the  exception  of  the  last,  into  an  an- 
terior and  a  posterior  branch  : — 

The  posterior  branches  are  small  in  size,  and  are  directed  back  to  the 
integuments  over  the  latissimus  dorsi  muscle. 

The  anterior  branches  are  continued  nearly  to  the  edge  of  the  rectus 
muscle,  and  in  increasing  in  size  from  above  down,  supply  the  integu- 
ments on  the  side  of  the  belly ;  they  furnish  offsets  to  the  digitations  of 
the  external  oblique  muscle. 

The  lateral  cutaneous  branch  of  the  last  dorsal  nerve  is  larger  than 
the  rest,  and  does  not  divide  like  the  others.  After  piercing  the  fibres  of 
the  external  oblique  muscle,  it  is  directed  over  the  iliac  crest  to  the  sur- 
face of  the  gluteal  region. 

The  anterior  cutaneous  nerves  of  the  abdomen  pierce  the  sheath  of  the 
rectus :  in  the  integuments  they  bend  outwards  towards  the  lateral  cuta- 
neous nerves.  The  number,  and  the  situation  of  these  small  nerves,  are 
very  uncertain. 

The  ilio-hypogastric  nerve  is  distributed  by  two  pieces  :  one  passes 
over  the  crista  ilii  (iliac  branch),  tiie  other  ramifies  on  the  lower  part  of 
the  abdomen  (hypogastric  branch): — 

The  iliac  branch  lies  close  to  the  crest  of  the  hip  bone  near  the  last 
dorsal  nerve,  and  enters  the  teguments  of  the  gluteal  region. 

The  hypogastric  branch  pierces  the  aponeurosis  of  the  external  oblifjue 
muscle  above  the  abdominal  ring,  and  is  distributed,  as  the  name  ex- 
presses, to  the  lower  part  of  the  abdomen. 


CUTANEOUS    VESSELS.  407 

The  ilio-inguinal  nerve  becomes  cutaneous  through  the  external  abdo- 
minal ring,  and  descends  to  the  teguments  of  the  scrotum,  and  upper  and 
inner  parts  of  the  thigh. 

Cutaneous  Vessels.  Cutaneous  vessels  run  with  both  sets  of  nerves 
on  the  abdomen  :  with  the  lateral  cutaneous  nerves  are  branches  from  the 
intercostal  arteries ;  and  with  the  anterior  cutaneous  are  offsets  from  the 
intercostal,  internal  mammary,  and  epigastric  vessels.  In  the  groin  are 
three  small  superficial  branches  of  the  femoral  artery,  viz.,  pudic,  epigas- 
tric, and  circumflex  iliac. 

The  lateral  cutaneous  arteries  have  the  same  distribution  as  the  nerves 
they  accompany.  The  anterior  or  chief  offsets  are  directed  towards  the 
front  of  the  abdomen,  and  end  about  the  outer  edge  of  the  rectus  muscle. 

The  anterior  cutaneous  vessels  are  irregular  in  number  and  in  position, 
like  the  nerves.  After  piercing  the  sheath  of  the  rectus,  they  run  out- 
wards with  the  nerves  towards  tlie  other  set  of  branches. 

Branches  of  the  femoral  artery.  Three  cutaneous  offsets  ascend  from 
the  thigh  between  the  layers  of  the  subcutaneous  fat,  and  ramify  in  the 
integuments  of  the  genital  organs  and  lower  part  of  the  abdomen.  The 
greater  portion  of  these  vessels  appears  in  the  dissection  of  the  thigh. 

The  external  pudic  branch  (superficial)  crosses  the  spermatic  cord,  to 
which  it  gives  offsets,  and  ends  in  the  integuments  of  the  under  part  of  the 
penis. 

The  superficial  epigastric  branch  ascends  over  Poupart's  ligament,  near 
the  centre,  and  is  distributed  in  the  fat  nearly  as  high  as  the  umbilicus. 

The  circumflex  iliac  branch  lies  usually  below  the  level  of  the  iliac 
crest,  and  sends  only  a  few  offsets  upwards  to  the  abdomen. 

Small  veins  accompany  the  arteries,  and  join  the  internal  saphenous 
vein  of  the  thigh. 

The  glands  of  the  groin  are  three  or  four  in  number,  and  lie  over  the 
line  in  Poupart's  ligament.  They  are  placed  between  the  strata  of  the 
superficial  fascia  ;  and  receive  lymphatics  from  the  abdominal  wall,  from 
the  upper  and  outer  portion  of  the  thigh,  and  from  the  superficial  parts  of 
the  genital  organs.  Their  efferent  ducts  pass  downwards  to  the  saphenous 
opening  in  the  thigh  to  enter  the  abdomen. 

Dissection.  After  the  examination  of  the  superficial  fat  with  its  ves- 
sels and  nerves  the  student  may  prepare  the  cutaneous  coverings  of  tlie 
penis  and  scrotum.  The  skin  may  be  divided  along  the  dorsum  of  the 
penis,  and  thrown  to  each  side ;  and  the  skin  of  the  scrotum  is  to  be  re- 
flected on  the  left  side  by  means  of  a  vertical  incision. 

Cutaneous  coverings  of  the  penis  and  scrotum.  The  penis  is  attached 
to  the  front  of  the  pubes  by  a  suspensory  ligament,  and  is  provided  with  a 
tegumentary  covering  which  is  continuous  with  that  of  the  abdomen,  but 
it  loses  the  fat  and  acquires  special  characters. 

Around  the  end  of  the  penis  it  forms  the  loose  sheath  of  the  prepuce  in 
the  following  way  :  When  the  skin  has  reached  the  extremity,  it  is  re- 
flected backwards  as  far  as  the  base  of  the  glans,  constituting  thus  a  sheath 
with  two  layers — the  prepuce;  it  is  afterwards  continued  over  the  glans, 
and  joins  the  mucous  membrane  of  the  urethra  at  the  orifice  on  the  sur- 
face. At  the  under  part  of  the  glans,  and  behind  the  aperture  of  the 
urethra,  the  integument  forms  a  small  triangular  fold,  frcenum  prcRpntii. 

Where  the  skin  covers  the  glans,  it  is  inseparably  united  with  that  part, 
is  very  thin  and  sensitive,  being  provided  with  papillae,  and  assumes  in 


408  DISSECTION    OF    THE    AEDOMEX. 

some  cases  tlie  characters  of  a  mucous  membrane.  Behind  the  glans  are 
some  sebaceous  follicles — glandulce  odorlfercB. 

In  the  scrotum  the  superficial  fascia  becomes  thin,  and  of  a  reddish 
color.  The  prolongation  around  the  testicle  on  one  side,  is  separate  from 
that  on  the  other  side  ;  and  the  two  pouches  coming  in  contact  in  the 
middle  line,  form  the  septum  scroti. 

The  subcutaneous  layer  in  the  scrotum,  penis,  and  front  of  the  perineum, 
contains  involuntary  muscular  fibres,  to  which  the  corrugation  of  the  skin 
is  owing.     This  contractile  structure  is  named  the  dartoid  tissue. 

Dissection.  By  removing  all  the  fatty  tissue  from  the  root  of  the  penis 
and  the  front  of  the  symphysis  pubis,  the  suspensory  ligament  will  be  de- 
fined. And  the  dorsal  arteries  and  nerves,  with  the  dorsal  vein  of  tlie 
penis,  which  will  be  partly  laid  bare,  are  to  be  ibllowed  forwards  in  the 
teguments. 

Tlie  suspensory  ligament  of  the  penis  is  a  band  of  fibrous  tissue,  of  a 
triangular  form,  which  is  attached  by  its  apex  to  the  front  of  the  symphy- 
sis pubis  near  the  lower  part.  Widening  below,  it  is  fixed  to  the  upper 
surface  of  the  body  of  the  penis,  and  is  prolonged  on  it  for  some  distance. 
In  the  ligament  are  contained  the  dorsal  vessels  and  nerves  of  the  penis. 

Dorsal  vessels  and  nerves.  Tlie  arteries  and  nerves  on  the  dorsum  of 
the  penis  are  the  terminal  parts  of  the  pudic  trunks  of  both  sides  (p.  399). 
Tlie  vein  accompanying  the  arteries  enters  the  pelvis  through  the  triangu- 
lar perinaeal  ligament. 

The  dorsal  artery,  one  on  each  side,  pierces  the  suspensory  ligament, 
and  extends  forwards  to  the  ghms,  where  it  ends  in  many  branches  for 
that  structure :  in  its  course  the  vessel  supplies  the  integuments  and  the 
body  of  the  penis.     It  may  be  derived  from  the  accessory  pudic  (p.  399). 

The  dorsal  vein  is  a  single  trunk,  and  commences  by  numerous  branches 
from  the  glans  penis  and  the  prepuce.  It  runs  backwards  by  the  side  of 
the  artery,  through  the  suspensory  ligament  and  the  triangular  ligament 
of  the  urethra,  to  join  the  prostatic  plexus  of  veins.  The  vein  receives 
branches  from  the  erectile  structure  and  the  teguments  of  the  penis. 

Each  dorsal  nerve  takes  the  same  course  as  the  artery,  and  ends  like  it 
in  numerous  branches  to  the  glans  penis.  It  furnishes  a  large  branch  to 
the  corpus  cavernosum  penis,  and  other  offsets  to  the  integuments  of  the 
dorsum,  sides,  and  prepuce  of  the  penis. 

In  the  female  these  vessels  are  much  smaller  than  in  the  male;  they 
occupy  the  upper  surface  of  the  clitoris — the  organ  that  represents  the 
penis. 

Dissection  of  the  muscles.  The  surface  of  the  external  muscle  of  the 
abdominal  wall  (fig.  135)  is  now  to  be  freed  from  fascia  on  both  sides  of 
the  body. 

It  is  not  advisable  to  begin  cleaning  this  muscle  in  front,  because  there 
it  has  a  thin  aponeurosis,  which  is  taken  away  too  readily  witii  the  fat. 
Beginning  the  dissection  at  the  posterior  part,  the  student  is  to  carry  the 
knife  obliquely  upwards  and  downwards  in  the  direction  of  the  fibres. 
The  tiiin  aponeurosis  beibre  referred  to  is  in  front  of  a  line  extended  up- 
wards from  the  anterior  part  of  the  iliac  crest;  and  as  the  dissector  ap- 
proaches that  spot,  lie  must  be  careful  not  to  injure  it,  more  particularly 
at  the  upper  part,  where  it  lies  on  the  margin  of  the  ribs,  and  is  very 
indistinct. 

On  the  right  side  the  external  abdominal  ring,  c,  may  be  defined,  to 
show  the  cord  passing  through  it;  and  on  the  left  side  a  thin  fascia  (inter- 


EXTERNAL    OBLIQUE    MUSCLE. 


409 


columnar),  wliich  is  connected  with  the  margin  of  that  opening,  is  to  be 
preserved.  Lastly  tlie  free  border  of  the  external  oblique  should  be  made 
evident  between  the  last  rib  and  the  iliac  crest. 

Muscles  of  the  abdominal  wall.  On  the  side  of  the  abdomen  are 
three  large  flat  muscles,  which  are  named  from  their  position  to  one 
anotlier,  and  from  the  direction  of  tlieir  fibres.  The  most  superficial  mus- 
cle is  the  external  oblique;  the  underlying  one,  the  internal  oblique;  and 
the  deepest,  the  transversalis. 

Along  the  middle  line  are  placed  other  muscles  which  have  a  vertical 
direction.     In   front  lie   the  rectus  and   pyramidalis,  and  behind  is  the 
quadratus  lumborum  :  these  are  encased  by 
slieaths  derived  from  the  aponeuroses  of  tiie 
lateral  muscles. 

The    EXTERNAL    OBLIQUE    MUSCLE   (fig. 

135,  ^)  is  fleshy  on  tlie  side,  and  aponeurotic 
on  the  fore  part  of  the  abdomen.  It  arises 
by  fleshy  processes  from  the  eight  lower 
ribs;  the  five  highest  pieces  alternating 
with  similar  jiarts  of  the  serratus  magnus, 
and  the  lowest  three  with  digitations  of  the 
latissimus  dorsi  muscle.  From  the  attacli- 
ment  to  the  ribs  tlie  fibres  are  directed  over 
the  side  of  the  abdomen  in  the  following 
manner: — the  lower  ones  descend  almost 
vertically  to  be  inserted  into  the  anterior 
half  or  more  of  the  iliac  crest,  at  the  outer 
margin:  and  the  upper  and  middle  fibres 
are  continued  forwards  obliquely  to  the 
aponeurosis  on  the  front  of  the  belly. 

The  aponeurosis  occupies  the  anterior 
part  of  the  abdomen,  in  front  of  a  line  from 
the  eighth  rib  to  the  fore  part  of  the  crista 
illi;  and  it  is  rather  narrower  about  the 
centre,  than  either  above  or  below.  Along 
the  middle  line  this  expansion  ends  in  the 
linea  alba — the  common  point  of  union  of 
the  aponeuroses  of  opposite  sides.  Above,, 
it  is  thin,  and  is  continued  on  the  thorax  to 
the  pectoralis  major  and  the  ribs.  Below, 
its  fibres  are  stronger  and  more  sei)arate 
than  above,  and  are  directed  obliquely 
downwards  and  inwards  to  the  pelvis:  some 
of  them  are  fixed  to  the  front  of  the  pubes; 

and  the  rest  are  collected  into  a  firm  band  b  (Poupart's  ligament)  between 
the  pubic  spine  and  the  iliac  crest. 

Connections.  The  muscle  is  subcutaneous.  Its  posterior  border  is 
unattached  between  the  last  rib  and  the  iliac  crest,  but  is  overlaid  com- 
monly by  the  edge  of  the  latissimus  dorsi,  except  a  small  part  below. 
Appearing  through  the  aponeurosis,  external  to  the  linea  alba,  is  a  white 
line,  the  linea  semilunaris,  marking  the  outer  edge  of  the  rectus  muscle 
(fig.  139);  and  crossing  between  the  two  are  three  or  four  whitish  marks, 
the  lineje  transversa^.  Numerous  small  apertures  in  the  tendon  transmit 
cutaneous  vessels  and  nerves ;  and  near  the  pubes  is  the  large  opening  of 


Dissection  op  the  first  Latrral 
Muscle  in  the  "Wai.i,  of  the  Belli. 

A.  External  oblique. 

B.  Poupart's  ligament. 

c.  External  abdominal  ring. 
D.  Gimbernat's  ligament. 


410  DISSECTION    OF    THE    ABDOMEN. 

the  external  abdominal  ring,  which  gives  passage  to  the  cord  in  the  male, 
and  tlie  round  ligament  in  the  female. 

Action.  Both  muscles  taking  their  fixed  point  at  the  pelvis  will  bend 
the  trunk  forwards  as  in  stooping;  but  supposing  the  spine  fixed  they  will 
draw  down  the  ribs.  If  they  act  from  the  thorax  they  will  elevate  the 
pelvis. 

Should  one  muscle  contract,  it  will  incline  the  trunk  or  the  pelvis  to 
the  same  side,  according  as  the  upper  or  tlie  lower  attacliment  may  be 
movable :  and  it  will  turn  the  thorax  to  the  opposite  side. 

Parts  of  the  aponeurosis.  Besides  the  general  arrangement  of  the 
aponeurosis  over  the  front  of  the  abdomen,  the  student  is  to  examine  more 
minutely  the  linea  alba  in  the  middle  line  ;  the  external  abdominal  ring 
with  the  fascia  prolonged  from  its  margin  ;  and  the  rounded  border  named 
Poupart's  ligament. 

Linea  alba  (fig.  139).  This  white  band  on  the  front  of  the  abdomen 
marks  the  place  of  meeting  of  the  aponeuroses  of  opposite  sides.  It  ex- 
tends from  the  xiphoid  cartilage  to  the  pubes,  and  serves  as  a  ligament 
between  the  chest  and  pelvis.  Its  breadth  is  wider  above  than  below  ; 
and  it  is  perforated  here  and  there  by  small  apertures,  which  allow  pellets 
of  fat  to  protrude  in  some  bodies.  A  little  below  the  centre  is  the  um- 
bilicus, which  projects  now  beyond  the  surface,  though  before  the  skin  was 
removed,  a  hollow  indicated  its  position. 

External  abdominal  ring  (fig.  135,  ^).  This  opening  is  situate  near 
the  pubes  between  the  diverging  fibres  of  the  aponeurosis.  It  is  somewhat 
triangular  in  form,  with  the  base  of  the  crest  of  the  pubes,  and  the  apex 
pointing  upwards  and  outwards.  The  long  measurement  of  the  aperture 
is  about  an  inch,  and  the  transverse  about  half  an  inch. 

Its  margins  are  named  pillars,  and  differ  in  form  and  strength.  The 
inner  one,  thin  and  straight,  is  attached  below  to  the  front  of  the  symphy- 
sis pubis,  where  it  crosses  the  corresponding  piece  of  the  opposite  side — 
that  of  the  right  muscle  being  superficial.  The  outer  margin  is  the  strong- 
est, and  is  not  straight  like  the  inner,  but  forms  a  kind  of  groove  for  the 
support  of  the  spermatic  cord :  this  margin  is  continuous  with  Poupart's 
ligament,  and  is  attached  below  to  the  pubic  spine  or  tuberosity.  A  thin 
membrane  (intercolumnar)  covers  the  opening,  and  is  derived  from  some 
fibres  on  the  surface  of  the  ay)oneurosis. 

The  ring  gives  passage  in  the  male  to  the  spermatic  cord,  and  in  the 
female  to  the  round  ligament ;  and  in  each  sex  the  transmitted  part  lies 
on  the  outer  pillar  as  it  passes  through,  and  obtains  a  covering  from  the 
intercolumnar  fibres.  Through  this  aperture  the  inguinal  hernia  protrudes 
from  the  wall  of  the  abdomen. 

The  intercolumnar  fibres  form  a  layer  over  the  aponeurosis,  and  bind 
together  its  parallel  fibres,  so  as  to  construct  a  firm  membrane.  Inferiorly, 
where  they  are  strongest,  a  bundle  is  connected  with  the  outer  third  of 
Poupart's  ligament,  and  is  continued  back  to  the  crista  ilii.  At  the  ex- 
ternal abdominal  ring  the  fibres  stretch  from  side  to  side,  and  becoming 
stronger  and  aggregated  together,  close  the  upper  part  of  that  opening ; 
and  as  they  are  prolonged  on  the  cord  from  the  margin  of  the  ring,  they 
give  rise  to  the  membrane  named  intercolumnar  fascia.  On  the  left  side, 
where  the  fascia  is  entire,  this  thin  covering  will  be  manifest  on  the  surface 
of  the  cord,  or  on  the  round  ligament  in  the  female. 

Dissection.  To  see  the  attachments  and  connections  of  Poupart's  liga- 
ment, it  will  be  necessary  to  reflect,  on  both  sides  of  the  body,  the  lower 


INTERNAL    OBLIQUE    MUSCLE.  411 

part  of  the  aponeurosis  towards  the  thigh,  as  in  fig.  140.  For  this  pur- 
pose an  incision  is  to  be  carried  through  the  aponeurosis  from  the  front  of 
the  iliac  crest  to  about  three  inches  from  the  linea  alba ;  and  the  tendon 
is  to  be  detached  from  the  subjacent  parts  with  the  handle  of  the  scalpel. 
When  the  aponeurosis  cannot  be  separated  farther  from  the  tendons  be- 
neath, near  the  linea  alba,  it  is  to  be  cut  in  the  direction  of  a  vertical  line 
to  the  symphysis  pubis. 

After  the  triangular  piece  of  the  aponeurosis  has  been  thrown  towards 
the  thigh,  the  spermatic  cord  is  to  be  dislodged  from  the  surface  of  Pou- 
part's  ligament,  to  see  the  insertion  of  this  band  into  the  pubes,  and  to  lay 
bare  the  fibres  (triangular  ligament)  which  ascend  therefrom  to  the  linea 
alba. 

Pouparfs  ligament  (fig.  136,  ^)  is  the  lower  border  of  the  aponeurosis 
of  the  external  oblique,  which  intervenes  between  the  front  of  the  crista 
ilii  and  the  pubes.  Externally  it  is  round  and  cord-like,  and  is  attached 
to  the  anterior  superior  iliac  spine.  Internally  it  widens  as  it  approaches 
the  pubes  (fig.  135,  ^),  and  is  inserted  into  the  pubic  spine  and  the  pec- 
tineal line  of  the  hip-bone  for  about  three-quarters  of  an  inch,  forming  a 
triangular-looking  piece  with  its  base  directed  outwards,  which  is  named 
Gimhernafs  ligament. 

Poupart's  ligament  is  not  straight  between  its  outer  and  inner  attach- 
ments, but  is  curved  downwards  to  the  thigh ;  and  it  retains  this  position 
as  long  as  the  fascia  lata  remains  uncut.  Its  outer  half  is  oblique,  and  is 
firmly  united  with  the  subjacent  iliac  fascia  ;  along  the  line  of  union  of 
the  two,  the  other  lateral  muscles  of  the  abdominal  wall  are  attached. 
Its  inner  half  is  placed  over  the  vessels  passing  from  the  abdomen  to  the 
thigh. 

Triangular  ligament.  From  the  insertion  of  Gimbernat's  ligament 
into  the  pectineal  line,  some  fibres  are  directed  upwards  and  inwards  to 
the  linea  alba,  where  they  blend  with  the  other  tendons.  As  the  fibres 
ascend,  they  diverge  and  form  a  thin  band,  to  which  the  above  name  has 
been  given. 

Dissection.  The  upper  part  of  the  external  oblique  is  now  to  be  taken 
away,  on  both  sides  of  the  body,  to  see  the  parts  underneath.  The  muscle 
may  be  detached  by  carrying  the  scalpel  through  the  digitations  on  the 
ribs  back  to  the  free  border,  and  then  through  the  insertion  into  the  crista 
ilii.  It  may  be  thrown  forwards  as  far  as  practicable,  after  the  nerves 
crossing  the  iliac  crest  are  dissected  out ;  but  in  raising  it  care  must  be 
taken  not  to  detach  the  rectus  muscle  from  the  ribs  above,  nor  to  cut 
through  the  tendon  of  the  internal  oblique  at  the  upper  part.  By  the 
removal  of  the  fatty  tissue  the  underlying  internal  oblique  muscle,  with 
some  nerves  on  its  surface  below,  will  be  prepared. 

At  the  lower  border  of  the  internal  oblique  the  cremaster  muscle  on  the 
cord  is  to  be  defined  (fig.  137)  :  it  is  about  as  wide  as  the  little  finger,  and 
consists  of  fleshy  loops  which  issue  through  the  external  abdominal  ring. 
Its  inner  attachment  is  tendinous,  and  is  easily  taken  away. 

Parts  covered  by  external  oblique  (fig.  136).  Beneath  the  external,  is 
the  internal  oblique  muscle,  with  the  ribs  and  the  intercostal  muscles.  At 
the  lower  part  of  the  abdomen  the  muscle  conceals  the  spermatic  cord,  and 
the  branches  of  the  lumbar  plexus  in  the  abdominal  wall. 

The  INTERNAL  OBLIQUE  MUSCLE  (fig.  136, '^)  is  flcshy  below  and  apo- 
neurotic above,  just  the  reverse  of  the  preceding  ;  and  its  fibres  (except  the 
lowest)  ascend  across  those  of  the  external  oblique.     The  muscle  arises 


412 


DISSECTION    OF    THE    ABDOMEN, 


along  the  outer  half  of  Poupart's  ligament ;  along  the  anterior  two-thirds 
of  the  crest  of  the  hip  bone  ;  and  from  the  tendon  of  the  transversalis 
muscle,  c,  (fascia  lumborum)  in  the  interval  between  that  bone  and  the 
last  rib.  The  fibres  diverge  on  the  abdomen  to  their  destination  :  The 
upper  are  fleshy  and  ascend  to  be  inserted  into  the  cartilages  of  the  lower 

three  ribs,  where  they  join  tlie  inter- 
Fig-  136.  nal  intercostal  muscles  of  the  lowest 
two  spaces.     The    remaining   fibres 
pass  obliquely  to  the  aponeurosis. 

The  aponeurosis  covers  the  fore 
part  of  the  abdomen  from  the  pelvis 
to  the  chest,  and  blends  with  its 
fellow  along  the  middle  line.  For 
tlie  most  part  it  incases  the  rectus; 
but  midway  between  the  umbilicus 
and  the  pubes  it  is  undivided,  and 
lies  in  front  of  that  muscle.  Supe- 
riorly it  is  attached  to  the  thorax 
after  the  following  manner:  The 
stratum  superficial  to  the  rectus  is 
fixed  to  the  ninth  rib,  and  blends 
with  the  aponeurosis  of  the  external 
oblique  ;  and  the  stratum  beneath  the 
muscle  joins  the  cartilages  of  the 
eighth  and  seventh  ribs,  and  the  en- 
siform  cartilage.  Infer iorly  its  fibres 
become  more  distinct  and  separate, 
and  are  inserted  into  the  front  of  the 
pubes,  and  into  the  pectineal  line  for 
half  an  inch  behind  the  attachment 
of  Gimbernat's  ligament. 

Connections.  The  internal  is  cov- 
ered by  the  external  oblique  muscle. 
It  is  attaciied  on  all  sides,  except 
between  Poupart's  ligament  and  the 
pubes  where  it  arches  over  the  cord, 
and  has  the  ere  master  muscle  con- 
The  parts  covered  by  the  internal  oblique  cannot  be  seen 
till  the  muscle  is  reflected. 

Action Both  muscles  will  depress  the  ribs;  and  will  assist  in  forcing 

back  the  viscera  of  the  belly,  which  have  been  carried  down  by  the  descent 
of  the  diaphragm. 

One  muscle  may  incline  the  body  laterally  ;  and  contracting  with  the 
external  oblique  of  the  otiier  side  (the  fibres  of  the  two  having  the  same 
direction)  it  will  rotate  the  trunk  to  the  same  side. 

The  CKEM ASTER  MUSCLE  (fig.  137,  °)  is  a  fasciculus  of  fibres,  which 
lies  along  the  lower  border  of  tlie  internal  oblique  muscle,  and  is  named 
from  suspending  the  testicle.  The  muscle  has  attachments,  at  the  inner 
and  outer  sides,  similar  to  those  of  the  internal  oblique.  Externally  it  is 
fleshy,  and  arises  from  Poupart's  ligament  below,  and  in  part  beneath  the 
internal  oblique,  with  which  some  of  the  fibres  are  connected.  Internally 
it  is  small,  and  is  inserted  by  tendon  into  the  front  of  the  pubes,  joining 
the  tendon  of  the  internal  oblique.  # 


Internal  Oblique  Muscle  of  the  Abdomi- 
nal Wall. 

A.  Internal  oblique. 

B.  Latissimus  dorsi,  cut. 

c.  Part  of  the  hinder  tendon  of  the  transver- 
salis muscle. 
D.  Poupart's  ligament. 
K    External:  F.  Internal  intercostals. 


TRANSVERSALIS    MUSCLE. 


413 


Between  the  two  points  of  attachment  the  fibres  descend  on  the  front 
and  sides  of  the  cord,  forming  loops,  with  the  convexity  downwards,  which 
reach  to  and  over  the  testis.  The  bundles  of  fibres  are  united  by  areolar 
tissue  so  as  to  give  rise  to  a  covering  on  the  front  of  the  cord,  which  in 
hernia  is  named  the  fascia  cremasterica.  Occasionally  the  fibres  may  be 
behind  as  well  as  on  the  sides  and 
front  of  the  cord.  Fig-  137. 

Action.  It  elevates  the  testicle 
towards  the  abdomen  under  the  in- 
fluence of  the  will;  but  it  may  be 
excited  to  contract  involuntarily  by 
cold,  fear,  etc. 

Dissection.  On  the  left  side  of 
the  body  the  student  is  not  to  make 
any  further  dissection  of  the  abdo- 
minal wall ;  and  the  layers  tliat  have 
been  reflected  in  the  groin  should  be 
replaced,  until  the  examination  of 
those  parts  in  connection  with  hernia 
is  resumed. 

On  the  right  side  the  dissection  is 
to  be  carried  deeper  by  the  removal 
of  the  internal  oblique  and  the  cre- 
master.  The  last  muscle  may  be 
reflected  from  the  cord  by  means  of 
a  longitudinal  incision. 

To  raise  the  internal  oblique,  it 
will  be  necessary  to  cut  it  through 
firstly  near  the  ribs  ;  secondly  near 
the  crest  of  the  hip  bone  and  Pou- 
part's  ligament;  and  lastly  at  the 
hinder  part,  so  as  to  connect  the  two 
first  incisions.  Its  depth  will  be  in- 
dicated by  a  fatty  layer  between  it 
and  the  transversal  is.  In  raising 
the  muscle  towards  the  edge  of  the 
rectus,  let  the  student  separate  with 
great  care  the  lower  fibres  from  those 
of  the  transversalis,  with  which  they 

are  often  conjoined;  and  dissect  out,  between  the  two,  the  intercostal 
nerves  and  arteries,  and  tlie  two  branches  of  the  lumbar  plexus  (ilio-hypo- 
gastric  and  ilio-inguinal)  near  the  front  of  the  crest  of  the  hip  bone  :  the 
offsets  of  the  intercostals  entering  the  muscle  must  be  cut. 

Parts  covered  hy  the  oblique  (fig.  138).  The  internal  oblique  conceals 
the  transversalis  muscle,  and  the  vessels  and  nerves  between  the  two. 
Near  Poupart's  ligament  it  lies  on  the  spermatic  cord  and  the  fascia  trans- 
versalis.    The  rectus  muscle  is  concealed  below  by  the  aponeurosis. 

The  TRANSVERSALIS  MUSCLE  (fig.  138,  ^)  forms  the  third  stratum  in 
the  wall  of  the  abdomen,  and  differs  from  the  two  oblique  in  having  a 
posterior  as  well  as  an  anterior  aponeurosis.  Like  the  former  muscle  it  is 
attached  on  all  sides,  except  where  the  spermatic  cord  lies.  At  the  pelvis 
it  ar/ses  along  the  outer  third  of  Poupart's  ligament,  and  the  anterior  two- 
thirds  of  the  iliac  crest.     At  the  chest  it  takes  origin  from  the  lower  six 


View  of  the  Lower  Part  of  the  Inter.vai. 
Oblique  with  the  Cremastek  Muscle  and 
the  Testicle. 

A.  External  oblique,  reflected. 

B.  Internal  oblique, 
c.  Rectus  abdominis. 

D.  Cremaster,  with  its  loops  over  the  sperma- 
tic cord  and  the  testicle. 


414 


DISSECTION    OF    THE    ABDOMEN. 


ribs,  viz.,  by  tendon  from  the  lowest  two,  and  by  fleshy  processes  from 
the  under  surface  of  the  cartilages  of  the  four  next  above.  And  between 
the  chest  and  the  pelvis  it  is  connected  with  the  lumbar  vertebrae  by  means 
of  the  posterior  aponeurosis  or  the  fascia  lumborum.  All  the  fibres  are 
directed  to  the  aponeurosis  in  front. 

Its  anterior  aponeurosis  is  widest  below,  as  in  the  most  external  muscle. 
Internally  it  is  continued  to  tlie  linea  alba,  passing  beneath  the  rectus  as 
low  as  midway  between  the  umbilicus  and  the  pubes,  but  in  front  of  the 
muscle  below  that  spot.  Its  attachment  below  to  the  pelvis  is  nearly  the 
same  as  the  internal  oblique ;  for  it  is  fixed  to  the  front  of  the  pubest  and 

to  the  pectineal  line  for  about  an 
Fig.  138.  inch,  but  beneath  the  oblique  muscle : 

some  of  the  fibres  are  spent  on  the 
transversalis  fascia,  and  are  con- 
nected with  a  thickened  band  of  that 
fascia  beneath  Poupart's  ligament, 
which  is  called  the  deep  crural  arch. 
Action.  The  chief  use  of  the 
muscle  will  be  applied  to  diminish- 
ing the  size  of  the  abdominal  cavity, 
and  compressing  the  viscera ;  but  it 
will  assist  the  internal  oblique  in  re- 
placing the  viscera  pushed  down  in 
inspiration. 

Conjoined  tendon.  The  aponeu- 
rosis of  the  internal  oblique  and 
transversalis  muscles  are  united 
more  or  less  near  their  attachment 
to  the  pubes,  and  give  rise  to  the 
conjoined  tendon.  The  aponeurosis 
of  the  oblique  muscle  extends  about 
half  an  inch  along  the  pectineal  line ; 
whilst  that  of  the  transversalis 
reaches  an  inch  along  the  bony 
ridge,  and  forms  the  greater  part  of 
the  conjoined  tendon. 

The  posterior  aponeurosis  of  the 
transversalis,  or  the  fascia  lumbo- 
rum, c,  is  described  in  the  dissection 
of  the  Back,  p.  357. 

Connections.     Superficial    to  the 
transversalis  are  the  two  muscles  be- 
fore examined ;   and  beneath    it   is 
the    thin   fascia   transversalis.     Its 
fleshy  attachments  to  the  ribs  digi- 
tate with  like  processes  of  the  diaphragm.     The  lower  border  is  fleshy  in 
the  outer,  but  tendinous  in  the  inner  half,  and  is  arched  above  the  internal 
abdominal  ring. 

Dissection.  To  remove  the  aponeurotic  layer  from  the  rectus  muscle 
of  the  right  side,  make  a  longitudinal  incision  througli  the  tendinous 
sheath,  and  turn  it  to  each  side.  As  the  fascia  is  reflected,  its  union  with 
three  or  more  tendinous  bands  across  the  rectus  will  have  to  be  cut 
through  ;  and  near  the  pubes  a  small  muscle,  the  pyramidalis,  will  be  ex 


Dissection  OF  THE  Third  Lateral  Mcscle 
IN  THE  Wall  of  the  Belly,  with  the  ves- 
sels and  nerves  on  it. 
A.  Transversalis  mnscle,  with  b,  its  anterior, 
and  c,  its  posterior  tendon  (fascia  lum- 
borum). 
D.  Poupart's  ligament. 

1.  Last  dorsal   nerve  with  its  accompanying 

artery. 

2.  Ilio-hypogastric  nerve  with  its  artery, 
tt  Intercostal  neves  and  arteries. 


RECTUS    MUSCLE. 


415 


posed.    The  dissector  should  leave  the  nerves  entering  the  outer  border  of 
the  rectus. 

On  the  left  side  of  the  body  the  rectus  should  not  be  laid  bare  below 
the  umbilicus,  for  the  sake  of  the  hernia  to  be  seen  on  this  side. 

Tlie  RECTUS  MUSCLE  (fig.  139,  ^)  extends  along  the  front  of  the  abdo- 
men from  the  pelvis  to  the  chest.  It  is  narrowest  inferiorly,  and  is  at- 
tached to  the  pubes  by  two  tendinous  processes ; — one,  internal  and  the 
smaller,  arises  from  the  front  of  the  symphysis,  where  it  joins  tlie  muscle 
of  the  opposite  side ;  and  tlie  external  process  is  attached  to  the  pubic 
crest.  Becoming  wider  towards  the  thorax,  the  rectus  is  inserted  by 
three  large  fleshy  processes  into  the  ensiform  cartilage,  and  the  cartilages 
of  the  last  three  true  ribs. 

The  muscle  is  contained  in  an  aponeurotic  sheath,  except  above  and 
below  ;  and  its  fibres  are  interrupt- 
ed at  intervals  by  irregular  tendi-  Fig.  139. 
nous  lines — the  inscriptiones  ten- 
dineae. 

Action.  It  will  draw  down  the 
thorax  and  the  ribs,  or  raise  the 
pelvis,  according  as  its  fixed  point 
may  be  above  or  below.  Besides 
imparting  movement  to  the  trunk, 
it  will  diminish  the  cavity  of  the 
thorax,  and  compress  the  viscera. 

Sheath  of  the  rectus^  d.  This 
sheath  is  derived  from  the  splitting 
of  the  aponeurosis  of  the  internal 
oblique  at  the  outer  edge  of  the 
muscle.  One  piece  passes  before 
and  the  other  under  the  rectus  ; 
and  tlie  two  unite  at  the  inner 
border  so  as  to  inclose  it  in  a 
sheath.  Inseparably  blended  with 
the  stratum  in  front  of  the  rectus  is 
the  aponeurosis  of  the  external 
oblique  ;  and  joined  in  a  similar 
manner  with  that  behind,  is  the 
aponeurosis  of  the  transversalis. 

The  sheath  is  deficient  behind, 
both  at  the  upper,  and  lower  part 
of  the  muscle.  Above,  the  muscle 
rests  on  the  ribs,  without  the  in- 
tervention of  the  sheath  v/hich  is 
fixed  to  the  margin  of  the  thorax. 
Below,  midway  between  the  um- 
bilicus and  the  pubes,  the  internal 
oblique  ceases  to  split,  and  passes 

altogether  in  front  of  the  rectus,  with  the  other  aponeuroses ;  at  the  spot 
where  the  sheath  is  wanting  inferiorly  the  muscle  is  in  contact  with  the 
fascia  transversalis,  and  a  white  semilunar  line  (the  fold  of  DougUis)  may 
be  sometimes  seen,  when  the  outer  edge  is  raised,  marking  the  cessation. 

The  Ihiece  transversce  (fig.  137),  on  the  surface  of  the  abdomen,  are 
caused  by  tendinous  intersections  of  the  rectus.     They  are  usually  three 


Eectus  Muscle  of  the  Abdomen,  dissected  oa 
the  right  side,  and  in  its  sheath  on  the  left. 
Close  to  the  pelvis  is  the  pyramidalis  exposed. 

A.  Rectus. 

B.  Internal  oblique. 

c.  Poupart's  ligament. 
D.  Sheath  of  the  rectus. 


416  DISSECTION    OF    THE    ABDOMEN. 

in  number,  and  have  the  following  position  :  one  is  opposite  the  umbilicus, 
another  at  the  ensiform  cartilage,  and  the  third  midway  between  the  two. 
If  there  is  a  fourth,  it  will  be  placed  below  the  umbilicus.  These  mark- 
ings seldom  extend  the  whole  length  or  breadth  of  the  muscular  fibres, 
more  particularly  above  and  below. 

Lima  semilunaris  (fig.  139).  This  line  corresponds  with  the  outer 
edge  of  the  rectus,  and  reaches  from  the  eighth  rib  to  tiie  pubic  spine  of  the 
hip-bone :  it  marks  the  line  of  division  of  the  aponeurosis  of  tlie  internal 
oblique  muscle. 

The  PYRAMiDALis  MUSCLE  (fig.  139)  is  triangular  in  form,  and  is  placed 
in  front  of  the  rectus  near  the  pelvis.  The  muscle  arises  by  its  base  from 
the  front  of  the  pubes,  and  is  inserted  into  the  linea  alba  about  midway 
between  the  umbilicus  and  the  pelvis.     This  small  vessel  is  often  absent. 

Action,  The  muscle  renders  tight  the  linea  alba ;  and  when  large  it 
may  assist  the  rectus  slightly  in  compressing  the  viscera. 

Nerves  of  the  abdominal  wall  (fig.  138).  Between  the  internal 
oblique  and  transversalis  muscles  are  situate  the  intercostal  nerves ;  and 
near  the  pelves  are  two  branches  of  the  lumbar  plexus.  Some  arteries 
accompany  the  nerves,  but  they  will  be  referred  to  with  the  vessels  of  the 
abdominal  wall. 

The  lower  six  intercostal  nerves  (fig.  138ttt)  enter  the  wall  of  the 
abdomen  from  the  intercostal  spaces.  Placed  between  the  two  deepest 
lateral  muscles,  the  nerves  are  directed  forwards  to  the  edge  of  the  rectus, 
and  through  this  muscle  to  the  surface  of  the  abdomen  near  the  middle 
line.  About  midway  between  the  spine  and  the  linea  alba,  the  nerves 
furnish  cutaneous  branches  to  the  side  of  the  abdomen  (lateral  cutaneous, 
p.  406)  ;  and  whilst  between  the  abdominal  muscles  they  supply  muscular 
branches,  and  offsets  of  communication  with  one  another.  A  greater  part 
of  the  lower  than  of  the  upper  nerves  is  visible,  owing  to  the  shortness  of 
the  last  intercostal  spaces. 

The  last  dorsal  nerve  (^)  is  placed  below  the  twelfth  rib,  and  therefore 
not  in  an  intercostal  space,  but  it  has  connections  and  a  distribution  like 
the  preceding.  As  it  extends  forwards  to  the  rectus  it  communicates 
sometimes  with  the  ilio-hypogastric  nerve.  Its  lateral  cutaneous  branch 
perforates  the  two  oblique  muscles  (p.  406). 

Two  branches  of  the  lumbar  plexus^  viz.,  ilio-hypogastric  and  ilio-ingui- 
nal,  are  contained  for  a  certain  distance  between  the  muscles  of  the  wall  of 
the  abdomen,  as  they  course  forwards  to  the  surface  of  the  body. 

The  ilio-hypogastric  nerve  (^)  perforates  the  back  of  tlie  transversalis 
muscle  near  the  iliac  crest,  and  gives  off  the  iliac  branch.  The  nerve  is 
then  directed  forwards  above  the  hip  bone,  and  is  connected  with  its  com- 
panion (ilio-inguinal).  Perforating  the  fleshy  part  of  the  internal  oblique 
near  the  front  of  the  iliac  crest,  and  the  aponeurosis  of  the  external  oblique 
near  the  linea  alba,  the  nerve  becomes  cutaneous  (p.  406). 

Its  iliac  branch  pierces  both  oblique  muscles  close  to  the  crista  ilii,  to 
reach  the  gluteal  region. 

The  ilio-inguinal  nerve  perforates  the  transversalis  muscle  near  the 
front  of  the  iliac  crest.  It  pierces  afterwards  the  internal  oblique,  and 
reaches  the  surface  of  the  thigh  through  the  external  abdominal  ring  (p. 
407) ;  it  furnishes  offsets  to  the  internal  oblique,  the  cremaster,  and  the 
pyramidalis. 

Dissection.  For  the  purpose  of  seeing  the  transversalis  fascia,  it  will 
be  necessary  to  raise,  on  the  right  side,  the  lower  part  of  the  transversalis 


FASCIA    TRANSVERSALIS.  417 

muscle  by  two  incisions ;  one  of  these  is  to  be  carried  through  the  fibres 
attached  to  Poupart's  ligament;  the  other,  across  the  muscle  from  the 
front  of  the  hip  bone  to  the  margin  of  the  rectus.  With  a  little  care  the 
muscle  may  be  separated  easily  from  the  thin  fascia  beneath. 

The  fascia  transversalis  (fig.  140,  ^)  is  a  thin  fibrous  layer  between 
the  transversalis  muscle  and  the  peritoneum.  In  the  groin  or  inguinal 
region,  where  it  is  unsupported  by  muscles,  the  fascia  is  considerably 
stronger  than  elsewhere,  and  is  joined  by  fibres  of  the  aponeurosis  of  the 
transversalis  muscle;  but  farther  from  the  pelvis  it  gradually  decreases  in 
strength,  until  at  the  thorax  it  becomes  very  thin. 

In  the  part  of  the  fascia  now  laid  bare,  is  the  internal  abdominal  ring, 
which  gives  passage  to  the  spermatic  cord,  or  the  round  ligament,  accord- 
ing to  the  sex;  this  opening  resembles  the  finger  of  a  glove  in  being  visible 
internally,  but  indistinguishable  externally  in  consequence  of  a  prolonga- 
tion from  the  margin.  On  the  inner  side  of  the  ring  the  fascia  is  thinner 
than  on  the  outer,  and  is  there  fixed  into  the  pube^  and  the  pectineal  line 
of  the  hip  bone,  behind  the  conjoined  tendon  with  which  it  is  united. 

At  Poupart's  ligament  the  fascia  is  joined  to  the  posterior  margin  of 
that  band  along  the  outer  half;  but  along  the  inner  half  it  is  directed 
down  to  the  thigh,  in  front  of  tlie  bloodvessels,  to  form  the  anterior  part  of 
a  loose  sheath  (crural)  around  them. 

Internal  abdominal  ring  (fig.  140).  This  opening  is  situate  midway 
between  the  symphysis  pubis  and  the  anterior  superior  iliac  spine,  and 
half  an  inch  above  Poupart's  ligament.  From  its  margin  a  thin  tubular 
prolongation  of  the  fascia  is  continued  around  the  cord,  as  before  said. 

Dissection.  The  tubiform  prolongation  on  the  cord  may  be  traced  by 
cutting  the  fascia  transversalis  horizontally  above  the  opening  of  the  ring, 
and  then  longitudinally  over  the  cord.  With  the  handle  of  the  scalpel 
the  thin  membrane  may  be  reflected  to  each  side,  so  as  to  lay  bare  the 
subperitoneal  fat. 

The  subperitoneal  fat  forms  a  layer  between  the  fascia  transversalis  and 
the  peritoneum.  Its  thickness  varies  much  in  different  bodies,  but  is 
greater  at  the  lower  part  of  the  abdomen  than  higher  up.  This  structure 
will  be  more  specially  examined  in  the  dissection  of  the  wall  of  the  abdomen 
from  the  inside. 

Dissection.  After  the  subperitoneal  fat  has  been  seen,  let  it  be  reflected 
to  look  for  the  remains  of  a  piece  of  peritoneum  along  the  cord,  in  the 
form  of  a  fibrous  thread. 

The  peritoneum^  or  the  serous  sac  of  the  abdominal  cavity,  projects  for- 
wards slightly  opposite  the  abdominal  ring.  Connected  with  it  at  that 
spot  is  a  fibrous  thread  (the  remains  of  a  prolongation  to  the  testis  in  the 
foetus)  which  extends  a  certain  distance  along  the  front  of  the  cord.  It  is 
generally  impervious,  and  can  be  followed  only  a  very  short  way,  but  it 
may  be  sometimes  traced  as  a  fine  band  to  the  tunica  vaginalis  of  the 
testis. 

In  some  bodies  the  process  may  be  partly  open,  being  sacculated  at  in- 
tervals; or  it  may  form  occasionally  a  single  large  bag  in  front  of  the 
cord.  Lastly,  as  a  rare  state,  the  tube  of  peritoneum  accompanying  the 
testis  in  its  passage  in  the  foetus  may  be  unclosed,  so  that  a  coil  of  intestine 
could  descend  in  it  from  the  abdomen. 

In  the  female  the  foetal  tube  of  peritoneum  remains  sometimes  pervious 
for  a  short  distance  in  front  of  the  round  ligament;   that  unobliterated 
passage  is  named  the  canal  of  Nuck. 
27 


418  DISSECTION    OF    THE    ABDOMEN. 

The  SPERMATIC  CORD  (fig.  140,  ^')  extends  from  the  internal  abdominal 
ring  to  the  testis,  and  consists  mainly  of  the  vessels  and  the  efferent  duct 
of  the  gland,  united  together  by  coverings  from  the  structures  by  or  tiirough 
which  they  pass. 

In  the  wall  of  the  abdomen  the  cord  lies  obliquely,  because  its  aperture 
of  entrance  amongst,  is  not  opposite  its  aperture  of  exit  from  tlie  muscles; 
but  escaped  from  the  abdomen,  it  descends  almost  vertically  to  its  destina- 
tion. As  it  lies  in  this  oblique  passage  named  the  inguinal  canal,  it  is 
placed  (externally)  beneath  the  internal  oblique,  and  rests  against  the 
fascia  transversalis ;  but  beyond  the  lower  border  of  the  oblique  muscle,  it 
lies  on  the  upper  surface  of  Poupart's  ligament,  with  the  aponeurosis  of 
the  external  oblique  between  it  and  the  surface  of  the  body,  and  the  con- 
joined tendon  behind  it. 

Its  several  coverings  are  derived  from  strata  in  the  wall  of  the  abdomen. 
Thus,  from  within  out  come,  the  subperitoneal  fat,  the  tube  of  the  fascia 
transversalis,  the  cremaster  muscle  continuous  with  the  internal  oblique, 
the  intercolumnar  fascia  from  the  external  oblique  muscle,  and  lastly  the 
superficial  fascia  and  the  skin. 

The  round  ligament,  or  the  suspensory  cord  of  the  uterus,  occupies  the 
inguinal  canal  in  the  female,  and  ends  in  the  integuments  of  the  groin. 
Its  coverings  are  similar  to  those  of  the  spermatic  cord,  exce[)t  it  wants 
the  cremaster. 

Dissection.  The  constituents  of  the  cord  will  be  displayed  by  cutting 
through  longitudinally,  and  turning  aside  the  different  surrounding  layers, 
and  removing  the  areolar  tissue.  The  dissector  should  trace  brandies  of 
the  genito-crural  nerve  and  epigastric  artery  into  the  cremasteric  covering. 
Vessels  and  nerves  of  the  cord.  In  the  cord  are  collected  together  the 
spermatic  artery  and  vein  which  convey  the  blood  to,  and  take  it  away 
from  the  testis ;  the  nerves  and  lymphatics  of  the  testicle ;  and  the  vas 
deferens  or  the  efferent  duct. 

In  the  female  a  branch  from  the  ovarian  artery  enters  the  round 
ligament. 

The  vas  deferens  reaches  from  the  testicle  to  the  urethra,  and  is  placed 
behind  the  other  vessels  of  the  cord ;  it  will  be  recognized  by  its  resem- 
blance in  feel  to  a  piece  of  whipcord,  when  it  is  taken  between  the  finger 
and  the  thumb.  As  it  enters  the  abdomen  through  the  opening  in  the 
fascia  transversalis  (internal  ring),  it  lies  on  the  inner  side  of  the  vessels 
of  the  testicle;  and  as  it  begins  its  descent  to  the  pelvis,  it  winds  behind 
the  epigastric  artery. 

Cremasteric  artery  and  nerve.  The  cremasteric  covering  of  the  cord  has 
a  separate  artery  and  nerve.  The  artery  is  derived  from  the  epigastric, 
and  is  distributed  to  the  coverings  of  the  cord.  The  genital  branch  of  the 
genito-crural  nerve  enters  the  cord  by  the  internal  abdominal  ring,  and 
ends  in  the  cremaster  muscle. 

Cutaneous  vessels  and  nerves  are  supplied  to  the  teguments  of  the  cord 
from  the  superficial  pudic  artery  and  the  ilio-inguinal  nerve. 

Dissection.  By  cutting  through  the  spermatic  cord  near  the  pubes,  and 
raising  it  towards  the  inner  abdominal  ring,  a  fibrous  band  below  Pou- 
part's ligament,  the  deep  crural  arch,  will  appear  :  it  passes  inwards  to  the 
pubes,  and  is  to  be  defined  with  some  care. 

The  remaining  vessels  of  tlie  abdominal  wall,  viz.,  the  epigastric  and 
circumflex  iliac,  and  the  ending  of  the  internal  mammary  artery  are  to  be 
next  dissected.    The  epigastric  and  mammary  arteries  will  be  observed  on 


VESSELS    IN    ABDOMINAL    WALL.  419 

raising  the  outer  edge  of  the  rectus,  one  above  and  the  other  below,  rami- 
fying in  the  muscle. 

The  epigastric,  with  its  earliest  branches,  may  be  traced  by  removing 
the  fascia  transversalis  from  it  near  Poupart's  ligament.  The  circumflex 
iliac  artery  lies  behind  the  outer  half  of  Poupart's  ligament,  and  should 
be  pursued  along  the  iliac  crest  to  its  ending. 

Deep  crural  arch.  Below  the  level  of  Poupart's  ligament  is  a  thin  band 
of  transverse  fibres  over  the  femoral  vessels,  which  has  received  the  name 
deep  crural  arch  from  its  position  and  resemblance  to  the  superficial  crural 
arch  (Poupart's  ligament).  This  fasciculus  of  fibres,  beginning  about  the 
centre  of  the  ligament,  is  prolonged  inwards  to  the  pubes,  where  it  is 
widened,  and  is  inserted  into  the  pectineal  line  at  the  deep  aspect  of  the 
conjoined  tendon  of  the  broad  muscles  of  the  abdomen.^  It  is  closely 
connected  with  the  front  of  the  crural  sheath. 

Vessels  in  the  Wall  of  the  Abdomen.  On  the  side  of  the  abdomen 
are  the  intercostal  and  lumbar  arteries  with  the  intercostal  nerves.  In  the 
sheath  of  the  rectus  lie  the  epigastric  and  internal  mammary  vessels ;  and 
around  the  crest  of  the  hip-bone  bends  the  circumflex  iliac  branch. 

The  intercostal  arteries  (fig.  138)  issue  between  the  false  ribs  (p.  337), 
and  enter  the  abdominal  wall  between  the  transversalis  and  internal  ob- 
lique muscles:  they  extend  forwards  with  the  nerves,  supplying  the  con- 
tiguous muscles,  and  some  end  in  the  teguments.  In  front  they  anasto- 
mose with  the  internal  mammary  and  epigastric  :  behind  they  communicate 
with  the  lumbar  arteries. 

The  lowest  artery  accompanies  the  last  intercostal  nerve  below  the  last 
rib,  and  is  distributed  with  the  nerve. 

The  internal  mammary  artery.  The  abdominal  branch  of  this  vessel 
(p.  239)  enters  the  wall  of  the  abdomen  beneath  the  cartilage  of  the  seventh 
rib.  Descending  in  the  sheath  of  the  rectus,  the  vessel  soon  enters  the 
substance  of  the  muscle,  and  anastomoses  in  it  with  the  epigastric  artery. 

The  epigastric  artery  (fig.  140,  a)  arises  from  the  external  iliac  about 
a  quarter  of  an  inch  above  Poupart's  ligament ;  it  ascends  in  the  sheath 
of  the  rectus  and  divides  above  the  umbilicus  into  branches  which  enter 
that  muscle,  and  anastomose  with  the  internal  mammary. 

As  the  artery  courses  to  the  rectus  it  passes  beneath  the  cord,  and  on 
the  inner  side  of  the  internal  abdominal  ring  ;  and  it  is  directed  obliquely 
inwards  across  the  lower  part  of  the  abdomen,  so  as  to  form  the  outer 
boundary  of  a  triangular  space  along  the  edge  of  the  rectus.  It  lies  at 
first  beneath  the  fascia  transversalis  ;  but  soon  perforates  the  fascia,  and 
enters  the  sheath  of  tlie  rectus  over  the  semilunar  border  at  the  posterior 
aspect. 

The  branches  of  the  artery  are  numerous,  but  inconsiderable  in  size : — 

a.  The  pubic  branch  is  a  small  transverse  artery,  which  runs  behind 
Poupart's  ligament  to  the  posterior  aspect  of  the  pubes,  and  anastomoses 
with  a  similar  branch  from  the  opposite  side.  Behind  the  pubes  it  com- 
municates with  a  small  offset  from  the  obturator  artery  (fig.  141,/)  :  the 
size  of  this  anastomosis  varies  much,  but  its  situation  is  internal  to  the 
crural  ring. 

'  Sometimes  this  structure  is  a  firm  distinct  band,  which  is  joined  by  some  of 
the  lower  fibres  of  the  aponeurosis  of  the  external  oblique.  At  other  times,  and 
this  is  the  most  common  arrangement,  it  is  only  a  thickening  of  the  fascia  trans- 
versalis with  the  fibres  added  from  the  tendon  of  the  transversalis  muscle. 


420  DrSSECTION    OF    THE    ABDOMEN. 

h.  A  cremasteric  branch  is  furnished  to  the  muscular  covering  of  the 
cord. 

c.  Muscular  branches  are  given  from  the  outer  side  of  the  artery  to  the 
abdominal  wall,  which  anastomose  with  the  intercostal  arteries  (p.  419), 
and  others  enter  the  rectus.  Cutaneous  offsets  pierce  the  muscle,  and 
ramify  in  the  integuments  with  the  anterior  cutaneous  nerves. 

Two  epigastric  veins  lie  with  the  artery;  they  join  finally  into  one, 
which  opens  into  the  external  iliac  vein. 

The  circumflex  iliac  artery  arises  from  the  outer  side  of  the  external 
iliac,  opposite  the  epigastric,  and  courses  around  the  iliac  crest,  as  the 
name  expresses.  Having  perforated  the  crural  sheath,  it  passes  beneath 
the  transversalis  muscle  to  the  middle  of  the  crest  of  the  hip-bone.  Here 
it  pierces  the  transversalis,  and  is  continued  backwards  between  this  and 
the  internal  oblique,  to  anastomose  with  the  ilio-lumbar  branch  of  the  in- 
ternal iliac  artery.     Its  olfsets  are  muscular  and  anastomotic. 

Branches.  Near  the  front  of  the  iliac  crest  a  small  branch  ascends  be- 
tween the  internal  oblique  and  transversalis  muscles,  supplying  them,  and 
anastomoses  with  the  epigastric  and  intercostal  arteries. 

As  the  vessel  extends  backwards  it  gives  lateral  offsets,  which  sup^ily 
the  neighboring  muscles,  and  communicate  on  the  one  side  with  the  ilio- 
lumbar, and  on  the  other  with  the  gluteal  artery. 

The  circumflex  iliac  vein  is  formed  by  the  junction  of  two  collateral 
branches,  and  crosses  the  external  iliac  artery  nearly  an  inch  above  Pou- 
part's  ligament,  to  open  into  the  external  iliac  vein. 


Section  II. 

HERNIA  OF  THE  ABDOMEN. 


The  lower  part  of  the  abdominal  wall,  which  has  been  reserved  on  the 
left  side  of  the  body,  should  now  dissected  for  inguinal  hernia. 

Dissection.  The  teguments  and  the  aponeurosis  of  the  external  oblique 
having  been  thrown  down  in  the  previous  examination  of  the  wall  of  the 
abdomen,  the  necessary  dissection  of  the  inguinal  region  will  be  completed 
by  raising  the  internal  oblique  muscle,  as  in  fig.  140. 

To  raise  the  oblique  muscle,  let  one  incision  be  made  across  the  flcvshy 
fibres  from  the  iliac  crest  towards  the  linea  alba ;  and  after  the  depth  of 
the  muscle  has  been  ascertained  by  the  layer  of  areolar  and  fatty  tissue 
beneath  it,  let  the  lowest  fibres  be  carefully  cut  through  at  their  attach- 
ment to  Poupart's  ligament.  By  raising  the  muscle  cautiously,  the  stu- 
dent will  be  able  to  separate  it  from  the  subjacent  transversalis,  so  that  it 
may  be  turned  upwards  on  the  abdomen.  The  separation  of  the  two  mus- 
cles just  mentioned  is  sometimes  difficult,  in  consequence  of  their  fibres 
being  blended  together,  but  a  branch  of  the  circumflex  iliac  artery  will 
mark  their  intermuscular  interval. 

The  cremaster  muscle  is  next  to  be  divided  along  the  cord,  and  to  be 
reflected  to  the  sides.  Let  the  dissector  then  clean  the  surface  of  the 
transversalis  muscle,  without  displacing  its  lower  arched  border;  and  trace 
with  care  the  conjoined  tendon  of  it  and  the  internal  oblique  to  show  the 


EXTERNAL    OR    OBLIQUE    HERNIA.  421 

exact  extent  outwards.  The  fascia  transversalis  and  the  spermatic  cord 
should  be  likewise  nicely  cleaned. 

Crossing  the  interval  apparent  below  the  border  of  the  transversalis 
muscle,  are  the  epigastric  vessels,  wiiich  lie  close  to  the  inner  side  of  the 
internal  abdominal  opening,  but  beneath  the  fascia  transversalis.  A  small 
piece  of  the  fascia  may  be  cut  out  to  show  the  vessels. 

Inguinal  Hernia.  A  protrusion  of  intestine  through  the  lower  part 
of  the  abdominal  wall  near  Poupart's  ligament  (the  part  answering  to  the 
inguinal  region),  is  named  an  inguinal  hernia.  The  escape  of  the  intes- 
tine in  this  region  is  predisposed  to  by  the  deficiencies  in  the  muscular 
strata,  by  the  passage  of  the  spermatic  cord  through  the  abdominal 
parietes,  and  by  the  existence  of  fossie  on  the  inner  surface  of  the  wall. 

The  gut  in  leaving  the  abdomen  either  passes  through  the  internal  ab- 
dominal ring  with  the  cord,  or  is  projected  through  the  part  of  the  abdom- 
inal wall  between  the  epigastric  artery  and  the  edge  of  the  rectus  muscle. 
These  two  kinds  of  hernia  are  distinguished  by  the  names  external  and 
internal,  from  their  position  to  the  epigastric  artery;  or  they  are  called 
oblique  and  direct,  from  the  direction  they  take  through  the  abdominal 
wall.  Thus,  the  hernia  protruding  through  the  internal  abdominal  ring 
with  the  cord  is  called  external  from  being  outside  the  artery,  and  oblique 
from  its  slanting  course  ;  whilst  the  hernia  between  the  edge  of  the  rectus 
and  the  epigastric  artery  is  named  internal  from  being  inside  the  artery, 
and  direct  from  its  straight  course. 

External  or  Oblique  Inguinal  Hernia  leaves  the  cavity  of  the 
abdomen  with  the  spermatic  cord,  and  traversing  the  inguinal  canal,  makes 
its  exit  from  that  passage  by  the  external  abdominal  ring. 

Anatomy  of  the  external  hernia.  To  acquire  a  knowledge  of  the  anatomy 
of  this  hernia  it  will  be  necessary  that  the  space  in  which  it  lies  (inguinal 
canal),  the  apertures  by  which  it  enters  and  leaves  the  wall  of  the  abdo- 
men (abdominal  rings),  and  the  coverings  it  receives  in  its  progress  to  the 
surface  of  the  body,  should  be  studied. 

The  inguinal  canal  (^g.  140)  is  the  interval  between  the  flat  muscles 
of  the  abdominal  wall,  which  contains  the  spermatic  cord  in  the  male, 
and  the  round  ligament  in  the  female.  Its  direction  is  oblique  down- 
wards and  inwards,  being  nearly  parallel  to,  but  above  Poupart's  ligament ; 
and  its  length  is  about  one  inch  and  a  half.  Superiorly  it  ceases  at  the  in- 
ternal abdominal  ring ;  and  inferiorly  it  ends  in  the  external  abdominal 
ring. 

Towards  the  surface  of  the  body  the  canal  is  bounded  by  the  teguments, 
and  the  two  oblique  muscles  in  this  way: — The  skin  with  the  subjacent 
fatty  layer,  and  the  aponeurosis  of  the  external  oblique,  a,  reach  the 
whole  length  of  the  passage ;  but  the  internal  oblique,  b,  extends  only 
along  its  outer  third  (half  an  inch). 

Towards  the  cavity  of  the  abdomen  the  wall  of  the  canal  is  constructed 
by  the  conjoined  tendon  of  the  internal  oblique  and  transversalis,  and  by 
the  deep  membranous  strata  in  the  wall  of  the  abdomen  in  this  wise  : — 
The  conjoined  tendon,  h,  placed  in  front  of  the  other  structures,  reaches 
along  the  inner  two-thirds  of  the  space  (about  an  inch)  ;  and  beneath  or 
behind  it  come  the  fascia  transversalis,  g,  the  subperitoneal  fat,  and  the 
peritoneum,  in  the  order  mentioned,  which  are  continued  all  along  the 
passage. 

Along  the  lower  part,  or  the  floor,  the  canal  is  limited  by  the  union  of 
the  fascia  transversalis  with  Poupart's  ligament,  and  by  the  fibres  of  the 


422 


DISSECTION    OF    THE    ABDOMEN. 


ligament  inserted  into  the  pectineal  line;  whilst  along  the  upper  part  its 
extent  is  determined  only  by  tlie  apposition  of  the  muscles. 

In  the  female,  the  canal  has  the  same  length  and  boundaries,  though  it 
is  usually  somewhat  smaller.     In  that  sex  it  lodges  tlie  round  ligament. 

The  internal  abdominal  ring  (fig.  140)  is  an  aperture  in  tlie  fascia 
transversalis,  which  is  situate  midway  between  the  symphysis  pubis  and 
the  iliac  crest,  and  half  an  inch  above  Poupart's  ligament.  It  is  oval  in 
form,  the  extremities  of  the  oval  being  directed  upwards  and  downwards, 
and  measures  about  half  an  inch;  the  fascia  at  its  outer  and  lower  parts  is 
stronger  than  at  the  opposite  sides. 

Fig.  140. 


DissrcTiox  FOR  Inouinal  Hernia, 
Muscles : 

A.  External  oblique  tendon,  thrown  down. 

B.  Internal  oblique,  the  lower  part  raised, 
c.  Cremaster  muscle  in  its  natural  position. 
D.  Transversalis  muscle  with  a  free  border, 
p.  Spermatic  cord. 

G.  Fascia  transversalis, 
H,  Conjoined  tendon. 


(Illustrations  of  Dissections.) 
Arteries  : 

a.  Epigastric  vessels. 

6.  Offset  of  the  circumflex  iliac  muscles. 


Arching  above  and  on  the  inner  side  of  the  aperture,  is  the  lower  border 
of  the  transversalis  muscle,  d,  wliich  is  fleshy  in  the  outer,  but  tendinous 
in  the  inner  half.  Below,  it  is  bounded  by  Poupart's  ligament.  On  the 
inner  side  lie  the  epigastric  vessels  (a). 

This  opening  in  the  fascia  transversalis  is  the  inlet  to  the  inguinal  canal, 
and  through  it  the  cord,  or  the  round  ligament,  passes  into  the  wall  of  the 
abdomen.     Tiie  external  hernia  enters  the  canal  the  same  spot.     All  the 


EXTERNAL    OR    OBLIQUE    HERNIA.  423 

protruding  parts  receive  as  a  covering  the  prolongation  from  the  margin 
of  the  opening. 

The  external  abdominal  ring  (fig.  135,  ^)  is  the  outlet  of  the  inguinal 
canal,  and  through  it  the  spermatic  cord  reaches  the  surface  of  the  body. 
This  aperture  is  phiced  in  the  aponeurosis  of  the  external  oblique  muscle, 
near  the  crest  of  the  pubes  ;  and  from  the  margin  a  prolongation  is  sent 
on  the  parts  passing  through  it  (p.  410). 

Course  and  coverings  of  the  hernia.  A  piece  of  intestine  leaving  the 
abdomen  with  the  cord,  and  passing  through  the  inguinal  canal  to  the 
surface  of  the  body,  will  obtain  a  covering  from  every  stratum  in  the 
lateral  part  of  the  wall  of  the  abdomen,  except  from  the  transversalis 
muscle. 

It  receives  its  investments  in  this  order :  As  the  intestine  is  thrust  out- 
wards, it  carries  before  it  first  the  peritoneum  and  the  subperitoneal  fat, 
and  enters  the  tube  of  the  fascia  transversalis,  f  (infundibuliform  fascia), 
around  the  cord.  Still  increasing  in  size  it  is  forced  downwards  to  the 
lower  border  of  the  internal  oblique  muscle  ;  where  it  will  have  the  cre- 
masteric fascia,  c,  applied  to  it.  The  intestine  is  next  directed  along  the 
front  of  the  cord  to  the  external  abdominal  ring,  and  in  passing  through 
that  opening  receives  the  investment  of  the  intercolumnar  or  spermatic 
fascia.  Lastly,  as  the  hernia  descends  towards  the  scrotum,  it  has  the 
additional  coverings  of  the  superficial  fascia  and  the  skin. 

In  a  hernia  which  has  passed  the  external  abdominal  ring,  the  cover- 
ings from  without  inwards  are  the  following:  the  skin  and  the  superficial 
fascia,  the  spermatic  and  cremasteric  fascia?,  the  fascia  transversalis,  the 
subperitoneal  fat,  and  the  peritoneum  or  hernial  sac.  Two  of  the  cover- 
ings, viz.,  the  peritoneal  and  subperitoneal,  originate  as  the  gut  protrudes, 
but  the  rest  are  ready  formed  around  the  cord,  and  the  intestine  slips  in- 
side them.  The  different  layers  become  much  thickened  in  a  hernia  that 
has  existed  for  some  time. 

Diagnosis.  If  the  hernia  is  small  and  is  confined  to  the  wall  of  the 
belly,  it  gives  rise  to  an  elongated  swelling  along  the  inguinal  canal.  If 
it  has  proceeded  farther,  and  entered  the  scrotum,  it  forms  a  flask-shaped 
tumor  with  the  large  end  below,  and  the  narrow  neck  occupying  the  in- 
guinal passage. 

Whilst  efforts  are  being  made  to  force  back  a  piece  of  protruded  intes- 
tine during  life,  the  direction  of  the  canal,  and  the  situation  of  the  internal 
abdominal  ring  should  be  borne  in  mind. 

Seat  of  stricture.  The  protruded  intestine  may  be  constricted  at  the 
internal  abdominal  ring;  in  the  inguinal  canal  by  the  fleshy  internal  ob- 
lique muscle  ;  and  at  the  external  abdominal  ring. 

The  stricture  is  placed  usually  at  the  inner  abdominal  ring,  and  may  be 
produced  in  tM'o  ways  :  either  by  a  constricting  fibrous  band  outside  the 
narrowed  neck  of  tiie  tumor,  or,  by  a  thickening  and  contraction  of  the 
peritoneum  itself  at  the  inner  surface  of  the  neck. 

Division  of  stricture.  To  set  free  the  intestine,  an  incision  is  made 
down  to  the  internal  abdominal  ring ;  and,  all  fibrous  bands  outside  the 
peritoneum  being  divided,  the  intestine  is  to  be  returned  into  the  abdo- 
men by  gentle  pressure. 

Supposing  the  intestine  cannot  be  replaced  in  the  abdomen  after  the 
previous  steps  have  been  taken,  the  surgeon  proceeds  to  lay  open  the  peri- 
toneum, and  to  divide  the  internal  stricture,  from  witliin  out,  on  a  director 


424  DISSECTION    OF    THE    ABDOMEN. 

placed  beneath  it.  With  a  view  of  avoiding  the  surrounding  vessels,  the 
cut  is  directed  upwards  on  the  front  and  mid-part  of  the  hernia. 

Other  designations.  This  kind  of  hernia  has  other  names  applied  to  it 
sometimes  by  surgeons,  according  as  it  has  passed  certain  points  in  the 
wall  of  the  abdomen.  If  the  intestine  remains  in  the  inguinal  canal, 
the  term  bubonocele  is  applied  to  the  swelling ;  but  if  it  has  extended  into 
the  scrotum,  the  appellation  scrotal  rupture,  or  oscheocele,  is  given  to  the 
tumor. 

Varieties  of  the  external  hernia.  There  are  two  varieties  of  the  oblique 
inguinal  hernia  (congenital  and  infantile),  which  are  distinguished  by  the 
condition  of  the  peritoneal  covering. 

Congenital  hernia.  This  kind  is  found  for  the  most  part  in  the  infant 
and  the  child,  though  it  may  occur  in  the  adult  male.  In  it  the  tube  of 
peritoneum,  which  accompanies  the  testicle  from  the  abdomen  in  the  foetus, 
remaining  unclosed,  the  intestine  descends  into  a  sac  already  formed  for 
its  reception. 

As  it  takes  the  course  of  the  inguinal  canal,  it  M'ill  possess  the  cover- 
ings before  enumerated  for  the  external  hernia ;  and  it  passes  at  the  first 
to  the  bottom  of  the  scrotum,  instead  of  being  arrested  at  the  top  of  the 
testis. 

With  care  it  may  be  distinguished,  whilst  it  is  of  moderate  size,  by  its 
position  in  front  of  the  testicle. 

For  the  seat,  cause,  and  division  of  the  stricture,  refer  to  what  is  before 
stated  for  external  hernia. 

Infantile  hernia,  is  much  rarer  than  congenital,  and  cannot  be  distin- 
guished from  the  common  external  hernia  during  life.  It  was  first  recog- 
nized in  the  young  child,  and  received  its  name  from  that  circumstance  ; 
but,  like  the  congenital,  it  may  be  met  with  in  the  adult.  Its  chief  dif- 
ferential character  is  derived  from  the  state  of  the  peritoneum. 

The  peritoneum  has  the  following  condition  : — the  tube  of  that  mem- 
brane passing  with  the  testicle  in  the  foetus,  is  closed  only  at  the  internal 
abdominal  ring,  instead  of  being  obliterated  from  that  point  down  to  the 
testicle,  so  that  a  large  serous  sac  will  be  situate  in  front  of  the  spermatic 
cord,  and  may  occupy  the  inguinal  canal.  With  this  state  of  tlie  perito- 
neum, should  an  external  hernia  with  its  coverinjjs  descend  alonjj  the  cord 
in  the  usual  way,  it  will  pass  behind  the  unobliterated  sac,  like  a  viscus 
into  serous  membrane.  In  tliis  way  tliere  will  be  two  sacs ;  an  anterior 
(the  tunica  vaginalis),  containing  serum,  and  a  posterior  inclosing  the 
intestine. 

The  infantile  hernia  is  first  recognized  during  an  operation  by  the  knife 
opening  the  tunica  vaginalis.  The  ojjcrator  then  proceeds  to  lay  bare  the 
neck  of  the  hinder  or  hernial  sac,  and  to  treat  the  stricture  of  it  as  before 
described  (p.  423). 

The  Internal  or  Direct  Inguinal  Hernia  escapes  on  the  inner  side 
of  the  epigastric  artery,  and  has  a  straight  course  through  the  abdominal 
parietes.  Its  situation  and  coverings,  and  the  seat  of  stricture,  will  be 
better  understood  after  the  examination  of  the  part  of  the  abdominal  wall 
through  which  it  passes. 

Anatomy  of  the  internal  hernia.  At  the  lower  part  of  the  abdominal 
wall  is  a  triangular  space  (fig.  140)  which  is  bounded  by  the  epigastric 
artery  on  one  side,  the  outer  edge  of  the  rectus  muscle  on  the  other,  and 
the  inner  half  of  Poupart's  ligament  below  :  it  measures  about  two  inches 
from  above  down,  and  one  inch  and  a  half  across  at  the  base. 


INTERNAL    OR    DIRECT    HERNIA.  425 

The  constituents  of  the  abominal  wall  in  this  spot  are,  the  teguments; 
the  strata  of  the  muscles ;  and  the  layers  lining  the  interior  of  the  abdo- 
men, viz.,  fascia  transversalis,  subperitoneal  fat,  and  peritoneum.  The 
muscles  have  the  undermentioned  arrangement: — The  aponeurosis  of  the 
external  oblique  is  pierced  by  an  aperture  (external  abdominal  ring)  towards 
the  lower  and  inner  angle  of  the  space  through  wliich  the  inguinal  hernia 
is  transmitted.  The  internal  oblique  and  transversalis,  which  come  next, 
are  united  together  in  the  conjoined  tendon  ;  as  this  descends  to  its  in- 
sertion into  the  pectineal  line,  it  covers  the  inner  two-thirds  (about  an  inch) 
of  the  space,  and  leaves  uncovered  about  half  an  inch  between  its  outer 
edge  and  the  epigastric  vessels,  where  the  fascia  transversalis  appears. 

Any  intestine  protruding  in  this  spot  must  make  a  new  path  for  itself, 
and  elongate  the  different  structures,  because  there  is  not  any  opening  by 
which  it  can  descend,  as  in  the  external  hernia.  Further,  the  coverings 
of  the  bernia,  and  its  extent  and  direction  in  the  abdominal  wall,  must 
vary  according  as  the  gut  projects  through  tbe  portion  of  the  space  covered 
by  the  conjoined  tendon,  or  through  the  part  external  to  that  tendon. 

Course  and  coverings  of  the  hernia.  The  common  kind  of  the  internal 
hernia  (inferior)  passes  through  the  part  of  the  triangular  space  which  is 
covered  by  the  conjoined  tendon. 

The  intestine  in  protruding  carries  before  it  the  peritoneum,  the  sub- 
peritoneal fatty  membrane,  and  the  fascia  transversalis ;  next  it  elongates 
the  conjoined  tendon,  or  as  in  a  sudden  rupture,  separates  the  fibres,  and 
escapes  between  them.  Then  the  intestine  advances  into  the  lower  part 
of  the  inguinal  canal,  opposite  the  external  abdominal  ring ;  and  passes 
through  that  0})ening  on  the  inner  side  of  the  cord,  receiving  at  the  same 
time  the  covering  of  the  fascias  permatica.  Lastly,  it  is  invested  by  the 
superficial  fascia  and  the  skin. 

In  number  the  coverings  of  the  internal  hernia  are  the  same  as  those  of 
the  external ;  and  in  kind  they  are  the  same,  with  this  exception,  that  the 
conjoined  tendon  is  substituted  for  the  cremasteric  fascia. 

The  position  of  the  openings  in  the  abdominal  wall  should  be  kept  in 
mind  during  attempts  to  reduce  this  kind  of  hernia ;  and  the  straightness 
of  the  course  of  the  internal,  in  comparision  with"  the  external  hernia, 
should  be  remembered. 

Diagnosis.  This  rupture  will  be  distinguished  from  external  hernia  by 
its  straight  course  through  the  abdominal  wall,  and  by  the  neck  being 
placed  close  to  the  pubes. 

After  this  hernia  has  acquired  a  large  size,  an  examination  during  life 
cannot  determine  whether  it  began  originally  in  the  triangular  space,  or 
at  the  internal  abdominal  ring  ;  for  as  an  external  hernia  increases,  its 
weight  drags  inwards  the  internal  ring  into  a  line  with  the  external,  and 
in  this  way  the  swelling  acquires  the  appearance  of  a  direct  rupture. 

Seat  of  stricture.  The  stricture  in  this  form  of  hernia  occurs  most 
frequently  external  to  the  neck  of  the  tumor,  though  it  may  be  inside 
from  thickening  of  the  peritoneum  ;  and  it  may  occasionally  be  found  at 
the  external  abdominal  ring. 

Division  of  the  stricture.  The  neck  of  the  tumor  is  to  be  laid  bare, 
and  all  fibrous  bands  around  it  are  to  be  divided  without  injury  to  the 
peritoneum  ;  but  if,  after  this  has  been  done,  the  intestine  cannot  be  put 
backwards  into  the  abdomen,  the  sac  is  to  be  opened,  and  the  internal 
constricting  band  is  to  be  divided  directly  upwards  on  a  director. 

In  the  operation  on  a  large  rupture  appearing  to  be  direct,  the  operator 


426  DISSECTION    OF    THE    ABDOMEN. 

should  cut  on  the  front  and  mid-part  of  tlie  tumor,  so  as  to  avoid  the  epi- 
gastric vessels,  whose  lateral  position  cannot  be  known. 

Variety  of  internal  hernia.  Another  kind  of  internal  hernia  (superior) 
occurs  through  that  part  of  the  area  of  the  triangular  space  which  is  ex- 
ternal to  the  conjoined  tendon.  Its  existence  is  determined  by  the  unusual 
position  of  the  obliterated  hypogastric  artery  inside  the  abdominal  wall 
(p.  427). 

The  intestine  protrudes  through  the  wall  of  the  abdomen  close  to  the 
epigastric  artery,  and  descends  along  nearly  the  whole  of  the  inguinal 
canal  to  reach  the  external  abdominal  ring ;  so  that  the  term  "  direct" 
would  not  apply  strictly  to  this  form  of  internal  hernia. 

Coverings.  As  the  gut  traverses  nearly  the  whole  of  the  inguinal 
canal,  it  has  exactly  the  same  coverings  as  the  external  hernia,  viz.,  the 
skin  and  the  superficial  fascia,  tlie  spermatic  and  cremasteric  fascioe,  the 
fascia  transversalis,  and  the  subperitoneal  fat  and  the  peritoneum. 

Diagnosis.  Tiiis  form  of  internal  hernia  would  be  considered  external 
during  life  from  its  course  and  its  form  ;  and  yet  it  must  be  remembered 
that  the  epigastric  vessels  are  placed  on  the  outer  part  of  its  neck,  whilst 
in  the  hernia  which  it  stimulates,  they  lie  on  the  inner  side.  Its  nature 
can  be  ascertained  with  certainty  only  after  death. 

Seat  of  stricture.  The  constriction  of  tlie  intestine  will  take  place 
from  similar  causes,  and  at  the  same  spots  as  in  the  external  hernia. 

Division  of  the  stricture.  From  an  inability  to  decide  always  in  the 
living  body  whether  a  small  hernia  is  internal  or  external,  the  rule  ob- 
served in  dividing  the  stricture  of  tlie  neck  of  the  sac  is,  to  cut  down  upon 
the  mid-part  of  the  tumor;  and  if  it  is  necessary  to  open  the  peritoneum, 
to  cut  directly  upwards,  as  in  the  other  kinds  of  inguinal  hernia. 

Umbilical  Hernia,  or  exomphalos,  is  a  protrusion  of  the  intestine 
through  or  by  the  side  of  the  umbilicus.  It  is  very  variable  in  size,  and 
its  course  is  straight  through  the  abdominal  wall. 

Coverings.  The  coverings  of  the  intestine  are  few  in  number  :  They 
are  the  skin  and  the  superficial  fascia ;  a  prolongation  from  the  tendinous 
margin  of  the  umbilical  opening ;  together  with  coverings  of  the  fascia 
transversalis,  the  subperitoneal  fat,  and  the  peritoneum.  Over  the  end  of 
the  tumor  the  supei-ficial  fascia  blends  with  the  other  contiguous  struc- 
tures, and  its  fat  disappears. 

If  the  hernia  is  suddenly  |)roduced,  it  may  want  the  investment  other- 
wise derived  from  the  edge  of  the  umbilicus. 

Seat  of  stricture.  The  stricture  on  the  intestine  is  generally  at  the 
margin  of  the  tendinous  opening  in  the  abdominal  wall ;  and  it  may  be 
either  outside,  or  in  the  neck  of  the  sac,  as  in  the  other  kinds  of  hernia. 
It  should  be  remembered  that  the  narrowed  neck  is  at  the  upper  part  and 
not  in  the  centre  of  the  swelling. 

Division  of  the  stricture.  The  constriction  may  be  removed  by  cutting 
externally  the  parts  around  the  neck.  Or  if  the  sac  is  to  be  opened,  the 
knife  may  be  carried  upwards  in  cutting  through  the  stricture ;  but  there 
is  not  any  vessel  liable  to  injury  in  the  operation. 

Other  Forms  of  Hernia.  At  each  of  the  other  apertures  in  the 
parietes  of  the  abdomen,  a  piece  of  intestine  may  be  jjrotruded,  so  as  to 
form  a  hernial  tumor.  For  instance  there  may  \m  femoral  hernia  below 
Poupart's  ligament,  with  the  femoral  vessels  ;  obturator  hernia  through 
the  thyroid  foramen,  with  the  artery  of  the  same  name ;  and  ischiatic 
hernia  through  the  ischiatic  notch. 


ANATOMY  OF  FEMORAL  HERNIA.  427 

The  femoral  hernia,  as  the  most  important,  will  be  noticed  presently ; 
but  the  student  must  refer  to  some  special  treatise  for  information  re- 
specting tlie  other  abdominal  herniae. 

Dissection.  The  abdomen  may  be  now  opened  to  see  the  cords  and 
the  depressions  on  the  posterior  surface  of  the  abdominal  wall.  A  trans- 
verse cut  may  be  made  through  the  umbilicus  across  the  front  of  the  ab- 
domen ;  and  on  holding  u{)  the  lower  half  of  the  wall,  fibrous  cords  will 
be  seen  ascending  to  the  umbilicus  from  the  pelvis. 

Cords  of  the  abdominal  wall.  In  the  middle  line  is  the  prominence  of 
the  remains  of  the  urachus,  which  reaches  from  the  summit  of  the  bladder 
to  the  umbilicus.  On  each  side  is  anotlier  cord  of  the  obliterated  hypo- 
gastric artery  ;  this  is  directed  from  the  side  of  the  pelvis  to  the  umbili- 
cus, and  lies  usually  behind  or  close  to  the  epigastric  artery,  near  Poupart's 
ligament. 

FosscE.  With  this  disposition  of  the  cords,  two  fossas  are  seen  near 
Poupart's  ligament,  one  on  each  side  of  the  obliterated  hy[)Ogastric  artery  ; 
tliey  correspond  with  the  situation  of  the  internal  and  external  abdominal 
rings,  and  with  the  places  where  the  external  and  internal  (common  kind) 
hernia?  occur. 

But  occasionally  the  cord  of  the  obliterated  hypogastric  is  moved  in- 
wards from  the  epigastric  artery,  to  the  line  of  junction  of  the  outer  with 
tlie  inner  two-thirds  of  the  triangular  space  through  which  the  direct 
hernia  comes.  In  this  position  of  the  cord  there  will  be  three  fossae  on 
the  lower  part  of  the  abdominal  wall ;  viz.,  an  inner  between  it  and  the 
urachus,  a  middle  one  between  it  and  the  epigastric  vessels,  and  an  exter- 
nal outside  the  epigastric  artery.  And  there  may  be  one,  two,  or  three 
inguinal  liernia?,  on  each  side  of  the  body,  according  to  the  depth  of  the 
fossai,  and  the  predisposition  to  protrusion  of  the  intestine. 

Femoral  Hernia.  In  this  hernia  the  intestine  leaves  the  abdomen 
below  Poupart's  ligament,  and  descends  in  a  loose  membranous  sheath 
around  the  femoral  vessels.  Only  so  much  of  the  structures  will  be  de- 
scribed here  as  can  be  now  seen,  the  rest  are  noticed  fully  in  the  dissection 
of  the  tliigh. 

Dissection.  The  dissection  for  the  femoral  hernia  is  to  be  made  on  the 
left  side  of  the  body. 

The  lower  portion  of  the  abdominal  wall  is  to  be  divided  from  the  um- 
bilicus to  the  pubes.  The  peritoneum  is  to  be  detached  from  the  inner 
surface  of  the  wall  near  Poupart's  ligament,  by  means  of  a  transverse  cut 
just  above  that  band;  and  is  to  be  raised  from  the  iliac  fossa.  The  layer 
of  the  sub[)eritoneal  fat  is  to  be  separated  in  the  same  way,  but  before  this 
can  be  done,  it  will  be  necessary  to  cut  through  the  spermatic  cord  at  the 
abdominal  ring;  as  this  layer  is  raised,  some  lymphatic  glands  will  be 
laid  bare  by  the  side  of  the  iliac  vessels.  Any  loose  tissue  remaining  is 
to  be  taken  away  to  show  the  upper  opening  of  tlie  membranous  crural 
sheath  containing  the  femoral  vessels,  and  the  interval  (crural  ring)  on 
their  inner  side  (fig.  141).  In  this  dissection  the  genito-crural  nerve  is 
seen  on  the  iliac  artery. 

Afterwards  the  fascia  transversalis  and  the  iliac  fascia  are  to  be  traced 
to  Poupart's  ligament,  to  see  the  part  that  each  takes  in  the  production  of 
the  crural  sheath. 

Anatomy  of  femoral  hernia.  The  membranes  concerned  in  the  femoral 
hernia  are,  the  peritoneum ;  the  subperitoneal  fat ;  the  transversalis  and 


428  DISSECTION    OF    THE    ABDOMEN. 

iliac  fasciae  lining  the  interior  of  the  abdominal  cavity,  with  the  sheatli  on 
the  femoral  vessels  to  which  they  give  origin  at  Poupart's  ligament. 

The  peritoneum  lines  the  inner  surface  of  the  abdominal  wall,  without 
having  any  aperture  for  the  escape  of  the  intestine ;  and  its  thinness  and 
weakness  are  apparent  now  it  is  detached. 

The  subperitoneal  fat  extends  as  a  continuous  layer  beneath  the  perito- 
neum, but  is  thickest  and  most  fibrous  at  the  lower  part  of  the  abdomen, 
where  the  iliac  vessels  pass  under  Poupart's  ligament.  At  that  spot  it 
extends  over  tlie  upper  opening  of  the  membranous  sheaths  around  the 
vessels;  and  internal  to  the  vein,  it  covers  the  space  of  the  crural  ring,  as 
well  as  a  lymphatic  gland  which  occupies  that  space. 

Where  this  layer  stretches  over  the  crural  ring  it  is  named  by  M.  Clo- 
quet  septum  crurale ;  and  it  is  described  by  him  as  being  concave  towards 
the  abdomen,  and  convex  towards  the  thigh.  An  inguinal  gland  is  gen- 
erally attached  to  its  under  surface. 

The  fascia  transversalis  has  been  before  noticed  (p.  417).  At  Pou- 
part's ligament  it  joins  the  iliac  fascia,  outside  the  situation  of  the  large 
iliac  artery  (fig.  141) ;  but  internal  to  that  spot  it  is  continued  downwards 
to  the  thigh  in  front  of  the  femoral  vessels,  and  forms  the  anterior  part  of 
the  crural  sheath. 

The  iliac  fascia  covers  the  iliacus  muscle,  and  lies  beneath  the  iliac 
vessels.  At  Poupart's  ligament  its  disposition  is  similar  to  that  of  the 
transversalis  fascia;  for,  external  to  the  iliac  vessels,  it  joins  the  fascia 
transversalis  along  the  line  of  the  ligament ;  but  opposite  the  vessels  it  is 
prolonged  into  the  posterior  part  of  the  crural  sheath. 

Fig.  141. 

Muscles  : 
A.  Iliacus  covered  by  the  iliac  fascia. 
B    Rectus. 

C.  Transversalis,  covered  by  the  transver- 
salis fascia. 

D.  Crural  ring. 

E.  Gimbernat's  ligament. 
Vessels  : 

a.  Iliac  artery. 

b.  Iliac  vein. 

c.  Epigastric  branch. 

d.  Circumflex  ilinc. 

e.  Obturator,  with  its  nerve. 
/.  Small  branch  joining  obturator  and-epi- 

gastric  arteries. 
ViKW  OP  THE  Parts  conckrned  in  Femokal  Hbrnia  (Quain's  plates). 

The  crural  sheath  is  a  loose  membranous  tube,  wliich  incloses  the  femo- 
ral vessels  as  they  enter  the  thigh,  and  is  obtained  from  the  fascite  lining 
tiie  abdomen.  Its  anterior  half  is  continuous  with  the  fascia  transversalis, 
and  its  posterior  is  derived  from  the  fascia  iliaca.  The  sheath  is  not  en- 
tirely filled  by  the  vessels,  for  a  space  (crural  ring)  exists  on  the  inner 
side  of  the  vein,  through  which  the  intestine  descends  in  femoral  hernia. 

The  crural  ring  (fig.  141,  °)  is  referred  to  also  in  the  dissection  of  the 
thigh,  but  its  boundaries  are  better  seen  in  the  abdomen.  It  is  the  inter- 
val in  the  sheath,  at  the  inner  side  of  the  femoral  vein,  which  is  about 
half  an  inch  wide,  and  is  filled  by  a  lymphatic  gland.  Bounding  it  inter- 
nally, fire  Gimbernat's  ligament,  E,  and  tlie  conjoined  tendon;  and  limit- 


STRICTURE    OF    FEMORAL    HERNIA.  429 

ing  it  externally  is  the  femoral  vein  (b)  without  the  intervention  of  the 
sheath.  In  front  is  Poupart's  ligament,  with  the  deep  arch  ;  and  behind 
is  the  piibes,  covered  by  the  pectineus  and  the  fascia  lata.  Along  the 
front  of  the  space,  but  at  some  little  distance  from  it,  lies  the  spermatic 
cord  in  the  male,  and  the  round  ligament  in  the  female. 

Two  of  the  boundaries,  anterior  and  inner,  are  firm  and  sharp-edged, 
though  their  condition  varies  with  the  position  of  the  limb;  ibr  if  the  thigh 
is  raised  and  approximated  to  its  fellow,  those  bounding  parts  will  be 
relaxed. 

Position  of  vessels  around  the  ring  (fig.  141).  On  the  outer  side  is  the 
femoral  vein  (b);  and  above  this  are  the  epigastric  vessels  (c).  In  front 
is  a  small  branch  (pubic)  from  the  epigastric  artery  to  the  back  of  the 
pubes ;  and  the  vessels  of  the  spermatic  cord  may  be  said  to  be  placed 
along  the  anterior  aspect  of  the  ring.  The  ring  is  bounded  in  the  male  by 
vessels  in  front  and  on  the  outer  side. 

But  in  some  bodies  the  obturator  artery  takes  origin  from  the  epigastric, 
and  lies  along  the  ring  as  it  passes  to  the  pelvis.  It  may  have  two  posi- 
tions with  respect  to  the  crural  ring : — either  it  is  placed  close  to  the  iliac 
vein,  so  as  to  leave  the  inner  side  of  that  space  free  from  vessels  ;  or  it 
arches  over  the  aperture,  descending  on  the  inner  side  at  the  base  of  Gim- 
bernat's  ligament ;  in  this  last  condition  the  ring  will  be  encircled  except 
at  the  posterior  part. 

Course  of  femoral  hernia.  The  intestine  leaves  the  abdomen  by  the 
opening  of  the  crural  ring ;  and  it  descends  internal  to  the  vein  in  the 
large  crural  sheath,  as  far  as  the  saphenous  opening  in  the  thigh,  where  it 
projects  to  the  surface. 

Coverings.  In  its  progress  the  intestine  will  push  before  it  the  peri- 
toneum, and  the  subperitoneal  fat  (septum  crurale) ;  and  it  will  displace, 
or  cause  to  be  absorbed,  the  gland  which  fills  the  crural  ring.  Having 
reached  the  level  of  the  saphenous  opening,  the  intestine  carries  before  it 
the  inner  side  of  the  crural  sheath,  and  a  layer  called  the  cribriform  fas- 
cia ;  and,  lastly,  it  is  invested  by  the  teguments  of  the  thigh.  The  dissec- 
tion of  the  thigh  may  be  referred  to  for  fuller  detail. 

Seat  of  stricture.  The  stricture  of  a  femoral  hernia  is  placed  opposite 
the  base  of  Gimbernat's  ligament,  or  lower  down  at  the  margin  of  the 
saphenous  opening  in  the  thigh.  And  the  constriction  may  be  caused 
either  by  a  fibrous  band  outside  the  upper  narrow  end  of  the  tumor,  or  by 
the  thickening  of  the  peritoneum  inside  that  [^art,  as  in  inguinal  hernia. 

Division  of  the  stricture.  To  free  the  intestine  from  the  constricting 
fibrous  band  arching  over  it,  an  incision  is  to  be  made  down  to  the  neck 
of  the  sac  at  the  inner  and  upper  part. 

And  to  relieve  the  deep  stricture  within  the  neck  of  the  sac,  the  peri- 
toneal bag  is  to  be  opened  and  a  director  introduced,  and  the  knife  is  to 
be  carried  horizontally  inwards,  or  upwards  and  inwards,  through  the 
thickened  sac  and  a  few  fibres  of  the  edge  of  Gimbernat's  ligament. 

Danger  to  vessels.  When  the  incision  is  made  upwards  and  inwards  to 
loosen  the  constricting  band  in  the  neck  of  the  tumor,  there  will  not  be 
any  vessel  injured  unless  the  cut  should  be  made  so  long  as  to  reach  the 
spermatic  cord  in  the  male,  or  the  small  pubic  branch  of  the  epigastric 
artery. 

And  wlien  the  incision  is  made  directly  inwards  with  the  same  view, 
there  is  not  usually  any  vessel  in  tiie  way  of  the  knife.  But  in  some  few 
instances  (once  in  about  eighty  operations,  Lawrence),  the  obturator  artery 


430  DISSECTION    OF    THE    ABDOMEN. 

takes  its  unusual  course  in  front  of  and  on  tlie  inner  side  of  the  neck  of 
the  hernia,  and  will  be  before  the  knife  in  the  division  of  the  stricture. 
As  this  condition  of  the  vessel  cannot  be  recognized  beforehand,  the  sur- 
geon will  best  avoid  the  danger  of  wounding  tiie  artery  by  a  cautious  and 
sparing  use  of  the  knife. 


Section  III. 

CAVITY  OF  THE  ABDOMEN. 


The  abdominal  cavity  is  the  space  included  between  the  spinal  column 
behind,  and  tlie  visceral  arches  of  the  vertebras  with  their  intervening 
muscles  in  front.  It  is  lined  by  a  serous  membrane  (peritoneum),  and 
contains  the  digestive,  urinary,  and  generative  organs,  with  vessels  and 
nerves. 

Dissection,  To  prepare  the  cavity  for  examination,  the  remainder  of 
the  abdominal  wall  above  tlie  umbilicus  is  to  be  cut,  along  the  left  side  of 
the  linea  alba,  as  far  as  the  xiplioid  cartilage.  Tlie  resulting  flaps  may  be 
thrown  to  the  sides. 

Size  and  form.  This  space  is  the  largest  in  the  body.  It  is  ovoidal  in 
form,  with  the  ends  upwards  and  downwards,  so  that  it  measures  more 
in  the  vertical  than  the  transverse  direction  ;  and  it  is  much  wider  supe- 
riorly than  inferiorly. 

Boundaries.  Above  it  is  limited  by  the  diaphragm  ;  below  by  the 
recto-vesical  fascia  and  the  levatores  ani,  and  the  structures  closing  the 
outlet  of  the  pelvis:  both  tliese  boundaries  are  concave  towards  the  cavity, 
and  are  in  part  fleshy,  so  that  the  space  will  be  diminished  by  their  con- 
traction and  flattening. 

In  front  and  on  the  sides  the  parietes  are  partly  osseous  and  partly 
muscular : — thus  towards  the  upper  and  lower  limits  is  the  bony  frame- 
work of  the  skeleton,  viz.,  the  ribs  in  one  direction  and  the  pelvis  in  the 
other;  but  in  the  centre  are  stretched  the  muscles  of  the  abdominal  wall. 

Behind  is  placed  the  spinal  column  with  the  muscles  contiguous  to  it, 
viz.,  the  psoas  and  the  quadratus  lumborum. 

Alterations  in  size.  The  dimensions  of  the  cavity  are  influenced  by 
the  varying  conditions  of  the  boundaries.  Its  depth  is  diminished  by  the 
contraction  and  descent  of  the  diaphragm,  and  the  contraction  and  ascent 
of  the  levatores  ani ;  and  the  cavity  is  restored  to  its  former  dimensions 
by  the  relaxation  of  those  muscles. 

The  width  is  lessened  by  the  contraction  of  the  abdominal  muscles  ;  but 
it  is  increased,  during  their  relaxation,  by  the  action  of  the  diaphragm 
forcing  outwards  the  viscera.  The  greatest  diminution  of  the  space  is 
effected  by  the  simultaneous  contraction  of  all  the  muscular  boundaries, 
as  in  the  expulsion  of  the  excreta. 

Division  of  the  space.  A  division  has  been  made  of  the  space  into  the 
abdomen  proper  and  the  cavity  of  the  pelvis. 

The  abdominal  portion  reaches  from  the  diaphragm  to  the  brim  of  the 
pelvis,  and  lodges  the  alimentary  tube  and  its  appendages,  together  with 
the  kidneys. 


CONNECTIONS    OF    STOMACH-  431 

The  pelvic  portion  is  situate  below  the  brim  of  the  pelvis,  and  contains 
chiefly  the  generative  and  urinary  organs. 

The  following  description  concerns  the  part  of  the  cavity  between  the 
diaphragm  and  the  brim  of  the  pelvis.  Towards  the  end  of  the  dissection 
of  the  abdomen,  the  pelvic  portion  will  receive  a  separate  notice. 

liegions.  The  upper  part  of  tlie  abdominal  cavity  is  divided  into  re- 
gions by  lines  extended  between  certain  points  of  the  parietes. 

If  two  circular  lines  are  carried  round  the  body,  so  that  one  shall  be 
opposite  the  cartilage  of  the  ninth  rib,  and  the  other  on  a  level  with  the 
most  prominent  point  of  the  crest  of  the  hip-bone,  the  cavity  will  be 
divided  into  tliree  circles  or  zones,  upper,  middle,  and  lower. 

Each  of  these  circles  has  been  further  subdivided  into  three  by  a  line, 
on  each  side,  from  the  cartilage  of  the  eighth  rib  to  the  centre  of  Poupart's 
ligament.  The  piece  marked  off,  on  each  side,  from  the  three  circles  by 
the  vertical  line  is  named  respectively,  from  above  downwards,  hypochon- 
driac, lumbar,  and  iliac  ;  whilst  the  central  part  of  each  circle  is  desig- 
nated from  above  down,  epigastric,  umbilical,  and  hypogastric. 

In  addition,  the  middle  and  lower  part  of  the  hypogastric  space  is 
named  pubic  region,  whilst  the  contiguous  portions  of  the  hypogastric  and 
iliac  parts  constitute  the  inguinal  region. 

Contents  and  their  position.  The  alimentary  tube,  the  liver,  pancreas, 
spleen,  and  kidney,  occupy  the  abdomen  proper. 

The  alimentary  tube  presents  differences  in  form,  and  is  divided  into 
stomach,  small  intestine,  and  large  intestine  ;  and  the  two  last  are  further 
subdivided,  as  it  will  afterwards  appear.  Tiie  several  viscei'a  have  the 
following  general  position  :  The  small  intestine  is  much  coiled,  and  occu- 
pies the  greater  part  of  the  cavity  ;  whilst  the  great  intestine  arches 
around  it.  Both  are  fixed  in  position  by  pieces  of  the  serous  lining. 
Above  the  arch  of  the  great  intestine  are  situate  the  stomach,  the  liver, 
the  spleen,  and  the  pancreas ;  and  below  it,  is  the  convoluted  small  gut. 
Behind  the  large  intestine,  on  each  side,  is  the  kidney  with  its  excretory 
tube. 

Superficial  view  of  the  contents.  On  first  opening  the  abdomen  the 
following  viscera  appear :  On  the  right  side  is  the  liver,  which  is  partly 
concealed  by  the  ribs.  On  the  left  side  a  piece  of  the  stomach  is  visible  ; 
but  this  viscus  lies  for  the  most  part  beneath  the  ribs  and  the  liver.  De- 
scending from  the  stomach  is  a  fold  of  peritoneum  (the  large  omentum), 
which  reaches  to  the  pelvis,  and  conceals  the  small  intestine :  in  some 
bodies  the  omentum  is  raised  into  the  left  hypochondriac  region,  and  leaves 
the  intestine  uncovered. 

If  the  bladder  is  distended,  a  small  part  of  it  may  come  into  view  just 
above  the  pelvis,  but  commonly  it  is  not  seen. 

Before  the  natural  position  of  the  viscera  is  disturbed,  their  situation  in 
the  different  regions  of  the  abdomen,  and  their  connections  with  surround- 
ing parts  should  be  examined. 

CONNECTIONS  OF  THE  VISCERA. 

The  stomach  (fig.  142,  a)  intervenes  between  the  gullet  and  the  small 
intestine,  and  is  partly  retained  in  position  by  pieces  of  the  serous  mem- 
brane. It  is  somewhat  of  a  conical  form,  with  the  larger  end  to  the  left 
side  ;  and  it  occupies  the  left  hypochondriac,  the  epigastric,  and  part  of 
the  right  hypochondriac  region. 


432 


DISSECTION    OF    THE    ABDOMEN, 


At  the  left  end  it  receives  the  ciesophagus  (b),  by  which  it  is  firmly 
fixed  to  the  diaphragm;  here  it  lies  beneath  the  ribs,  and  is  in  contact 
with  the  spleen  (w),  to  which  it  is  connected  by  a  fold  of  peritoneum 
(splenic  omentum)  :  when  this  part  of  the  stomach  is  distended  it  pushes 

Fig.  142. 


COSNECTIONS  OF  THB  LiVER,  STOMACH,  SpLKEJI,  AND  LARGE    INTESTINE,  the  small  intcstino 

having  been  taken  away. 
a.  Stomach,  and  b,  oesopbagas.  h.  Transverse. 

c  and  d.  Right  and  left  lobes  of  ihe  liver,  with        i.  Descendibg,  and  k,  sigmoid  flexure  of  tbe 

e,  the  suspensory  ligament.  colon. 

/.  Caecum.  I.  Duodenum. 

ff.  Ascending  colon.  m.  Spleen. 

up  the  diaphragm,  and  encroaches  on  the  space  for  the  heart  and  the  left 
lung.  The  right  extremity  ends  in  the  small  intestine,  and  reaches  towards 
the  gall  bladder  ;  it  is  in  contact  with  the  under  part  of  the  liver. 

The  anterior  surface  touches,  from  left  to  right,  the  diaphragm,  the  ab- 
dominal wall,  and  the  liver;  and  the  posterior  surface  corresponds  with 
the  pancreas,  the  pillars  of  the  diaphragm,  the  aorta  and  vena  cava,  and 
the  solar  plexus. 

The  upper  border  is  connected  to  the  liver  by  a  process  of  peritoneum, 
the  small  omentum  ;  and  the  lower  border  gives  attachment  to  another 
peritoneal  fold,  the  great  omentum  or  epiploon,  which  floats  freely  over 
the  intestine. 

The  form,  and  the  connections  of  the  stomach  with  the  surrounding 
parts  will  vary  with  tlie  size.     For  when  tiie  viscus  is  empty  it  is  flattened. 


CONNECTIONS    OF    INTESTINES.  433 

its  surfaces  looking  forwards  and  backwards,  and  its  borders  upwards  and 
dow^nwards  ;  but  when  distended,  it  becomes  somewhat  circular,  and  makes 
a  rotatory  movement,  so  as  to  bring  forwards  the  border  usually  lowest, 
and  to  turn  upwards  that  surface  which  is  directed  forwards  at  other  times. 

The  position  and  connections  of  the  stomach  may  be  altered  by  varia- 
tions in  tlie  size  of  any  of  the  surrounding  organs,  or  by  the  accumulation 
of  fluid  in  the  chest,  or  in  the  belly.  The  stomach  may  be  dragged  down 
likewise  by  the  great  omentum  entering  a  hernia ;  or  it  may  be  forced 
down  towards  the  pelvis  by  the  pressure  of  tight  stays.  In  these  different 
changes  in  position,  the  right  end  moves  more  than  the  left,  because  it  is 
attached  mainly  by  peritoneum  to  the  parts  around. 

The  small  intestine  (intestinum  tenue)  reaches  from  the  stomach  to  the 
right  iliac  region,  where  it  ends  in  the  large  intestine.  It  is  divided  into 
three  parts,  duodenum  (twelve  fingers'  length),  jejunum,  and  ileum  :  of 
the  last  two,  the  former  receives  its  name  from  its  empty  condition,  and 
the  latter  from  its  numerous  coils. 

The  duodenum  (fig.  142,  /)  cannot  be  satisfactorily  seen  at  present,  and 
it  will  be  examined  afterwards  (p.  445). 

The  Jejunujn  and  ileum  (fig.  143)  begin  on  the  left  side  of  the  second 
lumbar  vertebra,  without  any  distinct  mark  of  separation  from  the  duode- 
num. Two-fifths  of  the  intestine  belong  to  the  jejunum,  and  the  remain- 
ing three-fifths  to  the  ileum. 

This  part  of  the  intestinal  tube  forms  many  convolutions  in  the  umbili- 
cal, hypogastric,  lumbar,  and  iliac  regions  of  the  abdomen  ;  and  it  de- 
scends oftentimes,  but  more  frequently  in  the  female,  into  the  cavity  of  tie 
pelvis.  In  front  of  the  convolutions  is  the  great  omentum.  Beyond  the 
duodenum  the  intestine  is  fixed  posteriorly  to  the  spine  by  a  process  of 
peritoneum  named  the  mesentery,  which  contains  the  vessels  and  nerves. 
Surrounding  the  jejunum  and  ileum  is  the  large  intestine  or  colon  :  but 
on  the  left  side  of  the  body  the  colon  is  concealed  by  the  small  intestine. 

The  lai'ge  intestine,  or  the  colon  (fig.  142),  is  sacculated,  and  ig  more 
fixed  than  the  jejunum  and  ileum.  It  begins  in  the  right  iliac  region  in  a 
rounded  part  or  head  (caput  caecum  coli),  and  ascends  to  the  liver  through 
the  right  iliac,  lumbar,  and  hypochondriac  regions.  Crossing  then  the 
abdomen  below  the  stomach,  it  reaches  the  left  hypochondriac  region  ;  and 
it  lies  in  this  transverse  part  of  its  course  between  the  epigastric  and  um- 
bilical regions,  or  altogether  in  the  latter.  Finally,  it  descends,  on  the 
left  side,  through  the  regions  corresponding  with  those  it  occupied  on  the 
right,  and  forms  a  remarkable  bend  (sigmoid  flexure)  in  the  left  iliac 
fossa  ;  then  becoming  straighter  it  passes  through  the  pelvis  to  end  on  the 
surface  of  the  body. 

It  is  divided  into  six  parts,  viz.,  caecum,  ascending  colon,  transverse 
colon,  descending  colon,  sigmoid  flexure,  and  rectum. 

The  ccecum  (fig.  142,/)  (caput  caecum),  or  the  commencement  of  the 
colon,  is  placed  in  the  right  iliac  fossa,  in  which  it  is  fixed  by  the  perito- 
neum being  stretched  over  it.  In  front  usually  are  convolutions  of  the 
small  intestine,  but  when  it  is  distended  it  touches  the  abdominal  wall. 
Behind,  it  rests  on  the  iliac  fascia,  only  fatty  and  areolar  tissues  interven- 
ing. On  the  inner  side  it  is  joined  by  the  small  intestine ;  and  it  presents 
interiorly  a  worm-like  piece — the  vermiform  appendix. 

Sometimes  the  peritoneum  surrounds  the  caecum,  and  attaches  it  by  a 
process  to  the  abdominal  wall. 

The  ascending  colon  (fig.  142,  g)  reaches  from  the  cajcum  to  the  under 
28 


434  DISSECTION    OF    THE    ABDOMEN. 

surface  of  the  liver,  on  the  right  of  the  gall  bladder.  It  lies  against  the 
quadratns  lumborum  inferiorly,  but  higher  up  it  is  placed  in  front  of  the 
kidney.  To  its  inner  side  are  the  convolutions  of  the  small  intestine. 
The  peritoneum  fixes  the  colon  immovably  to  the  wall  of  the  abdomen, 
and  surrounds  commonly  about  two-thirds  of  the  circumference ;  but  it 
may  encircle  the  tube,  and  form  a  fold  behind,  as  in  the  caecum. 

The  transverse  colon  (fig.  142,  h)  passes  obliquely  upwards  and  to  the 
left,  along  the  curvature  of  the  stomach,  as  far  as  the  spleen  ;  in  this  course 
it  is  deeper  at  each  end  than  in  the  middle,  and  forms  the  arch  of  the  colon 
by  being  thus  bent. 

Above  the  arch  are  placed  the  liver  and  the  gall  bladder,  the  stomach 
and  the  spleen  :  and  below,  is  the  small  intestine.  In  front  lies  the  great 
omentum  ;  and  behind  is  a  long  process  of  peritoneum,  the  transverse 
meso-colon,  which  attaches  it  to  the  back  of  the  abdomen,  and  contains 
the  vessels  and  nerves. 

The  transverse  colon  is  more  movable  than  any  other  part  of  the  large 
intestine, — its  peritoneal  fold  allowing  it  to  be  raised  on  the  margin  of  the 
ribs.  Small  pieces  of  peritoneum,  containing  fat,  the  appendices  epiploirce, 
are  attached  along  it. 

The  descending  colon  (fig.  142,  i)  commences  below  the  spleen,  and 
reaches  to  the  left  iliac  fossa.  At  first  it  is  placed  deeply  in  the  left  hypo- 
chondriac region  ;  and  its  whole  course  is  deeper  than  that  of  the  right 
colon.  In  front  of  it  are  the  convolutions  of  the  small  intestine;  and  be- 
hind it  are  the  diaphragm,  the  outer  part  of  the  kidney,  and  the  quadratus 
lumborum. 

This  part  of  the  intestine  is  smaller  than  either  the  right  or  the  trans- 
verse portion,  and  is  less  surrounded,  commonly,  by  the  peritoneum  ;  but 
its  upper  end  is  attached  to  the  diaphragm  by  a  firm  process  (pleuro-eolic) 
of  that  membrane. 

The  sigmoid  flexure  of  the  colon  (fig,  142,  k')  is  lodged  in  the  left  iliac 
fossa,  to  which  it  is  attached  by  a  process  of  the  peritoneum,  the  sigmoid 
meso-colon,  but  it  often  hangs  in  the  cavity  of  the  pelvis.  The  intestine 
makes  two  turns  like  the  letter  S,  and  has  obtained  its  name  from  that 
circumstance.  Its  extent  is  from  the  crest  of  the  hip  bone  to  the  sacro- 
iliac articulation,  where  it  ends  in  the  rectum.  It  is  concealed  by  the 
small  intestine,  which  is  directed  more  to  the  left  than  the  right  side. 

The  rectum,  or  the  termination  of  the  large  intestine,  which  is  contained 
in  the  pelvis,  will  be  examined  in  the  dissection  of  that  cavity. 

The  liver  (fig.  142,  c,  d)  is  situate  in  the  right  hypochondriac,  and  epi- 
gastric regions,  and  reaches  slightly  into  the  left  hypochondriac.  Pieces 
of  peritoneum  (ligaments)  retain  it  in  place. 

The  upper  surface,  convex,  is  turned  to  the  vault  of  the  diaphragm, 
and  is  divided  into  two  parts  by  the  suspensory  ligament  {e)  ;  the  right 
))ortion,  more  prominent  than  the  left,  reaches  to  the  level  of  the  fifth  in- 
tercostal space.  The  under  surface  is  in  contact  with  the  stomach  and 
the  duodenum,  with  the  ascending  colon,  and  with  the  right  kidney  and 
suprarenal  body  ;  attached  to  this  surface  is  a  fold  of  the  peritoneum  (small 
omentum),  containing  the  hepatic  vessels. 

The  anterior  border  is  thin,  and  lies  in  the  adult  male  usually  within 
the  margin  of  the  ribs,  but  in  women  and  children  it  reaches  below  that 
line.  The  gall  bladder  projects  beyond  this  edge.  The  posterior  border 
is  thick,  and  is  connected  to  the  diaphragm  by  certain  ligaments  or  pieces 


REFLECTIONS    OF    PERITONEUM.  435 

of  tlie  peritoneum  ;  it  lies  on  tlie  large  vessels  (aorta  and  cava)  and  on  the 
pillars  of  the  diaphragm. 

The  liver  changes  its  situation  with  the  ascent  and  descent  of  the  dia- 
phragm in  respiration  ;  for  in  inspiration  it  descends,  and  in  expiration  it 
regains  its  former  level.  In  the  upright  and  sitting  postures,  too,  this 
viscus  descends  lower  than  in  the  horizontal  condition  of  the  body ;  so 
that  when  the  trunii  is  erect,  the  anterior  border  may  be  felt  underneath 
the  edge  of  the  ribs,  but  when  the  body  is  reclined  it  is  withdrawn  within 
the  margin  of  the  thorax. 

The  connections  of  the  liver  with  the  surrounding  parts  may  be  changed 
by  the  growth  of  tumors,  by  collections  of  fluid  in  the  chest  or  in  the 
abdomen,  or  by  constricting  the  space  for  its  lodgment,  as  in  tight  lacing. 

The  spleen  (tig.  142,  m)  lies  deeply  in  the  left  hypochondrium,  between 
the  stomach  and  the  ribs,  and  is  connected  by  peritoneum  to  the  great  end 
of  tlie  stomach  on  the  one  side,  and  to  the  diaphragm  on  the  other.  Its 
position  is  almost  vertical. 

The  outer  suiface  is  convex,  and  touches  the  diaphragm  opposite  the 
ninth,  tenth,  and  eleventh  ribs.  At  the  inner  surface,  w^hich  is  concave, 
the  vessels  enter  (p.  465),  and  to  it  is  attached  a  process  of  peritoneum, 
the  gastro-splenic  omentum :  the  part  in  front  of  the  vessels  touches  the 
stomach  ;  and  the  part  behind  them  is  in  contact  with  the  tail  of  the  pan- 
creas, the  suprarenal  capsule,  and  the  left  crus  of  the  diaphragm. 

Below  the  spleen  is  a  transverse  piece  of  the  peritoneum  (pleurocolic 
fold),  the  kidney,  and  the  beginning  of  the  descending  colon.  When  the 
stomach  is  distended  the  spleen  is  somewhat  behind  it. 

The  kidney  should  be  examined  on  the  left  side  of  the  body,  so  that  the 
duodenum  may  not  be  displaced.  In  order  that  it  may  be  seen,  the  de- 
scending colon  and  the  peritoneum  must  be  separated  from  the  abdominal 
wall,  and  its  casing  of  fat  should  be  torn  through. 

This  viscus  is  surrounded  with  fat,  and  is  situate  in  the  lumbar  region 
opposite  the  last  dorsal,  and  the  upper  two  or  three  lumbar  vertebrae.  Its 
position  is  somewhat  oblique,  and  the  upper  end  is  nearer  than  the  lower 
to  the  spinal  column. 

In  front  of  the  kidney  are  the  peritoneum  and  the  colon  ;  and  behind 
it  are  the  quadratus  lumborum  and  psoas  muscles,  with  the  diaphragm  and 
the  last  rib.  Above  each  kidney  and  resting  on  it,  is  the  suprarenal  cap- 
sule.    The  inner  border  looks  to  the  spine  and  receives  the  vessels. 

Difference  on  opposite  sides.  The  right  kidney  is  placed  rather  lower 
than  the  left ;  it  reaches  as  liigii  as  the  lower  border  of  the  eleventh  rib, 
whilst  its  fellow  is  opposite  the  upper  border  of  the  corresponding  rib.  In 
front  of  the  right,  besides  the  common  connections  before  specified,  is  the 
duodenum  :  and  before  the  left  one  is  the  lower  end  of  the  spleen.  Above 
the  right  is  the  liver,  and  above  the  left  the  spleen. 

The  connections  of  the  pancreas  may  be  omitted  for  the  present.  This 
viscus  is  described  at  page  446. 

THE    PERITONEUM. 

This  is  the  largest  serous  membrane  in  the  body.  Like  other  mem- 
branes of  the  kind  it  is  a  closed  sac  in  the  male,  but  in  the  female  its 
cavity  is  continuous  with  the  canals  of  the  Fallopian  tubes.  One  part  of 
it  lines  the  wall  of  the  abdomen  (parietal  layer),  and  another  is  reflected 
over  the  different  viscera  (visceral  layer),  except  where  the  vessels  enter. 


436  DISSECTION    OF    THE    ABDOMEN. 

The  inner  surface  is  smooth ;  but  the  outer  is  rough,  when  it  is  detached 
from  the  parts  with  which  it  is  naturally  in  contact.  The  membrane 
forms  processes  or  folds  as  it  passes  from  viscus  to  viscus  along  the  ves- 
sels ;  and  the  folds  attaching  the  viscera  to  the  abdominal  wall  consist  for 
tlie  most  part  of  two  layers,  one  on  each  side  of  tlie  vessels. 

The  continuity  of  the  sac  may  be  traced  in  a  horizontal  and  a  vertical 
direction. 

Horizontal  circle  around  the  abdomen.  Tlie  membrane,  when  followed 
outwards  from  the  umbilicus,  surrounds  partly  the  large  intestine  on  the 
left  side,  and  fixes  it  to  the  abdominal  wall.  From  the  colon  it  maybe 
traced  over  the  kidney  as  far  as  the  middle  line,  where  it  is  reflected  along 
the  front  of  the  vessels  supplying  the  small  intestine,  thence  around  the 
intestine,  and  back  to  the  spine  along  the  same  vessels.  Lastly,  it  may 
be  pursued  outwards  to  the  riojht  kidney,  to  the  colon  which  it  encircles 
like  the  left,  and  along  the  wall  of  the  abdomen  to  the  umbilicus. 

The  piece  of  membrane  fixing  the  colon  on  each  side  to  the  abdominal 
wall,  is  named  meso-colon,  and  that  attaching  the  small  intestine  is  the 
mesentery. 

Vertical  circle  from,  above  downioards.  From  the  under  surface  of  the 
liver  the  peritoneum  may  be  followed  along  the  hepatic  vessels,  one  piece 
before  and  the  other  behind  them  to  the  upper  border  of  the  stomach,  the 
two  forming  the  small  omentum.  At  the  stomach  the  two  pieces  disunite, 
one  passing  before,  and  the  other  behind  it;  but  beyond  that  viscus  they 
are  applied  to  each  other  to  form  the  great  omentum  or  epiploon.  After 
descending  in  contact  to  the  lower  part  of  the  abdomen  they  bend  back- 
wards, separating  to  inclose  the  transverse  colon  like  the  stomach,  and 
they  are  then  continued  to  the  spine,  giving  rise  to  the  transverse  meso- 
colon. At  the  attachment  of  the  transverse  meso-colon  to  the  abdominal 
wall,  the  two  companion  pieces  part  from  each  other — one  passing  up- 
wards, the  other  downwards.^ 

The  ascending  piece  is  continued  in  front  of  the  pancreas  and  the  pillars 
of  the  diaphragm,  and  blends  with  the  peritoneum  on  the  under  surface  of 
the  liver. 

The  descending  piece  or  layer  may  be  followed  from  the  transverse 
meso-colon  over  the  duodenum  and  the  great  vessels  on  the  spine  (aorta 
and  cava),  till  it  meets  with  the  artery  to  the  small  intestine,  along  which 
it  is  continued  to  form  the  mesentery,  as  before  explained  in  tracing  the 
peritoneum  in  a  circular  direction. 

From  the  root  of  the  mesenteric  artery  the  peritoneum  descends  to  the 
pelvis,  and  covers  partly  the  viscera  in  that  cavity.  For  instance,  sur- 
rounding the  upper  part  of  the  rectum,  it  attaches  this  to  the  abdominal 
"wall  by  the  meso-rectum ;  next,  it  is  continued  forwards  between  the  rec- 
tum and  the  bladder  in  the  male,  or  between  the  rectum  and  the  uterus  in 
the  female,  where  it  forms  a  pouch.  Thence  it  passes  from  the  pelvis  over 
the  back  and  sides  of  the  bladder. 

Lastly,  the  serous  membrane  is  continued  to  the  inguinal  region,  where 
it  presents  the  fosssB  before  alluded  to  (p.  427) ;  and  it  can  be  traced  up- 
wards on  the  wall  of  the  abdomen,  and  over  the  diaphragm  and  upper 
surface  of  the  liver,  to  the  under  surface  of  this  viscus. 

'  Sometimes  the  two  pieces  ascend  over  the  transverse  colon,  being  slightly 
attaclied  to  it  and  the  transverse  meso-colon,  as  high  as  the  pancreas  before  they 
separate.  In  that  case  the  descending  layer  would  form  a  distinct  mesentery  for 
the  transverse  colon,  like  that  for  the  small  intestine. 


KEFLECTIONS    OF    PERITONEUM.  437 

Folds  OF  the  Peritoneum.  After  tracing  the  continuity  of  the 
serous  sac  over  the  viscera,  the  student  is  to  learn  the  chief  processes  or 
folds  of  the  membrane  in  connection  with  the  alimentary  tube.  The 
pieces  of  the  peritoneum  fixing  the  liver  w'i\}  be  examined  afterwards;  and 
the  processes  on  the  viscera  of  the  pelvis  will  be  seen  with  the  dissection 
of  that  cavity. 

Folds  on  the  stomach.  The  processes  connected  with  the  stomach  are 
named  omenta.  They  are  three  in  number — one,  small  omentum,  is  at- 
tached to  the  upper  curve ;  another,  great  omentum,  to  the  lower  curve ; 
and  the  third,  splenic  omentum,  is  fixed  to  the  great  end  of  the  viscus. 

The  small  or  gastro-hepatic  omentum  is  stretched  between  the  under 
surface  of  the  liver  and  the  upper  border  of  the  stomach,  and  contains  the 
vessels  and  nerves  of  the  liver.  It  is  formed  by  two  pieces  of  peritoneum, 
as  before  explained,  and  presents  a  free  border  on  the  right  side.  Behind 
it  is  the  space  called  foramen  of  Winslow.  Its  lower  edge  is  fixed  to  the 
small  curve  of  the  stomach;  wiiilst  its  upper  border  is  attached  to  the 
transverse  fissure,  as  well  as  to  the  posterior  half  of  the  longitudinal  fissure 
of  the  liver,  blending  behind  with  the  left  lateral  ligament  of  that  viscus. 

The  gastro-colic  or  great  omentum  is  the  largest  fold  of  the  peritoneum, 
and  consists  of  two  pieces.  It  is  attached  above  to  the  spleen  and  the 
lower  border  of  the  stomach,  and  descends  in  front  of  the  large  intestine, 
but  lower  on  the  left  than  the  right  side  of  the  body.  At  the  lower  part 
of  the  abdomen  the  process  is  bent  backwards,  and  returns  to  the  spine, 
the  pieces  of  which  it  is  composed  separating  to  inclose  the  transverse 
colon.  The  anterior  part  of  the  omental  fold  is  separated  from  the  poste- 
rior by  a  space  (cavity  of  the  omentum). 

Between  its  layers  are  contained  some  fat,  vessels,  and  nerves;  and  the 
power  of  detaching  the  one  layer  from  the  other  diminishes  with  the  in- 
crease of  the  distance  from  the  stomach,  until  below  they  are  not  to  be 
separated,  and  the  membrane  they  form  is  thin  and  net-like. 

Cavity  of  the  omentum.  When  an  opening  is  made  through  the  great 
omentum  near  the  stomach,  and  this  viscus  is  raised,  a  space  is  seen  to 
extend  upwards  to  the  liver,  and  downwards  into  the  omentum:  this  is  the 
omental  cavity.  In  front  the  space  is  bounded  by  the  small  omentum,  the 
stomach,  and  the  anterior  part  of  the  great  omentum.  Behind  it,  are  the 
posterior  part  of  tlie  great  omentum,  the  transverse  colon,  and  the  ascend- 
ing layer  of  the  transverse  meso-colon.  This  space  communicates  with 
the  rest  of  the  peritoneal  cavity,  through  a  hole  (foramen  of  Winslow), 
behind  the  small  omentum. 

If  the  sac  of  the  omentum  were  perfect,  it  could  be  inflated  through  the 
foramen  of  Winslow.  Supposing  it  to  be  detached  and  removed,  there 
would  not  be  any  membrane  in  the  way  of  the  vessels  reaching  the  differ- 
ent viscera;  and  it  may  be  readily  conceived  how  the  peritoneum  could 
be  replaced  over  the  viscera,  and  around  the  vessels  without  being  perfo- 
rated by  them. 

The  foramen  of  Winslow  is  the  space  behind  the  small  omentum, 
through  which  the  omental  bag  opens  into  the  general  cavity  of  tlie  peri- 
toneum. In  front  of  it  is  the  small  omentum,  and  behind,  are  the  vena 
cava  and  the  spine.  Above  it  is  the  liver  (lobulus  Spigelii),  and  below  is 
the  duodenum. 

The  splenic  omentum  reaches  from  the  great  end  of  the  stomach  to  the 
concave  surface  of  the  spleen,  and  does  not  consist  usually  of  two  strata  or 


438  DISSECTION    OF    THE    ABDOMEN. 

pieces,  like  the  other  omenta.     It  covers  the  vessels  passing  between  the 
two  viscera,  and  is  continued  inferiorly  into  the  great  omentum. 

Folds  on  the  large  intestine.  Tiie  large  intestine  is  connected  to  the 
wall  of  the  abdomen  by  processes  of  the  peritoneum  (meso-colic),  whicli 
are  formed  of  two  pieces,  like  the  other  folds,  though  they  are  at  some 
distance  from  each  other.  Each  part  of  the  colon  has  a  separate  meso- 
colon attaching  it,  thus  there  is  an  ascending,  a  transverse,  a  descending, 
and  a  sigmoid  meso-colon.  The  caecum  is  fixed  by  a  meso-caecum,  and 
the  rectum  by  a  meso-rectum. 

The  meso-ccecum  attaches  the  caput  caecum  coli  to  the  right  iliac  fossa. 
Usually  the  peritoneum  does  not  surround  the  gut  so  as  to  form  a  fold  be- 
hind it,  but  in  some  bodies  the  serous  membrane  furnishes  a  suspensory 
process  to  this  part  of  the  intestine. 

By  the  ascending  and  descending  meso-colon  the  ascending  and  the 
descending  part  of  the  colon  are  kept  in  place.  In  these  folds,  as  in  that 
of  the  caecum,  the  peritoneum  does  not  commonly  surround  the  intestine, 
though  it  may  meet  behind  the  gut  and  form  processes  of  some  lengtli. 

The  upper  end  of  the  left  colon  has  a  distinct  fold  (pleuro-colic), 
fixing  it  to  the  wall  of  the  abdomen.  Attached  by  a  wide  part  to  tiie 
diaphragm  opposite  the  eleventh  or  tenth  rib,  it  passes  transversely  below 
the  spleen,  and  forms  the  lower  boundary  of  a  hollow  in  which  the  spleen 
rests. 

The  transverse  meso-colon  is  a  more  perfect  fold  than  either  of  the 
others  connected  with  the  large  intestine,  and  serves  as  a  partition  between 
the  small  intestine  and  the  stomach,  liver,  and  spleen.  By  one  side  it  is 
fixed  to  the  colon,  and  by  the  other  to  the  abdominal  wall  below  the  pan- 
creas.    It  incloses  the  vessels  of  the  colon  between  its  layers. 

The  sigmoid  meso-colon  is  a  long  process  of  the  serous  membrane,  and 
attaches  the  sigmoid  flexure  of  the  colon  to  the  left  iliac  fossa. 

The  meso-rectum  contains  the  hemorrhoidal  vessels,  and  connects  the 
rectum  to  the  front  of  the  sacrum. 

Small  processes  of  the  peritoneum  are  attached  along  the  tube  of  the 
great  intestine,  chiefly  to  the  transverse  colon  ;  they  are  the  appendices 
epiplo'icce,  and  contain  fat. 

Folds  to  the  small  intestine.  The  small  intestine  is  not  enveloped  by 
the  peritoneum  after  the  same  manner  throughout.  For  whilst  the  jejunum 
and  ileum  are  attached  to  the  abdominal  wall  by  one  process  (mesentery), 
the  duodenum  has  special  connections  with  the  serous  membrane. 

Serous  covering  of  the  duodenum.  The  first  part  of  the  duodenum  is 
surrounded  by  peritoneum,  like  the  stomach.  The  second  part  is  covered 
only  in  front.  And  the  last  part,  which  crosses  the  aorta,  is  but  slightly 
in  contact  with  the  serous  membrane  ;  for  it  lies  at  first  between  the 
strata  of  the  transverse  meso-colon,  and  then  beneath  the  superior  mesen- 
teric vessels. 

Fold  of  the  jejunum  and  ileum.  The  mesentery  supports  the  rest  of  tlie 
intestine,  and  is  stronger  than  any  other  piece  of  the  serous  membrane. 
Its  inner  end  is  narrow,  and  is  attached  to  the  spine  from  the  left  side  of 
the  second  lumbar  vertebra  to  the  junction  of  the  right  hip  bone  with  the 
sacrum.  The  other  end  of  the  fold  is  wide,  and  is  connected  with  the 
intestine.  Between  its  two  layers  are  the  superior  mesenteric  vessels  and 
nerves,  with  lymphatic  glands  and  lacteals. 

Ligaments  of  the  liver.  Along  the  upper  part  is  a  suspensory  process 
of  the  peritoneum,  and  there  is  a  wide  piece  along  the  posterior  border. 


UPPER    MESENTERIC    VESSELS.  439 

The  suspensory  or  falciform  ligament  is  placed  between  the  upper  con- 
vex surface  of  the  liver  and  the  parietes  of  the  abdomen.  It  is  triangular 
in  shape,  with  its  base  forwards.  The  lower  border  is  concave,  and  is 
attached  to  the  liver;  whilst  the  upper  border  is  convex,  and  is  connected 
to  tlie  abdominal  wall,  on  the  ri<Tht  side  of  the  linea  alba,  and  to  the  under 
part  of  the  diaphragm.  In  its  base  or  free  part  is  the  remains  of  the  um- 
bilical vein,  which  is  named  the  round  ligament. 

Tliis  fold  allows  the  umbilical  vein  to  reach  the  liver  without  piercing 
the  peritoneum ;  and  witii  a  little  care  the  dissector  will  be  able  to  detach 
the  serous  membrane  from  the  vein,  and  to  trace  it  on  each  side  into  the 
suspensory  ligament. 

The  coronary  ligament  is  a  short  but  wide  process  of  the  peritoneum, 
which  connects  the  hinder  part  of  the  liver  to  the  diaphragm.  It  reaches 
all  across  the  liver,  but  at  each  side  it  is  enlarged,  and  forms  a  triangu- 
larly-shaped  piece  ;  to  these  larger  portions  of  it  the  terms  right  and  left 
lateral  ligaments  have  been  applied. 

The  left  lateral  ligament  is  attached  to  the  liver  above  the  edge  of  the 
left  lobe,  and  is  formed  by  two  pieces  of  peritoneum,  which  are  in  contact; 
it  lies  in  front  of  the  oesophagean  opening  in  the  diaphragm. 

The  right  lateral  ligament  lies  deeply  in  the  hypochondriac  region,  in 
front  of  the  vena  cava  inferior  :  it  consists  of  two  pieces  of  peritoneum  not 
touching  each  other. 

MESENTERIC   VESSELS  AND  SYMPATHETIC  NERVE. 

Directions.  The  vessels  and  nerves  (mesenteric)  which  are  distributed 
to  the  greater  part  of  the  alimentary  tube,  may  be  first  dissected.  After 
these  have  been  examined,  and  the  connections  of  the  aorta  and  vena  cava 
have  been  learnt,  most  of  the  intestine  can  be  taken  out  to  give  room  for 
the  display  of  the  viscera  in  the  upper  part  of  the  abdomen. 

Mesenteric  Vessels.  The  superior  and  inferior  mesenteric  arteries 
are  two  large  branches  of  the  aorta,  which  supply  the  intestine,  except  a 
part  of  the  duodenum  and  the  lower  end  of  the  rectum.  Each  is  accom- 
1  anied  by  a  vein,  and  by  a  plexus  of  the  sympathetic  nerve. 

Dissection  (fig.  143).  For  the  dissection  of  the  superior  mesenteric 
vessels  and  nerves,  the  transverse  colon  and  the  great  omentum  are  to  be 
placed  on  the  margin  of  tlie  ribs,  and  one  layer  (anterior)  of  the  mesen- 
tery is  to  be  removed.  Whilst  tracing  the  branches  of  the  artery  to  the 
small  intestine,  corresponding  veins,  and  offsets  of  the  sympathetic  nerve 
on  the  arteries,  will  be  met  with  ;  these  last  are  removed  in  cleaning  the 
vessels.  Mesenteric  glands  and  a  few  lacteal  vessels  will  come  into  vieSv 
at  the  same  time. 

The  branches  from  the  right  side  of  the  vessel  to  the  large  intestine  are 
to  be  next  followed  :  and  after  all  the  branches  have  been  cleaned,  tlie 
trunk  of  the  artery  should  be  traced  back  beneath  the  pancreas.  The 
plexus  of  surrounding  nerves  should  be  also  defined. 

The  superior  mesenteric  artery  (fig.  143,  a)  supplies  branches  wholly 
to  the  small  intestine  beyond  the  duodenum,  and  to  half  the  large  intes- 
tine, viz.,  as  far  as  the  end  of  the  transverse  colon. 

Arising  from  the  aorta  near  the  diaphragm,  the  vessel  is  directed  down- 
wards between  the  layers  of  the  mesentery,  forming  an  arch  with  the  con- 
vexity to  the  left  side,  and  terminates  in  offsets  to  the  CiBCum  and  the  end 
of  the  small  intestine.     At  first  the  artery  lies  beneath  the  pancreas  and 


440 


DIS^SECTION    OF    THE    ABDOMEN. 


the  splenic  vein  ;  and  as  it  descends  to  the  mesentery  it  is  placed  in  front 
of  the  duodenum  and  the  left  renal  vein.  This  vessel  is  surrounded  by 
the  mesenteric  plexus  of  nerves,  and  is  accompanied  by  the  vein  of  the 
same  name. 

Branches.  AVhilst  the  vessel  is  covered  by  the  pancreas  it  gives  a  small 
branch  to  that  body  and  the  duodenum.  Its  other  branches  are  intestinal : 
those  from  the  left  or  convex  side  of  the  vessel  (rami  intestinales)  are  fur- 
nished to  the  jejunum  and  ileum ;  and  those  from  the  opposite  side  supply 
the  colon,  and  are  named  colic  arteries. 


Fig.  143. 


ScPEKiOK  Mesentkric  Artery  and  its  Branches  (Tiedemann). 

a.  Superior  mesenteric.  d.  Right  colic. 

b.  Inferior  pancreatico-duodenal.  e.  Ileo-colic. 

c.  Middle  colic.  /.  Intestinal  branches  to  the  jejunum  and  ilenm. 

a.  The  pancreatico-duodenal  branch  (inferior)  is  of  small  size  (fig.  143, 
J);  after  giving  twigs  to  the  pancreas,  it  runs  to  the  right  along  the  con- 
cavity of  the  duodenum,  and  anastomoses  with  the  other  duodenal  branch 
(p.  448). 

b.  The  intestinal  branches  for  the  jejunum  and  ileum  (fig.  143,/")  are 
about  twelve  in  number,  and  piu^s  from  the  left  side  of  the  artery  between 
the  layers  of  the  mesentery.  About  two  inches  from  their  origin  the 
branches  bifurcate,  and  the  resulting  pieces  unite  with  similar  offsets  from 
the  collateral  arteries,  so  as  to  form  a  series  of  arches.  From  the  con- 
vexity of  tlie  arclies  other  branches  take  origin,  which  divide  and  unite 
as  before.     This  i^rocess  is  repeated  four  or  five  times  between, the  origin 


LOWER    MESENTERIC    VESSELS.  441 

and  tlie  distribution,  but  at  each  branching  the  size  of  the  vessels  dimin- 
ishes. From  the  last  set  of  arches  twigs  are  sent  to  the  intestine  on  both 
aspects  of  the  tube,  and  anastomose  round  it. 

The  branches  of  the  large  intestine  are  three  in  number,  ileo-colic,  right 
colic,  and  middle  colic  arteries. 

c.  The  ileo-colic  artery  (o)  arises  from  the  right  side  of  the  trunk,  and 
divides  at  the  caecum  into  branches  which  encircle  the  head  of  the  colon. 
A  descending  offset  is  distributed  to  the  lower  part  of  the  ileum,  and  to 
the  cjBCum  and  the  vermiform  appendix  ;  whilst  an  ascending  offset  sup- 
plies the  beginning  of  the  ascending  colon,  and  anastomoses  with  the  right 
colic  artery. 

d.  The  right  colic  artery  (d)  is  commonly  an  offset  of  the  preceding, 
instead  of  a  separate  branch  from  the  trunk.  Near  the  ascending  colon  it 
divides  into  ascending  and  descending  pieces,  which  anastomose  with  the 
ileo-colic  artery  on  one  side,  and  with  the  middle  colic  on  the  other. 

e.  The  middle  colic  branch  (c)  springs  from  the  upper  part  of  the  artery, 
and  entering  between  the  layers  of  the  transverse  meso-colon  divides  into 
two  diverging  branches  : — the  right  one  anastomoses  with  the  artery  to  the 
ascending  colon,  and  the  left  inosculates  on  the  descending  colon  with  a 
left  colic  branch  (fig.  144,  c)  of  the  inferior  mesenteric  artery.  The 
intestinal  twigs  are  united  in  arches  before  entering  the  gut,  like  those  to 
the  small  intestine. 

The  superior  mesenteric  vein  (fig.  146,  b)  commences  in  that  part  of  the 
intestinal  tube  to  which  the  artery  is  distributed.  Its  radicles  unite  into 
one  trunk,  w^hich  accompanies  the  artery  beneath  the  pancreas,  and  there 
joins  the  splenic  vein  to  form  the  vena  portae. 

At  the  lower  border  of  the  pancreas  it  receives  the  right  gastro-epiploic 
l)ranch  of  the  stomach,  and  the  pancreatico-duodenal  veins  (fig.  146,  c). 

The  mesenteric  lymphatic  gands  are  numerous  between  the  layers  of  the 
me>entery.  An  upper  group  lies  by  the  side  of  the  artery,  and  contains 
the  largest  glands  ;  and  a  lower  group,  near  the  intestine,  is  lodged  in  the 
intervascular  spaces.  The  chylilerous  vessels  of  the  small  intestine,  and 
the  absorbents  of  the  i)art  of  the  large  intestine  supplied  by  the  superior 
mesenteric  artery,  pass  through  the  mesenteric  glands  in  their  course  to 
the  thoracic  duct. 

Along  the  side  of  the  ascending  and  the  transverse  colon  are  a  few 
other  small  lymphatic  glands  meso-colic,  which  receive  some  absorbents  of 
the  large  intestine. 

Dissection  (fig.  144).  By  drawing  the  small  intestine  over  to  the  right 
side,  the  dissector  will  observe  the  inferior  mesenteric  artery  on  the  front 
of  the  aorta  a  little  above  the  bifurcation.  The  peritoneum  should  be  re- 
moved from  it,  and  the  branches  should  be  traced  outwards  to  the  remain- 
ing half  of  the  large  intestine :  a  part  of  the  artery  enters  the  pelvis,  but 
this  will  be  dissected  afterwards.  On  the  artery  and  its  branches  the  in- 
ferior mesenteric  plexus  of  nerves  ramifies. 

The  mesenteric  vein  is  to  be  followed  upwards,  away  from  the  trunk  of 
the  artery,  to  its  junction  with  the  splenic,  or  with  the  superior  mesenteric 
vein. 

On  the  aorta  the  dissector  will  meet  with  a  plexus  of  nerves,  which  is 
to  be  left  uninjured. 

The  inferior  mesenteric  artery  (fig.  144,  6)  supplies  branches  to  the 
part  of  the  large  intestine  beyond  the   transverse  colon  ;  and  communi- 


442 


DISSECTION    OF    THE    ABDOMEN 


eating  with  the  superior  mesenteric,  assists  to  maintain  the  chain  of  anas- 
tomosis along  the  intestinal  tube. 

This  vessel  is  of  smaller  size  than  the  superior  mesenteric,  and  arises 
from  the  aorta,  from  one  to  two  inches  above  the  bifurcation.  At  first 
the  vessel  descends  on  the  aorta,  and  crosses  the  left  common  iliac  artery, 
as  it  courses  to  the  pelvis  to  end  in  branches  for  the  rectum  (superior 
haemorrhoidal).  The  following  branches  are  furnished  by  it  to  the  de- 
scending colon  and  the  sigmoid  flexure. 

Fig.  144. 


The  Lower  Mesenteric  Artery,  and  the  Aorta,  seeu  by  turning  aside  tlie  upper  iuesente:ic 
artery  and  the  small  intestine.     (Tiedemann). 
a.  Aorta. 
6.  Inferior  mesenteric  artery. 

c.  Left  colic. 

d.  Sigmoid,  and  e,  Superior  hsemorrhoidal 

branches. 


/.  Upper  mesenteric. 

g.  Renal. 

h.  Spermatic  of  the  left  side. 


a.  The  left  colic  artery  {c)  ascends  in  front  of  the  left  kidney,  and 
divides  into  an  ascending  and  a  descending  branch  for  the  supply  of  the 
descending  colon  :  by  the  ascending  offset  it  anastomoses  with  the  middle 
colic  branch  of  the  superior  mesenteric. 

h.  The  sigmoid  artery  (d)  is  distributed  to  the  sigmoid  flexure,  and 
divides  into  offsets  which  anastomose  above  with  f^a  preceding  colic, 
and  below  with  the  haemorrhoidal  brancii.  Here,  as  in  the  rest  of  tiie 
intestinal  tube,  arches  are  formed  by  the  arteries  beiore  they  reach  the 
intestine. 


VISCERAL    PLEXUSES    OF    SYMPATHETIC.  443 

c.  The  superior  hcemorrhoidal  artery  (e)  enters  between  the  layers  of 
the  meso-rectum,  and  is  distributed  to  the  lower  part  of  the  great  intes- 
tine :  it  will  be  described  in  the  dissection  of  the  pelvis. 

The  inferior  mesenteric  vein  (fig.  146,  c?)  begins  in  the  part  of  the  great 
intestine  to  which  its  companion  artery  is  distributed,  and  ascends  along 
the  psoas  muscle  to  open  into  the  splenic  vein  beneath  the  pancreas.  Oc- 
casionally it  joins  the  superior  mesenteric  vein. 

Both  mesenteric  veins  are  without  valves,  and  may  be  injected  from  the 
trunk  to  the  branches,  like  an  artery. 

Lymphatic  glands  are  ranged  along  the  descending  colon  and  the  sig- 
moid flexure.  The  absorbents  of  the  intestine,  after  passing  through 
those  glands,  enter  the  left  lumbar  lymphatic  glands. 

Sympathetic  Nerve.  The  following  plexuses  of  the  sympathetic 
on  the  vessels,  viz.,  superior  mesenteric,  aortic,  spermatic,  and  inferior 
mesenteric,  are  derived  from  the  solar  plexus  beneath  the  stomach.  The 
remaining  portion  of  the  sympathetic  nerve  in  the  abdomen  will  be  subse- 
quently referred  to. 

Dissection.  On  the  two  mesenteric  arteries  the  dissector  will  have 
made  out,  already,  the  plexuses  of  nerves  distributed  to  the  intestinal  tube 
beyond  the  duodenum. 

He  has  now  to  trace  on  the  aorta  the  connecting  nerves  between  the 
mesenteric  plexuses,  by  taking  the  peritoneum  from  the  aorta  between  the 
mesenteric  vessels.  From  the  upper  part  of  the  aortic  plexus  an  offset  is 
to  be  followed  along  the  spermatic  artery  ;  this  may  be  done,  on  the  left 
side,  where  the  vessel  is  partly  laid  bare. 

By  removing  the  peritoneum  from  the  front  of  the  sacrum,  and  follow- 
ing downwards,  over  the  iliac  arteries,  the  nerves  from  the  aortic  plexus 
and  the  lumbar  ganglia,  tlie  dissector  will  arrive  at  the  hypogastric  plexus 
of  the  pelvis,  opposite  the  top  of  the  sacrum. 

The  superior  ynesenteric  plexus  is  a  large  offset,  and  is  distributed  to 
the  same  extent  of  the  intestinal  tube  as  the  mesenteric  artery.  The 
nerves  surround  closely  the  artery  with  a  sheath,  but  near  tjie  intestine 
some  of  them  leave  the  vessels,  and  divide  and  communicate  before  enter- 
ing the  gut.  Branches.  The  secondary  plexuses  are  the  same  as  the  off- 
sets of  the  artery,  viz.,  intestinal  nerves  to  the  small  intestine;  and  an 
ileo-colic,  a  right  colic,  and  a  middle  colic  plexus  to  the  large  intestine. 

The  aortic  plexus  is  the  network  of  nerves  covering  the  aorta  below 
the  superior  mesenteric  artery  ;  it  is  stronger  on  the  sides  than  the  front 
of  the  aorta,  in  consequence  of  its  receiving  accessory  branches  from  the 
lumbar  ganglia,  especially  the  left.  At  the  upper  part  the  plexus  derives 
an  offset,  on  each  side  of  the  aorta,  from  the  solar  and  renal  plexuses.  It 
ends  interiorly,  on  each  side,  in  branches  which  cross  the  common  iliac 
artery,  and  enter  the  hypogastric  plexus  of  the  pelvis.  From  it  offsets 
are  furnished  to  the  spermatic  and  inferior  mesenteric  arteries. 

The  spermatic  plexus^  formed  by  roots  from  both  the  aortic  and  the 
renal  plexus,  runs  on  the  spermatic  artery  to  the  testicle ;  in  the  cord  it 
joins  other  filaments  on  the  vas  deferens. 

In  the  female,  the  nerves  on  the  ovarian  (spermatic)  artery  are  furnished 
to  the  ovary  and  the  uterus. 

The  inferior  mesenteric  plexus  supplies  the  part  of  the  intestinal  tube 
to  which  the  artery  is  distributed.  This  plexus  is  furnished  from  the  left 
part  of  the  aortic  plexus  ;  and  the  nerves  composing  it  are  whiter  and 
larger  than  in  either  of  the  preceding  plexuses  of  the  sympathetic.     Near 


444  DISSECTION    OF    THE    ABDOMEN. 

the  intestine  (sigmoid  flexure)  the  branching  of  the  nerves  and  the  union 
of  contiguous  twigs  are  well  marked.  Branches.  Its  secondary  plexuses 
are  named  from  the  arteries  they  accompany,  viz.,  left  colic,  sigmoid, 
and  superior  hasmorrhoidal :  they  ramify  on  the  vessels,  and  have  a  like 
distribution. 

The  hypogastric  plexus,  or  the  large  prevertebral  centre  for  the  supply 
of  sympathetic  nerves  to  the  viscera  of  the  pelvis,  is  situate  in  front  of 
the  upper  part  of  the  sacrum.  It  is  developed  more  on  the  sides  than  in 
the  centre  ;  and  the  nerves,  which  are  large  and  flat,  have  a  plexiform 
arrangement,  but  without  any  intermixed  ganglionic  masses. 

By  its  upper  part  it  receives  the  nerves  on  the  aorta,  and  is  joined  by 
some  filaments  from  one  or  two  of  the  upper  sacral  ganglia.  Inferiorly 
the  plexus  ends  in  two  parts,  right  and  left,  the  last  being  the  largest : 
each  is  continued  forwards  by  the  side  of  the  internal  iliac  artery  to  the 
pelvic  plexus  of  the  same  side,  and  to  the  viscera. 

CONNECTIONS  OF  AORTA  AND  VENA  CAVA. 

Before  the  viscera  are  removed  from  the  body,  the  connections  of  the 
abdominal  aorta  and  vena  cava  may  be  learnt.  , 

Dissection.  To  see  the  aorta  above  the  origin  of  the  superior  mesen- 
teric artery,  it  will  be  necessary  to  detach  the  great  omentum  from  the 
stomach,  without  injuring  the  gastro-epiploic  artery  along  the  great  curve  ; 
and  after  raising  the  stomach  and  the  spleen,  to  remove  the  peritoneum 
from  the  surface  of  the  pancreas.  A  short  arterial  trunk  (coeliac  axis) 
above  the  pancreas  is  not  to  be  cleaned  now,  otherwise  the  nerves  about 
it  would  be  destroyed. 

The  vena  cava  on  the  right  side  of  the  aorta  may  be  followed  as  far  as 
the  posterior  border  of  the  liver,  where  it  disappears.  The  connections 
of  its  upper  part  can  be  better  observed  after  the  dissection  of  the  ves- 
sels of  the  liver. 

The  aortcii  enters  the  abdomen  between  the  pillars  of  the  diaphragm, 
and  divides  into  iliac  arteries  opposite  the  left  side  of  the  iburth  lumbar 
vertebra.  At  the  beginning  the  vessel  occupies  the  middle  line  of  the 
spine,  but  it  gradually  inclines  to  the  left  as  it  descends. 

In  the  abdomen  the  aorta  lies  behind  all  the  viscera ;  but  it  is  crossed 
more  immediately  by  the  pancreas  and  duodenum,  which  it  touches  with- 
out the  intervention  of  peritoneum.  Its  connections  are  the  following  :  at 
first  it  is  covered  by  the  solar  plexus,  and  by  the  pancreas  and  the  splenic 
vein  ;  still  lower  (beyond  the  superior  mesenteric  artery)  by  the  left  renal 
vein  and  the  duodenum ;  and  thence  to  its  termination  by  the  peritoneum 
and  the  aortic  plexus.  The  vessel  lies  on  the  lumbar  vertebras,  with  the 
pillars  of  the  diaphragm  embracing  it  at  the  beginning.  To  its  right  side 
is  the  vena  cava.     Its  relation  to  other  deep  parts  is  mentioned  in  p.  489. 

The  vena  cava  inferior  commences  on  the  right  side  of  the  fifth  lumbar 
vertebra  by  the  union  of  the  common  iliac  veins,  and  reaches  thence  to 
the  heart. 

The  venous  trunk  is  placed  on  the  right  side  of  the  vertebral  column. 
It  lies  close  to  the  aorta,  and  is  concealed  by  the  same  viscera  as  high  as 
the  crus  of  the  diaphragm  ;  but  above  that  spot  it  is  inclined  away  from 
the  artery,  and  ascending  on  the  right  of  the  crus  of  the  diaphragm,  is 
imbedded  in  the  posterior  part  of  the  liver  for  an  inch  or  more.     Lastly, 


DUODENUM  AND  PANCREAS.  445 

it  leaves  the  abdomen  by  an  aperture  in  the  tendinous  centre  of  the  dia- 
phragm, on  the  right  of,  and  higher  th'in  the  aortic  opening. 

Its  connections  with  vessels  are  not  the  same  as  those  of  the  aorta. 
Beneath  it  are  the  right  lumbar,  renal,  capsular,  and  diaphragmatic 
arteries ;  and  crossing  over  it  below  the  kidney  is  the  spermatic.  Super- 
ficial to  it  beneath  the  pancreas  is  tlie  beginning  of  the  vena  portae.  Off- 
sets of  the  solar  plexus  of  nerves  descend  on  it,  as  on  the  aorta. 

CONNECTIONS  OF  THE  DUODENUM  AND  PANCREAS. 

Dissection.  To  see  satisfactorily  the  duodenum  and  the  pancreas  the 
intestinal  tube,  beyond  the  duodenum,  is  to  be  removed  in  the  following 
way  : — a  double  ligature  is  to  be  placed  on  the  upper  part  of  the  jejunum, 
another  on  the  lower  end  of  the  sigmoid  flexure  of  the  colon,  and  the  gut 
is  to  be  cut  through  at  the  points  at  which  it  is  tied.  The  detached  piece 
of  the  intestinal  tube  is  to  he  taken  away  by  cutting  through  the  vessels, 
and  the  peritoneum  connecting  it  to  the  wall  of  the  abdomen.  After  it 
has  been  separated,  it  is  to  be  set  aside  for  future  study  whilst  the  body  is 
turned. 

The  student  should  moderately  inflate  the  stomach  and  duodenum 
from  the  cut  extremity  of  the  latter,  and  remove  the  loose  peritoneum 
and  the  fat ;  whilst  cleaning  them,  he  should  lay  bare  the  larger  vessels 
and  nerves. 

On  turning  upwards  the  stomach  the  pancreas  may  be  traced  from  the 
spleen  on  the  one  hand  to  the  duodenum  on  the  other  (fig.  145).  By 
pulling  forwards  the  duodenum,  the  common  bile  duct  may  be  found, 
posteriorly,  between  the  intestine  and  the  head  of  the  pancreas  ;  and 
some  of  the  pancreas  should  be  removed,  to  show  its  duct  entering  the 
duodenum. 

Duodenum  (fig.  145,  d).  The  first  part  of  the  small  intestine,  or  the 
duodenum,  begins  at  the  pyloric  end  of  the  stomach,  and  crossing  the 
spinal  column,  ends  on  the  left  side  of  the  second  lumbar  vertebra.  It 
makes  a  curve  around  the  head  of  the  pancreas,  and  occupies  the  right 
hypochondriac,  right  lumbar,  and  umbilical  regions  of  the  abdomen. 
From  its  winding  course  around  the  pancreas  it  is  divided  into  three  parts 
— superior  transverse,  vertical,  and  inferior  transverse. 

The  superior  transverse  part  is  free  and  movable,  like  the  stomach  ;  it 
measures  about  two  inches  in  length,  and  is  directed  from  the  pylorus  to 
the  neck  of  the  gall  bladder,  ascending  slightly  between  one  point  and  the 
other.  In  front  it  is  overlapped  by  the  liver,  as  well  as  by  the  gall  blad- 
der when  this  is  distended ;  and  behind  it  are  the  bile  duct  and  the  vena 
portae. 

The  vertical  part  is  fixed  almost  immovably  by  the  peritoneum  and  the 
pancreas.  It  is  nearly  three  inches  in  length,  and  descends  from  the  gall 
bladder  as  far  as  the  third  lumbar  vertebra.  Superficial  to  this  [)art  is  the 
right  bend  of  the  colon  ;  and  beneath  it  are  the  kidney  and  its  vessels. 
On  its  inner  side  is  the  head  of  the  pancreas,  with  the  common  bile-duct. 
The  ducts  of  the  liver  and  pancreas  pour  their  contents  into  this  portion 
of  the  duodenum. 

The  inferior  transverse  part  is  the  longest  of  the  three,  and  is  continued 
across  the  spinal  column  to  end  in  the  jejunal  portion  of  the  small  intes- 
tine.    As  it  crosses  the  spine,  it  ascends  trom  the  third  to  the  level  of  the 


446  DISSECTION    OF    THE    ABDOMEN. 

second  lumbar  vertebra,  and  lies  between  the  layers  of  the  transverse 
meso-colon.      It  has  the  following  connections  with  the  ]).arts  around: — 

In  front  of  it  are  the  superior  mesenteric  vessels  witii  their  plexus  of 
nerves.  Beneath  it  lie  the  vena  cava  and  the  aorta,  with  the  pillars  of 
the  diaphragm  ;  and  the  left  renal  vein  is  sometimes  between  it  and  the 
aorta.     Above  it  is  the  pancreas. 

Pancreas  (fig.  145,  ^■).  The  pancreas  is  situate  behind  the  stomach, 
and  has  numerous  and  complicated  connections.  Of  an  elcngated  form,  it 
extends  across  the  spine  from  the  spleen  to  the  duodenum,  and  occupies 
the  left  hypochondriac,  the  umbilical,  and  the  right  lumbar  region  of  the 
abdomen. 

The  gland  is  covered  anteriorly  by  the  ascending  layer  of  the  transverse 
meso-colon.  It  is  in  contact  posteriorly  with  tlie  aorta,  the  vena  cava, 
and  the  pillars  of  the  diaphragm  ;  and  it  conceals  likewise  the  splenic  vein 
and  the  commencement  of  the  vena  portce. 

Projecting  above  the  upper  border,  near  the  centre,  is  the  arterial  trunk 
of  the  coelic  axis  :  to  the  left  of  that  vessel,  along  the  same  border,  is 
placed  the  splenic  artery ;  whilst  to  tlie  right  of  it  lie  the  hepatic  artery 
and  the  first  part  of  the  duodenum.  At  the  lower  border  the  superior 
mesenteric  vessels  emerge  opposite  the  coelic  axis ;  to  the  right  of  that 
spot  lies  the  third  part  of  the  duodenum,  and  to  the  left  the  inferior  mesen- 
teric ascending  to  join  the  splenic  vein. 

The  left  end  or  the  tail  of  the  pancreas  touches  the  spleen,  and  is  phiced 
over  the  left  kidney.  The  right  extremity  or  the  liead  is  received  into 
the  concavity  of  the  duodenum,  the  two  being  partly  separated  by  the 
common  bile  duct  and  the  pancreatico-duodenal  arteries.  Tliis  part  pro- 
jects above  and  below  the  body  of  the  gland,  like  the  head  of  a  hammer 
beyond  the  handle  ;  and  the  lower  projecting  piece  is  directed  to  the  left 
along  the  duodenum  beneath  the  superior  mesenteric  vessels. 

CcELIC  AXIS  AND  VENA  PORT^. 

A  short  branch  of  the  aorta — the  coeliac  axis,  furnishes  arteries  to  the 
stomach  and  duodenum,  the  liver,  pancreas,  and  spleen  ;  it  subdivides  into 
three  chief  branches — coronary,  hepatic,  and  splenic. 

The  veins  corresponding  with  the  arteries  (except  the  hepatic)  are  col- 
lected into  one  trunk — the  vena  portae. 

Dissection.  The  vessels  have  been  in  part  laid  bare  by  the  previous 
dissection,  and  in  tracing  them  out  fully  the  student  sliould  spare  the 
plexuses  of  nerves  around  each.  Supposing  the  liver  well  raised,  he  may 
first  follow  to  the  left  side  the  small  coronary  artery,  and  show  its  branches 
to  the  oesophagus  and  the  stomach.  Next  the  hepatic  artery,  with  the 
vena  porta?  and  the  bile  duct,  may  be  traced  to  the  liver  and  the  gall 
bhi(hler ;  and  a  considerable  brancli  of  it  should  be  pursued  beneath  the 
pylorus  to  the  stomach,  duodenum,  and  pancreas.  Lastly,  the  splenic 
artery,  which  lies  along  the  upper  border  of  the  pancreas,  is  to  be 
cleaned ;  and  its  branches  to  the  pancreas,  stomach,  and  spleen  should  be 
defined ;  this  is  a  difficult  task  without  the  aid  of  some  one  to  liold  aside 
the  stomach  and  spleen. 

The  veins  will  iiave  been  dissected  for  the  most  part  with  the  arteries ; 
but  the  origin  of  the  vena  porta3  is  to  be  made  out  beneath  tlie  pancreas, 
and  in  front  of  the  vena  cava. 

The  CcELiAC   AXIS  (fig.  145,  c)  is  the  first  visceral  branch  of  the  ab- 


CCELIAC    ARTERY    AND    BRANCHES.  447 

dominal  aorta,  and  arises  between  the  pillars  of  the  diaphragm.  It  is  a 
short  thick  trunk,  about  half  an  inch  long,  which  projects  above  the  upper 
border  of  the  pancreas,  and  is  surrounded  by  the  solar  plexus  of  the  sym- 
pathetic. Its  branches — coronary,  hepatic,  and  splenic — radiate  from  the 
trunk  (whence  the  name  axis)  to  their  distribution  to  the  viscera  in  the 
upper  part  of  the  abdomen. 

a.  The  coronary  artery  (c?)  is  the  smallest  of  the  three,  and  passes  be- 
tween the  layers  of  the  little  omentum  to  the  left  end  of  the  stomach.  At 
that  spot  it  furnishes  some  oesophageal  branches,  and  turns  from  left  to 
right,  along  the  upper  border  of  the  stomach,  to  anastomose  with  a  branch 
(pyloric)  (o)  from  the  hepatic  artery.  Its  offsets  to  the  ccsophagus  and 
the  stomach  are  thus  distributed  : — 

(Esophageal  branches  ascend  on  the  gullet  through  the  opening  in  the 
diaphragm,  supplying  that  tube;  and  they  anastomose  on  it  with  branches 
of  the  thoracic  aorta. 

Gastric  branches  are  given  to  both  sides  of  the  stomach,  and  those. on 
the  left  end  communicate  with  twigs  (vasa  brevia)  of  the  splenic  artery. 

b.  The  splenic  artery  {e)  is  the  largest  branch  of  the  coiliac  axis  in  the 
adult.  It  is  a  tortuous  vessel,  and  runs  almost  horizontally  to  the  spleen, 
along  the  upper  border  of  the  pancreas.  Near  the  spleen  it  divides  into 
terminal  branches,  about  seven  in  number  (from  four  to  ten),  which  enter 
that  viscus  by  the  surface  towards  the  stomach.  It  is  accompanied  by  the 
splenic  vein,  which  is  below  it;  and  it  distributes  branches  to  the  pan- 
creas and  the  stomach. 

Pancreatic  branches.  Numerous  small  branches  are  supplied  to  the 
gland;  and  one  of  these,  art.  pancreatica  magna^  arises  near  the  left  end, 
and  runs  to  the  right  in  the  substance  of  the  viscus  with  the  duct. 

Branches  for  the  stomach  arise  from  the  divisions  of  the  artery  near  the 
spleen.  Some  of  these,  i-asa  brevia^  turn  upwards  to  the  left  end  of  the 
stomach,  beneath  the  gastro-splenic  omentum,  and  ramify  in  the  coats  of 
tiiat  organ. 

Another  longer  branch,  art.  gastro'epiplo'ica  sinistra  (/)  turns  to  the 
righ.t  between  the  layers  of  the  great  omentum  along  the  great  curvature 
of  the  stomach,  and  inosculates  with  the  riglit  gastro-epiploic  branch  of  the 
hepatic  artery.  This  artery  distributes  twigs  to  both  surfaces  of  the 
stomach,  and  between  the  pieces  of  peritoneum  forming  the  great 
omentum. 

c.  The  hepatic  artery  (g)  is  intermediate  in  size  between  the  other 
two,  and  is  encircled  by  the  largest  plexus  of  nerves.  In  its  course  to  the 
liver  the  vessel  is  bent  first  to  the  right  towards  the  small  end  of  the 
stomach,  where  it  supplies  its  principal  branches  (superior  pyloric  and 
gastro-epiploic).  It  ascends  then  between  the  layers  of  the  little  omen- 
tum, on  th(;  left  side  of  the  bile  duct  and  vena  portne,  and  divides  near  the 
transverse  fissure  of  the  liver  into  two — the  right  and  left  hepatic. 
Branches  are  distributed  not  only  to  the  liver,  but  freely  .to  the  stomach, 
the  duodenum,  and  the  pancreas,  as  below: — 

The  superior  pyloric  branch  (o)  descends  to  the  upper  border  of  the 
stomach,  and  running  from  right  to  left  anastomoses  with  the  coronary 
artery;  it  distributes  small  arterial  twigs  on  both  surfaces  of  the  stomach. 

The  right  gastro-epiploic  branch  {hy  (art.  gast.  epiploica  dextra)  de- 

'  This  artery  is  named  commonly  fjastro-duodenal  as  far  as  to  the  spot  where  it 
gives  off  the  branch  to  the  duodenum  and  pancreas. 


448 


DISSECTION    OF    THE    ABDOMEN. 


sceiids  beneath  the  duodenum  near  the  pylorus,  and  turning  to  the  left 
along  the  great  curvature  of  the  stomach,  inosculates  witii  the  left 
gastro-epiploic  of  the  splenic  artery.  To  the  surfaces  of  the  stomach  some 
offsets  are  given;  and  others  descend  between  the  layers  of  the  omentum. 
It  furnishes  the  following  named  branches  to  the  stomach,  and  the  pan- 
creas and  duodenum : — 

Small  inferior  pyloric   branches  end  in   the   small  extremity  of  the 
stomach. 


Fig.  145. 


View  OF  the  C(emac  Axis,  axd  of  the  Viscera  to  which 
ITS  Branches  are  Supplied  (Tiedmann). 


A.  Liver. 

B.  Gall-bladder, 
c.  Stomach. 

D.  Duodenum, 

E.  Pancreas. 

F.  Spleen. 

Vessels  : 
a.  Aorta. 
h.  Upper  mesenteric. 

c.  Cooliac  axis. 

d.  Coronary. 

e.  Splenic. 

/.  Left  pastro-epiploic. 

g.  Hepatic. 

h.  Right  gastro-epiploic. 

t'.  Superior,  and  fr,  inferior  pan- 

creatico-duodenal. 
I.  Diaphragmatic  arteries. 
n.  Cystic, 
o.  Superior  pyloric. 


The  pancreatico-duodenal  branch  (?')  (superior)  arises  opposite  the  duo- 
denum, and  runs  between  the  intestine  and  the  pancreas  ;  it  anastomoses 
below  with  the  pancreatico-duodendal  branch  (inferior)  of  tlie  superior 
mesenteric  (fig.  146,  h).  Both  the  duodenum  and  the  pancreas  receive 
offsets  from  this  vessel.  On  the  posterior  aspect  of  the  same  viscera  is 
anotiier  small  offset  of  the  pancreatico-duodenal  with  a  similar  position 
and  distribution. 

The  hepatic  branches  (right  and  left)  sink  into  the  liver  at  the  trans- 
verse fissure,  and  ramify  in  its  substance  : — 

The  right  branch  is  divided  when  about  to  enter  the  transverse  fissure, 
and  supplies  the  following  small  artery  to  the  gall  bladder.  The  cystic 
artery  {n)  bifurcates  on  reaching  the  neck  of  the  gall  bladder,  and  its  two 
twigs  ramify  on  the  opposite  surfaces. 

The  left  branch  is  smaller  than  the  other,  and  enters  the  liver  at  the 
left  end  of  the  transverse  fissure  :  a  branch  to  the  Spigelian  lobe  of  the 
liver  arises  from  this  piece  of  the  artery. 

Portal  Veins.  The  veins  of  the  intestinal  tube,  and  of  the  spleen  and 
pancreas,  pour  their  blood  into  the  vena  portal.  The  two  mesenteric  veins 
and  their  branches  have  been  referred  to  (p.  441);  and  the  two  following, 
with  the  trunk  of  the  portal  vein,  remain  to  be  noticed. 

The  superior  coronary  vein  (fig.  146,/)  lies  along  the  upper  border  of 
the  stomach.  It  begins  in  the  (Esophagus  and  the  left  part  of  the  stomach, 
and  joins  the  vena  portae  at  the  pylorus. 

The  splenic  vein  (fig.  146)  is  large  in  size,  and  is  formed  by  the  union 
of  branches  from  the  spleen.     It  takes  much  the  same  course  as,  but  below 


VENA    PORT^    AND    BRANCHES, 


449 


the  artery,  and  runs  beneath  the  pancreas  to  the  front  of  the  vena  cava, 
where  it  joins  the  superior  mesenteric  vein  (b)  to  form  the  vena  portse. 

Between  its  origin  and  termination  it  receives  branches  corresponding 
with  the  following  arteries  : — vasa  brevia  (g),  left  gastro-epiploic  (e),  and 
pancreatic.  The  inferior  mesenteric  vein  (c?)  opens  into  it  about  its 
middle. 

The  vena  portce  (fig.  146,  a)  is  formed  by  the  union  of  the  splenic  and 
superior  mesenteric  veins.  Its  origin  is  placed  in  front  of  the  vena  cava, 
but  beneath  the  pancreas,  and  two  inches  from  the  right  end.  The  vessel 
is  about  four  inches  long,  and  is  directed  upwards  in  the  small  omentum, 
behind  the  bile  duct  and  the  hepatic  artery,  to  the  transverse  fissure  of  the 
liver,  where  it  divides  into  a  right  and  a  left  branch. 


Fig.  146. 


a.  Trunk  of  the  vena  portae. 

b.  Upper  mesenteric. 

c.  Right  gastro-epiploic. 

d.  Inferior  mesenteric. 

e.  Left  gastro-epiploic. 

/.  Coronary  of  the  stomach. 
g.  Vasa  brevia. 


Veka  Port^  and  the  Veins  Joininq  it  (Ilenle:    Anataraie  des  Menschen). 

In  its  course  it  is  joined  by  the  coronary  vein  (/),  and  by  the  cystic 
vein  near  the  liver. 

The  right  branch  enters  the  transverse  fissure  to  ramify  in   the  right 
lobe  of  the  liver. 

The  left  branch  is  distributed  to  the  left  part  of  the  liver,  and  gives  a 
small  branch  to  the  Spigelian  lobe. 
29 


450  DISSECTION    OF    THE    ABDOMEN. 

This  vein  commences  by  roots  in  the  viscera  above  mentioned,  like  any 
other  vein,  but  it  is  deficient  in  valves ;  and  it  ramifies  through  the  struc- 
ture of  the  liver  in  the  same  manner  as  an  artery.  Its  radicles  communi- 
cate with  the  systemic  veins  on  some  parts  of  the  intestinal  tube,  but  more 
particularly  on  the  rectum. 

Bile  Ducts.  Two  hepatic  ducts  issue  at  the  transverse  fissure  of  the 
liver  (fig.  158),  one  from  each  lobe,  and  unite  to  form  the  following : — 

The  common  hepatic  duct  is  an  inch  and  a  half  long,  and  receives  at 
its  termination  the  duct  of  the  gall  bladder,  the  union  of  the  two  giving 
origin  to  the  common  bile  duct. 

The  common  bile  duct  (ductus  communis  choledochus)  is  about  three 
inches  long.  It  descends  almost  vertically  beneath  the  upper  transverse 
portion  of  the  duodenum  ;  then  passing  between  the  pancreas  and  the 
vertical  piece  of  the  duodenum,  it  opens  into  this  portion  of  the  intestine 
at  the  inner  side,  and  above  the  middle.  Whilst  in  the  small  omentum 
the  duct  lies  to  the  right  of  the  hepatic  artery,  and  somewhat  before  the 
portal  vein. 

Before  piercing  the  coats  of  the  intestine  it  is  joined  commonly  by  the 
pancreatic  duct,  but  the  two  may  enter  the  duodenum  separately. 

SYMPATHETIC  AND  VAGUS  NERVES. 

Sympathetic  Nerve.  In  the  abdomen,  as  in  the  thorax,  the  sympa- 
thetic nerve  consists  of  a  gangliated  cord  on  each  side  of  the  vertebral 
column,  and  of  prevertebral  centres  or  plexuses,  which  furnish  branches 
to  the  viscera. 

Two  prevertebral  plexuses  exist  in  the  abdomen.  One  of  these,  the 
epigastric,  is  placed  behind  the  stomach,  and  supplies  nerves  to  all  the 
viscera  above  the  cavity  of  the  pelvis.  The  other,  the  hypogastric  plexus, 
is  situate  in  the  pelvis,  and  distributes  nerves  to  the  pelvic  viscera. 

The  knotted  or  gan?liated  cord  will  be  met  with  in  a  subsequent  stage 
of  the  dissection  ;  and  only  the  great  solar  plexus  with  its  offsets  is  to  be 
now  examined. 

Dissection.  To  denude  the  epigastric  plexus,  the  following  dissection 
is  to  be  made  :  After  the  air  has  been  let  out  of  the  stomach  and  duode- 
num, the  portal  vein,  the  common  bile  duct,  and  the  gastro-epiploic  vesr 
sels  are  to  be  cut  through  near  the  pylorus;  and  the  stomach,  duodenum, 
and  pancreas  are  to  be  drawn  over  to  the  left  side.  On  raising  the  liver 
the  vena  cava  appears ;  the  vein  is  to  be  cut  across  above  the  junction  of 
the  renal  vein  with  it,  and  the  lower  end  is  to  be  drawn  down  with  hooks. 

Beneath  the  vein  tlie  dissector  will  find  the  large  reddish  semi-lunar 
ganglion  ;  and  mixed  up  with  the  nerves  of  the  plexus  are  numerous 
lymphatic  glands,  and  a  dense  tissue,  which  require  to  be  removed  with 
care.  From  its  inner  part  he  can  trace  the  numerous  nerves  and  ganglia 
around  the  cojliac  and  superior  mesenteric  arteries,  and  the  secondary 
plexuses  on  the  branches  of  those  arteries.  From  the  outer  part  of  the 
ganglion  offsets  are  to  be  followed  to  the  kidney,  the  suprarenal  body,  and 
the  diaphragmatic  arteries :  at  its  upper  part  the  junction  with  the  large 
splanchnic  nerve  may  be  seen  ;  and  deeper  than  the  last,  one  or  two  smaller 
splanchnic  nerves  may  be  observed  in  a  fissure  of  the  diaphragm,  which 
throw  themselves  into  the  coeliac  and  renal  plexuses. 

The  student  should  then  trace  the  ending  of  the  pneumogastric  nerves 
on  the  stomach.    The  left  nerve  will  be  found  at  the  upper  border  in  front 


EPIGASTRIC    OR    SOLAR    PLEXUS.  451 

near  the  oesophagus ;  and  the  right  nerve  will  be  seen  at  a  corresponding 
point  on  the  opposite  aspect.  Branches  from  the  right  nerve  are  to  be 
followed  to  the  plexus  of  the  sympathetic  by  the  side  of  the  cfcliac  axis, 
and  from  the  left,  to  the  hepatic  plexus. 

The  EPIGASTRIC  or  solar  plexus  is  a  large  network  of  nerves  and 
ganglia,  which  lies  in  front  of  the  aorta  and  the  pillars  of  the  diaj)hragm : 
it  fills  the  space  between  the  suprarenal  capsules  of  opposite  sides,  and 
extends  downwards  to  the  pancreas,  surrounding  the  cceliac  axis  and  the 
superior  mesenteric  artery.  The  plexus  is  connected  on  each  side  with 
the  large  and  small  splanchnic  nerves  ;  and  it  is  joined  also  by  an  offset 
of  the  right  pneumo-gastric  nerve.  Large  branches  are  furnished  to  the 
different  viscera  along  the  vessels. 

The  semilunar  ganglia^  one  on  each  side,  are  the  largest  in  the  body, 
and  each  is  joined  at  the  upper  end  by  the  great  splanchnic  nerve.  Each 
is  situate  at  the  outer  part  of  the  plexus,  close  to  the  suprarenal  body,  and 
on  the  pillar  of  the  diaphragm  :  the  ganglion  on  the  right  side  is  beneath 
the  vena  cava.  Irregular  in  shape,  the  mass  is  oval,  or  divided  into 
smaller  ganglia :  from  its  outer  side  nerves  are  directed  to  the  kidney  and 
the  suprarenal  capsule. 

Offsets  of  the  plexus.  The  nerves  supplied  to  the  viscera  form  plexuses 
around  the  vessels ;  thus  there  are  coeliac,  mesenteric,  renal,  spermatic, 
diaphragmatic,  &c. 

JDiaphragmatic  plexus.  This  plexus  comes  from  the  upper  part  of  the 
semilunar  ganglion,  but  it  soon  leaves  the  artery  to  enter  the  substance  of 
the  diaphragm  :  a  communication  takes  place  between  the  phrenic  nerve 
of  the  cervical  plexus  (p.  80)  and  these  branches  of  the  sympathetic.  On 
the  right  side  is  a  small  ganglion  where  the  plexus  is  joined  by  the  spinal 
nerve ;  and  from  it  filaments  are  supplied  to  the  vena  cava  and  the  supra- 
renal body.     The  ganglion  is  absent  on  the  left  side.     (Swan.) 

The  suprarenal  ?ierves  are  very  large  and  numerous,  in  comparison  with 
the  size  of  the  part  supplied,  and  are  directed  outwards  to  the  suprarenal 
body.     One  of  the  splanchnic  nerves  communicates  with  this  plexus. 

The  renal  plexus  is  derived  from  the  semilunar  ganglion  and  outer  part 
of  the  plexus,  and  is  joined  by  the  smallest  splanchnic  nerve.  The  nerves 
surround  the  renal  artery,  having  small  ganglia  on  them,  and  enter  the 
kidney  with  the  vessels.  An  offset  is  given  from  the  renal  to  the  sper- 
matic plexus  (p.  443). 

The  cceliac  plexus  is  a  direct  continuation  of  the  plexus  around  its  artery: 
it  is  joined  by  the  small  splanchnic  nerve  on  each  side,  and  by  an  offset 
from»  the  right  pneumo-gastric  nerve.  The  plexus  divides  like  the  artery 
into  three  parts — coronary,  splenic,  and  hepatic. 

a.  The  coronary  plexus  accompanies  the  vessel  of  the  same  name  to  the 
upper  border  of  the  stomach,  where  it  ends :  it  communicates  with  the  left 
vagus  nerve. 

b.  The  splenic  plexus  furnishes  offsets  to  the  pancreas,  and  to  the 
stomach  along  the  left  gastro-epiploic  artery  :  and  it  is  joined  by  an  offset 
from  the  right  pneumo-gastric  nerve. 

c.  The  hepatic  plexus  is  continued  on  the  vena  portoe,  the  hepatic  artery, 
and  the  bile  duct  into  the  liver,  and  ramifies  on  those  vessels :  in  the  small 
omentum,  the  plexus  is  joined  by  offsets  from  the  left  vagus.  The  follow- 
ing secondary  plexuses  are  furnished  around  the  branches  of  tlie  hepatic 
artery,  and  have  the  same  name  and  distribution  as  the  vessels : — 

A  pyloric  plexus  is  distributed  along  the  upper  border  of  the  stomach. 


452  DISSECTION    OF    THE    ABDOMEN. 

Two  other  plexuses — gastro-epiplo'ic  (right)  and  pancreatico-duodenal, 
correspond  in  distribution  with  the  branches  of  each  artery. 

A  cystic  plexus  ramifies  in  the  coats  of  the  gall  bladder  with  its  artery. 

The  remaining  oflfsets  of  the  plexus,  viz.,  superior  and  inferior  mesen- 
teric, aortic,  and  spermatic,  have  been  already  noticed  (p.  443)  ;  but  the 
derivation  of  the  superior  mesenteric  and  aortic  plexuses  from  tlie  epigas- 
tric centre  can  be  now  seen. 

Ending  of  the  splanchnic  nerves.  The  large  nerve  perforates  the  crus 
of  the  diaphragm,  and  generally  ends  altogether  in  the  semilunar  gan- 
glion. 

The  small  nerve  comes  through  the  same  opening  in  the  diaphragm  as 
the  preceding,  and  joins  the  coeliac  plexus. 

The  smallest  nerve,  which  is  often  absent,  throws  itself  into  the  renal 
plexus. 

Ending  of  the  vagus  nerve.  The  pneu mo-gastric  nerves  end  in  the 
stomach  : — 

The  left  nerve  divides  into  branches,  which  extend  along  the  small  cur- 
vature, and  over  the  front  of  the  stomach  ;  these  send  offsets  to  the  hepatic 
plexus. 

The  right  nerve  is  distributed  to  the  posterior  surface  of  the  stomach 
near  the  upper  border ;  it  communicates  with  its  fellow,  and  with  tiie 
coeliac  and  splenic  plexuses. 

Dissection.  The  viscera  are  now  to  be  removed  from  the  abdomen,  in 
order  that  the  body  may  be  turned  ibr  the  dissection  of  the  Back  and 
lower  limbs. 

The  stomach  and  the  spleen,  with  the  duodenum  and  the  pancreas,  are 
to  be  taken  away  together  by  cutting  through  the  oeosphagus  near  the  dia- 
pliragm,  as  well  as  the  vessels  and  nerves  they  receive.  The  liver  is  to 
be  removed  from  the  abdomen  by  dividing  its  ligaments,  and  incising  the 
vena  cava  between  the  posterior  border  and  the  diaphragm. 

At  the  same  time  the  left  testicle,  and  the  right  kidney  with  the  supra- 
renal body,  should  be  removed  for  examination  whilst  the  body  is  turned ; 
the  former  can  be  taken  out  by  cutting  through  the  spermatic  cord,  and 
tlie  latter  by  dividing  the  vessels  about  the  middle. 

Directions.  Supposing  the  body  to  be  now  turned  for  the  dissection 
of  the  Back,  and  to  lie  with  the  face  downwards  for  the  usual  time,  the 
dissector  may  look  first  to  the  fascia  lumborum,  which  is  described  in  the 
Dissection  of  the  Back,  p.  357. 

The  rest  of  the  time  should  be  occupied  in  learning  the  viscera  included 
in  the  followins  Section. 


Section  IV. 

ANATOMY  OF  THE  VISCERA  OF  THE  ABDOMEN. 
THE    STOMACH. 

The  stomach  is  the  dilated  part  of  the  alimentary  tube  between  the 
oesophagus  and  the  small  intestine,  into  which  the  masticated  food  is   re- 
ceived to  be  changed  into  chyme. 
'Dissection.     To  see  the  form,  the  stomach  must  be   blown  up  moder- 


STRUCTURE  OF  STOMACH.  453 

ately,  and  the  surface  cleaned  ;  but,  previously,  let  the  student  detach  the 
spleen,  and  cut  through  the  duodenum  close  to  the  pylorus. 

Forms  and  Divisions.  The  stomach  is  somewhat  conical  in  form  (fig. 
147).  Its  size  varies  much  in  different  bodies,  and  is  sometimes  much 
diminished  by  a  constriction  in  the  centre;  when  it  is  moderately  dis- 
tended, it  is  about  twelve  inches  long  and  four  wide.  There  are  two  ends, 
two  orifices,  two  surfaces,  and  two  borders  or  curves  to  be  examined. 

Extremities.  The  left  end  or  tuberosity  (fundus  ventriculi)  is  the 
largest  part  of  the  stomach,  and  projects  about  three  inches  to  the  left  of 
the  opening  of  thb  oesophagus.  The  right  or  pyloric  end,  much  smaller 
than  the  other,  is  cylindrical,  and  forms  the  apex  of  the  cone  to  which  the 
stomach  is  likened. 

Openings.  The  left  opening  (cardiac),  which  communicates  with  the 
oesophagus,  is  at  the  highest  part  of  the  stomach,  and  is  funnel-shaped 
towards  the  cavity  of  the  organ.  The  right  or  pyloric  orifice  opens  into 
the  duodenum,  and  is  guarded  internally  by  a  muscular  band  (pylorus)  : 
at  the  same  spot  the  stomach  is  slightly  constricted  externally,  where  a 
firm  circular  ring  may  be  felt. 

Surfaces.  The  surfaces  (anterior  and  posterior)  are  somewhat  flattened 
when  the  viscus  is  empty,  but  rounded  when  it  is  distended :  the  parts  in 
contact  with  them  have  been  referred  to  (p.  431). 

Borders.  The  upper  border  or  small  curve  is  concave  towards  the  left 
opening,  but  convex  at  the  opposite  end ;  and  the  lower  border  or  large 
curve  is  convex,  except  near  the  right  end,  where  it  is  concave — the  con- 
cavity of  the  one  border  corresponding  with  the  convexity  of  the  other. 
An  arterial  arch,  and  a  fold  of  peritoneum  (omentum)  are  fixed  to  each 
border. 

Structure.  In  the  wall  of  the  stomach  are  four  coats,  viz.,  serous, 
muscular,  fibrous,  and  mucous ;  and  belonging  to  these  there  are  vessels, 
nerves,  and  lymphatics. 

Serous  coat.  The  peritoneum  gives  a  covering  to  the  stomach,  and  is 
adherent  to  the  surface,  except  at  each  margin,  where  an  interval  exists 
corresponding  w^ith  the  attaclmient  of  the  small  and  large  omentum  :  in 
those  spaces  are  contained  the  vessels,  nerves,  and  lymphatics.  During 
distension  of  the  stomach  the  spaces  above  mentioned  are  much  di- 
minished. 

The  muscular  coat  will  be  laid  bare  by  the  removal  of  the  serous  cover- 
ing. It  consists  of  three  sets  of  fibres — longitudinal,  circular,  and  oblique  ; 
these  lie  from  without  inwards  in  the  order  mentioned,  and  are  unstriated 
or  involuntary. 

The  longitudinal  fibres  (fig.  147,  a)  are  derived  from  the  oesophagus; 
they  spread  over  the  surfaces,  and  are  continued  to  the  pylorus  and  the 
small  intestine.  The  fibres  are  most  marked  along  the  borders,  particu- 
larly at  the  smaller  one;  and  at  the  pylorus  they  are  stronger  than  in  the 
centre  of  the  stomach. 

•  The  circular  fibres  (fig.  147,  b)  form  the  middle  stratum,  and  will  be 
best  seen  by  removing  the  longitudinal  fibres  near  the  pylorus.  They 
reach  from  the  left  to  the  riglit  end  of  the  stomach  ;  but  at  the  pylorus 
they  are  most  numerous  and  strongest,  and  form  a  ring  or  sphincter  {c) 
around  the  opening. 

The  oblique  fibres  (fig.  147,  e)  are  continuous  with  the  circular  or  deep 
layer  of  the  oesophagus.  On  the  left  and  right  of  the  cardie  orifice  they 
are  so  arranged  as  to  form  a  kind  of  sphincter  {d  and  e)  (Henle);  but 


454  DISSECTION    OF    THE    ABDOMEN. 

those  on  the  left  (e),  the  strongest,  arch  over  the  great  end  of  tlie  stomach, 
and  spread  out  on  the  anterior  and  posterior  surfaces,  gradually  disappear- 
ing on  them. 

Fibrous  coat.  By  removing  the  muscular  layer  over  a  small  space,  the 
fibrous  coat  will  appear  as  a  white  shining  stratum  of  areolar  tissue.  This 
coat  gives  strength  to  the  stomach,  and  serves  as  a  bed  in  which  the  larger 
vessels  and  nerves  ramify  before  their  distribution  to  the  mucous  layer. 
If  a  small  opening  is  made  in  this  membrane,  the  mucous  coat  will  project 
through  the  stomach  to  be  distended  with  air. 

Fig.  147. 


Diagram  Repbesenting  the  Arrangement  of  the  Muscular  Fibres  of  the  Stomach. 

Part  of  each  of  the  two  external  coats  is  removed. 

o.  External  or  longitudinal  fibres.  c.  Oblique  fibres,  more  numerous,  on  the  right  of 

h.  Middle  or  circular.  the  cardiac  orifice,  and  covering  the  great 

c.  Sphincter  of  the  pylorus.  end  of  the  stomach. 

d.  Oblique  fibres  on  the  left  of  the  cardiac 

opening. 

The  mucous  coat  will  come  into  view  on  cutting  open  the  stomach,  but 
the  appearances  now  described  can  be  recognized  only  in  a  recent  stomach. 

This  coat  is  a  thickish  layer,  of  a  pale  rose  color  soon  after  death  in  the 
healthy  condition.  In  the  empty  state  of  the  stomach  the  membrane  is 
less  vascular  than  during  digestion  ;  and  in  infancy  the  natural  redness  is 
greater  than  in  childhood  or  old  age.  When  the  stomach  is  contracted  the 
membrane  is  thrown  into  numerous  wavy  ridges  or  rugcB,  which  become 
longitudinal  along  the  great  curve,  towards  the  pylorus. 

The  thickness  of  the  mucous  membrane  is  greatest  near  the  pylorus  ; 
and  at  that  spot  it  forms  a  fold,  oj)])Osite  the  muscular  ring,  which  assists 
in  closing  the  o})ening.  If  this  membrane  and  its  submucous  layer  are 
removed  from  the  pyloric  part  of  the  stomach,  the  ring  of  muscular  fibres 
(sphincter  of  the  pylorus)  will  be  more  perfectly  seen. 

Microscopic -structure  of  the  mucous  membrane.  With  the  aid  of  a  lens, 
the  surface  of  the  mucous  membrane,  when  well  washed,  may  be  seen  to 
be  covered  by  shallow  depressions  or  alveoli  (fig.  148),  which  measure 
from  ^^(jtli  to  1  igth  of  an  inch  across.  Generally  hexagonal  or  polyjro- 
nal  in  outline,  the  hollows  become  larger  and  more  elongated  towards  the 
small  end  of  the  stomach  ;  and  near  tlie  pylorus  the  margins  of  the  alveoli 
project,  and  become  irregular.  In  the  bottom  of  each  depression  are  the 
apertures  of  minute  tubes. 


STRUCTURE    OF    STOMACH 


455 


By  means  of  a  thin  section  under  the  microscope  the  membrane  may 
be  observed  to  be  composed  almost  altogether  of  minute  vertical  tubes, 
which  lie  side  by  side,  and  project  into  the  submucous  tissue.  Measuring 
from  ^^<yth  to  ^^h  of  an  inch  in  length,  the  tubes  are  closed  at  the  deep 
end  ;  but  they  open  on  the  surface  of  the  stomach  both  in  the  alveoli  (fig. 
148)  and  in  the  interalveolar  spaces.  They  are  formed  of  a  homogeneous 
membrane,  and  are  for  the  most  part  straight,  but  towards  the  pylorus 
they  increase  in  length,  and  are  somewhat  sacculated  at  the  deep  extrem- 
ity; some  are  divided  into  two  or  more  pieces  (fig.  149). 


Fig.  148. 


At.veolar  Depressions  of  the 
Mccotjs  Mkmbrane  of  the  Sto- 
mach, magnified  32  diameters, 
with  the  minute  tubes  opening 
into  them      (Sprott  Boyd.) 


Enlarged  Eepresentation  of  the  Tubes  of  the 
Stomach. 

.  Gastric  tube  from  the  pyloric  end  lined,  throughout, 
by  columnar  epithelium  (Kolliker). 

.  Gastric  tube  from  the  cardiac  end,  with  a  columnar 
epithelium  lining  near  the  mouth,  and  flattened  nu- 
cleated granular  cells  beyond  (Thomson). 


At  the  cardiac  end  of  the  stomach  the  tubes  are  lined  at  the  free  end 
by  columnar  epithelium  (fig.  149,  b);  but  in  the  closed  end  by  flattened 
and  granular  nucleated  cells,  which  are  named  peptic  glands,  and  are  sup- 
posed to  give  origin  to  the  gastric  fluid.  Towards  the  pylorus  the  tubes 
are  closed  throughout  by  columnar  epithelium  (fig.  149,  a)  and  secrete 
mucus. 

A  columnar  epithelium  covers  the  surface  of  the  mucous  membrane,  and 
enters  the  small  tubules. 

On  the  attached  surface  of  the  mucous  membrane  is  a  thin  layer  of  in- 
voluntary muscular  fibres,  separating  it  from  the  fibrous  coat :  it  is  said  to 
send  offsets  amongst  the  tubules. 

Bloodvessels.  The  arteries  of  the  stomach,  after  supplying  the  mus- 
cular coat,  ramify  in  the  submucous  tissue;  from  this  anastomosis  fine 
offsets  are  continued  on  the  tubes  to  the  inner  surface  of  the  mucous  mem- 
brane, where  they  form  a  network.  The  vet?is  begin  in  the  mucous  mem- 
brane, receive  branches  from  the  muscular  coat,  and  deliver  their  blood 
into  the  portal  system. 

Lymphatics.  Two  layers  of  absorbents,  superficial  and  deep,  exist  in 
the  stomach  :  the  latter  begin  in  a  plexus  beneath  the  tubules,  and  form  a 


456  DISSECTION    OF    THE    ABDOMEN. 

network   in   the  fibrous  layer.     Both   sets  leave   the  stomach    with    the 
bloodvessels. 

Nerves.  The  nerves  are  derived  from  the  pneumo-gastric  and  sympa- 
thetic (p.  451),  and  can  be  followed  to  the  fibrous  coat;  small  ganglia 
have  been  observed  on  them. 


SMALL    INTESTINE. 

The  three  parts  into  which  the  small  intestine  is  divided,  have  the  fol- 
lowing characters: — 

The  duodenum  measures  as  much  as  the  breadth  of  twelve  fingers,  viz., 
about  ten  inches,  and  is  more  fixed  than  the  rest  of  the  intestinal  tube. 
It  is  wider  than  either  the  jejunum  or  the  ileum,  and  its  muscular  coat  is 
also  thicker.  Into  it  the  common  bile  and  pancreatic  ducts  pour  their 
contents. 

The  jejunum  and  the  ileum  together  measure  about  twenty  feet  in 
length,  and  are  connected  with  the  mesentery.  There  is  not  any  percep- 
tible difference  between  the  termination  of  the  one  and  the  commencement 
of  the  other,  but  two-fifths  of  the  length  are  assigned  to  the  jejunum, 
and  three-fifths  to  the  ileum.  Between  the  ends,  however,  a  marked  dif- 
ference may  be  perceived ;  for  the  upper  part  of  the  jejunum  is  thicker 
and  more  vascular  than  the  lower  part  of  the  ileum,  and  its  width  is  also 
greater. 

Structure.  In  the  small  intestine  the  wall  is  formed  by  the  same 
number  of  layers  as  in  the  stomach,  viz.,  serous,  muscular,  fibrous,  mucous, 
and  submucous. 

Dissection.  The  different  layers  are  to  be  examined  on  pieces,  about 
three  inches  long,  taken  from  the  duodenum,  the  upper  part  of  the  jejunum, 
and  the  lower  end  of  the  ileum.  After  the  pieces  have  been  cut  off,  they 
are  to  be  distended  with  air ;  and  the  serous  covering  is  to  be  torn  off  for 
a  short  distance,  to  show  the  muscular  coat,  but  in  doing  this,  the  external 
longitudinal  fibres  will  be  taken  away  without  great  care. 

The  serous  coat  is  closely  connected  with  the  subjacent  muscular  layer. 
To  the  jejunum  and  ileum  it  furnishes  a  covering,  except  at  the  attached 
part  where  the  vessels  enter :  at  tliis  spot  the  peritoneum  is  reflected  off  to 
form  the  mesentery,  and  a  space  exists  resembling  that  at  the  borders  of 
the  stomach.  The  peritoneum  surrounds  the  duoJenum  only  partly;  this 
j>eculiarity  has  been  described  at  p.  438. 

The  muscular  coat  is  constructed  of  two  sets  of  fibres,  a  superficial  or 
longitudinal,  and  a  deep  or  circular.  The  fibres  are  pale  in  color,  and  are 
not  striated. 

The  longitudinal  fibres  form  a  thin  covering,  which  is  most  marked  at 
the  free  border  of  the  gut. 

The  circular  fibres  are  much  more  distinct  than  the  others,  and  give 
the  chief  strength  to  the  muscular  coat :  they  do  not  form  complete  rings 
around  the  intestine. 

Dissection.  On  the  removal  of  a  part  of  the  muscular  stratum  from 
the  jejunum  or  the  ileum,  the  submucous  fibrous  layer  will  come  into  view. 

The  fibrous  coat  has  the  same  position  and  use  as  the  corresponding 
layer  in  the  stomach. 

Dissection.  In  tlie  upper  part  of  the  duodenum  the  student  is  to  seek 
some  small  compound  glands — those  of  Brunner,  which  are  imbedded  in 
the  submucous  tissue.     They  lie  beneath  the  mucous  membrane,  and  will 


COATS    OF    SMALL    INTESTINE, 


457 


be  seen  shining  through  the  fibrous  hiyer,  wlien  the  muscular  coat  has 
been  taken  away. 

The  pieces  of  intestine  may  be  opened  and  washed  to  sliow  the  mucous 
coat,  but  the  gut  should  be  cut  along  the  line  of  attachment  of  the  mesen- 
tery, so  as  to  avoid  Peyer's  glands  on  the  opposite  side. 

Mucous  coat.  The  lining  membrane  is  thicker  and  more  vascular  at 
the  beginning  than  at  the  ending  of  the  small  intestine.  It  is  marked  by 
numerous  prominent  folds  (valvulsB  conniventes) ;  and  the  surface  of  the 
membrane  is  covered  with  small  processes  (villi)  like  the  pile  of  velvet. 
Occupying  the  substance  of  the  mucous  coat  are  numerous  glands ;  and 
covering  the  whole  is  a  columnar  epithelium. 

A  thin  layer  of  non-striated  muscular  fibres  (muscularis  mucoscB)  covers 
the  outer  surface  of  this  coat  (fig.  154,  c?),  and  sends  inwards  prolonga- 
tions between  the  tubules  into  the  villi. 

The  valvnlce  conniventes  (fig.  150)  (valves  of  Kerkring)  are  permanent 
ridges  of  the  mucous  membrane,  which  are  arranged  circularly  in  the 
intestine,  and  project  into  the  alimentary  mass.  Crescentic  in  form, 
they  extend  round  the  intestine  for  half  or  two-thirds  of  its  circle,  and 

Fig.  150. 


Tre  Duodenum  opened  showing  the  Vax,vul;e  Conniventes,  and  the  opknino  of  the  Bile 
Duct.    The  duct  of  the  paucreas  is  also  represeated  ia  greater  part  of  its  course. 
a.  Duodenum.  d.  Pancreatic  duct. 

6.  Pancreas.  e.  Opening  of  the  common  duct  in  the  intestine 

c.  Common  bile  duct.  (Henle). 


some  end  in  bifurcated  extremities.  Larger  and  smaller  folds  are  met 
with,  sometimes  alternating ;  and  the  larger  are  about  two  inches  long, 
with  one-third  of  an  inch  in  depth  towards  the  centre.  Each  is  formed 
of  a  doubling  of  the  mucous  membrane,  which  incloses  vessels  between 
the  layers. 

They  begin  in  the  duodenum,  about  one  or  two  inches  beyond  the  py- 
lorus, and  are  continued  in  regular  succession  to  the  middle  of  the  jeju- 
num;  but  beyond  that  point  they  become  smaller  and  more  distant  from 
one  another,  and  finally  disappear  about  the  middle  of  the  ileum,  having 
previously  become  irregular  and  rudimentary.  The  folds  are  largest  and 
most  uniform  beyond,  and  not  far  from  the  o{)ening  of  the  bile  duct. 

The  aperture  of  the  common  bile  and  pancreatic  ducts  (fig.  150,  e)  is  a 


458 


DISSECTION    OF    THE    ABDOMEN. 


narrow  orifice,  from  three  to  four  inches  from  tlie  pylorus,  and  is  situate 
in  a  small  prominence  of  the  mucous  membrane,  at  the  inner  and  posterior 
part  of  the  duodenum  (p.  445).  A  probe  passed  into  the  bile  duct  will 
show  the  oblique  course  (half  an  inch)  under  the  mucous  coat.  Some- 
times the  pancreatic  duct  opens  by  a  distinct  orifice. 

Microscopic  structure  of  the  mucous  membrane.  With  the  use  of  the 
microscope,  and  with  pieces  of  fresh  intestine,  the  student  will  be  able  to 
make  out  the  nature  of  the  villi,  the  glandular  bodies,  and  the  epithelium. 

Villi,  When  a  piece  of  the  lower  part  of  the  duodenum,  from  which 
the  mucus  is  M'ashed  away,  is  examined  in  water,  the  mucous  membrane 
will  be  seen  to  be  studded  over  thickly  with  small  projections,  like  those 
on  velvet.  These  bodies  exist  along  the  whole  of  the  small  intestine,  and 
are  irregular  in  form  (fig.  153,  ^)  some  being  triangular,  others  conical  or 
cylindrical  with  a  large  end.  Their  length  is  from  ^'^jth  to  ^^-th  of  an 
inch  ;  and  they  are  best  marked  where  the  valvular  conniventes  are  largest. 
In  the  duodenum  their  number  is  estimated  at  50  to  90  in  a  square  line, 
but  in  the  lower  end  of  the  ileum  at  only  40  to  70  on  the  same  surface 
(Krause). 

Each  villus  is  an  extension  of  the  mucous  coat,  and  is  covered  by  col- 
umnar epithelium.  One  or  sometimes  two  arterial  twigs  form  a  capillary 
network  beneath  the  mucous  covering  (fig.  144,  ^),  and  end  generally  in 
a  single  emerging  vein.  A  single  lacteal,  or  two  forming  a  loop  with 
cross  branches  (fig.  151,  ^),  occupies  the  centre,  and  communicates  with 


Fig.  151. 


A.  Vessels  of  the  Villi  in  the  Mouse,  In- 
jected BY  Gerlach  (KoUicker). 
a.  Artery,  aud  b,  vein. 


B.    LACTEALS  and  Pl-KXUS  OF  VESSELS    IN  TWO 

Villi,  Injected  by  Teichman. 

a.  Lacteal  vessel,  sinjjle  in  one  villus,  double 

in  the  other. 

b.  Plexus  of  vessels. 

c.  Plexusoflacteals  below  the  villi.    (Quain's 

Auatoiuy.) 


plexus  below  the  villus.  Around  the  lacteals  a  thin  layer  of  unstriated 
muscular  fibre  is  arranged  longitudinally  (Briicke).  Nerves  have  not 
been  detected  in  the  villus. 

Glands.     In  the  glandular  apparatus  of  the  small  intestine  are  included 


PATCHES    OF    PEYER. 


459 


the  crypts  of  Lieberkiihn,  solitary  glands,  and  Peyer's  and  Brunner's 
glands. 

The  crypts  of  Lieherkilhn  (fig.  154,  a)  are  minute  simple  tubes,  similar 
to  those  in  the  stomach,  though  not  so  closely  aggregated,  which  exist 
throughout  the  small  intestine.  They  open  on  the  surface  of  the  mucous 
membrane  by  small  orifices  between  the  villi,  and  around  the  larger 
glands ;  but  closed  at  the  opposite  end,  they  project  into  the  submucous 
layer,  and  are  seldom  branched.  Their  length  is  from  ^^^th  to  g^th  of  an 
inch :  they  are  filled  with  a  translucent  fluid  containing  granules,  and  are 
lined  by  a  columnar  epithelium. 

The  so-called  solitary  glands  (fig.  153,  ®)  are  roundish  white  eminences, 
about  the  size  of  mustard  seed  if  distended,  which  are  scattered  along  the 
small  intestine,  but  in  greatest  numbers  in  the  ileum.  Placed  on  all  parts 
of  the  intestine,  and  even  on  or  between  the  valvulas  conniventes;  they 
are  covered  by  the  villi  of  the  mucous  membrane,  and  are  surrounded  at 


Fie?.  152. 


A.  Patch  of  Peter's  Glands  four  times  en- 

LAROKD. 

a.  Surface  of  the  mucous  membrane  covered 

with  villi. 

b.  Pits  over  the  follicles  where  the  villi  are  ab- 

sent. 


MAaNiPiEi>  Representation  of  an  Injec- 
tion IN  the  Rabbit,  by  Fret,  op  the 
Vessels  SuRROUNDrsa  and  Penetratino 
TH  K  Follicles  in  a  Patch  of  Peter  (KoI- 
licker). 


the'r  circumference  by  apertures  of  the  crypts  of  Lieberkiihn.  They  are 
closed  lymph  follicles  beneath  the  mucous  coat,  which  project  into  the 
gut;  and  they  are  formed  of  a  network  of  reticular  connective  tissue  with 
lymph-corpuscles  between  the  meshes.  Fine  capillary  vessels  permeate 
the  mass;  and  it  is  surrounded  by  a  plexus  of  lymphatic  vessels. 

The  glands  of  Peyer  (fig.  153,  ^)  (glanduloe  agminatoe)  exist  chiefly  in 
the  ileum,  in  the  form  of  oval  patches,  which  measure  from  half  an  inch 
to  two  inches  or  more  in  length,  and  about  half  an  inch  in  width.  They 
are  situate  on  the  part  of  the  intestine  opposite  to  the  attachment  of  the 
mesentery,  and  their  direction  is  longitudinal  in  the  gut:  usually  they  are 
from  twenty  to  thirty  in  number.  In  the  lower  part  of  the  ileum  they  are 
largest  and  most  numerous;  but  they  decrease  in  number  and  size  up- 


460 


DISSECTION    OF    THE    ABDOMEN 


wards  from  that  spot,  till  at  the  lower  part  of  the  jejunum  they  become 
irregular  in  form,  and  may  consist  only  of  small  roundish  masses. 

The  mucous  membrane  over  them  is  hollowed  into  pits  (fig.  152,  J), 
and  is  generally  destitute  of  villi  on  the  subjacent  follicles  (fig.  153,  *), 
but  between  the  pits  it  has  the  same  characters  as  in  other  parts. 

Fig.  153. 


%■ 


&???« 


•c>; 


A.  A  PIECE  OP  MtTcors  Membrane  enlarcied,  with  its  villi  and  tubules.  Tart  of  a  patch  of 
Peyer's  glands  is  also  represented  with  the  follicles  (a),  each  having  a  ring  of  tubes  at  the  cir- 
cumference. B.  A  "  solitary  gland"  of  the  small  intestine,  also  enlarged,  covered  by  villi 
(Boebm). 


A  patch,  when  examined  by  the  microscope,  appears  to  be  but  a  collec- 
tion of  lymph  follicles  like  the  *' solitary  glands"  (fig.  153),  which  are 
round  or  oval  in  form,  and  are  covered  by  the  mucous  membrane.  Around 
each  follicle  is  a  ring  of  apertures  of  the  crypts  before  described.     The 

follicles  have  the  same  composition  as  the 
scattered  "solitary  glands." 

Fine  arterial  twigs  (fig.  152,  ^)  ramify 
on  the  follicles,  and  send  inwards  capillary 
offsets  which  form  a  network  in  the  inte- 
rior, and  converge  to  the  centre.  Lacteal 
vessels  form  plexuses  around  and  beneath 
the  follicle,  but  do  not  penetrate  the  wall. 

The  Glands  of  B runner  (fig.  154,  b)  are 
small  compound  bodies,  similar  to  the  buc- 
cal and  labial  glands  of  the  mouth,  which 
exist  in  the  duodenum.  For  a  few  inches 
near  the  pylorus  they  are  most  numerous, 
and  there  they  are  visible  without  a  lens, 
being  nearly  as  large  as  hemp  seed.  The 
glands  consist  of  lobules,  with  appertaining 
excretory  tubes :  and  each  ends  on  the  sur- 
face of  the  mucous  membrane  by  a  duct 
(c),  whose  aperture  is  slightly  larger  than 
the  mouths  of  the  contiguous  crypts  of 
Lieberkiihn;  they  secrete  mucus. 

Epithelium.  The  epithelial  lining  of  the 
mucous  membrane  of  the  small  intestine  is 
of  the  columnar  or  cylindrical  kind.  On 
the  villi  it  forms  a  distinct  covering  of 
elongated  pieces.     It  sinks  into  the  crypts 


Magnified  View  of  the  Mucous 
Membrane  of  thr  Duodenum,  with 
the  tubules  of  LieberkUhn  and  a 
gland  of  Brunner. 

(t.  Tubules. 

h.  Gland  of  Brunner. 

c.  Duct  of  the  gland. 

d.  Submucous  layer  of  muscular  fibres 

(KOUlker). 


LARGE    INTESTINE.  461 

of  Lieberkiihn,  and  into  the  ducts  of  the  glands  of  Brunner,  and  gives  them 
a  lining. 

Dissection.  To  demonstrate  the  areolar  tissue  between  the  coats  of  the 
intestine,  a  piece  of  the  bowel  turned  inside  out  is  to  be  inflated  forcibly  ; 
and  to  insure  the  success  of  the  attempt,  a  few  cuts  may  be  previously 
made  through  the  peritoneal  coat.  The  air  enters  the  wall  of  the  intes- 
tine where  the  peritoneal  covering  is  injured,  and  spreads  through  the 
whole  gut ;  but  opposite  the  solitary  glands,  and  the  patches  of  Peyer,  the 
mucous  coat  is  more  closely  connected  with  the  contiguous  structures,  and 
the  subjacent  portion  will  not  be  distended  with  the  air.  The  piece  of  the 
intestine  may  be  examined  when  it  is  dry. 

Vessels  of  the  intestine.  The  branches  of  arteries  ramify  in  the  sub- 
mucous layer,  and  end  in  a  network  of  small  twigs  in  the  mucous  mem- 
brane, which  supplies  the  folds,  the  villi,  and  the  glands.  Opposite 
Peyer's  patches  the  intestine  is  most  vascular ;  and  the  vessels  form  circles 
around  the  follicles,  before  supplying  offsets  to  them.  The  veins  have 
their  usual  resemblance  to  the  companion  arteries. 

The  absorbents  consist  of  a  superficial  set  (lymphatics)  in  the  muscular 
coat ;  and  of  a  deep  plexiform  set  (lacteals)  in  both  the  mucous  and  sub- 
mucous layers.  The  two  sets  join,  and  all  end  in  larger  trunks  in  the 
mesentery. 

Nerves  of  the  small  intestine  come  from  the  upper  mesenteric  plexus, 
and  entering  the  coats  by  the  side  of  the  arteries,  form  plexuses  with  in- 
terspersed ganglia.  One  such  plexus  is  contained  in  the  muscular  coat 
between  the  longitudinal  and  circular  fibres  (Auerbach)  ;  and  another  is 
placed  in  the  submucous  layer  (Meissner)  :  they  join  freely  by  branches 
through  the  intestinal  coats,  and  reach  from  the  pylorus  to  the  extremity 
of  the  alimentary  tube. 

Structure  of  the  common  bile  duct.  The  bile  duct  consists  of  an  exter- 
nal or  strong  fibrous  layer,  and  of  an  internal  or  mucous  coat  which  is 
lined  by  columnar  epithelium.  On  the  surface  of  the  inner  membrane  are 
the  openings  of  numerous  branched  mucous  glands,  which  are  imbedded 
in  the  fibrous  coat ;  some  of  them  are  aggregated  together,  and  are  visible 
with  a  lens. 

LARGE    INTESTINE. 

The  large  intestine  is  the  part  of  the  alimentary  canal  between  the 
termination  of  the  ileum  and  the  anus.  Its  division  and  its  attachment 
by  peritoneum  to  the  abdominal  wall,  have  been  described  (p.  483). 

In  length  this  part  of  the  alimentary  canal  measures  about  five  or  six 
feet — one-fifth  of  the  length  of  the  intestinal  tube.  The  diameter  of  the 
colon  is  largest  at  the  commencement  in  the  caecum,  and  gradually  de- 
creases as  far  as  the  rectum,  wliere  there  is  a  dilatation  near  the  end. 

When  compared  with  the  small  intestine,  the  colon  is  distinguished  by 
the  following  characters  :  It  is  of  greater  capacity,  being  in  some  parts  as 
large  again,  and  is  more  fixed  in  its  position  :  it  is  also  free  from  convolu- 
tion, except  in  the  left  iliac  fossa,  where  it  forms  the  sigmoid  flexure. 
Instead  of  being  a  smooth  cylindrical  tube,  the  colon  is  sacculated,  and  is 
marked  by  three  longitudinal  muscular  bands,  which  alternate  with  as 
many  rows  of  dilatations  ;  but  at  the  lower  part  of  the  large  intestine 
(rectum),  the  surface  is  smooth,  and  the  longitudinal  bands  have  disap- 
peared.    Attached  to  the  surface  at  intervals,  especially  along  the  trans- 


462 


DISSECTION    OF    THE    ABDOMEN. 


Fiff.  155. 


verse  colon,  are  processes  of  peritoneum   containing  fat — the  appendices 
epiploicae. 

Dissection,  For  the  purpose  of  examining  the  large  intestine  the 
student  should  cut  off  and  blow   up   the  caecum,  with   part  of  the   ileum 

entering  it ;  he  should  prepare  in  a  similar 
way  a  piece  of  the  transverse  colon,  and  a 
piece  of  the  sigmoid  flexure  (about  four  inches 
of  each).  The  areolar  tissue  and  the  fat  are 
to  be  removed  with  care  from  each,  after  it 
has  been  inflated. 

The  CJECUM,  or  the  head  of  the  colon  (fig. 
155,  a)  (caput  crecum  coli)  is  the  rounded 
part  of  the  large  intestine  which  projects,  in 
the  form  of  a  pouch,  below  the  junction  of 
the  ileum  with  it.  It  measures  about  two 
inches  and  a  half  in  length,  and  tliough 
gradually  narrowing  iriferiorly,  the  caecum  is 
the  widest  part  of  the  colon — hence  the  name 
caput  coli.  At  its  inner  side  it  is  joined  by 
the  small  intestine  (/>)  ;  and  still  lower  there 
is  a  small  worm-like  projection  (c) — the  ver- 
miform appendix. 

Appendix  vermiformis  (fig.  155,  c).  This 
little  convoluted  projection  is  attached  to  tlie 
lower  and  hinder  part  of  the  caecum,  of  wliich 
it  was  a  continuation,  at  one  period,  in  tlie 
embryo.  From  three  to  six  inches  in  length, 
the  appendix  is  rather  larger  than  a  goose- 
quill,  and  is  connected  to  the  inner  part  of 
the  caecum  by  a  fold  of  peritoneum.  It  is 
hollow,  and  has  an  aperture  of  communica- 
tion with  the  intestine  (d).  In  structure  it 
resembles  the  rest  of  the  colon. 

Dissection.  To  examine  the  interior  of  the 
csecum,  and  the  valve  between  it  and  tlie 
small  intestine,  the  specimen  should  be  dried, 
and  tlie  following  cuts  should  be  made  into 
it:  One  oval  piece  is  to  be  taken  from  the 
ileum  near  its  termination  ;  another  from  the 
side  of  the  caecum,  opposite  the  entrance  of  the  small  intestine. 

lleo-ccecal  valve  (fig.  155).  This  valve  is  situate  at  the  entrance  of  tlie 
ileum  into  the  csecum.  It  is  composed  of  two  pieces,  each  with  a  different 
inclination,  which  project  into  the  interior  of  the  caecum,  and  bound  a 
narrow,  nearly  transverse  aperture  of  communication  between  the  two 
differently-sized  portions  of  the  alimentary  canal. 

The  upper  piece  of  the  valve,  ileo-colic  {e)  projects  horizontally  into 
the  large  intestine,  opposite  the  junction  of  the  ileum  with  the  colon.  And 
the  lower  piece,  ileo-coecal  (/),  which  is  the  larger  of  the  two,  has  a  ver- 
tical direction  between  the  ileum  and  the  caecum.  At  each  extremity  of 
the  opening  the  pieces  of  the  valve  are  blended  together;  and  the  result- 
ing prominence  {g)  extends  transversely  on  each  side  of  the  intestine, 
forming  ih^frcBna  or  retinacula  of  the  valve. 


Interior  of  a  Caecum  dkiep  and 
laid  open. 

«•  Caecum. 

6.  Small  intestine- 

c.  Vermiform  appendix,  and  d,  its 
aperture. 

e.  Ilio-colic  piece  of  the  valve  at 
the  junction  of  the  small  in- 
testine, 

/.  Ilio-caecal  piece  of  the  valve. 

g.  Retinaculum  of  the  valve  on 
each  side. 


STRUCTURE    OF    THE    COLON.  463 

The  size  of  the  opening  depends  upon  the  distension  of  the  intestine ; 
for  when  the  retinacuhi  of  the  valve  are  stretched  the  margins  of  the 
aperture  are  approximated,  and  may  be  made  to  touch. 

Each  piece  of  the  valve  is  formed  by  circular  muscular  fibres  of  the  in- 
t'?stinal  tube,  covered  by  mucous  membrane  ;  as  if  the  ileum  was  thrust 
obliquely  through  the  wall  of  the  csecum,  after  being  deprived  of  its  peri- 
toneal coat  and  layer  of  longitudinal  fibres.  This  construction  is  easily 
seen  on  a  fresh  specimen  by  dividing  the  peritoneum  and  the  longitudinal 
fibres,  and  gently  drawing  out  the  ileum  from  the  caecum. 

The  opening  of  the  appendix  into  the  csecum  {d)  is  placed  below  that 
of  the  ileum.  A  piece  of  mucous  membrane  partly  closes  the  aperture, 
and  acts  as  a  valve. 

Folds  or  ridges  are  directed  transversely  in  the  interior  of  the  gut,  and 
correspond  Avith  depressions  on  the  outer  surface  :  these  folds  result  from 
the  doubling  of  the  wall  of  the  intestine,  and   the  largest  inclose  vessels. 

Structure  of  the  Colox.  The  coats  of  the  large  are  similar  to 
those  of  the  small  intestine,  viz.,  serous,  muscular,  fibrous,  and  mucous. 

Serous  coat.  The  peritoneum  does  not  clothe  the  large  intestine, 
throughout,  in  the  same  degree.  It  covers  the  front  of  the  caecum,  and 
the  front  and  sides  of  the  ascending  and  descending  colon  ;  but  in  neither 
does  it  reach  commonly  the  posterior  aspect  (p.  438).  The  transverse 
colon  is  incased  like  the  stomach,  and  has  intervals  along  the  borders, 
where  the  transverse  meso-colon  and  the  great  omentum  are  attached. 

The  muscular  coat  is  formed  by  longitudinal  and  circular  fibres,  as  in 
the  small  intestine. 

The  longitudinal  fibres  may  be  traced  as  a  thin  layer  over  the  surface, 
but  most  are  collected  into  three  longitudinal  bands,  about  a  quarter  of  an 
inch  in  width.  On  the  vermiform  appendix  the  fibres  form  a  uniform 
layer ;  but  they  are  continued  thence  into  the  bands  on  the  c^cum  and 
colon  :  on  the  rectum  tliey  are  diffused  over  the  surface.  When  the 
bands  are  divided  the  intestine  elongates — the  sacculi,  and  the  ridges  in 
the  interior  of  tlie  gut,  disappearing  at  the  same  time. 

The  circular  fibres  are  spread  over  the  whole  surface,  but  are  most 
marked  in  the  folds  projecting  into  the  intestine.  In  the  rectum  (to  be 
afterwards  seen)  they  form  the  band  of  the  internal  sphincter  muscle. 

Th^  fibrous  coat  resembles  that  of  the  small  intestine.  It  will  be  ex- 
posed by  removing  the  peritoneal  and  muscular  coverings. 

The  mucous  coat^  which  may  be  examined  on  opening  the  intestine,  is 
smooth,  and  of  a  pale  yellow  color;  and  it  is  not  thrown  into  special  folds, 
except  in  the  rectum.  The  surface  is  free  from  villi ;  and  by  this  circum- 
stance the  mucous  membrane  of  the  large,  can  be  distinguished  from  that 
of  the  small  intestine.  This  difference  in  the  two  portions  of  the  alimen- 
tary tube  is  well  marked  on  the  ilio-c«cal  valve ;  for  the  surface  looking 
to  the  small  intestine  is  studded  with  villi,  whilst  the  lower  surface,  covered 
by  the  lining  membrane  of  the  caecum,  is  free  from  those  small  eminences. 

Microscopic  appearances.  In  a  piece  of  fresh  intestine  the  microscope 
will  show  the  mucous  membrane  to  possess  small  tubes  or  crypts,  and 
some  larger  solitary  follicles;  with  an  epithelial  covering  on  the  free  sur- 
face, and  a  thin  muscular  layer  {muscidaris  mucosae)  on  the  other,  whose 
arrangement  is  similar  to  that  of  the  small  intestine. 

The  tubules  (fig.  156,  ^)  occupy  the  whole  length  of  the  large  gut,  and 
resemble  those  of  the  small  intestine,  but  are  more  numerous  and  closer 
together.     Their  orifices  on  the  surface  are  circular  ('),  and  are  more  uni- 


464 


DISSECTION    OF    THE    ABDOxMEN. 


formly  diffused  than  the  apertures  of  the 
tubules  in  the  small  gut.  A  vertical  section  of 
the  membrane  (^)  will  show  the  tubes  to  ex- 
tend vertically  from  the  surface  into  the  sub- 
mucous coat,  and  to  be  longer  than  the  crypts 
of  Lieberkiihn  in  the  jejunum  and  ileum  ;  they 
measure  from  ^^^th  to  ^j^^th  of  an  inch  in  length. 
The  so-called  solitary  glands  (fig.  156,  ^) 
are  scattered  here  and  there  througli  the  large 
intestine  ;  but  they  are  in  greatest  number  in 
the  caecum  and  vermiform  appendix.  They 
are  whitish  rounded  bodies  from  -^^ih  to  y^^th 
of  an  incli  in  diameter,  and  are  situate  in  the 
submucous  layer  amongst  the  tubules.  They 
are  lymph  follicles  with  a  structure  like  that 
in  the  small  intestine. 

The  epithelium  is   of  the  columnar  kind, 
and  enters  the  tubules. 
The  distribution  of  the  vessels  in  the  wall  of  the  large  intes- 
tine is  the  same  as  in  the  smaller  bowel. 

Nerves.     In  the  coats  of  the  large  intestine  the  nerves  have  the  plexi- 
form  arrangement  like  that  in  the  small  gut. 

The  absorbent  vessels  form  two  sets  as  in  tlie  small  intestine;  after  leav- 
ing the  gut  they  join  the  lymphatic  glands  along  the  side  of  the  colon. 


Enlarged  View  of  "a  Solitary 
Gland,"  and  of  the  tubules  of 
the  mucous  coat.     (Boehra.) 

A.  Gland  of  the  large  intestine. 

B.  Tubules  of  the  mucous  mem- 

brane. 

1.  Surface  opening. 

2.  Side  view  of  the  tubes. 

3.  Pits  for  the  closed  ends  of  the 

tubes     in      the     submucous 
tissue. 


THE    PANCREAS. 

The  pancreas  (fig.  145,  e)  is  a  narrow  flattened  gland,  from  six  to  eight 
inches  in  length,  which  has  some  resemblance  to  a  dog's  tongue.  It  is 
larger  at  the  right  than  the  left  end ;  and  it  is  divided  into  head,  tail,  and 
body. 

The  head^  or  the  right  extremity,  occupies  the  concavity  of  the  duo- 
denum; and  the  left  extremity,  or  the  tail,  is  rounded,  and  touches  the 
spleen. 

The  body  of  the  gland  is  narrowest  a  little  to  the  right  of  the  vertebral 
column,  and  is  thickest  at  the  upper  border ;  it  measures  about  one  incii 
and  a  half  in  breadth,  and  from  half  an  inch  to  an  inch  in  thickness. 
The  connections  of  the  pancreas  with  surrounding  parts  are  described  at 
p.  446. 

Dissection.  Let  the  pancreas  be  placed  on  the  anterior  surface,  and 
let  the  excretory  duct  be  traced  from  the  head  to  the  tail  by  cutting  away 
the  substance  of  the  gland.  The  small  duct  will  be  recognized  by  its 
whiteness. 

Structure.  The  pancreas  is  a  gland  consisting  of  separate  lobules, 
and  is  provided  with  a  special  duct.  It  is  destitute  of  a  distinct  capsule  ; 
but  it  is  surrounded  by  areolar  tissue,  which  projects  into  the  interior, 
and  connects  together  its  smaller  pieces.  The  fluid  secreted  by  it  assists 
in  the  digestion  of  the  aliment. 

The  lobules  are  soft  and  loose,  and  of  a  grayish-white  color,  and  are 
united  into  larger  masses  by  areolar  tissue,  vessels,  and  ducts.  Each  con- 
sists ultimately,  as  in  the  parotid,  of  the  branchings  of  the  excretory  duct, 
which  end  in  closed  vesicular  extremities,  and  are  surrounded  by  a  plexus 
of  vessels.     In  the  vesicles  the  epithelium  is  spheroidal. 


THE    SPLEEN.  465 

The  duct  of  the  pancreas  (fig.  150,  d)  (canal  of  Wirsung)  extends  the 
entire  length  of  the  gland,  and  is  somewhat  nearer  the  lower  than  the 
upper  border.  It  begins  in  the  tail  of  the  pancreas,  where  it  presents  a 
bifurcated  extremity;  and  as  it  continues  onwards  to  the  head,  it  receives 
many  branches.  It  finally  ends  by  opening  into  the  duodenum,  either  in 
union  with,  or  separate  from  the  common  bile  duct  (p.  457).  Of  the  tribu- 
tary branches,  the  largest  is  derived  from  the  head  of  the  pancreas. 

The  duct  measures  from  y^^th  to  yV^^^  ^^  ^"  moh.  in  diameter  near  the 
duodenum.  It  is  formed  ol'  a  Jibrous  and  a  mucous  coat :  the  latter  is 
lined  by  a  cylindrical  epithelium^  and  is  provided  with  small  glands  in  the 
duct  and  its  largest  branches. 

Vessels^  lymphatics,  and  nerves.  The  arteries  and  veins  have  been 
described  (p.  447);  and  the  lymphatics  join  the  lumbar  glands.  The 
nerves  are  furnished  by  the  solar  plexus. 

THE    SPLEEN. 

The  spleen  is  a  vascular  spongy  organ  of  a  bluish  or  purple  color,  some- 
times approaching  to  gray.  Its  texture  is  friable,  and  easily  broken  under 
pressure.     The  use  of  the  spleen  is  unknown. 

The  viscus  is  somew^iat  elliptical  in  shape,  and  is  placed  vertically 
against  the  great  end  of  the  stomach.  Its  size  varies  much.  In  the 
adult  it  measures  commonly  about  five  inches  in  length,  three  or  four 
inches  in  breadth,  and  one  inch  to  one  inch  and  a  half  in  thickness.  Its 
weight  lies  between  four  and  ten  ounces,  and  is  rather  less  in  the  female 
than  the  male. 

At  the  outer  aspect  it  is  convex  towards  the  ribs,  the  inner  surface  is 
marked  by  a  longitudinal  ridge,  nearer  the  posterior  than  the  anterior 
border,  into  which  the  vessels  plunge  to  ramify  in  the  interior.  Before 
and  behind  the  ridge,  the  surface  is  flattened  or  somewhat  hollowed.  The 
spot  where  the  vessels  enter  is  named  the  hilum  of  the  spleen. 

The  anterior  border  is  thinner  than  the  posterior,  and  is  often  notched. 
Of  the  two  extremities,  the  lower  is  more  pointed  than  the  upper. 

Small  masses  or  accessory  spleens  (splenculi),  varying  in  size  from  a 
bean  to  a  moderate-sized  plum,  are  found  occasionally,  near  the  fissure  of 
the  spleen,  in  the  gastro-splenic  omentum,  or  in  the  great  omentum. 

Structure.  Enveloping  the  spleen  are  two  coverings,  a  serous  and  a 
fibrous.  It  is  formed  by  a  network  of  fibrous  or  trabecular  tissue,  which 
contains  in  its  meshes  the  splenic  pulp,  with  the  Malpighian  corpuscles. 
Throughout  the  mass  the  bloodvessels  and  the  nerves  ramify.  No  duct 
exists  in  connection  with  this  organ. 

The  serous  or  peritoneal  coat  incases  the  spleen,  and  covers  the  surface 
except  at  the  hilum  and  the  posterior  border.  It  is  closely  connected  to 
the  subjacent  fibrous  coat. 

The,  fibrous  coat  (tunica  propria)  gives  strength  to  the  spleen,  and  forms 
a  complete  case  for  it.  At  the  fissure  on  the  inner  surface  this  investment 
passes  into  the  interior  with  the  vessels,  to  which  it  furnishes  sheaths  : 
and  if  an  attempt  is  made  to  detach  this  coat,  numerous  fibrous  processes 
will  be  seen  to  be  connected  with  its  inner  surface.  Its  color  is  whitish  ; 
and  its  structure  is  made  up  of  areolar  and  elastic  tissues. 

Dissection.     The  spongy  or   trabecular  structure  will  best  appear,  by 
washing  and  squeezing  a  piece  of  fi-esh  bullock's  spleen  under  water,  so  as 
to  remove  the  grumous-looking  material. 
30 


466 


DISSECTION    OF    THE    ABDOMEN 


The  trabecular  tissue  (fig.  157)  forms  a  network  througli  the  whole  in- 
terior of  the  spleen,  similar  to  that  of  a  sponge,  wliich  is  joined  to  the 
external  casing,  and  forms  sheaths  around  the  vessels.  Its  processes  or 
threads  are  white,  flattened  or  cylindrical,  and  average  from  -r^^th  to  ^'^th 
of  an  inch  :  they  consist  of  fibrous  and  elastic  tissues,  with  a  tew  muscular 
fibres.  The  interstices  communicate  freely  together,  and  contain  the 
proper  substance  of  the  spleen,  and  the  vessels. 

Microscopic  appearances.  The  characters  of  the  spleen  substance  can- 
not be  ascertained  without  the  aid  of  the  microscope. 

The  splenic  pnlp  is  a  soft  red-brown  mass,  which  is  lodged  in  the  areolae 

of  the  trabecular  structure.     Under  the  microscope  this  material  is  seen 

to  be  composed  of  a  fine  network   of  ramifying 

connective  tissue  corpuscles,  with  blood-cells  in  its 

meshes. 

The  Malpighian  corpuscles  are  small  rounded 
whitish  bodies,  about  e'jth  of  an  inch  in  diameter, 
and  are  connected  with  the  outer  coat  of  the 
smallest  branches  of  the  arteries ;  they  project 
into  the  pulp  of  the  spleen,  and  are  surrounded  by 
it.  In  structure  they  are  like  the  lymph  follicles 
of  the  intestine,  consisting  of  reticular  tissue,  with 
lymph  corpuscles  in  its  meshes,  through  which 
blood-capillaries  pass. 

Bloodvessels.  Tiie  larger  branches  of  the  splenic 
artery  are  surrounded  by  sheaths  of  fibrous  tissue 
in  the  trabecula3 ;  but  the  smallest  branches  leave 
the  sheathing,  and  break   up  into   tufts  of  capil- 
laries, which    open  into  the  fine   meshes   of  the 
spleen  substance.     In  the  smallest  branches,  with 
which  the  Malpighian  corpuscles  are   united,  the 
outer  coat  is  thickened  by  lymphoid  tissue,  and  is 
directly  continuous  with  those  bodies  in  structure. 
The  splenic  vein  begins   in  the  meshes  of  the 
splenic  pulp  by  open  channels.     From   the  union 
of  these  radicles  arise  small  branches,  which  unite 
into  trunks  larger  than  the  accompanying  arteries, 
and  issue  by  the  fissure  of  the  spleen  ;  in  their  course  they  receive  acces- 
sory branches,  some  joining  at  a  right  angle. 

Nerves  and  lymphatics.  The  lymphatics  are  superficial  and  deep,  and 
enter  the  glands  in  the  gastro-splenic  omentum.  In  the  spleen  they  begin 
in  the  corpuscles  of  Malpighi,  and  in  the  outer  coat  of  the  smallest  arteries  ; 
they  are  conveyed  to  the  hilum  of  the  spleen  on  the  vessels.  The  nerves 
come  from  the  solar  plexus,  and  surround  the  artery  and  its  branches. 


A  Drawing  of  thr  Tra- 
becular Structurk  of 
THE  Spleen  of  the  Ox, 
at  some  distance  from  the 
hilum. 


THE    LIVER. 

The  liver  secretes  the  bile,  and  is  the  largest  gland  in  the  body.  Its 
duct  opens  into  the  duodenum  with  that  of  the  ])ancreas. 

Dissection  (fig.  158).  Preparatory  to  examining  the  liver,  the  vessels 
at  the  under  surface  should  be  dissected  out.  This  proceeding  will  be 
facilitated  by  distending  the  vena  cava  and  vena,  porta;  with  tow  or  cotton 
wool,  and  tlie  gall-bladder  with  air  through  its  duct.  The  several  vessels 
and  the  ducts  are  then  to  be  defined,  and  the  gall-bladder  to  be  cleaned. 


LOBES    AND    FISSURES    OF    LIVER.  467 

On  following  outwards  the  left  branch  of  the  vena  portae  to  the  longi- 
tudinal or  antero-posterior  fissure,  it  will  be  found  united  anteriorly  with 
the  round  ligament  or  the  remains  of  the  umbilical  vein,  and  posteriorly 
with  the  fine  fibrous  remnant  of  the  ductus  venosus. 

The  liver  is  of  a  red-brown  color  and  firm  consistence  ;  and  weighs 
commonly  in  the  adult  from  three  to  four  pounds  (fifty  to  sixty  ounces). 
Transversely  the  gland  measures  from  ten  to  twelve  inches  ;  from  front  to 
back  between  six  and  seven  inches;  and  in  thickness,  at  the  right  end, 
about  three  inches  ;  but  this  last  measurement  varies  with  the  spot  ex- 
amined. 

In  shape  the  liver  is  somewhat  square.  It  has  many  named  parts,  viz., 
two  surfaces,  two  borders,  and  two  extremities ;  and  the  under  surface  is 
further  marked  by  lobes  and  fossae,  and  by  fissures  which  contain  vessels. 

The  connections  and  the  ligaments  of  the  liver  are  described  at  p.  434 
and  p.  438. 

Surfaces.  On  the  upper  aspect  the  liver  is  convex  :  extending  from 
front  to  back  in  the  suspensory  ligament,  which  divides  the  upper  surface 
into  two  unequal  parts,  of  which  the  right  is  the  larger.  The  under  sur- 
face is  rendered  irregular  by  lobes,  fissures,  and  fossa? :  in  contact  with  it 
is  the  gall-bladder ;  and  a  longitudinal  sulcus  divides  it  into  a  right  and  a 
left  lobe. 

Borders.  The  anterior  border  is  thin,  and  is  marked  by  two  notches  : 
one  is  opposite  the  longitudinal  sulcus  on  the  under  surface  before  alluded 
to,  and  the  other  is  over  the  large  end  of  the  gall-bladder.  The  posterior 
border  is  much  thicker  at  the  right  than  at  the  left  end ;  and  at  the  thick- 
ened part  it  touches  the  right  kidney  and  the  diaphragm.  Opposite  the 
vertebral  column  is  a  hollow  in  this  border  ;  and  the  vena  cava  is  partly 
imbedded  in  it  on  the  right  of  the  spine. 

Extremities.  The  right  extremity  is  thick  and  rounded;  and  the  left 
is  tliin  and  flattened. 

Lobes.  On  the  under  surface  the  liver  is  divided  primarily  into  two 
lobes,  a  right  and  a  left,  by  the  antero-posterior  or  longitudinal  fissure  ; 
and  occupying  this  surface  of  the  right  lobe  are  three  others,  viz.,  the 
square,  tlie  Spigelian,  and  the  caudate  lobe : — 

The  left  lobe.  «,  is  smaller  and  thinner  than  the  right,  and  there  is  a 
slight  depression  inferiorly  where  it  touches  the  stomach. 

The  right  lobe,  a,  forms  the  greater  part  of  the  liver,  and  is  separated 
from  the  left  by  the  longitudinal  fissure  on  the  one  aspect,  and  by  the  sus- 
pensory ligament  on  the  other.  To  it  the  gall-bladder  is  attached  below  ; 
and  the  following  lobes  are  projections  on  its  under  surface : — 

The  square  lobe,  c  (lobulus  quadratus),  is  situate  between  the  gall- 
bladder and  the  longitudinal  fissure.  It  reaches  anteriorly  to  tlie  margin 
of  the  liver,  and  posteriorly  to  the  fissure  (transverse)  by  which  the  ves- 
sels enter  the  interior  of  tlie  viscus. 

The  Spigelian  lobe,  d,  lies  behind  the  transverse  fissure,  and  forms  a 
roundish  projection  on  the  surface.  On  its  left  side  is  the  longitudinal 
fissure;  and  on  its  right,  the  vena  cava  inferior. 

The  caudate  lobe,  e,  is  a  slight,  elongated  eminence,  which  is  directed 
from  the  Spigelian  lobe  behind  tlie  transverse  fissure,  so  as  to  form  the 
posterior  boundary  of  that  sulcus.  Where  the  fissure  terminates  this  pro- 
jection subsides  in  the  right  lobe. 

Fissures.  Extending  horizontally  half  across  the  right  part  of  the  liver 
between  the  Spigelian  and  caudate  lobes  on  the  one  hand,  and  the  square 


468 


DISSECTION    OF    THE    ABDOMEN 


lobe  on  the  other,  is  the  transverse  or  portal  fissure.  It  is  situate  nearer 
the  posterior  than  the  anterior  border,  and  contains  the  vessels,  nerves, 
ducts,  and  lymphatics  of  the  liver.  At  tiie  left  end  it  is  united  at  a  right 
angle  with  the  longitudinal  fissure. 


Fig.  158. 


Under  Surface  of  the  Liver. 


A.  Kight,  and  B,  left  lobe. 

c.  Quadrate  lobe. 

D.  Spigelian,  and  e,  caudate  lobe. 

F.  Longitudinal  fissure. 

G.  Gall-bladder. 
a.  Vena  cava. 
6.  Vena  portse. 


c.  Round  ligament. 

d.  Obliterated  ductus  venosus. 

e.  Common  hepatic  duct. 
/.  Cystic  duct. 

g.  Common  bile  duct. 
h.  Hepatic  artery. 


The  longitudinal  fissure,  f,  extends  from  the  front  to  the  back  of  the 
liver,  between  the  right  and  left  lobes.  In  the  part  anterior  to  the  trans- 
verse fissure  lies  the  remnant  of  the  umbilical  vein  (c),  which  is  called 
round  ligament,  and  is  oftentimes  arched  over  by  a  piece  of  the  hepatic 
substance  (pons  hepatis).  In  the  part  behind  that  fissure  is  contained  a 
small  obliterated  cord  (rtf),  the  remains  of  the  vessel  named  ductus  venosus 
in  the  foetus. 

The  groove  for  the  vena  cava  is  placed  on  the  right  side  of  the  Spigelian 
lobe,  and  is  frequently  bridged  over  by  the  liverl  If  the  cava  be  opened, 
two  large  and  some  smaller  hepatic  veins  will  be  observed  entering  it. 

FosscB.  On  the  under  surface  of  the  right  lobe  are  three  depressions — 
one  for  the  gall-bladder  to  the  right  of  the  square  lobe ;  another  for  the 
colon,  near  the  anterior  edge;  and  a  third  for  the  kidney  near  the  posterior 
border. 

Vessels  of  the  transverse  Jissure.  The  vessels  in  the  transverse  fissure, 
viz.,  vena  portOR,  hepatic  artery  and  duct,  have  the  following  position :  the 
duct  is  anterior,  the  portal  vein  posterior,  and  the  artery  between  the 
other  two. 

The  hepatic  duct  (fig.  158,  e)  is  formed  by  two  branches  from  the  liver, 
one  from  eacli  lobe,  which  soon  blend  in  a  common  tube.  After  a  distance 
of  one  inch  and  a  half  it  is  joined  by  the  duct  of  the  gall-bladder  (/)  ;  and 
the  union  of  the  two  gives  rise  to  the  common  bile  duct  (^). 


STRUCTURE    OF    LIVER.  469 

The  hepatic  artery  (h)  is  divided  into  two,  one  for  each  lobe,  and  its 
branches  are  surrounded  by  nerves  and  lymphatics. 

The  veiia  portce  (h)  branches,  like  the  artery,  into  two  trunks  for  the 
right  and  left  lobes,  and  gives  an  offset  to  the  Spigelian  lobe;  its  left 
branch  is  the  longest. 

FcEtal  condition  of  the  umhilical  vein.  Before  birth  the  previous  um- 
bilical vein  occupies  the  longitudinal  fissure,  and  opens  posteriorly  into 
the  vena  cava;  the  portion  of  the  vessel  behind  the  transverse  fissure  re- 
ceives the  name  ductus  venosus.  Branches  are  supplied  from  it  to  both 
lobes  of  the  liver;  and  a  large  one,  directed  to  the  right  lobe,  is  continuous 
with  the  left  piece  of  the  vena  porta?.  Purified  or  placental  blood  circu- 
lates through  the  vessel  at  that  period. 

Adult  state.  After  birth  the  part  of  the  umbilical  vein  in  front  of  the 
transverse  fissure  is  closed,  and  becomes  eventually  the  round  ligament 
(fig.  158,  c).  The  ductus  venosus  is  also  obliterated,  only  a  thin  cord  (d) 
remaining  in  its  place.  Whilst  the  lateral  branches,  which  are  in  the 
same  line  as,  and  continuous  with  the  left  branch  of  the  vena  portce,  remain 
open,  and  subsequently  form  part  of  the  left  division  of  the  vena  portae. 
Occasionally  the  ductus  venosus  is  found  more  or  less  pervious. 

Structure  of  the  Liver.  The  substance  of  the  liver  consists  of 
small  bodies  called  lobules  or  acini;  together  with  vessels  which  are  con- 
cerned both  in  the  production  of  the  secretion,  and  in  the  nutrition  of  the 
organ.     The  whole  is  surrounded  by  a  fibrous  and  a  serous  coat. 

Serous  coat.  The  peritoneum  invests  the  liver  almost  completely,  and 
adheres  closely  to  the  subjacent  coat.  At  certain  spots  intervals  exist  be- 
tween the  two,  viz.,  in  the  fissures  occupied  by  vessels,  along  the  line  of 
attachment  of  the  ligaments,  and  at  the  surface  touching  the  gall-bladder. 

The  jibrous  covering  is  very  thin,  but  it  is  rather  stronger  where  the 
peritoneum  is  not  in  contact  with  it.  It  invests  the  liver,  and  is  continu- 
ous at  the  transverse  fissure  with  the  fibrous  sheath  (capsule  of  Glisson) 
surrounding  the  vessels  in  the  interior.  When  the  membrane  is  torn  from 
the  surface,  it  will  be  found  connected  with  fine  shreds  entering  into  the 
liver. 

Size  and  form  of  the  lobules.  The  lobules  (fig.  161,  /)  constitute  the 
proper  secreting  substance,  and  can  be  seen  either  on  the  exterior  of  the 
liver,  on  a  cut  surface,  or  by  means  of  a  rent  in  the  mass.  As  thus  ob- 
served, these  bodies  are  about  the  size  of  a  pin's  head,  and  measure  from 
^^^th  to  y^^th  of  an  inch  in  diameter.  Closely  massed  together  they  pos- 
sess a  dai'k  central  point;  and  there  are  indications  of  lines  of  separation 
between  them,  though  they  communicate  by  vessels.  By  means  of  trans- 
verse and  vertical  sections  of  the  lobules,  their  form  \Vill  appear  flattened 
on  the  exterior,  but  many  sided  in  the  interior  of  the  liver.  Tliey  are 
clustered  around  the  smallest  divisions  of  the  hepatic  vein,  to  which  each 
is  connected  by  a  small  twig  issuing  from  the  centre,  something  like  the 
union  of  the  stalk  with  the  body  of  a  small  fruit. 

To  study  the  minute  structure  of  the  lobules,  a  microscope  will  be  neces- 
sary ;  and  the  different  vessels  of  the  liver  should  be  minutely  injected. 

Constituents  of  the  lobules.  Each  lobule  is  composed  of  minute  hepatic 
cells,  which  are  arranged  web-like  amongst  the  ducts  and  vessels ;  and  it 
is  provided  with  a  capillary  network  of  vessels,  and  with  a  plexus  of  the 
bile  duct. 

Cells  of  the  lobules.  The  hepatic  or  biliary  cells  (fig.  159,  a)  form  the 
chief  part  of  the  lobule  ;  they  are  irregular  in  form,  being  rounded  or 


470 


DISSECTION    OF    THE    ABDOMEN 


Fig.  159. 


many  sided,  and  possess  a  bright  nucleus,  or  even  more  than  one.  In 
size  they  vary  from  joVu^^  *^  ^J^^^  of  an  incli.  They  are  of  a  yellowish 
color,  and  inclose  granular  particles,  together  with  fat  and  yellow  coloring 

matter.  These  nucleated  cells  adhere 
together  by  their  surfaces  so  as  to  form 
rows  radiating  from  the  centre,  with 
spaces  (b)  between  them  for  the  blood- 
vessels and  ducts.  The  cells  are  con- 
cerned in  the  secretion  of  the  bile. 

Vessels  of  the  lobule  (fig.  160,  b). 
The  smallest  branches  of  the  venaportcB, 
after  uniting  in  a  circle  around  the  lo- 
bule, where  they  are  named  interlobular 
(«),  enter  its  substance,  and  form  therein 
a  network  of  capillaries  (c)  near  the  cir- 
cumference. 

A  small  branch  of  the  hepatic  vein  {d) 
occupies    the    centre  of  the  lobule ;    its 
radicles    communicate    with    the    portal 
network,  and  it  issues  from  the  base  of 
A  Magnified  Reprksf.ntation  of  the     the  lobule  as  the  intralobular  vein. 

Hepatic  CELLS    ^vith  their  arrange-  rpj^^  radicks  of  the  bile  duct  (fig.  160, 

ment  la  the  lobule  (Henle).  .    .        .  ...        ,        i    ,      i       .  /V         . 

^  (,gjjg  a)  begin  witlim  the   lobule  in  a  fine  in- 

6.  Intercellular  spaces.  tralobular  plexus  of  ducts  {g)  between 


Fig.  160. 


I.  Two  lobules  of  the  liver  showing  the  plexus 
of  ducts  in  the  interior,  near  the  circum- 
ference (Kiernan);  recent  inquiries  de- 
monstrate the  existence  of  a  plexus 
throuu'hout  the  lobule. 

g.  Intralobular  plexus. 

/.  Interlobular  ducts. 

e.  Small  branches  of  the  hepatic  ducts. 


.  Lobules  of  an  injected  liver  to  show  tbe 
arrangement  of  the  veins. 

«.  Smallest  branches  of  the  vena  portffi  end- 
ing in  the  interlobular  veins,  h. 

c.  Plexus  of  portal  veins  within  the  lobule. 

d.  Intralobular  commencement  of  the  hepa- 
tic vein  joining  the  plexus  of  the  portal 
vein. 


the  hepatic  cells  (Chrzonszczewsky) ;  they  leave  the  lobule  at  the  cir- 
cumference, and  are  joined  together  outside  it  in  the  smallest  interlobular 
branches  (/). 


VESSELS    AND    DUCT    OF    LIVER 


471 


From  the  arrangement  of  the  vessels,  it  appears  that  the  portal  vein 
conducts  the  blood  from  which  bile  is  secreted ;  that  tiie  hepatic  vein  car- 
ries away  the  superfluous  blood ;  and  that  the  secreted  bile  is  received  by 
the  plexus  of  the  biliary  duct. 

Vessels  of  the  Liver.  Two  sets  of  bloodvessels  ramify  in  the  liver : 
One  enters  the  transverse  fissure,  and  is  directed  transversely  in  spaces 
(portal  canals)  where  it  is  enveloped  by  areolar  tissue.  The  other  set 
(hepatic  veins)  run  from  the  anterior  to  the  posterior  border  of  the  liver 
without  a  like  sheath.  Tlie  ramifications  of  these  different  vessels  are  to 
be  followed  in  the  liver. 

The  capsule  of  Glisson  is  a  layer  of  areolar  tissue,  which  envelops  the 
vessels  and  the  ducts  in  the  transvei'se  fissure.  In  this  sheath  the  vessels 
ramify,  and  in  it  they  are  minutely  divided  before  their  termination  in 
the  lobules.  If  a  transverse  section  is  made  of  a  portal  canal,  the  vessels 
will  retract  somewhat  into  the  loose  surrounding  tissue. 

The  vena  portcE  ramifies  in  the  liver  like  an  artery ;  and  the  blood  cir- 
culates through  it  in  the  same  manner,  viz.,  from  trunk  to  branches.  After 
entering  the  transverse  fissure  the  vein  divides  into  large  branches  ;  these 
lie  in  the  portal  canals  or  spaces,  with  offsets  of  the  hepatic  artery,  the 
hepatic  duct,  and  the  nerves  and  lym- 
phatics (fig.  161,  p).  The  division  is  Fig.  161. 
repeated  again  and  again  until  the  last 
branches  of  the  vein  {interlobular,  fig. 
1 60,  h')  penetrate  between  the  lobules  ; 
there  they  unite,  and  end  in  the  interior 
as  before  explained. 

In  the  portal  canals  the  offsets  of  the 
vena  portcR  are  joined  by  small  vagi- 
nal and  surface  veins,  which  convey 
blood  from  branches  of  the  hepatic 
artery. 

The  hepatic  artery  (fig.  161,  c), 
whilst  surrounded  by  the  capsule,  fur- 
nishes vaginal  branches,  which  ramify- 
in  the  sheath,  giving  it  a  red  appear- 
ance in  a  well-injected  liver,  and  sup- 
ply twigs  to  the  coats  of  the  vena 
portje  and  biliary  ducts,  and  to  the  areo- 
lar tissue :  from  the  vaginal  branches  a 
few  offsets  {capsular)  are  given  to  the 
coat  of  the  liver.  Finally  the  artery 
ends  in  fine  interlobular  branches,  from 
which  offsets  enter  the  lobule,  and  con- 
vey blood  into  the  network  between  the 
branches  of  the  vena  portiie  and  hepatic 
vein  (Chrzonszczewsky). 

The  hepatic  vein  (vence  cava?  hepaticje)  begins  by  a  plexus  in  the  inte- 
rior of  each  lobule  (fig.  IGO,  d),  and  its  smallest  radicle  issues  from 
the  base  of  the  lobule  as  the  intralobular  vein  ;  these  are  received  into 
the  sablobular  branches,  which  anastomose  together,  and  unite  into  larger 
vessels.  Finally,  uniting  with  neighboring  branches  to  produce  larger 
trunks,  the  hepatic  veins  are  directed  from  before  backwards  to  the  vena 
cava  inferior,  into  wdiich  they  open  by  large  orifices.     The  venae  cavae  he- 


Vesskls  in  a  Portal  Canal,  and  the 
LoBULKS  OF  THU  LiVER  (Kieraan). 

I.  Lobules  of  the  liver. 

p.  Branch  of  the  vena  portae,  with,  a,  a, 
vaginal  branches  which  supply  inter- 
lobular offsets. 

c.  Hepatic  artery. 

d.  Hepatic  duct. 

i,  i.  Openings  of  the  interlobular  branches 
of  the  portal  vein. 


472  DISSECTION    OF    THE    ABDOMEN. 

paticoe  may  be  said  to  be  without  a  sheath,  except  in  the  larger  trunks  ; 
so  that  when  they  are  cut  across  the  ends  remain  patent,  in  consequence 
of  their  close  connection  with  the  liver  structure. 

Hepatic  duct  (fig.  160,  e).  The  duct  commences  in  the  biliary  plexus 
within  the  lobules.  On  leaving  the  lobules  the  radicles  communicate  by 
the  interlobular  branches  (/)  ;  and  the  smaller  ducts  soon  unite  into  larger 
vaginal  branches  (o?),  which  lie  in  the  portal  canals  with  the  other  vessels. 
Lastly,  the  ducts  are  collected  into  a  right  and  a  left  trunk  (lig.  158,  e), 
and  leave  the  liver  at  the  transverse  fissure.^ 

Structiwe.  The  moderately-sized  hepatic  ducts  consist  of  a  fibrous  coat, 
lined  by  a  mucous  layer  with  cylindrical  epithelium  ;  and  penetrating  the 
wall  is  a  longitudinal  row  of  openings,  on  each  side,  leading  into  sacs,  and 
into  branched  tubes  which  sometimes  communicate.  In  the  fine  inter- 
lobular ducts  the  coat  is  formed  by  a  homogeneous  structure,  with  colum- 
nar epithelium  (Henle). 

Lymphatics  of  the  liver  are  superficial  and  deep.  The  superficial  of 
the  upper  surface  join  the  lympliatics  in  the  thorax  by  piercing  the  dia- 
phragm, and  end  for  the  most  part  in  the  sternal  glands  ;  those  on  the 
under  surface  enter  chiefly  the  glands  by  the  side  of  the  abdominal  aorta, 
a  few  uniting  with  the  deep  lymphatics,  and  the  coronary  of  tiie  stomach. 

The  deep  lymphatics  accompany  the  vessels  through  the  liver,  and 
communicate  with  one  of  the  large  contributing  trunks  of  the  thoracic 
duct. 

Serves  come  from  the  sympathetic  and  the  pneumo-gastric,  and  ramify 
with  the  vessels;  but  their  mode  of  ending  is  not  ascertained. 


THE  GALL-BLADDER. 

The  gall-bladder  (fig.  1G2)  is  the  receptacle  of  the  bile.  It  is  situate 
in  a  depression  on  the  under  surface  of  the  right  lobe  of  the  liver,  and  to 
the  right  of  the  square  lobe.  It  is  pear-slia})ed,  and  its  larger  end  (fundus) 
is  directed  forwards  beyond  the  margin  of  tlie  liver ;  whilst  the  smaller 
end  (neck)  is  turned  in  the  opposite  direction,  and  bends  downwards  to 
termidate  in  the  cystic  duct  by  a  zigzag  part. 

In  length  the  gall-bladder  measures  tliree  or  four  inches,  and  in  breadth 
rather  more  than  an  inch  at  the  widest  part.  It  holds  rather  more  than 
an  ounce. 

By  one  surface  it  is  in  contact  with  the  liver,  and  on  the  opposite  it  is 
covered  by  peritoneum.  The  larger  end  touches  the  abdominal  wall  oppo- 
site the  tip  of  the  cartilage  of  the  tenth  rib,  where  it  is  contiguous  to  the 
transverse  colon  ;  and  the  small  end  is  in  contact  with  the  duodenum. 

Structure.  The  gall-bladder  possesses  a  peritoneal,  a  fibrous  and  mus- 
cular, and  a  mucous  coat. 

The  serous  coat  is  stretched  over  the  under  or  free  surface  of  the  gall- 
bladder, and  surrounds  the  large  end. 

The  Jibrous  coat  is  strong,  and  forms  i\w.  framework  of  the  sac  ;  inter- 
mixed with  it  are  some  involuntary  muscular  fibres^  the  chief  being  lon- 
gitudinal, but  others  circular. 

•  Aberrant  ducts  'exist  between  the  pieces  of  the  peritoneum  in  the  left  lateral 
ligament  of  the  liver,  and  in  the  pons  bridging  over  the  vena  port*  and  vena  cava  ; 
they  anastomose  together,  and  are  accompanied  hy  branches  of  the  vessels  of  the 
liver,  viz.,  vena  portse,  hepatic  artery,  and  hepatic  vein. 


STRUCTURE    OF    GALL-BLADDER. 


473 


Fig.  162. 


The  nnicons  coat  is  marked  internally  by  numerous  ridges  and  interven- 
ing depressions,  which  give  an  areolar  or  honeycomb  appearance  to  the  sur- 
face. On  laying  open  the  gall-bladder  this  condition 
will  be  seen,  with  the  aid  of  a  lens,  to  be  most  developed 
about  the  centre  of  the  sac,  and  to  diminish  towards 
each  extremity.  In  the  bottom  of  the  larger  pits 
are  depressions  leading  to  recesses.  The  surface  of 
the  mucous  membrane  is  covered  by  a  columnar  epi- 
thelium. 

Where  the  gall-bladder  ends  in  the  cystic  duct  (fig. 
162)  its  coats  project  into  the  interior,  and  give  rise 
to  ridges  resembling  those  in  the  sacculated  large  in- 
testine. 

The  cystic  duct  (b)  joins  the  hepatic  duct  at  an 
acute  angle,  to  form  the  ductus  communis  choledo- 
chus.  It  is  about  an  inch  and  a  half  long,  and  is  dis- 
tended and  somewhat  sacculated  near  the  gall-bladder. 

Structure.  The  coats  of  the  duct  are  formed  like 
those  of  the  sac  from  which  it  leads,  but  the  muscular 
fibres  are  very  few.  The  mucous  lining  is  provided 
with  glands,  as  in  the  hepatic  and  common  bile  ducts 
(p.  472).    _ 

On  opening  the  duct  the  mucous  membrane  may  be 
observed  to  form  about  twelve  semilunar  projections 
(fig.  162,  c),  which  are  arranged  obliquely  around  the 
tube,  and  increase  in  size  towards  the  gall-bladder. 
This  structure  is  best  seen  on  a  gall-bladder  which 
has  been  inflated  and  dried  :  as  in  this  state  the  parts 
of  the  duct  between  the  ridges  are  most  stretched. 

Bloodvessels  and  nerves.  The  vessels  of  the  gall- 
bladder are  named  cystic.  The  artery  is  a  branch 
of  the  hepatic  ;  and  the  cystic  vein  opens  into  the  vena 
portoe  near  the  liver.  The  nerves  are  derived  from 
the  hepatic  plexus,  and  entwine  around  the  vessels. 
The  lymphatics  ibllow  the  cystic  duct,  and  join  the  deep  lymphatics  on 
the  spinal  column. 


Gall-Bladder  and  its 

Duct 
a.  Gall-bladder. 
h.  Bile  duct  sacculated. 

c.  Ridges  in  the  interior. 

d.  Common  bile  duct. 

c.  CommoD  hepatic  duct. 


THE  KIDNEY  AND  THE  URETER. 

The  kidney  has  a  characteristic  form :  flattened  on  the  sides,  it  is  larger 
at  the  upper  than  tlie  lower  extremity,  and  is  hollowed  out  at  one  part  of  its 
circumference.  For  the  purpose  of  distinguishing  between  the  right  and 
left  kidneys,  let  the  excavated  margin  be  turned  to  the  spinal  column,  with 
the  ureter  or  the  excretory  tube  beliind  the  other  vessels  ;  and  let  that  end 
be  directed  downwards,  towards  which  the  ureter  is  naturally  inclined. 

With  the  special  form  above  mentioned,  the  kidney  is  of  a  deep  red 
color,  with  an  even  surface.  Its  average  length  is  about  four  inches  ;  its 
breadth  two  ;  and  its  thickness  about  one  inch  ;  but  the  left  is  commonly 
longer  and  more  slender  than  the  right  kidney.  Its  usual  weight  is  about 
five  ounces  and  a  half  in  the  male,  and  rather  less  in  the  female. 

The  upper  extremity  of  the  kidney  is  rounded,  is  thicker  than  the  lower, 
and  is  surmounted  by  the  suprarenal  body.     The  lower  end  is  flat,  and 


474 


DISSECTION    OF    THE    ABDOMEN 


Fig.  163. 


more  pointed.     The  position  with  respect  to  the  spinal  column  has  been 
before  detailed  (p.  435). 

On  the  anterior  surface  the  viscus  is  rounded,  but  on  the  opposite  sur- 
face it  is  generally  flattened. 

The  outer  border  is  convex  ;  but  the  inner  is  excavated,  and  is  marked 
by  a  longitudinal  fissure,  hiluni.  In  the  fissure  the  vessels  are  thus  placed 
with  respect  to  one  another :  The  divisions  of  the  renal  vein  are  in  front, 

the  ureter  is  behind,  and  the  branches  of  the 
artery  lie  between  the  two.  On  the  ves- 
sels the  nerves  and  lymphatics  ramify  ;  and 
areolar  tissue  and  fat  surround  the  whole. 
Opposite  the  fissure  is  a  hollow  in  the  inte- 
rior of  the  kidney,  named  sinus,  in  which 
the  vessels  and  the  duct  are  contained  be- 
fore they  pierce  the  renal  substance. 

Dissection.  To  see  the  interior  it  will 
be  necessary  to  cut  through  the  kidney 
from  the  inner  to  the  outer  border ;  and  to 
remove  the  loose  tissue  from  the  vessels, 
and  from  the  divisions  of  the  excretory 
duct.  The  hollow  or  sinus  containing  the 
bloodvessels  now  comes  completely  into 
view. 

The  interior  of  the  kidney  fig.  163)  ap- 
pears on  a  section  to  consist  of  two  diffe- 
rent materials,  viz.,  of  an  external  granular 
or  cortical  part ;  and  of  internal,  darker 
colored,  pyramidal  masses,  which  converge 
towards  the  centre.  But  these  unlike- 
looking  parts  are  constructed  of  urine  tubes, 
though  with  a  different  arrangement. 

The  pyramidal  masses  (d)  (pyramids  of 
Malpighi),  are  twelve  or  eighteen  in  num- 
ber, and  converge  to  the  sinus  of  tlie  kid- 
ney. The  apex  of  each  mass,  which  is  free 
from  cortical  covering,  is  directed  to  the 
sinus,  and  ends  in  a  smooth,  rounded  part,  named  mamilla  or  papilla  (c). 
In  it  are  the  openings  of  the  urine  tubes,  which  are  about  twenty  in  num- 
ber, some  being  situate  in  a  central  depression  and  the  others  on  the  sur- 
face ;  and  it  is  surrounded  by  one  of  tiie  divisions  (calyx)  of  the  excretory 
tube.  Occasionally  two  of  the  masses  are  united  in  one  papillary  termina- 
tion. The  base  is  embedded  in  the  cortical  substance,  and  is  resolved  into 
bundles  of  tubes  which  are  prolonged  into  the  cortical  covering. 

Each  pyramidal  mass  is  constructed  of  uriniferal  tubes  (tubes  of  Bellini) 
which  open  below  at  the  apex  of  the  papilla  (fig.  1G4,  a)  ;  and  the  cut 
surface  has  a  grooved  apj)earance  indicatory  of  its  construction.  If  the 
mass  is  compressed,  urine  will  exude  from  the  tubes  through  the  apertures 
in  the  apex. 

The  cortical  Qv  investing  joarf  (fig.  163,  e)  forms  about  three-fourths  of 
the  kidney  ;  it  covers  the  pyramidal  masses  with  a  layer  about  two  lines 
in  thickness,  and  sends  prolongations  between  the  same  nearly  to  their 
apices.  Its  color  is  of  a  light  red,  unless  the  kidney  is  blanched  ;  and  its 
consistence  is  so  slight  that  the  mass  gives  way  beneath  the  finger.     In 


SeotionthrocghtheKidney,  show- 
ing THB  Medullary  and  Cortical 
Portions,  and  the  beginning  op 
THK  Urkter  (Heale). 

a.  Ureter, 

b.  Pelvis  of  the  ureter. 

c.  Calyx  of  tbe  excretory  tube. 

d.  Pyramidal  portions. 

e.  Cortical  porcioii  of  the  kidney. 


EXCRETORY    TUBES    OF    KIDNEY.  475 

the  injected  kidney  red  points  (Malpighian  bodies)  are  scattered  amongst 
the  cortex,  giving  it  a  granular  appearance. 

Structure  of  thp:  Kidney.  The  mass  of  the  kidney  consists  of 
minute  convoluted  tubes,  intermixed  with  bloodvessels,  lymphatics,  nerves, 
and  an  intertubular  matrix.     The  whole  is  incased  by  a  fibrous  coat. 

The  Jibrous  coat  is  a  white  layer,  which  is  connected  with  the  kidney 
by  fine  processes  and  vessels,  but  is  readily  detached  from  it  by  slight 
force.  At  the  inner  margin  of  the  kidney  it  sinks  into  the  sinus,  and 
sends  processes  on  the  entering  vessels  and  excretory  duct. 

Stroma  or  matrix.  Between  the  tubules  and  the  vessels  of  the  kidney 
is  a  uniting  materal,  which  surrounds  and  isolates  them,  and  is  most  abund- 
ant in  the  cortical  substance.  It  somewhat  resembles  areolar  tissue  in  its 
nature,  and  is  fibrous  at  some  spots. 

To  obtain  a  knowledge  of  the  anatomy  of  the  secreting  tubes,  and  of  the 
bloodvessels,  the  dissector  will  require  a  microscope,  and  good  fine  injec- 
tions of  the  kidney. 

Secretory  tubules.  The  uriniferous  tubes  (tubuli  uriniferi)  occupy  suc- 
cessively the  cortical  substance,  and  the  Malpighian  pyramids ;  but  they 
have  a  different  arrangement  in  each  part  as  below  (fig.  164,  a). 

In  the  Malpighian  pyramid  tubes  are  straight,  and  ascend  from  the 
apertures  in  the  apex,  bifurcating  repeatedly,  as  far  as  the  base,  and  form- 
ing a  cone  which  resembles  the  stem  and  branches  of  a  tree.  At  the  wide 
end  of  the  pyramid  they  are  collected  into  bundles  which  reach  nearly  to 
the  surface  of  the  kidney,  and  become  convoluted  as  they  enter  the  cortex, 
but  some  unite  in  arches  (Henle).  Near  the  apex  they  measure  3^0^^^  ^^ 
an  inch  across,  but  the  last  subdivisions  are  only  half  that  size,  or  ^Joth 
of  an  inch. 

Descending  between  the  straight  tubes  are  the  small  "'  looped  tubes"  of 
Henle  (fig.  }  64,  g).  These  run  down  from  the  cortical  substance  nearly 
to  the  apex  of  the  pyramid,  where  they  turn  upwards,  forming  loops  with 
the  convexity  down,  and  ascend  to  open  into  the  straight  tubes  :  their  size 
is  about  a  third  of  the  others. 

In  the  cortical  substance  the  tubes  are  more  numerous  and  very  convo- 
luted (fig.  165)  ;  they  have  an  average  width  of  g^o^^^  of  an  inch,  and  are 
surrounded  by  a  capillary  plexus  of  bloodvessels  (fig.  166,  a).  At  the 
one  end  (farther)  each  tube  is  dilated  into  the  Malpighian  corpuscle  {b)  ; 
and  at  the  other  it  passes  into  a  straight  tube  or  joins  an  "  arch"  at  the 
base  of  the  pyramid.  The  ''  looped  tube&"  of  Henle  (fig.  164)  have  the 
same  arranfjement  as  the  larger  tubuli  uriniferi  in  the  cortical  substance. 

The  wall  of  the  convoluted  tubes  consists  of  a  thin  basement  membrane, 
and  is  lined  by  a  thick,  nucleated,  and  granular  epithelium. 

Malpighian  corpuscles  (fig.  166,  a).  These  small  bodies  are  connected 
with  the  free  ends  of  the  convoluted  tubes,  one  to  each  :  and  are  arninged 
in  double  rows  in  the  cortical  substance  between  the  pyramids,  one  row 
being  on  each  side  of  an  interpyramidal  branch  of  artery,  from  which  they 
receive  tn'igs ;  each  measures  about  ji^yth  of  an  inch,  and  consists  of  an 
incasing  capsule  with  an  inclosed  tuft  of  bloodvessels  (glomerulus). 

The  capsule  (b)  is  the  dilated  end  of  the  convoluted  tube,  and  is  per- 
forated at  tlie  extremity  by  two  small  bloodvessels.  Its  wall  consists  of 
a  thin  basement  membrane,  and  is  lined  by  a  transparent  laminar  epithe- 
lium. 

The  glomerulus  (fig.  166,  b)  is  formed  by  the  intercommunications 
of  two  vessels  piercing  the  capsule,  and  is  clothed  with  epithelium.     One 


476 


DISSECTION    OF    THE    ABDOMEN 


of  the  two,  the  afferent  vessel  (rf),  is  an  offset  of  the  renal  artery,  and 
divides  into  convoluted  loops  of  the  fineness  of  capillaries,  which  form  the 
exterior  of  the  tuft.  The  other,  the  efferent  vessel  (/),  begins  in  the 
interior  of  tlie  tuft  by  the  union  of  the  loops  on  the  outer  surface  ;  and 


Fig.  164. 


Fig  165, 


Plan  of  the  Arrangement  of  the  Urini- 
FERAL  Tubes. 

a.  Tube  at  its  ending  in  the  pyramid. 

h.  Divisions  of  the   same   tube  in  the  pyra- 
mid. 

d.  Arches  of  Heule. 

c.  Twisted  tubes  joining  the  "arches." 

g.  Looped  tube  of  Henle,  with  Its  convo- 
luted part,/,  and  Malpighian  corpuscle, 
e,  in  the  cortical  substance. 


Plan  of  Contorted  Urine  Tcbes  ending  in 
Malpiohian  Corpuscles,  which  are  con- 
nected with  the  small  arteries  {d). 

a.  Urine  tube. 

h.  Malpighian  corpuscles. 

c.  Interpyramidal  branch  of  renal  artery 
(Bowman). 


passing  out  is  distributed  in  a  close  network  of  capillaries  (^)  on  the  con- 
voluted urine  tubes ;  and  in  one  with  elongated  meshes  on  the  straighter 
tubes  near  the  pyramids.  The  office  of  the  glomerulus  is  to  secrete  the 
watery  part  of  the  urine. 

Bloodvessels.  The  artery  and  vein  distributed  to  the  kidney  are 
very  large  in  proportion  to  the  size  of  the  orsan  they  nourish. 

Renal  artery.  As  the  artery  enters  the  kidney  it  divides  into  four  or 
five  branches,  which  are  invested  by  slieaths  of  the  fibrous  capsule,  and 
reach  the  bases  of  the  pyramids  of  Malpiglii,  where  they  form  arches. 
From  those  arches  arise  small  interpyramidal  branches,  which  ascend 
towards  the  surface,  and  furnish  the  afferent  twigs  to  the  Malpighian 
bodies,  whose  arrangement  has  been  referred  to.  Otlier  offsets  are  sup- 
plied to  the  capsule  and  matrix  of  the  kidney  ;  the  former  anastomose  with 
the  subperitoneal  branches  of  the  lumbar  arteries. 

Straight  vessels  descend  amongst  the  tubes  in  the  pyramids  of  Malpighi, 
and  some  form  loops  like  the  tubes  of  Henle. 

Renal  vein.  This  vein  begins  in  the  capillary  plexuses  on  the  convo- 
luted urine  tubes;  and  its  small  branches,  receiving  twigs  from  the  matrix 


BLOODVESSELS    OF    KIDNEY 


477 


and  the  fibrous  coat,  unite  into  larger  veins,  which  anastomose  freely 
around  the  bases  of  the  pyramids  of  Malpighi.  At  this  spot  they  are 
joined  by  offsets  from  capillary  plexuses  in  the  pyramids  ;  and  the  larger 
trunks  then  accompany  the  arteries  to  the  sinus  of  the  kidney.  Finally 
all  are  united  into  one  trunk,  which  opens  into  the  vena  cava. 

Fig.  166. 


a.  Urine  tube. 

b.  End-dilatation. 

c.  laterpyramidal  artery. 

d.  Afferent  brancli. 

e.  Glomerulus. 

/.  Efferent  vessel. 

g.  Ple.xus  of  capillaries  around  the 

urine  tube. 
h.  Radicles  of  the  veins. 
,  e.  Glomerulus. 
d.  Afferent,  and 
/.  Efferent  vessel  of  the  glomerulus 

(Bowman). 


Plan  of  the  Vessels  connected  with  the  Urine  Tubes. 


Nerves.  The  ramifications  of  the  sympathetic  nerve  may  be  traced  to 
the  smaller  branches  of  the  artery. 

The  ahsorhents  are  superficial  and  deep : — The  deep  absorbents  are  sup- 
posed to  begin  in  a  plexus  between  the  urine  tubes.  Both  unite  at  the 
hilum  of  the  kidney,  and  join  the  lumbar  glands. 

The  URETER  is  the  tube  by  which  the  fluid  secreted  in  the  kidney  is 
conveyed  to  the  bladder.  Between  its  origin  and  termination  the  canal 
measures  from  sixteen  to  eighteen  inches  in  length.  Its  size  corresponds 
commonly  with  that  of  a  large  quill.  Near  the  kidney  it  is  dilated  into  a 
funnel-shaped  part,  named  pelvis ;  and  near  the  bladder  it  is  again  some- 
what enlarged,  though  the  lower  aperture  by  which  it  terminates  is  the 
narrowest  part  of  the  tube.  Its  relative  anatomy  must  be  studied  after- 
wards, when  the  body  is  in  a  suitable  position. 

In  its  course  from  the  one  viscus  to  the  other,  the  ureter  is  close  beneath 
the  peritoneum,  and  is  directed  obliquely  downwards  and  inwards  along 
the  posterior  wall  of  the  abdomen  as  far  as  the  pelvis;  here  it  changes  its 
direction,  and  becomes  almost  horizontal.  At  first  the  ureter  is  placed 
over  the  psoas,  inclining  on  the  right  side  towards  the  inferior  vena  cava; 
and  about  the  middle  of  the  muscle  it  is  crossed  by  the  spermatic  vessels. 
Lower  down  it  lies  over  the  common  or  the  external  iliac  artery,  being 
beneath  the  sigmoid  flexure  on  the  left  side,  and  the  end  of  the  ileum  on 
the  right  side.  Lastly,  it  lies  below  the  level  of  the  obliterated  hypo- 
gastric artery. 

Sometimes  the  ureter  is  divided  into  two  for  a  certain  distance. 

Part  in  the  kidney  (fig.  163,  h).  Near  the  kidney  the  ureter  is  dilated 
into  a  pouch  called  pelvis ;  and  it  begins  by  a  set  of  cup-shaped  tubes, 
named  calices  or  infundibula,  which  vary  in  number  from  seven  to  thir- 
teen. Each  cup-shaped  process  embraces  the  rounded  end  of  a  pyramidal 
mass,  and  receives  the  urine  from  the  apertures  in  that  projection  ;  some- 
times a  calyx  surrounds  two  or  more  masses.     The  several  calices  are 


478  DISSECTION    OF    THE    ABDOMEN. 

united  together  to  form  two  or  three  larger  tubes  ;  and  these  are  finally 
blended  in  the  ureter. 

Structure.  Besides  an  external  fibrous  layer,  the  ureter  possesses  a 
muscular  and  a  mucous  coat. 

The  muscular  covering  is  composed  of  an  external  or  longitudinal,  and 
of  an  internal  or  circular  stratum. 

Tlie  mucous  coat  is  thrown  into  longitudinal  folds  during  the  contracted 
state  of  the  ureter.  Its  epithelium  consists  of  layers  of  cells  of  different 
shapes ;  thus,  at  the  free  surface  they  are  squarish,  at  the  attached  sur- 
face rounded,  whilst  in  the  intermediate  strata  they  are  cylindrical  (Kol- 
liker). 

The  calices  resemble  the  rest  of  the  duct  in  having  a  fibrous,  a  muscu- 
lar, and  a  mucous  coat.  Around  the  base  of  the  pyramid  the  calyx  is 
continuous  with  the  enveloping  tunic  of  the  kidney;  and  at  the  apex  the 
mucous  lining  is  prolonged  into  the  uriniferal  tubes  through  the  small 
openings. 

Vessels.  The  arteries  are  numerous  but  small,  and  are  furnished  by 
the  renal,  spermatic,  internal  iliac,  and  inferior  vesical.  The  veins  cor- 
respond with  the  arteries. 

The  lymphatics  are  received  into  those  of  the  kidney. 

THE  SUPRARENAL  BODY. 

This  small  body,  whose  use  is  unknown,  has  received  its  name  from  its 
position  to  the  kidney.  Its  vessels  and  nerves  are  numerous,  but  it  is  not 
provided  with  any  excretory  duct. 

One  on  each  side,  it  is  situate  on  the  upper  extremity  and  fore  part  of 
the  kidney ;  and  without  care  it  may  be  removed  with  the  surrounding 
fat,  which  it  resembles.  Its  color  is  a  brownish-yellow.  It  is  like  a 
cocked  hat  in  form,  with  the  upper  part  convex,  and  the  base  or  lower 
part  hollowed,  where  it  touches  the  kidney. 

In  the  adult  it  measures  about  one  inch  and  a  half  in  depth,  and  rather 
less  in  width  ;  and  its  weight  is  between  one  and  two  drachms,  but  the  left 
is  commonly  larger  than  the  right. 

Areolar  tissue  attaches  the  suprarenal  body  to  the  kidney ;  and  large 
vessels  and  nerves  retain  it  in  place.  The  connections  with  the  surround- 
ing parts  are  the  same  as  those  of  the  upper  end  of  the  kidney.  Tlius  it 
rests  on  the  diaphragm  on  both  sides ;  whilst  above  the  right  is  the  liver, 
and  above  the  left  the  pancreas  and  the  spleen.  On  the  inner  side  of  the 
right  capsule  is  the  vena  cava,  with  part  of  the  solar  plexus ;  and  internal 
to  the  left  is  the  aorta,  with  the  same  plexus  of  nerves. 

Structure  (fig.  167).  A  perpendicular  section  shows  the  suprarenal 
body  to  be  formed  of  a  firm  or  external  (cortical)  part,  and  of  an  internal 
(medullary)  soft  and  dark  material.  With  the  microscope  this  body  may 
be  seen  to  consist  of  cells,  which  are  lodged  in  spaces  formed  by  a  stroma 
of  areolar  tissue,  with  vessels  and  nerves. 

The  whole  is  surrounded  by  a  \.\\m  Jihrous  capsule  (a),  which  sends  pro- 
cesses into  the  interior,  and  along  the  bloodvessels. 

The  cortical  part,  yellowish  in  color  and  striated,  forms  about  two- 
thirds  of  the  thickness  of  the  whole  body.  Its  stroma  of  areolar  tissue  (a) 
forms  a  thin  surface  layer,  and  is  connected  internally  with  processes  or 
septa,  whicii  are  so  arranged  as  to  build  up  spaces  elongated  from  without 
inwards,  and  arranged  vertically  around  the  centre ;  but  near  the  surface 


CHARACTERS    OF    TESTIS, 


479 


Fig.  167. 


there  are  smaller  oval  spaces,  some  of  them  crossing  the  deeper  and  larger. 
The  spaces  or  loculi  (b)  are  filled  by  columnar  masses  of  cells,  but  slight 
force  readily  removes  these  from  their  containing  hollows. 

The  central  or  medullary  portion  (c)  is  rather  red  in  color,  or  it  may  be 
dark  brown  or  black  from  the  presence  of  blood.  About  half  as  thick  as 
the  cortical  part,  it  possesses  internally  small  round  or  oval  spaces,  on  a 
section,  which  are  vein  trunks  cut  across.  The  areolar  tissue  of  its  stroma 
is  very  fine,  and  forms  a  network  with  small  but  regular  meshes  ;  and  the 
medullary  is  separated  generally  from  the  cortical 
portion  by  a  layer  of  areolar  tissue.  Cells  fill  the 
meshes. 

Cells.  The  cells  filling  the  loculi  of  the  stroma 
in  the  cortex  are  nucleated  with  oil  globules  and 
fine  granules  ;  and  being  packed  in  masses,  they 
take  on  a  polygonal  form  :  they  measure  about  the 
jT^^j^th  of  an  inch.  In  the  medullary  portion  the 
cells  resemble  those  of  the  cortex,  except  that  they 
do  not  contain  oil  particles ;  and  they  are  rather 
larger  and  more  granular,  measuring  about  xoVu^^ 
of  an  inch. 

Bloodvessels.  Numerous  arteries  are  furnished 
to  the  suprarenal  body  from  the  diaphragmatic  and 
renal  vessels,  and  from  the  aorta.  In  the  interior 
the  arteries  ramify  in  the  cortex  along  the  septa 
between  the  cell  masses  ;  and  frequently  anasto- 
mosing together,  end  in  a  fine  capillary  network, 
with  elongated  meshes,  around  the  loculi.  In  the 
medullary  part    the    fine    arteries    are    distributed 


through  the  stroma. 


The  veins  originate   in  capillary  plexuses ;  and 


the    several    radiclee 


in    large    branches 


Vertical  StcrIo^  of  the 
Suprarenal  Body. 

a.  Surface  layer  of  stroma. 

b.  Cells  in  the  cortex. 

c.  Medullary  portion. 

d.  Spaces  in  the  medullary 
part  (Harley). 


which  pass  through  the  centre  of  the  medullary 
part,  are  collected  finally  into  one  trunk  ;  this  opens  on  the  right  side  into 
the  vena  cava,  and  on  the  left  into  the  renal  vein.  Other  smaller  veins 
pass  out  through  the  cortex  to  the  renal  vein  and  the  vena  cava. 

Nerves.  The  nerves  are  very  numerous  and  large,  and  pass  inwards 
along  the  septa  of  the  cortical  part :  branching,  they  extend  between  the 
cortical  and  medullary  parts  in  the  layer  of  areolar  tissue,  and  in  the  me- 
dullary substance  they  form  a  network  in  the  are(jlar  structure,  but  their 
ending  is  unknown. 

Lymphatics  are  superficial  and  deep,  and  both  join  those  of  the  kidney ; 
the  arrangement  of  the  deep  is  undetermined. 


THE    TESTES. 

The  testes  are  the  glandular  organs  for  the  secretion  of  the  semen. 
Each  is  suspended  in  the  scrotum  by  the  spermatic  cord  and  its  coverings 
(p.  418),  but  the  left  is  usually  lower  than  the  right;  and  each  is  pro- 
vided with  an  excretory  duct  named  vas  deferens.  A  serous  sac  partly 
surrounds  each  organ. 

Dissection.  For  the  purpose  of  examining  the  serous  covering  of  the 
testicle  (tunica  vaginalis),  make  a  small  aperture  into  it  at  the  upper  part, 
and  inflate  it.     The  sac  and  the  spermatic  cord  are  then  to  be  cleaned  ; 


480 


DISSECTION    OF    THE    ABDOMEN. 


and  the  vessels  of  the  latter  are  to  be  followed  to  their  entrance  into  the 
testicle. 

The  tunica  vaginalis  (fig.  168,  d)  is  a  serous  bag,  which  is  continuous 
in  the  foetus  with  the  peritoneal  lining  ot  the  abdomen,  but  becomes  subse- 
quently a  distinct  sac  through  the  obliteration  of  the  part  connecting  tlie  two. 
It  invests  the  testicle  after  the  manner  of  other  serous  membranes :  for 
the  testicle  is  placed  behind  it,  so  as  to  be  partly  enveloped  by  it.     The  sac, 
however,  is  larger  than  is  necessary  for  covering 
Fig.  168.  the  testicle,  and  projects  some  distance  above  it. 

Like  other  serous  membranes,  it  has  an  external 


rouo;h,  and  an  internal  secerning  smooth  surface 


and  like  them  it  has  a  visceral  and  a  parietal 
part.  To  examine  its  disposition  tiie  sac  should 
be  opened. 

The  visceral  layer  (tunica  vaginalis  testis) 
covers  the  testicle,  except  posteriorly  where  the 
vessels  lie.  On  the  outer  side  it  extends  farther 
back  than  on  the  inner,  and  forms  a  pouch  be- 
tween the  testis  and  the  arched  body  (epididymis) 
on  this  aspect  of  the  organ. 

The  parietal  part  of  the  sac  (tunic,  vagin. 
scroti)  is  more  extensive  than  the  piece  covering 
the  testicle,  and  lines  the  contiguous  layer  of  the 
scrotum. 

Form  and  position  of  the  testis  (fig.  168). 
The  testicle  is  oval  in  shape,  with  a  smooth  sur- 
face, and  is  flattened  on  tiie  sides.  The  ante- 
rior, which  is  flattened,  is  pierced  by  the  sperma- 
tic vessels  and  nerves.  Stretching  like  an  arcii 
along  the  outer  part  is  the  epididymis  {b).  At- 
tached to  the  upper  end  of  the  testis  is  a  small 
body  (c)  two  or  three  lines  in  length  (corpus 
Morgagni),  which  is  the  remains  of  the  upper 
end  of  the  fwjtal  duct  of  MuUer  ;  and  occasionally 
other  smaller  projections  of  the  tunica  vaginalis 
are  connected  with  the  top  of  the  epididymis. 

The  testis  is  suspended  obliquely,  so  tiiat  the 
upper  part  is  directed  forwards  and  somewhat 
outwards,  and  the  lower  end  backwards  and 
rather  inwards. 

Size  and  weight.     The  length  of  the  testis  is 

an  inch  and  a   half  or  two  inches  ;  from  before 

backwards  it  measures  rather  more  tlian  an  inch, 

and  from  side  to  side  rather  less  tlian  an  inch. 

Its  weight  nearly  an  ounce,   and  the  left  is  frequently  larger  than    the 

other. 

Structure.  The  substance  of  the  testicle  is  composed  of  minute  se- 
cerning tubes,  around  whicli  the  bloodvessels  are  disposed  in  plexuses. 
Surrounding  and  supporting  the  delicate  seminiferal  tubes  is  a  dense 
covering — the  tunica  albuginea.  Its  excretory  or  efferent  duct  is  named, 
vas  deferens, 

Dissection.  With  the  view  of  examining  the  investing  fibrous  coat,  let 
the  testis  be  placed  on  its  outer  side,  viz.,  that  on  which  the  epididymis 


The  Testis  with  the  Tunica 
Vaginalis  laid  open. 

a.  Testicle. 

b.  Head  of  the  epididymis. 

c.  Corpus  Morgagni. 

d.  Parietal  part  of  the  tunica 

vaginalis. 
c.  Vessels    of    the    spermatic 

cord 
/.  Vas  deferens. 


STRUCTURE    OF    THE    TESTIS.  481 

lies,  and  let  it  be  fixed  firmly  in  that  position  with  pins.  The  fibrous  coat 
is  to  be  cut  through  along  the  anterior  part,  and  thrown  backwards  as  far 
as  the  entrance  of  tlie  bloodvessels.  Whilst  raising  this  membrane  a 
number  of  fine  bands  will  be  seen  traversing  the  substance  of  the  testicle, 
and  a  short  septal  piece  (mediastinum)  may  be  perceived  at  the  back  of  the 
viscus,  where  the  .vessels  enter  ;  but  it  will  be  expedient  to  remove  part  of 
the  mass  of  tubes  in  the  interior,  to  bring  more  fully  into  view  the  media- 
stinum, and  to  trace  back  some  of  the  finer  septa  to  it. 

The  tunica  albuginea^  or  the  fibrous  coat  of  the  testicle,  is  of  a  bluish- 
white  color,  and  resembles  in  appearance  the  sclerotic  coat  of  the  eyeball. 
This  membrane  protects  the  secreting  part  of  the  testicle,  and  maintains 
the  shape  of  the  organ  by  its  dense  and  unyielding  structure:  it  also  sends 
inwards  processes  to  support  and  separate  the  seminal  tubes.  These  seve- 
ral offsets  of  the  membrane  appear  in  the  dissection  ;  and  one  of  them  at 
the  back  of  the  testicle,  which  is  larger  than  the  rest,  is  the  mediastinum. 

The  mediastinum  testis  (fig.  169,  d)  (corpus  Highmorianum)  projects 
into  the  gland  for  a  third  of  an  inch  with  the  bloodvessels.  It  is  situate 
at  the  back  of  the  testis,  extending  from  the  upper  nearly  to  the  lower  part, 
and  is  rather  larger  and  deeper  above  than  below.  It  is  formed  of  two 
pieces,  which  are  united  anteriorly  at  an  acute  angle.  To  its  front  and 
sides  the  finer  septal  processes  are  connected ;  and  in  its  interior  are  con- 
tained the  bloodvessels  behind,  and  a  network  of  seminal  ducts  in  front 
(rete  testis). 

Of  thiijiner  processes  of  the  tunica  albuginea  (fig.  169,  b)  which  enter 
the  testis,  there  are  two  kinds.  One  set  round  and  cord-like,  but  of  diffe- 
rent lengths,  is  attached  posteriorly  to  the  mediastinum,  and  serves  to 
maintain  the  shape  of  the  testis.  The  other  set  forms  delicate  membranous 
septa,  which  divide  the  mass  of  seminal  tubes  into  lobes,  and  join  the 
mediastinum,  like  the  rest. 

Within  the  tunica  albuginea  is  a  thin  vascular  layer,  tunica  vasculosa 
(Sir  A.  Cooper),  which  lines  the  fibrous  coat,  covering  the  different  septa 
in  the  interior  of  the  gland.  It  is  formed  of  the  ramifications  of  the  blood- 
vessels, united  by  areolar  tissue,  like  the  pia  mater  of  the  brain  ;  in  it  the 
arteries  are  subdivided  before  they  are  distributed  on  the  secerning  tubes, 
and  the  small  veins  are  collected  into  larger  trunks. 

Form  and  length  of  the  seminal  tubes  (tubuli  seminiferi).  The  secern- 
ing or  seminal  tubes  are  very  convoluted,  and  are  but  slightly  held  together 
by  fine  areolar  tissue  and  surrounding  bloo:lvesseIs,  so  that  they  may  be 
readily  drawn  out  of  the  testis  for  some  distance  :  their  length  is  said  by 
Lauth  to  be  two  feet  and  a  quarter. 

Ending^  size,  and  structure.  Within  the  lobes  of  the  testis  some  tube-? 
end  in  distinct  closed  extremities;  but  the  rest  communicate,  forming 
loops  or  arches.  The  diameter  of  the  tubules  varies  from  ijj^th  to  yjijtli 
of  an  inch.  The  wall  of  the  tubule  is  formed  of  a  thin  translucent  mem- 
brane, but  it  has  considerable  strength.  Lining  the  interior  in  the  child 
is  a  nucleated  granular  epithelium,  with  polygonal  cells;  but  in  the  adult 
the  tube  is  filled  by  cells  in  different  stages  of  development  of  the  sper- 
matic corpuscles.     On  the  exterior  is  a  plexus  of  bloodvessels. 

Names  from,  the  arrangement  of  the  tubes.  To  different  parts  of  the 
seminal  tubes,  the  following  names  have  been  applied.  AVhere  the  tubules 
are  collected  into  masses,  they  form  the  lobes  of  the  testis.  As  they  enter 
the  fibrous  mediastinum  they  become  straight,  and  are  named  tubuli  recti. 
Communicating  in  the  mediastinum,  they  produce  the  rete  testis.  And, 
31 


482 


DISSECTION    OF    THE    ABDOMEN. 


Ustly,  as  they  leave  the  upper  part  of  the  gland  they  are  convoluted,  and 
are  called  coni  vasculosi,  or  vasa  efferentia. 

The  lohes  of  the  testis  (fig.  109,  o.)  are  formed  by  bundles  of  the  semi- 
niferal  tubes,  and  are  situate  in  tiie  intervals  between  the  processes  of  the 


a.  Lobes  of  the  testis. 

6.  Septa  betweea  the  lobes. 

c.  Tubuli  recti. 

d.  Mediastinum  testis. 

e.  Rete  testis. 
/.  Vasa  efferentia. 
g.  Globus  major. 

h.  Body,  and  i,  globus  minor  of  the  epididymis. 
li.  Vas  deferens. 
I.  Vas  aberrans. 
n.  Rete  testis,  cut. 
o.  Finer  septa. 
p.  Epididymis,  cut  across. 
r.  Mediastinum,  cut  across. 

Vertical  and  Horizontal  Sections  of  the  Testis  to  show  the  arrangement  op  the 
Srminal  Tubes,  and  Septa. 

tunica  albuginea  :  their  nunnber  is  differently  stated : — according  to  one 
authority  (Berres)  they  are  250;  but  according  to  another  (Krause)  400 
or  more.  They  are  conical  in  form,  with  the  base  of  each  at  the  circum- 
ference, and  the  apex  at  the  mediastinum  testis;  and  those  in  the  centre 
of  the  testicle  are  the  largest. 

Each  is  made  up  of  one,  two,  or  more  tortuous  seminal  tubules  ;  and  the 
minute  tubes  in  one  lobe  are  united  wdth  those  in  the  neighboring  lobes. 
Towards  the  apex  of  each  lobe  the  tubules  become  less  bent,  and  are 
united  together;  and  the  tubuli  of  the  several  lobes  are  further  joined  at 
the  same  spot  into  larger  canals — the  tubuli  recti. 

TubuH  recti  (fig.  169,  c).  The  seminal  tubes  unite  together,  becoming 
larger  (^V^h  of  an  inch)  and  straighter  in  direction,  and  are  named  tubuli 
recti  or  vasa  recta:  they  are  about  twenty  in  number,  and  piercing  the 
fibrous  mediastinum  enter  into  the  rete  testis. 

Rete  testis  (fig.  169,  e).  In  the  mediastinum  the  seminal  tubes  have 
very  thin  walls,  and  are  situate  in  the  anterior  part,  in  front  of  the  blood- 
vessels; they  communicate  freely  so  as  to  form  a  network. 

Vasa  efferentia  (fig.  169,/).  About  twelve  or  twenty  seminal  tubes 
issue  from  the  top  of  the  rete,  and  leave  the  upper  part  of  the  testicle  as 
the  vasa  efferentia:  these  are  larger  than  the  tubes  with  which  they  are 
continuous,  and  end  in  the  common  excretory  duct..  Though  straight  at 
first  they  soon  become  convoluted,  and  have  been  named  coni  vasculosi. 
In  the  natural  state  they  are  about  half  an  inch  in  length,  but  when  un- 
ravelled they  measure  six  inches;  and  they  join  the  excretory  duct  at  in- 
tervals of  about  three  inches.  They  have  a  muscular  coat  of  longitudinal 
and  circular  fibres;  and  the  epithelium  of  the  mucous  lining  is  columnar 
and  ciliated. 

The  EXCRETORY  DUCT  rcceivcs  the  vasa  efferentia  from  the  upper  part 
of  the  gland,  and  extends  thence  to  the  urethra.  Its  first  part,  which  is 
in  contact  with  the  testis,  is  very  flexuous,  and  forms  the  epididymis:  but 
the  remainder  is  straight,  and  is  named  vas  deferens. 


DUCT    OF    TESTIS.  483 

The  epididymis  (fig.  169,  h)  extends  in  the  form  of  an  arch  along  the 
outer  side  of  the  testis,  from  the  upper  to  the  lower  end,  and  receives  its 
name  from  its  situation.  Opposite  the  upper  part  of  tlie  testicle  it  pre- 
sents an  enlarged  portion  or  head,  the  globus  major  {^g) ;  and  at  the  lower 
end  of  that  organ  it  becomes  more  pointed  or  tail-like — globus  minor  (i), 
before  ending  in  the  vas  deferens.  The  intervening  narrow  part  of  the 
epididymis  is  called  the  body  (h).  Its  head  is  attached  to  the  testis  by 
the  vasa  efferentia;  and  its  lower  part  is  fixed  to  the  tunica  albuginea  by 
fibrous  tissue,  and  by  the  reflection  of  the  tunica  vaginalis. 

The  epididymis  is  formed  of  a  single  tube,  bent  in  a  zigzag  way,  whose 
coils  are  united  into  a  solid  mass  by  fibrous  tissue.  After  the  removal  of 
the  serous  membrane  and  some  fibrous  tissue  this  part  of  the  tube  may  be 
uncoiled;  it  will  then  measure  twenty  feet  in  length.  The  diameter  of  its 
canal  is  about  y^th  of  an  inch,  though  there  is  a  slight  diminution  in  size 
towards  the  globus  minor,  but  it  is  increased  finally  in  the  vas  deferens. 

The  vas  deferens  (fig.  169,  k)  begins  opposite  tlie  lower  end  of  the  tes- 
tis, at  the  termination  of  the  globus  minor  of  the  epididymis.  At  first  this 
part  of  the  excretory  duct  is  slightly  wavy,  but  afterwards  it  becomes  for 
the  most  part  a  firm  round  tube :  near  its  termination  it  is  enlarged  again 
and  sacculated,  but  this  condition  will  be  referred  to  with  the  viscera  of 
the  pelvis. 

In  its  course  to  the  urethra  it  ascends  on  the  inner  side  of  the  testicle, 
and  along  the  bloodvessels  of  the  spermatic  cord  with  w^iich  it  enters  the 
internal  abdominal  ring;  it  is  then  directed  over  the  side  of  the  bladder, 
and  through  the  prostate  to  open  into  the  urethra.  The  length  of  this 
part  of  the  excretory  duct  is  about  two  feet,  and  the  width  of  its  canal 
about  ^^^th  of  an  inch. 

Opening  sometimes  into  the  vas  deferens,  at  the  angle  of  union  with  the 
epididymis,  is  a  small  narrow  crecal  appendage,  the  vas  aberrans  of  Haller 
(fig.  169,  /).  It  is  convoluted,  and  projects  upwards  for  one  or  two  inches 
amongst  the  vessels  of  the  cord.  Like  the  epididymis,  it  is  longer  when 
it  is  uncoiled  :  its  capacity  is  greatest  at  the  free  end.     Its  use  is  unknown. 

Structure,  The  excretory  duct  of  the  testis  has  a  thick  muscular  coat, 
which  is  covered  externally  by  fibrous  tissue,  and  lined  internally  by  mu- 
cous membrane.  To  the  feel  the  duct  is  firm  and  wiry,  like  whip-cord. 
On  a  section  its  w^all  is  dense  and  of  a  rather  yellow  color,  but  it  is  thinnest 
at  the  head  of  the  epididymis. 

The  muscular  coat  is  composed  of  longitudinal  and  circular  fibres  ar- 
ranged in  strata.  Both  externally  and  internally  is  a  longitudinal  layer, 
the  latter  being  very  thin  ;  and  between  them  is  the  layer  of  circular  fibres. 

The  mucous  membrane  is  marked  by  longitudinal  folds  in  the  straight 
part  of  the  canal,  and  by  irregular  ridges  in  the  sacculated  portion.  A 
columnar  epithelium,  though  not  ciliated,  covers  the  inner  surface  ;  but  in 
the  epididymis  it  is  ciliated  (Becker). 

Organ  of  Giraldes}  In  the  spermatic  cord  of  the  foetus  and  child,  close 
above  the  epididymis,  is  a  small  whitish  granular-looking  body  ("  Corps 
Innomine,"  Giraldes),  about  half  an  inch  long — the  remains  of  the  low^er 
part  of  the  Wolffian  body  of  the  embryo.  With  slight  magnifying  power 
its  com{)onent  white  granules  are  resolved  into  small  vesicles,  and  convo- 
luted  tubes  of  varying  shape,  filled  with  a  clear  thick  fluid;  their  wall 

1  Sur  uii  Organe  place  dans  le  Cordon  Spermatique,  et  dont  I'existence  n'a  pas 
ete  signalee  par  les  Anatomistes.  Par  F.  Giraldes.  Proceedings  of  the  Royal 
Society  for  May,  1858. 


48-4  DISSECTION    OF    THE    ABDOMEN. 

consists  of  a  thin  membrane,  lined  by  fluttened  epithelium,  with  plexuses 
of'  bloodvessels  ramifying  on  the  exterior. 

Bloodvessels  and  nerves  of  the  testicle.  The  branches  of  the  spermatic 
artery  supply  offsets  to  the  epididymis,  and  pierce  the  back  of  the  testicle 
to  enter  the  posterior  part  of  the  mediastinum.  The  vessels  are  finely 
divided  in  the  vascular  structure  lining  the  interior  of  the  tunica  albugi- 
nea;  and  offsets  are  continued  on  the  fine  septa  to  the  seminal  tubules,  on 
which  they  are  distributed  in  capillary  plexuses. 

The  spermatic  vein  begins  by  radicles  in  the  plexuses  around  the  seminal 
tubes,  and  issues  from  the  gland  at  the  posterior  part,  being  there  joined 
by  veins  from  the  epididymis.  As  it  ascends  along  the  cord  its  branches 
form  the  spermatic  plexus ;  it  joins  the  vena  cava  on  the  right  side,  and 
the  renal  vein  on  the  left  (p.  492). 

The  arrangement  of  the  lymphatics  in  the  testicle  is  unknown  ;  external 
to  that  body  they  ascend  on  the  bloodvessels,  and  join  the  lumbar  glands. 

The  nerves  are  derived  from  the  sympathetic,  and  accompany  the  arte- 
ries to  the  testis  :  their  ending  has  not  been  seen. 

Vessels  of  the  vas  deferens.  A  special  artery  is  furnished  to  the  excre- 
tory duct  from  the  upper  or  lower  vesicle,  and  reaches  as  far  as  the  testis, 
where  it  anastomoses  with  the  spermatic  artery.  Veins  from  the  epididy- 
mis enter  the  spermatic  vein.  The  nerves  are  derived  from  the  hypogastric 
plexus. 


Section  V. 

DIAPHRAGM  WITH  AORTA  AND  VENA  CAVA. 

Directions.  After  the  body  is  replaced  in  its  former  position  on  the 
Back,  the  student  should  ])repare  first  the  diaphragm,  next  the  large  ves- 
sels and  their  branches,  and  then  the  deep  muscles  of  the  abdomen. 

Dissection.  For  the  dissection  of  the  diaphragm  it  will  be  necessary  to 
remove  the  peritoneum,  defining  especially  tiie  central  tendinous  part,  and 
the  fleshy  processes  or  pillars  which  are  fixed  to  the  lumbar  vertebrje. 
Whilst  cleaning  the  muscle  the  student  should  be  careful  of  the  vessels  and 
nerves  on  the  surface,  and  of  others  in  and  near  the  pillars. 

On  the  right  side  two  aponeurotic  bands  or  arches,  near  the  spine, 
which  give  attachment  to  the  muscular  fibres,  should  be  dissected :  one 
curves  over  the  internal  muscle  (psoas);  the  other  extends  over  the  exter- 
nal muscle  (quadratus),  and  will  be  made  more  evident  by  separating  the 
fascia  covering  the  quadratus  from  it. 

The  DIAPHRAGM  (fig.  168,  ^)  forms  the  vaulted  movable  partition  be- 
tween the  thorax  and  the  abdomen.  It  is  fleshy  externally,  where  it  is 
attached  to  the  surrounding  ribs  and  the  spinal  column,  and  has  its  tendon 
in  the  centre. 

The  origin  of  the  muscle  is  at  the  circumference,  and  is  similar  on  each 
side  of  the  middle  line.  Thus,  it  is  connected  by  fleshy  sli])S  with  the  |)os- 
terior  part  of  the  xiphoid  cartilage,  and  the  inner  surface  of  the  six  lower 
ribs;  with  two  aponeurotic  arches  between  the  last  rib  and  the  spinal 
column — one  being  placed  over  the  quadratus  lumborum,  and  the  other 
over  the  psoas  muscle  ;  and,  lastly,  it  is  connected  with  the  lumbar  verte- 
brae by  a  thick  muscular  part  or  pillar.      From   this  extensive  origin   the 


DIAPHRAGM    AND    ITS    ACTION. 


485 


fibres  are  directed  inwards,  with  different  degrees  of  obliquity  and  length, 
to  the  central  tendon,  but  some  have  a  peculiar  disposition  in  the  pillars 
which  will  be  afterwards  noted. 

The  abdominal  surface  is  concave,  and  is  covered  for  the  most  part  by 
the  peritoneum.  In  contact  with  it  on  the  right  side  are  the  liver  and  the 
kidney;  and  on  tlie  opposite  side,  the  stomach,  the  spleen,  and  the  left 
kidney:  in  contact  also  with  the  pillars  is  the  pancreas,  together  with  the 
solar  plexus  and  the  semilunar  ganglia.  The  thoracic  surface  is  covered 
by  the  pleura  of  each  side  and  the  pericardium,  and  is  convex  towards  the 
thorax  (p.  343).  At  the  circumference  of  the  midritf  the  fleshy  processes 
of  origin  alternate  with  like  parts  of  the  transversalis  muscle;  but  a  slight 
interval  separates  the  slips  to  the  xiphoid  cartilage  and  seventh  rib,  and  a 
second  space  exists  sometimes  between  the  fibres  from  the  last  rib  and  the 
arch  over  the  quadratus  lumborum  muscle.  In  it  are  certain  apertures  for 
the  transmission  of  parts  from  the  tiiorax  to  the  abdomen. 

The  muscle  is  convex  towards  the  chest,  and  concave  to  the  abdomen. 
Its  arch  reaches  higher  on  the  right  than  the  left  side  (p.  30G),  and  is  con- 


Yicr.  170. 


A.  Diaphragm. 

B.  Psoas  raaguus. 

c.  Quadratus  lumborum. 

a.  Left  piece  of  the  teudon  of  the  diaphragm  ; 
6,  middle;  and  c,  right  piece. 


Ua'deb  Surface  of  the  Diaphraom. 

d.  Left,  and  e,  right  cms. 


/.  Inner,  and  g,  outer  arched  ligament. 
A-  Opening  for  vena  cava  ;  i,  for  oesophagus,  t, 
for  aorta,  y,  for  sympathetic  nerves. 


stantly  varying  during  life  in  respiration.  In  forced  expiration  the  muscle 
ascends,  and  reaches  as  high  as  the  upper  border  of  the  right  fourth  rib  at 
the  sternum,  and  the  upper  edge  of  the  fiftii  rib  on  the  left  side,  close  to 
the  sternum.  In  forced  inspiration  it  descends,  and  its  slope  would  be 
represented  by  a  line  drawn  from  the  middle  of  the  ensiform  cartilage  to 
the  eleventh  rib. 

Action.  As  the  muscle  moves  up  and  down  during  respiration,  it  is 
depressed  by  the  contraction  of  the  fleshy  fibres  which  are  attached  to  the 
ribs  and  spine,  and  is  raised  during  their  relaxation. 


486  DISSECTION    OF    THE    ABDOMEN. 

When  the  diaphragm  descends  it  changes  its  shape.  The  central  tendon, 
-wliich  moves  but  sliglitly,  remains  the  higliest  part  of  the  arch,  whilst  the 
sides  which  contract  freely  are  sloped  from  the  tendon  to  the  wall  of  the 
thorax.  During  the  ascent  the  midriff  retains  nearly  the  same  form  as  in 
a  state  of  rest,  for  the  tendon  is  the  lowest  part  of  the  arch,  and  the  bulges 
on  the  sides  reach  rather  higher. 

With  the  movement  of  tlie  diaphragm  the  size  of  the  cavities  of  the 
abdomen  and  thorax  will  be  altered.  In  inspiration  the  thorax  is  enlarged, 
and  the  abdomen  diminished ;  and  the  viscera  in  the  upper  part  of  the 
latter  cavity,  viz.,  liver,  stomach,  and  spleen,  are  partly  moved  from  be- 
neath the  ribs.  In  expiration  tlie  cavity  of  the  thorax  is  lessened,  and 
that  of  the  abdomen  is  restored  to  its  former  size  ;  and  the  displaced  viscera 
return  to  their  usual  place.  By  the  contraction  of  tlie  fibres  the  aperture 
for  the  oesophagus  will  be  rendered  smaller,  and  that  tube  may  be  com- 
pressed ;  but  the  other  openings  for  tlie  vena  cava  and  aorta  do  not  ex- 
perience change. 

Preparatory  to  the  making  of  a  great  muscular  effort,  the  midriff  con- 
tracts, and  descends  for  the  purpose  of  permitting  a  full  quantity  of  air  to 
enter  the  thorax.  Till  the  effort  is  over  tlie  diaphragm  remains  in  a  de- 
pressed position.  '  Its  action  is  commonly  involuntary,  but  the  movement 
can  be  controlled  by  the  will  at  any  stage. 

Parts  of  the  diaphragm.  The  following  named  parts,  which  have  been 
noticed  shortly  in  describing  the  muscle,  are  now  to  be  referred  to  more 
fully,  viz.,  the  central  tendon,  the  pillars,  the  arches,  and  the  apertures. 

The  central  tendon  (cordiform  tendon)  occupies  the  middle  of  the  dia- 
phragm (fig.  170),  and  is  surrounded  by  muscular  fibres;  the  large  vena 
cava  pierces  it.  It  is  of  a  pearly  white  color,  and  its  tendinous  fibres 
cross  in  different  directions.  In  form  it  resembles  a  trefoil  leaf:  of  its 
three  segments  the  right  (c)  is  the  largest,  and  the  left  {a)  the  smallest. 

The  pillars  (crura)  are  two  large  muscular  and  tendinous  processes  {d 
and  e),  one  on  each  side  of  the  abdominal  aorta.  They  are  pointed 
and  tendinous  below,  where  they  are  attached  to  the  upper  lumbar  verte- 
brae, but  large  and  fleshy  above ;  and  between  them  is  a  tendinous  arch 
over  the  aorta. 

In  each  pillar  the  fleshy  fibres  pass  upwards  and  forwards,  diverging 
from  each  other :  the  greater  number  join  the  central  tendon  without  in- 
termixing, but  the  inner  fibres  of  the  two  crura  cross  one  another  in  the 
following  manner  : — Those  of  the  right  (e)  ascend  by  the  side  of  the  aorta, 
and  pass  to  the  left  of  the  middle  line  decussating  with  the  fibres  of  the 
opposite  crus  between  that  vessel  and  the  opening  of  the  ojsophagus.  The 
fibres  of  the  other  crus  {d)  may  be  traced  in  the  same  way,  to  form  the 
right  half  of  the  oesophagean  opening.  In  the  decussation  the  fasciculus  of 
fibres  from  the  right  crus  is  generally  larger  than  that  from  the  left,  and 
is  commonly  anterior  to  it. 

The  pillars  differ  somewhat  on  opposite  sides.  The  right  {e)  is  the 
larger  of  the  two,  and  is  fixed  by  tendinous  processes  to  the  bodies  of  the 
first  three  lumbar  vertebra?,  and  their  intervertebral  substance,  reaching 
to  the  disk  between  the  third  and  fourth  vertebrae.  The  left  pillar  {d) 
(sometimes  absent)  is  situated  more  on  the  side  of  the  spine,  is  partly  con- 
cealed by  the  aorta,  and  does  not  reach  so  far  as  the  right  by  the  depth  of 
a  vertebra,  or  of  an  intervertebral  substance. 

The  arches  (ligamenta  arcuata)  are  two  fibrous  bands  on  each  side  over 


SPECIAL    PARTS    OF    DIAPHRAGM.  487 

the  quadratus  lumborum  and  psoas  muscles,  which  give  origin  to  fleshy 
fibres. 

The  arch  over  the  psoas  (lig.  arcuat.  internum/)  is  the  strongest,  and 
is  connected  by  the  one  end  to  the  tendinous  part  oP  the  pillar  of  the  dia- 
phragm, and  by  the  other  to  the  transverse  process  of  the  first  or  the  second 
lumbar  vertebra. 

The  arch  over  the  quadratus  lumborum  (lig.  arcuat.  externum  ^^)  is  only 
a  thickened  part  of  the  fascia  covering  that  muscle,  and  extends  from  the 
same  transverse  process  (first  or  second  lumbar)  to  tlie  last  rib. 

Apertures.  There  are  three  large  openings  for  the  aorta,  the  vena  cava, 
and  the  oesophagus  ;  with  some  smaller  fissures  for  nerves  and  vessels. 

The  opening  for  the  aorta  (/»)  is  rather  behind,  than  in  the  diaphragm, 
for  it  is  situate  between  the  pillars  of  the  muscle  and  the  spinal  column  :  it 
transmits  the  aorta,  the  thoracic  duct,  and  tlie  vena  azygos. 

The  opening  for  the  oesophagus  and  tlie  pneumo-gastric  nerves  (/)  is 
rather  above  and  to  the  left  of  the  aortic  aperture  ;  it  is  placed  in  the 
muscular  part  of  the  diaphragm,  and  is  bounded  by  the  fibres  of  the  pillars 
as  above  explained. 

The  opening  for  the  vena  cava  (/^)  (foramen  quadratum)  is  situate  in 
the  right  division  of  the  central  tendon  ;  and  its  margins  are  attached  to 
the  vein  by  tendinous  fibres,  except  at  the  inner  part. 

There  is  a  fissure  (/)  in  each  pillar  for  the  three  splanchnic  nerves  ; 
and  through  that  in  the  left  crus  passes  also  the  small  azygos  vein. 

Dissection.  After  the  diaphragm  has  been  learnt,  the  ribs  that  support 
it  on  each  side  may  be  cut  through,  and  the  pieces  of  the  ribs  with  tlie 
fore  part  of  the  diaphragm  may  be  taken  away,  to  make  easier  the  dissec- 
tion of  the  deeper  vessels  and  muscles.  But  the  posterior  part  of  the  dia- 
phragm with  its  pillars  and  arches  should  be  left ;  and  the  vessels  ramify- 
ing on  it  should  be  followed  back  to  their  origin. 

The  large  vessels  of  the  abdomen,  viz.,  the  aorta  and  the  vena  cava,  are 
to  be  cleaned  by  removing  the  fat,  the  remains  of  the  sympathetic,  and 
the  lymphatic  glands  ;  and  their  branches  are  to  be  followed  to  the  dia- 
phragm, to  the  kidney  and  suprarenal  body,  and  to  the  testicle.  In  like 
manner  the  large  iliac  branches  of  the  aorta  and  cava  are  to  be  laid  bare 
as  far  as  Poupart's  ligament.  The  ureter  and  the  spermatic  vessels  are  to 
be  cleaned  as  they  cross  the  iliac  artery  to  the  limb  ;  and  on  the  iliac 
trunk  near  the  thigh,  branches  of  a  small  nerve  (genito-crural)  are  to  be 
sought. 

The  muscles  are  to  be  laid  bare  on  the  right  side,  but  on  the  left  side 
the  fascia  covering  them  is  to  be  shown  ;  and  the  fat  is  to  be  cleared  away 
from  about  the  kidney. 

The  psoas  muscle,  the  most  internal  of  all,  lies  on  the  side  of  the  spine, 
with  the  small  psoas  superficial  to  it  occasionally.  On  its  surface,  and  in 
the  fat  external  to  it,  the  following  branches  of  the  lumbar  plexus  will  be 
found  :  The  genito-crural  nerve  lies  on  the  front.  Four  other  nerves  issue 
at  the  outer  border — the  ilio-hypogastric  and  ilio-inguinal  near  the  top,  the 
external  cutaneous  about  the  centre,  and  the  large  anterior  crural  at  tiie 
lower  part.  Along  the  inner  border  of  the  psoas  the  gangliated  cord  of 
the  6ym|)athetic  is  to  be  sought,  along  with  a  chain  of  lumbar  lymphatic 
glands  ;  and  somewhat  below  the  pelvic  part  of  the  muscle  the  obturator 
nerve  may  be  recognized.  External  to  the  psoas  is  the  quadratus  lum- 
borum, and  crossing  it  near  the  last  rib  is  the  last  dorsal  nerve,  with  an 


488 


DISSECTION    OF    THE    ABDOMEN 
Fig.  171. 


Deep  view  of  the  Muscles,  "V 

E8SELS 

,  AN 

(Illus 

tration 

3  Of 

Muscles  and  viscera  : 

A. 

Diaphragm  with  B.int 
ternal  arched  ligame 

ernal 
nt. 

and  c, 

e.K- 

D. 

End  of  the  oesophagus 

cut. 

K. 

Small  psoas. 

P. 

Large  psoas. 

G. 

QuadratQS  lumborum. 

H. 

Iliacus. 

I. 

Kidney. 

J. 

Recturn. 

K. 

Bladder. 

Vessels  : 

a. 

Diaphragmatic  artf^ry 

b. 

Aorta. 

c. 

Renal. 

d 

8p'»rmatic. 

e. 

Upper  mesenteric,  cut. 

/. 

Lower  mesenteric. 

D  Nerves  op  this  Abdominal  Cavitt. 
Dissections.) 

g    Common  iliac,  and    /(,   external    iliac 

artery. 
"k.  Epigastric  artery,  cut ;  by  its  side  is  the 
vas  deferens,  bonding  into  the  pelvis. 
/.  Circumflex  iliac. 
in.  Vena  cava. 
n.  Renal  vein.  ' 

0.  Right  spermatic  vein,  30,  common  iliac 

vein,  and  r,  external  iliac  (this  letter 
is  put  on  the  left  artery  instead  of  the 
v<dn  just  below  it). 
s.  Ureter. 
Nerves  : 

1.  Phrenic. 

2.  Iliohypogastric. 
.3.  Ilio-inguinal. 

4.  Evternal  cutaneous  of  tho  thigh. 
5  and  6.  Genito-crural. 
7.  Anterior  crural. 


I 


ABDOMINAL  AORTA  AND  BRANCHES.  489 

artery.  In  the  hollow  of  the  hip-bone  is  the  iliacus  muscle  which  unites 
below  with  the  large  psoas. 

The  ABDOMINAL  AORTA  (fig.  171,  b)  extends  from  the  last  dorsal  ver- 
tebra to  the  left  side  of  the  body  of  the  fourth  lumbar  vertebra,  where  it 
divides  into  the  common  iliac  arteries.  Its  commencement  is  between 
the  pillars  of  the  dia|)hragm,  and  its  teimination  is  placed  on  the  left  side 
of  the  umbilicus,  and  nearly  on  a  level  with  the  highest  part  of  the  crest 
of  the  hip-bone. 

The  chief  connections  of  the  vessels  with  surrounding  parts  have  been 
before  referred  to  (p.  444),  but  some  deep  vessels  in  relation  with  it  come 
now  into  view.  As  the  aorta  lies  on  the  spine  it  rests  on  the  left  lumbar 
veins,  which  end  in  the  inferior  cava.  And  between  it  and  the  riglit  crus 
of  the  diaphragm  lie  the  vena  azygos  major,  and  the  thoracic  duct.  Along 
the  sides  of  the  vessel  are  the  lumbar  lymphatic  glands,  from  wliich  large 
vessels  run  beneath  it  to  end  in  the  beginning  of  the  thoracic  duct. 

The  branches  of  the  aorta  are  numerous,  and  arise  in  the  following 
order  :  First,  are  the  diaphragmatic  arteries,  two  in  number,  which  leave 
the  sides  of  the  vessel  immediately  it  appears  in  the  abdomen.  Close  to 
the  tendinous  ring  of  the  diaphragm,  the  single  trunk  of  the  coeliac  axis 
arises  from  the  front :  and  about  a  quarter  of  an  inch  lower  down,  also  on 
the  front,  the  trunk  of  the  superior  mesenteric  artery  begins.  Half  an 
inch  lower  the  renal  arteries,  right  and  left,  take  origin  from  the  sides  of 
the  aorta.  On  the  lateral  part  of  the  vessel,  close  above  each  renal,  is 
the  small  capsular  branch  ;  and  below  the  renal  is  the  spermatic  artery. 
From  the  front  of  the  arterial  trunk,  one  to  two  inches  above  the  bifurca- 
tion, springs  the  inferior  mesenteric  artery  ;  and  from  the  angle  of  division 
the  small  middle  sacral  artery  runs  downwards.  Four  small  lumbar 
branches  on  each  side  come  from  the  posterior  part  of  the  vessel,  opposite 
the  bodies  of  the  lumbar  vertebrae. 

The  branches  may  be  classified  into  two  sets — one  to  the  viscera  of  the 
abdomen  (visceral),  and  another  to  the  abdominal  wall  (parietal). 

Tlie  visceral  branches  are  coeliac  axis,  superior  and  inferior  mesenteric, 
renal,  capsular,  and  spermatic.  This  set  has  been  examined,  except  the 
renal,  capsular,  and  spermatic. 

The  renal  arteries  (fig.  171,  c)  leave  the  aorta  nearly  at  a  right  angle, 
and  are  directed  outMards,  one  on  each  side.  Near  the  kidney  each  di- 
vides into  four  or  five  branches,  which  enter  the  renal  substance  between 
the  vein  and  the  ureter.  P^ach  artery  lies  beneath  its  companion  vein, 
being  surrounded  by  a  plexus  of  nerves,  and  supplies  small  twigs  to  the 
suprarenal  body  (inferior  capsular),  to  the  ureter,  and  to  the  fatty  layer 
about  the  kidney. 

The  arteries  of  opposite  sides  have  some  differences.  The  left  is  the 
shortest,  owing  to  the  position  of  the  aorta  :  the  right  crosses  the  spine, 
and  passes  beneath  the  vena  cava. 

The  middle  capsular  artery  is  a  small  branch  which  runs  almost  trans- 
versely outwards  to  the  suprarenal  body  :  this  offset  anastomoses  with  tht5 
other  branches  of  the  suprarenal  body  from  the  renal  and  diaphragmatic 
arteries.     It  is  of  large  size  in  the  fcetus. 

The  spermatic  artery  of  the  testicle  (fig.  171,  d)  is  remarkable  for  its 
small  size  in  proportion  to  its  length  ;  for  leaving  the  cavity  of  the  abdo- 
men ;  and  for  having  the  part  in  the  abdomen  straight,  but  that  in  the 
cord  tortuous. 

From  its  origin   below  the   renal,  the  vessel  passes   downwards  along 


490  DISSECTION    OF    THE    ABDOMEN. 

the  posterior  wall  of  the  abdomen  to  the  internal  ahdominal  rinj?,  where 
it  enters  the  spermatic  cord  (p.  418).  In  its  course  beneath  the  peri- 
toneum the  vessel  runs  along  the  front  of  the  psoas,  crossing  over  the 
ureter ;  and  on  the  right  side  it  passes  over  the  vena  cava.  It  is  accom- 
panied by  the  spermatic  vein,  and  the  spermatic  plexus  of  nerves.  In  the 
foetus  before  the  testicle  leaves  the  abdomen  the  spermatic  artery  is  very 
short,  but  the  vessel  elongates  as  the  part  supplied  is  removed  from  its 
former  site. 

In  the  female  the  corresponding  artery  (ovarian)  descends  into  the 
pelvis  to  end  in  the  ovary  and  the  uterus. 

The  parietal  branches  of  the  aorta  are  the  diaphragmatic,  lumbar,  and 
middle  sacral. 

The  diaphragmatic  arteries  (inferior  phrenic)  (fig.  171,  a)  are  directed 
outwards  along  the  under  surface  of  the  diaphragm  near  the  posterior 
part,  the  left  artery  passing  beliind  the  (rsophageal  opening,  and  the  right 
behind  the  vena  cava.  Each  ends  in  two  branches  :  One  (internal)  passes 
onwards  towards  the  fore  part  of  the  diaphragm,  and  anastomoses  with  its 
fellow,  and  with  the  branch  (superior  phrenic)  to  the  diaphragm  from  the 
internal  mammary  (p.  239).  The  other  (external)  is  larger,  and  is  di- 
rected outwards  to  the  side  of  the  muscle,  where  it  communicates  with 
the  musculo-phrenic  and  intercostal  arteries. 

Branches.  Small  offsets  to  the  suprarenal  body  from  the  external  divi- 
sion of  this  artery  are  named  superior  capsular.  Some  twigs  are  given 
by  the  left  artery  to  the  oesophagus,  and  by  the  right  to  the  vena  cava. 

On  the  under  surface  of  the  diaphragm  are  two  branches  of  the  internal 
mammary  artery ;  one  (superior  phrenic,  p.  2iy9)  accompanies  the  phrenic 
nerve,  and  ramifies  over  the  middle  of  the  muscle ;  the  other  (musculo- 
phrenic, p.  239)  appears  opposite  the  ninth  rib,  and  passing  along  the 
edge  of  the  thorax,  gives  offsets  to  the  lower  intercostal  spaces. 

The  other  parietal  branches,  viz.,  lumbar  and  middle  sacral,  are  not 
learnt  in  this  stage  :  the  former  will  be  seen  after  the  lumbar  plexus,  and 
the  latter  in  the  pelvis. 

The  COMMON  ILIAC  ARTERY  (fig.  171,  g)  is  directed  outwards  from  the 
bifurcation  of  the  aorta,  and  divides  into  two  large  trunks  opposite  the 
fibro-cartilage  between  the  base  of  the  sacrum  and  the  last  lumbar  verte- 
bra : — one  of  these  (external  iliac)  supplies  the  lower  limb,  and  the  other 
(internal  iliac)  enters  the  pelvis.  Placed  obliquely  on  the  vertebral 
column,  the  vessel  measures  about  two  inches  in  length.  It  is  covered  by 
the  peritoneum,  and  is  crossed  by  branches  of  the  sympathetic  nerve,  and 
sometimes  by  the  ureter.  It  is  accompanied  by  a  vein  of  the  same  name. 
Usually  it  does  not  furnish  any  named  branch,  but  it  may  give  origin  to 
the  ilio-lumbar,  or  a  renal  artery.  On  opposite  sides  the  vessels  have 
some  differences. 

The  right  artery  is  rather  the  longest,  in  consequence  of  the  position  of 
the  aorta  on  the  left  side  of  the  spine.  To  its  outer  side  at  first  is  the 
vena  cava,  and  near  its  termination  is  the  psoas  muscle.  The  companion 
vein  {p)  is  at  first  beneath,  but  becomes  external  to  the  artery  at  the 
upper  part ;  and  beneath  tlie  right  artery  also  is  the  left  common  iliac  vein. 
The  left  artery  is  crossed  by  the  colon  and  the  inferior  mesenteric  vessels; 
and  its  companion  vein  is  situate  below  it. 

The  length  of  tlie  common  iliac  ranges  from  less  than  half  an  inch  (in 
one  ctise)  to  four  inclies  and  a  lialf ;  but  in  tlie  majority  of  instances  it 
varies  between  one  inch  and  a  half  and  three  inches  (Qaain). 


I 


ILIAC    ARTERIES    AND    VEINS.  491 

The  EXTERNAL  ILIAC  ARTERY  (fig.  171,  k)  is  the  first  part  of  the  ves- 
sel leading  to  the  lower  limb,  and  is  contained  in  the  cavity  of  the  abdo- 
men. Its  extent  is  from  the  bifurcation  of  the  common  iliac  to  the  lower 
border  of  Poupart's  ligament,  where  it  becomes  femoral.  And  its  direction 
would  be  indicated,  on  tlie  surface  of  the  abdomen,  by  a  line  from  the  left 
of  the  umbilicus  to  the  middle  of  the  space  between  the  symphysis  pubis 
and  the  front  of  the  iliac  crest. 

The  vessel  lies  above  the  brim  of  tlie  pelvis  in  its  course  to  Poupart's 
ligament,  and  is  covered  closely  throughout  by  the  peritoneum  and  the 
subperitoneal  fat.  To  its  outer  side  is  the  psoas,  except  at  its  termination 
under  Poupart's  ligament,  where  the  muscle  lies  beneath  it.  A  chain  of 
lymphatic  glands  is  placed  along  the  front  and  inner  side  of  the  artery. 

Near  its  origin  it  is  crossed  sometimes  by  the  ureter ;  and  near  Pou- 
part's ligament  the  vas  deferens  bends  down  along  its  inner  side,  whilst 
the  spermatic  vessels,  and  part  of  the  genito-crural  nerve  lie  on  it  for  a 
short  distance. 

The  position  of  the  external  iliac  vein  (/•)  is  not  the  same  on  both  sides. 
The  left  vein  is  altogether  internal  to  the  artery  ;  whilst  the  right,  though 
internal  in  position  on  the  pubes,  afterwards  lies  beneath  the  arterial 
trunk.  The  circumflex  iliac  vein  crosses  it  nearly  an  inch  above  Poupart's 
ligament. 

Branches.  Two  branches,  epigastric  and  circumflex  iliac,  arise  about 
a  quarter  of  an  inch  from  the  end  of  the  artery,  and  are  distributed  to 
the  wall  of  the  abdomen  (p.  419,  420). 

Some  small  unnamed  twigs  are  given  to  the  psoas  muscle  and  the  lym- 
phatic glands. 

Peculiarities  in  usual  branches.  The  epigastric  and  circumflex  branches  may  wan- 
der over  the  lower  inch  and  a  half  or  two  inches  of  the  artery. 

In  unusual  branches.  Though  the  trunk  of  the  vessel  is  commonly  free  from  any 
unusual  branch,  it  may  be  occupied  between  the  middle  and  the  end  by  the  obtu- 
rator artery,  or  by  the  internal  circumflex  artery  of  the  thigh. 

Iliac  Veins  and  Vena  Cava  (fig.  171).  The  larger  veins  of  the 
abdomen  correspond  so  closely  with  the  arteries,  both  in  number,  extent, 
and  connections,  as  to  render  unnecessary  much  detail  in  their  descrip- 
tion. As  the  veins  increase  in  size  from  the  circumference  towards  the 
centre  of  the  body,  those  most  distant  from  the  heart  will  be  first  re- 
ferred to. 

The  external  iliac  (r)  is  a  continuation  of  the  femoral  vein  beneath 
Poupart's  ligament.  It  has  an  extent  like  the  artery  of  the  same  name, 
and  ends  by  uniting  with  the  vein  from  the  pelvis  (internal  iliac),  to  form 
the  common  iliac  vein.  On  the  pubes  it  is  inside  its  companion  artery, 
and  lies  between  the  psoas  and  pectineus  muscles ;  the  left  vein  remains 
internal  to,  but  the  right  slips  beneath  its  artery. 

The  veins  opening  into  it  are  the  epigastric  and  circumflex  iliac  (p.  420). 

The  common  iliac  vein  (fig.  171,  /?)  ascends  by  the  side  of  its  accom- 
panying artery,  the  right  almost  vertically,  and  the  left  obliquely,  to  the 
right  side  of  the  body  of  the  fifth  lumbar  vertebra  (the  upper  part),  where 
it  blends  with  its  fellow  in  one  trunk — the  vena  cava. 

The  right  vein  is  the  shortest,  and  lies  at  first  behind,  but  afterwards 
outside  the  artery  of  the  same  name.  The  left  is  altogether  below  the 
artery  of  its  own  side,  and  crosses  beneath  the  right  common  iliac  artery. 

Each  vein  j*eceives  the  ilio-lumbar,  and  the  lateral  sacral  branch  ;  and 
the  common  iliac  of  the  left  side  is  joined  by  the  middle  sacral  vein. 


492  DISSECTION    OF    THE    ABDOMEN. 

The  VENA  CAVA  INFERIOR  (fig.  171,  w)  collects  and  conveys  to  the 
heart  the  blood  of  tlie  lower  half"  of  the  body.  Taking  the  origin  on  tlie 
right  side  of  the  fiftli  lumbar  vertebra,  below  the  bifurcation  of  tlie  aorla, 
this  Inrge  vein  ascends  on  the  right  side  of  the  vertebral  column,  and 
reaches  the  heart  by  perforating  the  diaphragm.  Its  connections  with  the 
surrounding  parts  have  been  already  noticed  (p.  444),  but  the  description 
may  be  referred  to,  as  the  position  of  the  branches  of  the  aorta  to  it  can 
be  better  seen  now. 

Branches.  The  cava  receives  parietal  branches  (lumbar  and  dia- 
phragmatic), from  the  wall  of  the  abdomen  and  the  diaphragm  ;  and  vis- 
ceral branches  from  the  testicle,  the  kidney,  the  suprarenal  body,  and  the 
liver. 

The  veins  belonging  to  the  digestive  apparatus,  viz.,  the  intestinal  canal, 
the  spleen,  and  the  pancreas,  are  united  to  form  the  vena  portae  ([>.  448) ; 
and  the  blood  contained  in  those  veins  reaches  the  cava  by  the  ven^e  cava? 
hepaticiv?,  after  it  has  circulated  through  the  liver. 

The  spermatic  vein  (fig.  171,  o)  enters  the  abdomen  by  the  internal 
abdominal  ring,  after  forming  the  spermatic  plexus  in  the  cord  (p.  484). 
At  first  there  are  two  branches  in  the  abdomen,  which  lie  on  the  sides  of 
the  spermatic  artery;  but  these  soon  join  into  one  trunk.  On  the  left 
side  it  opens  into  the  renal  vein  at  right  angles,  and  a  small  valve  exists 
sometimes  over  the  aperture  ;  on  the  right  side  it  enters  the  inferior  cava 
below  the  renal  vein.  As  the  vein  ascends  to  its  destination,  it  receives 
ojje  or  more  branches  from  the  wall  of  the  abdomen,  and  from  the  fat 
about  the  kidney. 

In  the  female  this  vein  (ovarian)  has  the  same  ending  as  in  the  male, 
and  it  forms  a  plexus  in  the  broad  ligament  of  the  uterus.  Valves  are 
absent  from  the  vein  and  its  branches,  but  occasionally  there  is  one  at  its 
union  with  the  renal. 

The  renal  or  emulgent  vein  (fig.  171,  n)  is  of  large  size,  and  joins  the 
vena  cava  at  a  right  angle.  It  commences  by  many  branches  in  the  kid- 
ney; and  the  trunk  resulting  from  their  union  is  superficial  to  the  renal 
artery. 

The  right  is  the  shortest,  and  joins  the  cava  higher  up  usually  than  the 
other.  The  left  vein  crosses  the  aorta  close  to  the  origin  of  the  superior 
mesenteric  artery :  it  receives  separate  branches  from  the  left  spermatic 
and  suprarenal  veins. 

The  suprarenal  vein  is  of  considerable  size  when  it  is  compared  with 
the  body  from  which  it  comes.  I'he  right  opens  into  the  cava,  and  the 
left  into  the  renal  vein. 

The  hepatic  veins  enter  the  vena  cava  where  it  is  in  contact  with  the 
liver.     These  veins  are  described  in  the  dissection  of  the  liver  (p.  468). 

The  Idmhar  veins  correspond  in  number  and  course  with  the  arteries  of 
the  same  name :  they  will  be  dissected  after. 

The  diaphragmatic  veins  (inferior),  two  with  each  artery,  spring  from 
the  under  surface  of  the  diaphragm.  They  join  the  cava  either  as  one 
trunk  or  two. 

DEEP  MUSCLES  OF  THE  ABDOMEN. 

The  deep  muscles  in  the  interior  of  the  abdomen  are  the  psoas,  iliacus, 
and  quadratus  lumborum. 

The  PSOAS  MAGNUS  (fig.  171,  '')  reaches  from  the  lumbar  vertebra?  to 
the  femur,  and  is  situate  partly  in  the  abdomen  and  partly  in  the  thigh. 


PSOAS    AND    ILIACUS    MUSCLES.  493 

The  muscle  arises  from  the  front  of  the  transverse  processes  of  the 
lumbar  vertebrae;  from  the  bodies  and  intervertebral  disks  of  the  last 
dorsal  and  all  the  lumbar  vertebrae  by  five  ileshy  pieces — each  piece  being 
connected  with  the  intervertebral  substance  and  the  borders  of  two  con- 
tiguous vertebrae,  and  with  tendinous  bands  over  the  bloodvessels  opposite 
tlwi  middle  of  tiie  vertebrie.  The  fibres  give  rise  to  a  roundish  belly, 
which  gradually  diminishes  towards  Poujjart's  ligament,  and  ends  inte- 
riorly in  a  tendon  on  the  outer  aspect,  which  receives  fibres  of  the  iliacus, 
and  passes  beneath  Poupart's  ligament  to  be  inserted  into  the  small  tro- 
chanter of  the  femur. 

The  abdominal  part  of  the  muscle  has  the  following  connections: — In 
front  are  the  internal  arch  of  the  diaphragm,  the  kidney  with  its  vessels 
and  duct,  the  spermatic  vessels,  and  the  genito-crural  nerve,  and,  near 
Poupart's  ligament,  the  ending  of  tlie  external  iliac  artery.  Posteriorly 
the  muscle  is  in  contact  with  the  transverse  processes,  with  part  of  the 
quadratus  lumborum,  and  with  tlie  innominate  bone. 

The  outer  border  touches  the  quadratus  and  iliacus;  and  branches  of 
the  lumbar  plexus  issue  from  beneath  it.  Tlie  inner  border  is  partly  con- 
nected to  the  vertebrt^,  and  is  partly  free  along  the  margin  of  the  pelvis: 
— along  the  attached  part  of  this  border  lies  the  sympathetic  nerve,  with 
the  cava  on  the  right,  and  the  aorta  on  the  left  side ;  along  the  free  or 
pelvic  part  are  the  external  iliac  artery  and  vein. 

Action.  If  the  femur  is  free  to  move  it  is  raised  towards  the  belly;  and 
as  the  flexion  proceeds,  the  limb  is  rotated  out  by  the  attachment  of  the 
muscle  to  the  trochanter  minor.  The  psoas  is  always  combined  with  the 
iliacus  in  flexion  of  the  hip-joint. 

When  the  lower  limbs  are  fixed  the  two  muscles  will  draw  down  the 
lumbar  part  of  the  spine,  and  bend  the  hip-joints,  as  in  stooping  to  the 
ground.  One  muscle  under  the  same  circumstances  can  incline  the  spine 
laterally. 

The  PSOAS  PARVUS  (fig.  171,  ^)  is  a  small  muscle  with  a  long  and  flat 
tendon,  which  is  placed  on  the  front  of  the  large  psoas,  but  is  rarely  pre- 
sent. Its  fibres  ainse  from  the  bodies  of  the  last  dorsal  and  first  lumbar 
vertebras,  with  the  intervening  fibro-cartilage.  Its  tendon  becomes  broader 
interiorly,  and  is  inserted  into  the  ilio-pectineal  eminence  and  the  brim  of 
the  pelvis,  joining  the  fascia  over  the  iliacus  muscle. 

Action.  If  the  spine  is  immovable  the  two  muscles  will  make  tense 
the  pelvic  fascia.  The  pelvis  being  fixed  they  may  assist  in  bending  the 
lumbar  part  of  the  spinal  column. 

The  ILIACUS  MUSCLE  (fig.  171,  ")  occupies  the  iliac  fossa  on  the  inner 
aspect  of  the  hip-bone,  and  is  blended  inferiorly  with  the  psoas.  It  is 
triangular  in  form,  and  has  a  fleshy  origin  from  the  iliac  fossa  and  the 
ilio-lumbar  ligament,  from  the  base  of  the  sacrum,  and  from  the  capsule 
of  the  hip-joint  in  front.  The  fibres  pass  inwards  to  the  tendon  of  the 
pvsoas,  uniting  with  it  even  to  its  insertion  into  the  femur,  but  some  reach 
separately  the  femur  near  the  small  trochanter. 

Above  Poupart's  ligament  the  muscle  is  covered  by  the  iliac  fascia;  but 
over  the  right  iliacus  is  placed  the  ctccum,  and  over  the  left,  the  sigmoid 
flexure.  Beneath  it  are  the  innominate  bone  and  the  capsule  of  the  hip- 
joint;  and  between  it  and  the  grooved  anterior  margin  of  the  bone,  above 
the  joint,  is  a  bursa.  The  inner  margin  is  in  contact  with  the  psoas  and 
the  anterior  crural  nerve.  The  connections  of  the  united  psoas  and  iliacus 
below  Poupart's  ligament  are  given  with  the  dissection  of  the  thigh. 


494  DISSECTION    OF    THE    ABDOMEN. 

Action.  The  iliacus  flexes  the  hip-joint  with  the  psoas  when  the  femur 
is  movable,  and  bends  forwards  the  pelvis  when  the  limb  is  fixed.  In 
consequence  of  its  union  with  the  psoas,  the  two  are  described  as  the  flexor 
ot  the  hip-joint  by  Tlieile. 

The  QUADRATus  LUMBORUM  (fig.  171  ^)  is  a  short  thick  muscle  be- 
tween the  crest  of  the  hip-bone  and  the  last  rib.  About  two  inches  wide 
inferiorly,  it  arises  from  the  ilio-vertebral  ligament,  and  from  the  iliac 
crest  of  the  hip-bone  behind,  and  an  incii  outside  that  band.  The  fibres 
ascend  to  be  inserted  by  distinct  fleshy  and  tendinous  slips  into  the  apices 
of  the  transverse  processes  of  the  four  upper,  or  all  the  lumbar  vertebrse  ; 
and  into  the  body  of  the  last  dorsal  vertebra,  and  the  lower  border  of  the 
last  rib  for  a  variable  distance. 

This  muscle  is  encased  in  a  sheath  derived  from  the  fascia  lumborum. 
Crossing  the  surface  are  branches  of  the  lumbar  plexus,  together  with  the 
last  dorsal  nerve  and  its  vessels.  Beneath  the  quadratus  is  the  mass  of 
the  erector  spinae  muscle. 

Action.  Both  muscles  keep  straight  the  spine  (one  muscle  antagonizing 
the  other)  ;  and  by  fixing  the  last  rib  they  aid  in  the  more  complete  con- 
traction of  the  diaj)hragm. 

One  muscle  will  incline  laterally  the  lumbar  part  of  the  spine  to  the 
same  side,  and  depress  the  last  rib. 

Fascia  of  the  quadratus.  Covering  the  surface  of  the  quadratus  is  a 
thin  membrane,  which  is  derived  from  the  hinder  aponeurosis  of  the  trans- 
versalis  abdominis  (fascia  lumborum,  p.  357)  ;  it  passes  in  front  of  the 
quadratus  to  be  fixed  to  the  tips  and  borders  of  the  lumbar  transverse  pro- 
cesses, to  the  ilio-lumbar  ligament  below,  and  to  the  last  rib  above.  This 
fascia  forms  the  thickened  band  called  ligamentum  arcuatum  externum, 
to  which  the  diaphragm  is  connected. 

Fascia  of  the  iliacvs  and  psoas.  A  fascia  covers  the  two  flexor  muscles 
of  the  hip-joint,  and  extends  in  different  directions  as  far  as  their  attach- 
ments. Over  the  iliacus  muscles  the  membrane  is  thickest ;  and  a  strong 
accession  is  received  from  the  tendon  of  the  small  psoas.  Its  disposition 
at  Poupart's  ligament,  and  the  part  that  it  takes  in  the  formation  of  the 
crural  sheath,  have  been  before  explained  (p.  428). 

Opposite  the  pelvis  the  membrane  is  inserted  into  the  brim  of  that 
cavity  for  a  short  distance,  and  into  the  hip  bone  along  the  edge  of  the 
psoas.  Opposite  the  spinal  column  it  becomes  thin,  and  is  fixed  on  the 
one  side  to  the  lumbar  vertebrae  and  the  ligamentum  arcuatum  internum, 
but  is  blended  on  the  other  with  the  fascia  on  the  quadratus.  The  fascia 
should  be  divided  ov<t  the  psoas  on  the  left  side,  and  reflected  towards  the 
brim  of  the  pelvis. 

Dissection.  The  student  is  now  to  clean  the  lymphatic  glands  lying 
along  the  vertebrae,  and  to  trace  upwards  some  lymphatic  vessels  to  the 
thoracic  duct. 

To  show  the  origin  of  the  duct,  the  diaphragm  is  to  be  divided  over  the^ 
aorta,  and  its  pillars  are  to  be  thrown  to  the  sides ;  a  [)iece  may  be  cut  out 
of  tiie  aorta  opposite  the  first  lumbar  vertebra.     Tlie  beginning  of  the  duct 
(chyli  receptaculum),  and  of  the  vena  azygos,  may  be  well  seen  ;  and  the 
two  may  be  followed  upwards  into  the  thorax. 

On  the  left  side  the  student  may  trace  the  splanchnic  nerves  and  the 
small  vena  azygos  tin-ough  the  [)illar  of  the  diapl»ragm  ;  and  may  show  the 
trunk  of  the  sympathetic  nerve  entering  the  abdomen  beneath  the  arch 
over  the  psoas  muscle. 


I 


SPINAL    AND    SYMPATHETIC    NERVES.  495 

Lymphatic  glands.  A  chain  of  glands  is  placed  along  the  side  of  the 
external  iliac  artery,  and  along  the  front  and  sides  of  the  lumbar  vertebrae ; 
they  are  connected  by  short  tubes,  which  increase  in  size  and  diminish  in 
number,  until  at  the  upper  part  of  the  lumbar  vertebrae  three  or  four 
trunks  unite  in  the  thoracic  duct.  Into  the  glands  the  lymphatics  of 
the  lower  limbs,  and  those  of  the  viscera  and  wall  of  the  abdomen  are 
received. 

Receptaculum  chyli  (Pecquet).  The  thoracic  duct  begins  in  the  ab- 
domen by  the  union  of  three  or  four  larg«  lymphatic  vessels.  Its  com- 
mencement is  marked  by  a  dilatation,  which  is  placed  on  the  right  side  of 
tlie  aorta,  about  opposite  the  first  lumbar  vertebra.  The  duct  enters  the 
thorax  by  passing  through  the  diaphragm  with  the  aorta. 

Beginning  of  the  azygos  veins.  The  right  vein  (vena  azygos  major) 
begins  opposite  the  first  or  second  lumbar  vertebra  by  a  small  branch, 
which  is  united  with  a  lumbar  vein.  It  enters  the  thorax  with  the  tho- 
racic duct  and  the  aorta,  to  the  right  of  which  it  lies. 

Tlie  left  or  small  azygos  vein  begins  on  the  left  side  of  the  spine,  joining 
one  of  the  lumbar  veins,  and  passes  through  the  pillar  of  the  diaphragm, 
or  through  the  aortic  opening. 

The  anatomy  of  these  veins  is  given  in  the  description  of  the  thorax, 
p.  338. 


Section  YI. 

SPINAL  AND  SYMPATHETIC  NERVES. 

The  spinal  nerves  of  the  loins  are  united  in  a  plexus,  and  supply  the 
limb  and  the  contiguous  parts  of  the  trunk. 

Dissection.  The  lumbar  nerves  and  their  plexus  are  to  be  learnt  on  the 
left  side,  although  the  woodcut  shows  them  on  the  right  side  ;  and  to  bring 
them  into  view,  the  dissector  should  cut  through  the  external  iliac  vessels, 
and  afterwards  scrape  away  the  psoas.  For  the  most  part  the  fleshy  fibres 
may  be  removed  freely  ;  but  a  small  branch  (accessory  of  the  obturator) 
should  be  first  looked  for  at  the  inner  border  of  the  muscle.  In  the  sub- 
stance of  the  quadratus  lumborum  a  communication  may  be  sometimes 
found  between  the  last  dorsal  and  the  first  lumbar  nerve. 

The  cord  of  the  sympathetic  nerve  lies  along  the  edge  of  the  psoas,  and 
offsets  of  it  join  the  spinal  nerves  ;  these  are  to  be  followed  back  along  the 
lumbar  arteries. 

On  the  right  side  the  psoas  is  to  be  left  untouched,  in  order  that  the 
place  of  emergence  of  the  different  nerve  branches  from  it  may  be  noticed. 

Lumbar  Spinal  Nerves.  The  anterior  primary  branches  of  the  lum- 
bar nerves  enter  the  lumbar  plexus,  with  the  exception  of  the  last.  Five 
in  number,  they  increase  in  size  from  the  first  to  the  last,  and  are  joined 
by  filaments  of  the  sympathetic  near  the  intervertebral  foramina.  Before 
entering  the  plexus  they  supply  branches  to  the  psoas  and  quadratus  lum- 
borum muscles. 

The  fifth  nerve  (fig.  177)  receives  a  communicating  branch  from  the 
fourth,  and  is  to  be  followed  into  the  pelvis  to  its  junction  with  the  sacral 
plexus.     After  the  two  are  united,  the  name  lumbosacral  is  applied  to 


496 


DISSECTION    OF    THE    ABDOMEN. 


the  common  trunk  ;  and  from  this,  before  it  enters  the  sacral  plexus,  arises 
the  superior  gluteal  nerve  ('). 

The  LUMBAR  PLEXUS  (tig.  172)  is  formed  by  the  intercommunication 
of  the  first  four  lumbar  nerves.  Contained  in  the  substance  of  the  psoas 
near  the  posterior  surface,  it  consists  of  communicating  loops  between  tlie 
several  nerves,  and  increases  in  size  from  above  downwards,  lii^e  tiie  in- 
dividual nerves.  Superiorly  it  is  sometimes  united  by  a  small  branch  with 
the  last  dorsal  nerve ;  and  inferiorly  it  joins  the  sacral  plexus  through  the 
larore  lumbo-sacral  cord. 


Fig.  172. 


a.  External  iMac  artery,  cut  ac-oss. 
6.  Thoracic  duct. 

c.  Azygos  vein. 

Nerves  :  The  figures  1  to  o  mark  the 
trunks  of  the  five  lumbar  nerves, 

d.  Splanchnic  nerves. 
€,    Last  dorsal. 

/.  liio-hypogastric. 
ff.  Ilio-inguinal. 
h,  Gonito-crural. 
i.  External  cutaneous. 
k.  Anterior  crural. 
I.  Accessory  to  obturator. 
n.  Obturator. 
o.  Gangliated  cord  of  the  sympathotic. 


Di.ssncTroN  of  thr  Lumbar  Plkxus  and  its  Branches.    (Illustrations  of  Dissections.) 


The  hranche.s  of  the  plexus  are  six  in  number,  and  supply  the  ]ow(»r 
part  of  the  abdominal  wall  and  muscular  covering  of  the  spermatic  cord, 
the  fore  part  of  the  thigh,  and  the  inner  side  of  the  leg. 

The  first  two  branches  (ilio-hypogastric  and  ilio-inguinal)  end  as  cutane- 
ous nerves  of  the  buttock,  lower  part  of  the  abdomen,  and  the  scrotum. 

a.  The  ilio-hypogastric  branch  (fig.  172,  /*)  is  derived  from  the  first 
nerve,  and  appears  at  the  outer  border  of  the  psoas  muscle,  near  the  upper 
part.  It  is  directed  over  the  quadratus  lumborum  to  the  iliac  crest,  and 
enters  the  wall  of  the  abdomen  by  penetrating  the  transversalis  abdominis. 


LUMBAR    PLEXUS    AND    BRANCHES.  497 

Its  termination  in  the  integuments  of  the  buttock  and  abdomen,  by  means 
of  an  iliac  and  a  hypogastric  branch,  has  been  already  mentioned  (p.  416). 

b.  The  ilio-inguinal  branch  {(f)  arises  with  the  preceding  from  the  first 
nerve,  and  issues  from  the  psoas  nearly  at  the  same  spot.  Of  smaller  size 
than  the  ilio-hypogastric,  this  branch  courses  outwards  over  the  quadratus 
and  iliacus  muscles  towards  the  front  of  the  crest  of  the  hip  bone,  where 
it  pierces  the  transversalis  abdominis.  The  farther  course  of  the  nerve  in 
the  abdominal  wall,  and  its  distribution  over  the  scrotum  and  the  groin, 
are  before  noticed  (p.  416). 

c.  The  genito-crural  nerve  (h)  is  distributed  to  the  cremaster  muscle 
and  the  limb.  It  arises  from  the  second  lumbar  nerve,  and  from  the  con- 
necting loop  between  the  first  two ;  it  pierces  the  fibres  of  the  psoas,  and 
descending  on  the  surface  of  the  muscle  divides  into  the  two  following 
pieces.  Sometimes  the  nerve  is  divided  in  the  psoas,  and  the  pieces  per- 
forate separately  the  muscle. 

Tiie  cremasteric  branch  descends  on  the  external  iliac  artery,  and  fur- 
nishes offsets  around  it :  it  passes  from  the  abdomen  with  the  spermatic 
vessels,  and  is  distributed  in  the  cremaster  muscle.  In  the  female  the 
nerve  is  lost  in  the  round  ligament. 

The  crural  branch  issues  beneath  Poupart's  ligament  to  supply  the  in- 
tegument of  the  thigh. 

d.  The  external  cutaneous  nerve  of  the  thigh  {%)  arises  from  the  second 
nerve  of  the  plexus,  or  from  the  loop  between  it  and  tlie  third,  and  appears 
about  the  middle  of  the  outer  border  of  the  psoas.  The  nerve  then  crosses 
the  iliacus  to  the  interval  between  the  anterior  iliac  spinous  processes,  and 
leaves  the  abdomen  beneath  Poupart's  ligament,  to  be  distributed  on  the 
outer  aspect  of  the  limb. 

e.  The  anterior  crural  nerve  {k)  is  the  largest  offset  of  the  plexus,  and 
supplies  branches  mainly  to  the  extensor  muscles  of  the  knee  joint,  and 
to  the  teguments  of  the  front  of  the  thigh  and  inner  side  of  the  leg. 
Taking  origin  from  the  third  and  fourth  nerves,  and  receiving  a  fasciculus 
also  from  the  second,  this  large  trunk  appears  towards  the  lower  part  of 
the  psoas,  where  it  lies  between  that  muscle  and  the  iliacus.  It  passes 
from  the  abdomen  beneath  Poupart's  ligament ;  but  before  the  final  branch- 
ing in  the  thigh,  the  nerve  furnishes  the  following  twigs  : — 

Some  small  branches  are  furnished  to  the  iliacus  from  the  upper  part  of 
the  nerve. 

A  branch  to  the  femoral  artery^  whose  place  of  origin  varies  much,  is 
distributed  around  the  upper  part  of  that  vessel. 

/.  The  obturator  nerve  (n)  appertains  to  the  adductor  muscles  of  the 
thigh.  Derived  from  the  third  and  fourth  nerves  in  the  plexus,  it  is  di- 
rected beneath  the  psoas  to  tlie  inner  or  pelvic  border;  escaped  from  be- 
neath the  muscle  the  nerve  crosses  the  pelvic  cavity  below  the  external 
iliac,  but  above  the  obturator  vessels,  and  enters  the  thigh  through  the 
aperture  in  the  upper  part  of  the  thyroid  foramen.  Occasionally  the  ob- 
turator gives  origin  to  the  following  branch : — 

The  accessory  obturator  nerve  (/)  arises  from  the  trunk  of  the  obturator, 
or  from  the  third  and  fourth  nerves  of  the  plexus.  Its  course  is  along  the 
inner  border  of  the  psoas  beneath  the  investing  fascia,  and  over  the  hip 
bone  to  the  thigh,  where  it  ends  by  joining  the  obturator  nerve,  and  sup- 
plying the  hip  joint. 

Gangliated  cord  of  the  SYMPATHETIC.  The  lumbar  part  of  the 
gangliated  cord  of  the  sympathetic  in  the  abdomen  is  placed  on  the  side 
32 


498  DISSECTION    OF    THE    ABDOMEN. 

of  the  spinal  column  (fig.  172)  ;  it  lies  along  the  inner  border  of  the  psoas 
muscle,  nearer  the  front  of  the  vertebrae  than  in  the  thorax,  and  is  some- 
what concealed  on  the  right  side  by  the  vena  cava.  The  cord  possesses 
four  or  five  oblong  ganglia  opposite  the  bodies  of  the  vertebrae,  which  sup- 
ply connecting  and  visceral  branches. 

Connecting  branches.  From  each  ganglion  two  small  branches  are  di- 
rected backwards  along  the  centre  of  tiie  body  of  the  vertebra,  with  tlie 
lumbar  artery ;  these  unite  with  one  or  two  spinal  nerves  near  the  inter- 
vertebral foramen.  The  connecting  branches  are  long  in  the  lumbar 
region  in  consequence  of  the  gangliated  cord  being  raised  by  the  psoas 
muscle  to  the  fore  part  of  the  vertebrae. 

Branches  of  distribution.  Most  of  the  internal  branches  throw  them- 
selves into  the  aortic  and  hypogastric  plexuses,  and  so  reach  the  viscera 
indirectly.  Some  filaments  enter  the  vertebrae  and  their  connecting  liga- 
ments. 

Last  dorsal  nerve  (fig.  172,  e).  The  anterior  primary  branch  of  the 
last  dorsal  resembles  the  intercostal  nerves  in  its  distribution,  but  differs 
from  them  in  not  be^ng  contained  in  an  intercostal  space.  Lying  below 
the  last  rib,  the  nerve  is  directed  outwards  across  the  upper  part  of  the 
quadratus  lumborum,  and  beneath  the  fascia  covering  that  muscle,  as  far 
as  the  aponeurosis  of  the  transversalis  abdominis  (fascia  lumborum)  ;  here 
it  enters  the  wall  of  the  abdomen,  and  ends  in  an  abdominal  and  a  cuta- 
neous branch  (p.  416).     The  lowest  intercostal  artery  accompanies  it. 

Near  the  spine  it  furnishes  a  small  branch  to  the  quadratus  muscle;  and 
it  may  communicate  by  means  of  this  with  the  first  lumbar  nerve. 

The  LUMBAR  ARTERIES  of  the  aorta  (p.  489),  are  furnished  to  the  Back, 
the  spinal  canal,  and  the  wall  of  the  abdomen :  they  resemble  the  aortic 
intercostals  in  their  course  .and  distribution.  Commonly  four  in  number 
on  each  side,  they  arise  opposite  the  centre  of  the  lumbar  vertebrae,  and 
the  vessels  of  opposite  sides  are  sometimes  joined  in  a  common  trunk ; 
they  then  pass  backwards  beneath  the  pillar  of  the  diaphragm  and  the 
psoas,  to  reach  the  interval  between  the  transverse  processes,  where  each 
ends  in  an  abdominal  and  a  dorsal  branch.  The  arteries  of  the  riglit  side 
lie  beneath  the  vena  cava. 

The  dorsal  branch  continues  to  the  Back  between  the  transverse  pro- 
cesses, and  supplies  an  offset  to  the  spinal  canal  (pp.  368,  384). 

The  abdominal  branches  are  directed  outwards  beneath  the  quadratus 
lumborum,  and  enter  the  posterior  part  of  the  abdominal  wall,  where  they 
anastomose  with  the  lower  intercostal  above,  and  with  the  circumflex  iliac 
and  ilio-lumbar  arteries  below :  these  branches  supply  the  psoas  and  quad- 
ratus muscles;  and  the  last  furnishes  an  offset  to  tlie  teguments  with  the 
ilio-hypogastric  nerve. 

The  LUMBAR  VEINS  are  the  same  in  number,  and  have  the  same  course 
as  the  arteries.  Commencing  by  the  union  of  a  dorsal  and  an  abdominal 
branch  at  the  root  of  the  transverse  process,  each  trunk  is  directed  for- 
wards to  the  vena  cava.  They  open  into  the  posterior  |)art  of  the  cava, 
cither  singly,  or  conjointly  with  those  of  the  opposite  side.  On  the  left 
side  the  veins  are  longer  than  on  the  right,  and  })ass  beneath  the  aorta. 

Around  the  transverse  processes,  and  beneath  the  psoas  muscle,  the  lum- 
bar veins  communicate  freely  with  one  another,  with  the  ilio-lumbar,  and 
sometimes  with  the  common  iliac,  so  as  to  form  a  plexus  of  veins.  Issuing 
from  the  upper  part  of  the  plexus  is  a  small  branch,  the  ascending  lumbar 
vein,  which  joins  the  azygos  vein  of  the  corresponding  side  of  the  body. 


CAVITY  OF  THE  PELVIS. 


The  cavity  of  the  pelvis  is  a  part  of  the  general  abdominal  space  (p. 
431),  and  is  situate  below  the  brim  or  inlet  of  the  true  pelvis. 

Boundaries.  The  space  is  surrounded  by  the  firm  bony  ring  of  the 
pelvic  bones :  it  is  bounded  behind  by  the  sacrum  and  the  coccyx,  with 
the  pyriformis  muscles  and  the  sacro-sciatic  ligaments  ;  and  laterally  and 
in  front,  by  the  innominate  bones  covered  by  the  obturator  muscles. 

Inferiorly,  or  towards  the  perinoeum,  the  cavity  is  limited  by  the  fascia 
reflected  from  the  wall  to  the  viscera,  and  by  tlie  levatores  ani  and  coccygei 
muscles  :  only  in  this  last  direction,  where  the  bounding  structures  are 
movable,  can  alterations  be  made  in  the  size  of  the  space. 

Contents.  In  the  pelvis  are  contained  the  urinary  bladder,  the  low^er 
end  of  the  large  intestine  or  the  rectum,  and  some  of  the  generative  or- 
gans, according  to  the  sex.  All  the  viscera  possess  vessels,  nerves,  and 
lymphatics ;  and  the  serous  membrane  is  reflected  over  them. 


Section  I. 

PELVIC  FASCIA  AND  MUSCLES  OF  THE  OUTLET. 

On  the  wall  of  the  pelvis  is  a  thin  fascia  (pelvic)  which  extends  from 
the  brim  to  the  outlet,  and  covers  the  obturator  muscle. 

Dissection.  To  bring  into  view  the  pelvic  fascia,  tlie  internal  iliac  ves- 
sels, and  the  psoas  (if  this  has  not  been  removed  in  the  dissection  of  the 
lumbar  plexus),  are  to  be  taken  away  on  the  left  side  of  tlie  body.  The 
obturator  vessels  and  nerve  are  to  be  cut  through  on  the  same  side  ;  and 
the  peritoneum  being  detached  from  the  wall  of  tlie  pelvis,  the  fascia  will 
be  seen  on  scraping  away  with  the  handle  of  the  scalpel  a  large  quantity 
of  fat.  By  this  proceeding  the  membrane  is  dissected  in  its  upp(?r  half, 
or  as  low  as  the  situation  of  a  piece  of  fascia  (recto-vesical)  which  is  at- 
taclied  to  the  viscera. 

To  display  the  lower  half,  the  studenl  must  ra"se  the  outlet  of  the  pelvis  ; 
and,  should  the  perina^um  be  undissected,  the  fat  must  be  taken  from  tlie 
ischio-rectal  hollow.  The  lower  part  of  the  fascia  will  now  appear  on  the 
outer  side  of  that  fossa,  as  it  covers  tlie  obturator  muscle. 

An  additional  step  for  showing  the  arrangement  of  the  fascia  may  be 
taken,  by  removing  the  external  obturator  muscle  and  the  obturator  m<^ni- 
brane,  and  then  scraping  away  through  the  thyroid  hole  the  obturator  in- 
ternus  muscle,  so  as  to  look  at  the  fascia  through  that  aperture. 


500  DISSECTION    OF    THE    PELVIS. 

The  PELVIC  FASCIA  is  a  thin  membrane  in  close  contact  with  the 
obturator  muscle,  and  is  fixed  to  the  bone  around  the  attachment  of  the 
fleshy  fibres,  so  that  it  might  be  called  the  sj  ecial  fascia  (obturator)  of  that 
muscle. 

Superiorly  it  is  fixed  into  the  brim  of  the  pelvis  for  a  short  distance  at 
the  lateral  aspect  of  the  cavity.  In  Cront  of  that  spot  it  does  not  extend 
so  high  as  the  brim,  but  is  inserted  into  the  bone  around  the  attachment 
of  the  muscle,  except  opposite  the  hole  for  the  obturator  vessels  and  nerve, 
where  it  is  united  with  the  obturator  membrane.  Interiorly  the  fascia  is 
attached  to  the  hi})  bone  along  the  side  of  the  pubic  arch,  and  to  the 
margin  of  the  great  sacrosciatic  ligament  where  the  obturator  internus 
issues  from  the  pelvis. 

The  outer  surface  of  the  fascia  is  in  contact  with  the  obturator  muscle. 
The  inner  surface  corresponds  above  with  the  cavity  of  the  pelvis,  and 
below,  with  the  ischio-rectal  fossa.  With  this  surface  the  thin  membrane 
(recto-vesical)  supporting  the  viscera  of  the  pelvis  is  united  ;  the  place  of 
union  being  indicated,  on  looking  into  the  pelvis,  by  a  whitish  line  near 
to,  and  on  a  level  with  the  ischial  spine.  At  the  posterior  border  of  the 
obturator  muscle  the  fascia  is  joined  by  a  thin  membrane  (fascia  of  the 
pyriformis)  which  covers  the  })yriformis  muscle  and  the  sacral  plexus,  but 
is  beneath  the  iliac  vessels  by  branches  of  which  it  is  ])erforated. 

The  recto-vesical  fascia  may  be  now  seen  in  part ;  but  it  will  be  better 
displayed  after  the  hip  bone  has  been  taken  away. 

JJissection.  To  obtain  a  side  view  of  the  pelvis  it  will  be  necessary  to 
detach  the  left  innominate  bone.  The  pelvic  fascia  is  first  to  be  separated 
from  the  bone  and  the  obturator  muscle.  The  innominate  bone  is  next  to 
be  sawn  through,  in  front,  rather  external  to  tlie  symphysis,  and,  behind, 
at  the  articulation  with  the  sacrum.  After  the  bone  has  been  pulled  some- 
what away  from  the  rest  of  the  j)elvis,  the  ischial  spine  with  the  recto- 
vesical fascia  attached  to  it  may  be  cut  off  with  a  bone-forceps ;  and  the 
rest  of  the  bone  may  be  then  removed  by  cutting  through  the  pyriformis 
muscle,  the  vessels  and  nerves  passing  through  the  sacro-sciatic  notch,  and 
any  other  structure  that  may  retain  it. 

A  block  is  afterwards  to  be  placed  beneath  the  pelvis.  The  bladder  is 
to  be  moderately  distended  with  air  through  the  ureter,  and  the  urethra 
is  to  be  tied.  Some  tow  is  to  be  introduced  into  the  rectum,  also  into  the 
vagina  if  it  is  a  female  pelvis  ;  and  a  small  piece  is  to  be  placed  in  the 
pouch  of  peritoneum  between  the  bladder  and  the  rectum.  After  the 
viscera  are  thus  made  prominent,  tlie  ischial  sj)ine  and  the  recto-vesical 
fascia  should  be  raised  with  hooks  whilst  the  levator  ani  and  coccygeus 
muscles  below  it  are  cleaned. 

Parts  closing  the  pelvis  below.  In  addition  to  the  recto-vesical  fascia, 
the  following  parts  close  the  pelvic  cavity  on  each  side,  between  the  sacrum 
and  the  pubic  symphysis. 

Behind,  the  student  will  meet  with  the  pyriformis  passing  through  the 
great  sacro-sciatic  notch,  with  the  gluteal  vessels  and  nerve  above  it. 
N(?xt  comes  the  coccygeus  muscle,  c,  on  the  small  sacro-sciatic  ligament, 
between  the  ischial  spine  and  the  coccyx  :  one  border  of  the  muscle 
reaches  towards  the  pyriformis,  the  other  to  the  levator  ani  ;  and  between 
its  hinder  border  and  the  pyriformis  lie  the  sacral  plexus  of  nerves  Q),  and 
the  sciatic  and  pudic  vessels. 

The  greater  part  of  the  rest  of  the  pelvic  outlet  is  closed  by  the  levator 
ani,  D,  which  extends  forwards  from  the  coccygeus  to  the  symphysis  pubis. 


PARTS  IN  OUTLET  OF  PELVIS. 


501 


It  meets  its  fellow  inferiorly,  but  the  muscles  of  opposite  sides  are  sepa- 
rated in  front  by  the  urethra,  with  the  vagina  in  the  female  ;  and  the  inter- 
val between  them  is  closed  by  the  triangular  ligament  of  the  perineum,  h. 
The  COCCYGEUS  muscle  (fig.  173,  ^)  is  flat  and  triangular,  and  assists 
to  close  the  outlet  of  the  pelvis.  It  arises  from  the  upper  part  of  the 
ischial  spine,  and  some  fibres  are  attached  to  the  small  sacro-sciatic  ligament. 
Widening  as  it  passes  inwards  the  muscle  is  inserted  mio  the  side,  and  the 
contiguous  anterior  surface  of  the  coccyx,  and  into  the  side  of  the  lower 
piece  of  the  sacrum. 


Fig.  173. 


Side  view  of  the  Muscles  in  the  outllt  of  the  Pelvis  (Illustrations  of  Dissectious), 


Muscles  : 

A.  Gluteus  maximus,  cut. 

B.  Psoas  and  Iliacus,  cut. 
c.  Coccygeus. 

D.  Levator  ani. 

E.  External  and  sphincter. 

F.  Ejaculator  urinae. 

Q.  Ischial  spine,  cut  off. 
H.  Triangular  ligament. 


Arteries  : 

a.  External  iliac  artery,  cut. 

b.  Its  accompanying  vein. 

c.  Obliterated  hypogastric  cord. 

d.  Upper  vesical,  and 

e.  Lower  vesical. 
/.  Internal  pudic. 

Nerves  : 

1.  Sacral  plexus. 

2.  Inferior  hemorrhoidal. 

3.  Pudic. 


The  inner  surface  looks  to  the  pelvis,  and  is  in  contact  with  the  rec- 
tum on  the  left  side;  the  opposite  surface  rests  on  the  small  sacro-sciatic 
ligainent.  The  upper  or  hinder  border  is  contiguous  to  the  pyriformis 
muscle,  vessels  and  nerves  intervening ;  and  the  anterior  or  lower  border 
is  parallel  with  the  levator  ani  muscle. 

Action.  Uniting  in  its  action  with  the  hinder  fibres  of  the  levator  ani, 
the  muscle  will  draw  slightly  forwards  the  coccyx. 

The  LEVATOR  ANI  (fig.  173,  ^)  is  a  thin  flat  muscle,  wliich  is  attached 
above  to  the  side  of  the  pelvis,  and  descends  below  into  the  outlet  of  the 
cavity,  where  it  joins  its  fellow  and  supports  the  viscera. 

It  arises  anteriorly  by  fleshy  fibres  from  an  oblique  line  above  the  ob- 
turator internus  ;  lower  down  from  the  fascia  on  that  muscle,  and  from  the 
back  of  the  triangular  ligament.  Posteriorly  it  is  fixed  to  the  lower  and 
inner  surface  of  the  ischial  spine.  And  between  those  osseous  atfac^i- 
ments  the  muscle  takes  origin  from  the  under  part  of  the  recto-vesical  fas- 
cia, but  not  in  a  straight  line.     All  the  fibres  are  directed  downwards   to 


502  DISSECTION    OF    THE    PELVIS. 

be  inserted  after  the  following  manner  :  The  anterior,  the  longest,  descend 
by  the  side  of  the  {)rostate  and  join,  in  front  of  the  rectum,  with  the  mus- 
cle of  the  opposite  side  in  the  central  point  of  the  perinaeum  ;  the  middle 
fibres  blend  with  the  side  of  the  rectum  ;  whilst  the  posterior  meet  the 
opposite  muscle  behind  the  gut,  and  are  attached  in  part  to  the  side  of  the 
coccyx  (p.  390). 

The  anterior  fibres  of  the  levator  are  in  contact  with  the  triangular 
perineal  ligament  ;^  and  there  is  an  interval  between  the  two  muscles, 
which  allows  the  urethra,  with  the  vagina  in  the  female,  to  pass  from  the 
pelvis.  The  posterior  border  is  parallel  to  the  coccygeus  muscle.  'The 
upper  surface  is  contiguous  to  the  recto-vesical  fascia  ;  and  tiie  under  sur- 
face looks  to  the  perina^um  (ischio-rectal  fossa).  The  two  muscles,  by 
their  union,  form  a  fleshy  layer  or  diaphragm  across  the  outlet  of  the  pel- 
vis, similar  to  that  which  separates  the  abdomen  from  the  chest  ;  this  par- 
tition is  convex  below  and  concave  above,  and  gives  passage  to  the  rec- 
tum. 

Action.  By  the  union  of  the  muscles  of  opposite  sides  below  the  urethra 
this  tube  can  be  raised,  and  compressed  during  their  contraction.  Whilst 
the  urine  is  flowing  the  fibres  are  passive,  but  towards  the  end  of  micturi- 
tion they  contract  suddenly,  and  help  the  other  muscles  in  clearing  the 
passage. 

As  the  levatores  descend  by  the  side  of  the  vesiculce  seminales,  and  the 
j)rostate,  they  will  compress  and  evacuate  the  contents  of  those  viscera. 

The  hindmost  fibres,  which  are  fixed  to  the  coccyx,  will  assist  the  coc- 
cygeus in  moving  forwards  that  bone. 

Dissection.  The  recto-vesical  fascia  will  be  seen  by  detaching  the  fleshy 
fibres  of  the  levator  ani  and  the  coccygeus  at  tlieir  origin,  and  throwing 
both  downwards.  The  thin  membrane  descends  on  the  levator  ani  to  the 
side  of  the  bladder  and  the  rectum,  and  sends  downwards  sheaths  around 
the  prostate  and  the  gut.  To  demonstrate  those  sheaths  one  incision  is  to 
be  made  along  the  prostate,  and  another  along  the  lower  end  of  the  rectum, 
below  the  fascia  ;  and  the  tubes  are  to  be  isolated  from  the  viscera. 

The  recto-vesical  fascia  supports  and  partly  invests  the  viscera  of  tlie 
])elvis.  Covering  the  pelvic  surface  of  the  levator  ani  it  is  fixed  above, 
like  that  muscle,  to  the  wall  of  the  pelvis  in  front  and  behind,  and  between 
those  attachments  it  joins  the  pelvic  fascia.  Below  it  meets  the  fascia  of 
the  opposite  side,  in  the  centre  of  the  pelvis,  and  forms  a  partition  across 
the  cavity,  like  that  of  the  levatores  ani,  which  is  perforated  by  the  blad- 
der and  the  rectum.  The  partition  is  supported  anteriorly  by  being  fixed 
to  the  pubes,  and  posteriorly,  where  it  blends  with  the  fascia  on  the  cocy- 
geus,  by  being  inserted  into  the  coccyx  :  it  is  concave  above  and  convex 
below,  and  divides  the  cavity  of  the  pelvis  from  the  perinieal  space.  This 
septal  piece  is  attached  to  the  viscera  which  pierce  it,  forming  ligaments 
for  them  ;  and  from  the  under  surface  tubes  are  prolonged  on  the  rectum 
and  the  prostate. 

The  slieath  on  the  rectum  incloses  the  lower  three  inches  of  the  intestine, 
and  gradually  becomes  very  thin  towards  the  anus ;  between  it  and  the 
intestine  are  inter[)Osed  the  branches  of  the  upper  hemorrhoidal  vessels, 
with  a  layer  of  fat. 

'  The  anterior  part  of  the  muscle  which  descends  by  the  side  of  the  prostate,  and 
unites  with  its  fellow  below  the  uieinl)raiious  part  of  the  urethra,  thus  supporting 
that  canal  as  in  a  sling,  is  named  sometimes  levator  seu  compressor  prostatic. 


I 


VISCERA    IN    THE    MALE.  .  503 

On  the  prostate  the  sheath  is  tliinner  than  on  the  rectum,  and  is  con- 
tinued forwards  to  the  apex  of  that  body,  where  it  blends  with  the  trian- 
gular ligament  of  the  urethra:  it  is  separated  from  the  capsule  of  the 
prostate  by  a  plexus  oP  veins,  and  by  some  small  arteries. 

In  the  female  the  fascia  has  much  the  same  arrangement  as  in  the  male  ; 
but  the  vagina  perforates  the  membrane,  and  receives  a  tube  from  it,  like 
the  prostate. 

The  true  ligaments  of  the  bladder  are  two  on  each  side,  anterior  and 
lateral,  and  are  parts  of  the  recto-vesical  fascia. 

The  anterior  reaches  from  the  posterior  part  of  the  pubes  to  the  upper 
surface  of  the  prostate,  and  the  neck  of  the  bladder ;  it  is  a  narrow  white 
band,  and  incloses  some  muscular  fibres  of  the  bladder.  Between  the 
ligaments  of  opposite  sides,  the  recto-vesical  fascia  dips  down  to  reach  the 
triangular  ligament  of  the  perinagum,  and  closes  the  pelvis  between  the 
levatores  ani. 

The  lateral  ligament  is  a  piece  of  the  same  fascia,  which  is  fixed  to  the 
upper  border  of  the  prostate  gland,  to  the  side  of  the  bladder  close  above 
the  vesicula  seminalis,  and  to  the  back  of  the  bladder  between  the  vesi- 
cular ;  from  this  part  of  the  fascia  an  offset  is  continued  downwards  over 
the  vesicula  seminalis,  so  as  to  join  a  like  piece  from  the  other  side,  and 
form  a  sheath  for  those  bodies. 

There  are  other  ligaments  of  the  bladder  (false  ligaments),  which  are 
derived  from  the  peritoneum  investing  it,  and  will  be  described  in  the  fol- 
lowing Section. 

Ligament  of  the  rectum.  On  each  side  of  the  rectum  is  a  strong  wide 
piece  of  the  recto-vesical  fascia,  which  is  connected  externally  to  the  ischial 
part  of  the  hip  bone,  and  supports  that  viscus  like  the  bladder. 


Section  II. 

CONNECTIONS  OF  THE  VISCERA  IN  THE  MALE. 

Directions.  If  the  student  dissects  a  female  pelvis,  he  will  find  the 
description  of  it  at  page  509. 

Contents  and  position  (fig.  174).  The  viscera  in  the  cavity  of  the  male 
pelvis  are,  the  lower  end  of  the  large  intestine  (rectum)  ;  the  bladder  with 
its  excretory  tube — the  urethra ;  together  with  some  generative  organs. 
These  have  the  following  relative  situation  : — 

The  rectum  (k)  is  behind  all,  and  takes  a  curved  course,  with  the  con- 
vexity backwards,  along  the  front  of  the  sacrum  and  coccyx.  The  bladder 
(a)  is  placed  in  the  concavity  of  the  rectum,  its  neck  being  surrounded 
by  the  prostate  gland  (6)  ;  and  the  urethra  (d)  curves  forwards  from  it 
above  the  intestine.  Beneath  the  bladder — between  it  and  the  rectum — 
are  the  little  seminal  sacs  (g)  with  the  vasa  deferentia/.  Some  of  these 
organs  are  partly  surrounded  by  the  peritoneum. 

Dissection.  All  the  recto-vesical  fascia,  except  the  anterior  true  liga- 
ment of  the  bladder,  may  be  taken  from  the  prostate  and  rectum.  The 
obliterated  (hypogastric)  cord  from  the  internal  iliac  artery  should  be  fol- 
lowed forwards  along  the  bladder  from  the  back  of  the  pelvis ;  and  the 
branches  of  the  same  artery  to  the  bladder  should  be  cleaned.     When  the 


504  ,  DISSECTION    OF    THE    PELVIS. 

fat  has  been  cleared  from  the  rectum  without  injuring;  its  arteries,  the 
j)ouch  of  the  peritoneum,  in  which  tow  has  been  placed,  will  be  brought 
into  view,  with  the  ureter  (//)  passing  to  the  bladder  across  its  side. 

The  part  of  the  bladder  below  the  peritoneum  is  to  be  cleaned,  and  the 
vas  deferens  (/),  wliich  lies  on  the  lateral  aspect  of  the  viscus,  is  to  be 
followed  down  to  the  seminal  sac.  Take  av/ay  with  care  the  remains  of 
the  sheath  of  the  vesicula  seminalis,  defining  at  the  same  time  the  vas 
deferens  inside  the  latter. 

The  'peritoneum  does  not  envelop  the  viscera  in  the  pelvis  so  completely 
as  in  the  upper  part  of  the  abdomen.  After  partly  surrounding  the  upper 
portion  of  the  rectum,  and  fixing  it  by  a  process — meso-rectum,  the  mem- 
brane clothes  the  back  of  the  bladder,  projecting  for  some  way  between 
this  viscus  and  the  rectum,  where  it  forms  the  recto-vesical  pouch  i  on 
each  side  the  serous  membrane  is  arrested  by  the  obliterated  hypogastric 
artery,  and  gives  rise  to  a  fold,  the  posterior  ligament  of  tlie  bladder.  It 
covers  the  posterior  surface,  and  each  lateral  region  of  the  bladder  as  far 
forwards  as  the  obliterated  hypogastric  ;  but  at  that  cord  it  is  reflected  to 
the  wall  ot  the  pelvis  and  abdomen.  All  the  anterior  surface  of  the  blad- 
der is  therefore  uncovered  by  peritoneum  ;  and  when  the  bladder  is  dis- 
tended it  rises  above  the  pubes,  so  as  to  allow  of  its  being  punctured  in 
front  without  injury  to  the  serous  membrane. 

The  recto-vesical  pouch  is  Avide  behind,  where  it  corresponds  with  the 
interval  between  the  iliac  arteries,  and  is  narrow  in  front  between  the 
rectum  and  the  bladder.  Anteriorly  it  extends  slightly  into  the  interval 
between  the  vesiculae  seminales,  and  ends  usually  about  one  inch  and  a 
half  from  the  tip  of  the  coccyx.  The  distance  of  tlie  pouch  from  the  anus 
is  commonly  about  four  inches  ;  but  it  will  vary  with  tiie  state  of  the 
bladder,  for  if  this  viscus  is  distended  the  peritoneum  will  be  raised,  and 
removed  farther  from  the  end  of  the  intestine. 

False  ligaments  of  the  bladder.  Where  the  peritoneum  is  reflected 
from  the  bladder  to  the  pelvic  wall,  it  gives  rise  to  a  wide  piece  of  mem- 
brane, which  constitutes  the  false  ligaments  of  that  viscus,  tliough  without 
any  subdivision  of  it  into  pieces.  These  are  said  to  be  five  in  number — 
two  posterior,  two  lateral,  and  one  superior. 

The  posterior  ligament  (one  on  each  side)  reaches  from  the  back  of  the 
pelvis  to  the  bladder,  and  contains  the  obliterated  hypogastric  artery,  the 
ureter,  and  smaller  vessels,  and  nerves.  Between  these  is  the  hollow  of 
the  recto-vesical  pouch. 

The  lateral  ligament^  also  one  on  each  side,  the  widest,  is  reflected  from 
the  side  of  the  bladder  to  the  iliac-fossa  and  the  wall  of  the  pelvis.  Along 
its  line  of  attachment  to  the  bladder  is  the  obliterated  hy|)Ogastric  artery. 

The  superior  ligament  is  prolonged  from  the  top  of  the  bladder  to  the 
abdominal  wall,  along  the  remains  of  the  obliterated  hypogastric  vessels. 

The  RECTUM,  or  the  lower  part  of  the  great  intestine  (fig.  174,  Ic)  ex- 
tends from  the  articulation  between  the  sacrum  and  the  left  hip  bone  to 
the  anus,  and  is  kept  in  place  by  the  peritoneum,  the  recto-vesical  fascia, 
and  the  levatores  ani.  The  intestine  is  about  eight  inches  long,  and  has 
a  winding  course,  for  it  follows  the  curve  of  the  sacrum  and  coccyx:  it  is 
divided  into  three  parts — upper,  middle,  and  lower. 

The  upper  part,  longer  than  the  others,  extends  obliquely  from  the 
sacro-iliac  articulation  to  tlie  centre  of  the  third  piece  of  the  sacrum.  Sur- 
rounded almost  entirely  by  the  ])eritoneum,  it  lies  against  the  sacrum,  and 
on  the  pyriformis  muscle  and  sacral  plexus  of  the  left  side.     In  contact 


RECTUM. 


505 


with  it,  are  tlie  biMnches  of  the  left  internal  artarj,  and  the  left  Jireter. 
In  some  bodies  tliis  part  of  the  intestine  is  much  curved  to  the  right 
side.^ 

The  middle  piece  lies  beneatli  the  bhidder,  and  reaches  to  the  tip  of  the 
coccyx:  it  is  about  three  inches  in  lengtli,  and  is  covered  by  peritoneum 
on  the  front  and  sides  above,  but  only  in  front  below.  Resting  on  it  is 
the  triangular  part  of  the  bladder,  witli  the  back  of  the  prostate  and  the 
vesiculiB  seminales  and  vasa  deferentia;  and  beneath  it  are  the  sacrum  and 
coccyx.     On  each  side  is  the  coccygeus  muscle. 

Fig.  174. 


Side  view  of  the  DisaecTtD  Malk  Pelvis. 

a.  Urinary  bladder.  g.  Vesicula  seminalis. 

6.  Prostate.  h.  Ureter. 

c.  Membranous  part  of  the  nrethra.  i.  Recto-vesical  fascia. 

d.  Spongy  part  of  the  urethra.  k.  Rectum. 

e    Cms  penis,  detached.  I.  Levator  ani,  cut. 
/.  Vas  deferens. 

The  lower  part  is  about  an  inch  and  a  lialf  long,  and  is  curved  from  the 
tip  of  the  coccyx  to  the  anus:  at  first  it  is  dilated,  but  at  the  anus  it  is 
contracted.  This  end  of  the  intestine  is  without  peritoneal  covering,  and 
is  supported  by  the  lower  part  of  the  triangular  ligament  of  the  urethra, 
and  by  the  levatores  ani  muscles. 

Above  the  extremity  of  the  rectum  (in  this  position  of  the  body)  are  the 
fore  part  of  the  prostate,  the  membranous  part  of  the  uretlira,  and  the 


'  It  is  not  uncommon  to  see  the  i-ectum  on  the  right  side  of  the  sacrum.  In  the 
dissecting-room  of  University  College  in  one  winter  (1854-1855),  I  saw  three  ex- 
amples of  the  rectum  in  that  situation.  In  two  bodies  the  lower  end  of  the  left 
colon  crossed  tiie  spine  at  the  top  of  the  sacrum,  and  the  rectum  descended 
through  the  pelvis,  on  the  right  of  the  middle  line,  to  the  end  of  the  coccyx.  In 
the  third  the  large  intestine  crossed  the  spine  twice,  once  at  top  of  the  sacrum, 
and  again  about  the  middle  of  that  bone. 


506  DISSECTION    OF    THE    PELVIS. 

bulb  of  tlie  corpus  spongiosum  urethroe ;  but  as  the  gut  recedes  from  the 
urethra  there  is  an  anguhir  interval  left  between  tliem.  The  levatores  ani 
muscles  descend  on  its  sides,  and  unite  beneath  it,  supporting  it  in  a  sling; 
and  the  sphincter  muscles  surround  the  aperture.  Sometimes  the  end  of 
the  intestine  within  the  anus  is  very  much  enlarged,  especially  in  women 
and  old  men ;  and  in  that  condition  in  the  male  it  rises  up  on  each  side  of 
the  prostate. 

The  URINARY  BLADDER  (vcsica  Urinaria)  is  situate  in  the  fore  part  of 
the  pelvis  (fig.  174,  a),  and  is  the  receptacle  for  the  fluid  secreted  by  the 
kidneys. 

When  the  bladder  is  contracted  it  is  flattened,  and  of  a  triangular  form, 
and  lies  against  the  anterior  wall  of  the  pelvis;  but  when  distended  it  be- 
comes of  a  conical  shape,  with  the  larger  part  towards  the  rectum,  and 
the  apex  to  tlie  abdominal  wall.  In  distension  during  life  it  is  slightly 
curved  over  the  anterior  part  of  the  pelvis,  as  it  projects  above  the  bone  ; 
and  if  a  line  through  its  centre  were  prolonged,  it  would  touch  anteriorly 
the  abdominal  wall  somewhere  (according  to  the  distension)  between  the 
umbilicus  and  the  pubes,  and  posteriorly  the  end  of  the  sacrum  or  the 
coccyx. 

The  position  and  form  of  the  bladder  are  not  the  same  in  early  life  as 
in  the  adult.  For  in  the  child  this  viscus  rises  above  the  brim  of  the 
pelvis  into  the  hypogastric  region  of  the  abdomen,  and  the  cervix  is  the 
lowest  part.  But  in  the  adult  the  bladder  is  contained  within  the  space 
inclosed  by  the  pelvic  bones,  and  the  base  projects  inferiorly. 

The  organ  is  maintained  in  position  by  the  recto-vesical  fascia  and  the 
peritoneum,  which  form  its  ligaments  (pp.  502  and  504).  The  connec- 
tions of  the  bladder  moderately  full  are  the  following : — 

The  summit  or  apex  is  rounded,  and  from  its  anterior  part  three  liga- 
mentous cords  are  prolonged  to  the  umbilicus  ;  the  central  one  of  these  is 
the  remains  of  the  urachus;  and  the  two  lateral  are  formed  by  the  oblite- 
rated hypogastric  arteries.  If  the  bladder  is  distended  the  apex  is  above, 
but  otherwise  below  the  pubes.  All  the  surface  behind  the  obliterated 
vessels  is  covered  by  peritoneum. 

The  base  (fundus)  is  large,  and  rests  on  the  middle  piece  of  the  rectum : 
in  the  state  of  emptiness  of  the  bladder  the  base  is  scarcely  prominent, 
but  in  distension  of  tlie  viscus,  it  extends  lower,  and  becomes  widened. 
Connected  with  the  fundus  are  the  vesiculae  seminales  and  the  vasa  defe- 
rentia;  and  between  these  is  a  triangular  space,  from  which  the  perito- 
neum is  partly  absent. 

Surfaces  of  the  body.  The  front  of  the  body  is  in  contact  with  the 
posterior  surface  of  the  symj)hysis  pubis,  and  with  the  abdominal  wall  if  it 
is  distended,  and  is  altogether  free  from  peritoneum  ;  wliilst  the  posterior 
surface  is  entirely  covered  by  the  serous  membrane,  and  is  touched  often 
by  the  small  intestine. 

Extending  along  the  upper  part  of  each  lateral  region  is  the  obliterated 
hypogastric  vessel ;  and  running  down  behind  tliis  is  the  vas  deferens, 
which  passes  internal  to  tlie  ureter.  Near  the  under  [)art  the  ureter  enters 
the  bladder.  All  the  side  of  the  bladder  behind  the  hypogastric  vessel  is 
covered  by  peritoneum,  but  the  rest  is  uncovered. 

The  neck  (cervix)  is  the  narrow  anterior  part  of  the  bladder  that  joins 
the  urethra:  in  the  state  of  contraction  it  is  the  lowest  part  of  the  viscus, 
but  in  distension  it  is  above  the  level  of  the  fundus.  It  is  surrounded  by 
the  prostate  gland. 


CONNECTIONS  OF  BLADDER.  507 

The  ureter  (fig.  174,  h)  crosses  the  common  or  the  external  iliac  artery, 
and  forms  an  arch  below  the  level  of  the  obliterated  hypogastric  vessel ;  it 
enters  the  bladder  near  the  lower  part,  and  somewhat  on  the  side,  at  the 
distance  of  one  inch  and  a  half  or  two  inches  from  the  prostate  gland. 

The  PROSTATE  GLAND  (fig.  174,  h)  surrounds  the  neck  of  the  bladder. 
It  is  placed  about  an  inch  below  the  level  of  the  symphysis  pubis,  and  is 
supported  by  the  rectum.  Its  shape  is  conical  with  the  base  turned  back- 
wards, and  its  size  equals  nearly  that  of  a  large  chestnut.  In  the  present 
position  of  the  pelvis,  a  line  from  the  apex  through  the  middle  of  the  gland 
would  be  directed  obliquely  downwards  and  backwards  towards  tlie  end  of 
the  sacrum  ;  but  in  the  erect  state  of  the  body,  upwards  and  backwards 
from  the  triangular  ligament. 

The  upper  surface  is  about  an  inch  below  the  symphysis  pubis,  and  is 
connected  to  it  by  the  anterior  true  ligaments  of  the  bladder.  On  this 
surface  are  branches  of  the  dorsal  vein  of  the  penis. 

The  under  surface  has  the  greatest  extent,  and  is  contiguous  to  the 
rectum  ;  this  is  the  part  that  is  felt  by  the  finger  introduced  into  the  bowel 
through  the  anus. 

The  apex  touches  the  posterior  layer  of  the  triangular  ligament ;  and 
the  base  surrounds  the  neck  of  the  bladder,  and  the  vesiculae  seminales 
with  the  vasa  deferentia. 

The  prostate  is  enveloped  by  a  sheath  obtained  from  the  recto-vesical 
fascia  (p.  502),  and  a  plexus  of  veins  (prostatic)  surrounds  it.  Through 
the  gland  the  urethra  takes  its  course  to  the  penis  ;  and  the  ejaculatory 
ducts  pierce  it  obliquely  to  open  into  the  urethra  (fig.  180,/).  The  size 
of  the  prostate  alters  much,  and  in  old  men  it  may  acquire  a  considerable 
magnitude. 

The  VESicuLiE  SEMINALES  (fig.  174,  g)  are  two  small  sacculated  bodies, 
each  about  two  inches  long,  between  the  under  part  of  the  bladder  and 
the  rectum.  Each  is  pyramidal  in  form,  and  has  the  larger  end  turned 
backwards  towards  the  ureter,  whilst  the  smaller  is  surrounded  by  the 
prostate.  Along  the  inner  side  is  the  vas  deferens.  At  the  prostate  gland 
the  vesicula3  approach  one  another,  only  the  vasa  deferentia  intervening ; 
but  further  backwards  they  diverge,  and  inclose  with  the  pouch  of  the 
peritoneum  the  triangular  space  at  the  under  aspect  of  the  bladder.  The 
vesicula3  are  contained  in  a  membranous  sheath,  which  is  derived  from 
the  recto-vesical  fascia,  and  is  lined  by  involuntary  muscular  fibres. 

The  VAS  DEFERENS  or  the  excretory  duct  of  the  testis  (fig.  174,/)  in 
its  course  to  the  urethra  enters  the  abdomen  by  the  internal  abdominal 
ring;  and  crossing  the  obliterated  hypogastric  artery,  is  directed  inwards 
along  tlie  side  and  under  part  of  the  bladder  to  the  base  of  the  prostate, 
where  it  forms  tiie  common  ejaculatory  duct  by  joining  with  the  duct 
from  the  vesicula  seminalis.  The  position  of  this  tube  to  tlie  external 
iliac  artery  has  been  noticed ;  on  the  bladder  it  passes  internal  to  the 
ureter  and  the  vesicula  of  the  same  side.  By  the  side  of  the  vesicula  the 
duct  is  much  enlarged,  and  is  sacculated. 

The  URETHRA  is  the  excretory  [jassage  for  the  urine  and  semen  (fig. 
174),  and  reaches  from  the  bladder  to  the  end  of  the  penis.  In  lengtli  it 
measures  about  eight  inches,  and  it  presents  one  or  two  curv^es  according 
to  the  state  of  the  penis.  At  first  the  canal  is  directed  forwards  through 
the  triangular  ligament  of  the  perinreum  to  the  body  of  the  penis,  forming 
a  large  curve  with  the  concavity  to  the  pubes.  Thence  to  its  termination 
the  urethra  is  applied  to  the  penis ;  and  whilst  this  body  remains  pendent 


508  DISSECTION    OF    THE    PELVIS. 

the  canal  forms  a  second  bend  with  the  concavity  downwards,  but  if  tl  e 
penis  is  raised  the  tube  makes  but  one  curve.  The  canal  is  divided  into 
three  parts — prostatic,  membranous,  and  spongy. 

The  prostatic  part  (b)  is  contained  in  the  prostate  gland,  and  receives 
its  name  from  that  circumstance.  Its  length  is  about  one  inch  and  a 
quarter,  and  in  the  erect  posture  it  is  inclined  downwards  to  the  triangular 
})erinaeal  ligament.  Its  connections  are  the  same  as  those  of  the  gland 
(p.  507). 

The  membranous  part  (c),  about  three-quarters  of  an  inch  long,  inter- 
venes between  the  apex  of  the  prostate  and  the  front  of  the  perinceal  trian- 
gular ligament.  It  slants  downwards  in  the  erect  [msture  to  the  ibre  part 
of  the  triangular  ligament ;  and  as  the  bulb  of  the  next  portion  of  the 
urethral  tube  is  directed  backwards  below  it,  the  under  part  measures 
only  half  an  inch. 

This  division  of  the  urethra  is  the  weakest :  but  it  is  supported  by  the 
triangular  ligament  (n).  Surrounding  it  are  the  muscular  fibres  of  the 
constrictor  urethrae ;  and  close  below  it  are  Cowper's  glands  with  the 
rectum. 

The  spongy  part  {d)  is  so  named  from  its  being  surrounded  by  a  cellu- 
lar and  vascular  structure.  It  is  applied  to  and  assists  to  form  the  body 
of  the  penis,  and  terminates  anteriorly  in  the  orifice  named  meatus  uri- 
narius  in  the  end  of  the  glands.  It  is  the  longest  part  of  the  urethra,  and 
measures  about  six  inches.  At  its  commencement  this  division  of  the 
excretory  canal  is  covered  for  two  inches  by  the  ejaculator  urinae  muscle 
(fig.  130). 

The  curve  of  the  urethra  is  the  fixed  bend  at  the  inner  extremity,  which 
lies  below  the  pubes.  It  extends  from  the  bladder  to  an  inch  and  a  half 
in  front  of  the  triangular  ligament,  and  consists  of  the  prostatic  and  mem- 
branous portions,  with  a  fourth  of  the  spongy  part.  Its  covexity,  which 
is  turned  downwards,  is  greatest  at  the  fore  part  of  the  triangular  ligament 
in  the  erect  posture  :  and  from  this  point  it  curves  up  and  back  to  the 
bladder,  and  up  anteriorly  to  the  penis. 

It  is  surrounded  by  voluntary  and  involuntary  muscular  fibres  :  thus, 
behind  the  ligament,  by  the  involuntary  muscular  tissue  of  the  prostate; 
within  the  ligament  by  the  voluntary  constrictor  urethra,  with  a  thin  in- 
voluntary layer  inside  that  muscle ;  and  before  the  ligament  by  the  volun- 
tary ejaculator  urinae. 

Its  size  is  smallest  where  the  tube  pierces  the  perinatal  ligament  (ii), 
and  lies  between  the  layers ;  and  is  largest  in  the  middle  of  the  prostatic 
part. 

Dissection.  The  tegumentary  covering  of  the  penis  may  be  removed, 
to  see  the  component  parts  of  that  body  ;  and  after  its  removal  the  spongy 
})art  of  the  urethra  will  be  better  seen :  the  teguments  should  be  replaced 
after  tlie  part  has  been  learnt. 

The  PENIS  is  attached  to  the  fore  part  of  tiie  pelvis,  and  hangs  in  front 
of  the  scrotum.  It  is  constructed  of  two  firm  fibrous  bodies  (fig.  174,  e) 
named  corpora  cavernosa,  which  are  filled  with  a  })lexus  of  vessels,  and 
make  up  the  principal  part.  liclow  these  is  a  soft  spongy  substance 
(corpus  spongiosum)  which  surrounds  the  urethra,  and  forms  the  head  or 
the  glans  penis.  The  tegumentary  investment,  which  covers  the  whole, 
is  noticed  at  p.  -107. 

The  body  of  the  penis  is  grooved  above  and  below  along  the  middle 
line,  and  is  covered  anteriorly  by  tlie  glans  penis;  along  its  under  surface 


VISCERA    IN    THE    FEMALE.  509 

the  urethra  is  conducted.  Besides  the  attachment  of  the  corpora  cavernosa 
to  the  bone,  the  body  of  the  penis  is  connected  with  the  front  of  tlie 
symphysis  pubis  by  the  suspensory  ligament. 

The  corpus  spongiosum  iirethrce  incloses  the  urethral  canal  in  front  of 
the  triangular  ligament,  and  forms  the  head  of  the  penis.  It  is  a  vascular 
and  erectile  texture,  like  the  corpora  cavernosa,  but  is  much  less  strong. 
Commencing  posteriorly  by  a  dilated  part — the  bulb,  it  extends  forwards 
around  the  urethra  to  the  extremity  of  the  penis,  where  it  swells  into  the 
conical  glans  penis. 

The  bulb  (tig.  174,  d)  is  directed  backwards,  slightly,  below  the  mem- 
branous part  of  the  urethra,  and  is  fixed  by  fibrous  tissue  to  the  front  of 
the  triangular  ligament.  The  ejaculator  urinae  muscles  cover  it.  This 
enlargement  presents  usually  a  central  depression,  with  a  bulging  on  each 
side,  and  is  subdivided  into  two  lobes. 

The  glans  penis  (fig.  181,  /)  is  somewhat  conical  in  form,  and  covers 
the  truncated  end  of  the  corpora  cavernosa.  Its  base  is  directed  back- 
wards, and  is  marked  by  a  slightly  prominent  border — the  corona  glandis; 
it  is  sloped  obliquely  along  the  under  aspect,  from  the  apex  to  the  base. 
In  the  apex  is  a  vertical  slit,  in  which  the  urethral  canal  terminates ;  and 
below  that  aperture  is  an  excavation,  which  contains  the  piece  of  the 
teguments  named /rte/iMm  preputii. 


Section  III. 

CONNECTIONS  OF  THE  VISCERA  IN  THE  FEMALE. 

In  the  pelvis  of  the  female  are  contained  the  lower  end  of  the  intestinal 
tube,  and  the  bladder  and  urethra,  as  in  the  male  ;  but  there  are  in 
addition  the  uterus  with  its  accessories,  and  the  vagina. 

Position.  The  rectum  is  posterior  to  the  rest  as  in  the  male  pelvis,  and 
forms  a  like  curve.  In  the  concavity  of  the  bent  intestine  lie  the  uterus 
with  its  appendages,  and  the  tube  of  the  vagina.  And  in  front  of  all  are 
the  bladder  and  the  uretliral  canal.  Thus  there  are  three  tubes  connected 
with  the  viscera  in  this  sex,  viz.,  the  urethra,  the  vagina,  and  the  rectum ; 
and  all  are  directed  forwards,  one  above  another,  to  the  surface. 

Directions.  Tiie  description  in  Section  I.  (p.  499)  must  be  used  for 
instructions  respecting  the  removal  of  the  innominate  bone,  and  tlie  dis- 
tension of  the  viscera ;  also  for  the  muscles  of  the  pelvic  outlet  and  the 
anatomy  of  the  fasciae.  After  the  student  has  learnt  the  muscles  and  tlie 
fascia,  p.  499,  which  are  nearly  alike  in  both  sc^es,  he  may  make  the 
following  special  dissection  of  the  viscera  of  the  female  pelvis. 

Dissection.  On  taking  away  the  recto-vesical  fascia  and  much  fat,  the 
viscera  will  come  into  view.  To  maintain  the  position  of  the  uterus,  raise 
it  up  with  a  piece  of  string  passed  through  the  upper  [)art.  The  reflec- 
tions of  the  peritoneum  on  the  viscera  are  to  be  preserved  ;  and  a  piece  of 
cotton  wool  is  to  be  placed  between  the  rectum  and  the  uterus. 

The  obliterated  cord  of  the  internal  iliac  artery  is  to  be  followed  on  the 
bladder;  and  the  ureter  is  to  be  traced  forwards  by  the  side  of  the  uterus 
to  the  bladder.     Afterwards  the  urethra,  the  vagina,  and  the  rectum  are 


610  DISSECTION  OF  THE  PELVIS. 

to  be  cleaned  and  partly  separated  from  one  another  at  the  anterior  part 
of  the  pelvis ;  but  the  arteries  on  the  rectum  are  to  be  preserved. 

The  peritoneum  gives  a  partial  covering  to  the  viscera,  as  in  the  male 
pelvis.  Investing  the  upper  part  of  the  rectum,  and  forming  behind  it 
the  meso-rectum,  the  membrane  is  continued  to  the  posterior  part  of  the 
vagina,  and  the  back  of  the  uterus.  It  covers  tlie  posterior,  and  the 
greater  part  of  the  anterior  surface  of  the  uterus,  and  can  be  traced  to 
the  bUidder  without  again  touching  the  vagina  :  on  each  side  of  the  uterus 
it  forms  a  wide  fold  (broad  ligament),  which  attaches  that  viscus  to  the 
wall  of  the  abdomen.  As  the  peritoneum  is  followed  upwards  it  may  be 
observed  to  cover  the  posterior  surface  of  the  bladder,  and  the  lateral  part 
behind,  the  position  of  the  obliterated  hypogastric  artery. 

In  the  pelvis  the  serous  membrane  forms  the  following  ligaments  for  the 
uterus  and  bladder. 

The  broad  ligament  of  the  uterus  (fig.  175)  passes  from  the  side  of  the 
uterus  to  the  wall  of  the  abdomen,  and  supports  that  organ.  By  its  posi- 
tion across  the  pelvis,  it  divides  the  cavity  into  an  anterior  and  a  posterior 
portion  :  in  the  former  are  placed  the  bladder,  urethra,  and  vagina ;  in 
the  latter  the  upper  part  of  the  rectum,  and  the  small  intestine  when  it 
reaches  the  pelvis. 

Each  ligament  shows  traces  of  a  subdivision  into  three  pieces,  corre- 
sponding with  the  bodies  contained  between  its  two  layers.  Thus  there 
is  a  posterior  piece  belonging  to  the  ovary  and  its  ligament,  l  ;  an  anterior, 
near  the  upper  part,  which  is  appropriated  to  the  round  ligament,  n  ;  and 
a  middle  piece,  the  highest  of  all,  surrounds  the  Fallopian  tube,  m. 

Anterior  and  posterior  ligaments  of  the  uterus.  As  the  peritoneum  is 
reflected  from  the  rectum  to  the  uterus,  and  from  the  uterus  to  the  bladder, 
it  forms  two  anterior  and  to  posterior  folds  or  ligaments.  The  anterior  or 
vesicO'Uterine  pair  is  smaller  than  the  [)osterior  or  recto-uterine. 

The  recto-uterine  pouch  corresj)onds  with  the  recto-vesical  in  the  male. 
On  each  side  it  is  bounded  by  the  obliterated  hypogastric  artery :  and  be- 
low, it  reaches  beyond  the  uterus,  so  as  to  touch  the  back  of  the  vagina. 

T\\Q  false  ligaments  of  the  bladder  are  the  same  as  in  the  male,  and  are 
five  in  number,  viz.,  two  posterior,  two  lateral,  and  a  superior  :  they  are 
all  blended  in  one  large  piece  of  peritoneum  that  reaches  from  the  bladder 
to  the  side  and  front  of  the  pelvis.  In  the  female  the  posterior  ligament, 
containing  the  vessels  of  the  bladder,  is  less  marked  than  in  the  male. 

The  RECTUM  (fig.  175,  ^)  is  not  so  curved  in  the  female  as  in  the  male, 
and  is  generally  larger.  Descending  along  the  middle  of  the  sacrum  and 
coccyx  to  the  anus,  the  intestine  is  divided  into  three  parts  : — 

The  first  part  ends  over  the  third  piece  of  the  sacrum,  and  is  enveloped 
by  the  peritoneum,  except  posteriorly:  its  connections  are  similar  to  those 
of  the  rectum  in  the  male,  p.  504. 

The  middle  part  reaches  to  the  tip  of  the  coccyx,  and  has  the  vagina 
above  and  in  contact  with  it.  The  peritoneum  extends  on  the  front  ibr  a 
short  distance. 

The  lower  part  curves  to  the  anus  away  from  the  vagina  so  as  to  leave 
between  the  two  a  space,  whicii  corresponds,  on  the  surface  of  the  body, 
with  the  part  of  the  perinasiim  between  the  anus  and  the  vulva.  Tlie 
levatores  ani  are  on  the  sides,  and  unite  below  it,  and  the  sphincter  mus- 
cles surround  the  extremity. 

The  UTERUS  (fig.  175,  °)  is  somewhat  conical  in  shape,  and  flattened 
from  before  backwards.     Unless  enlarged,  it  lies  below   the  brim  of  the 


CONNECTIONS    OF    UTERUS 


511 


pelvis,  between  the  bladder  and  the  rectum ;  and  it  is  retained  in  place  by 
the  ligaments.  Its  wider  end  is  free  and  placed  upwards,  and  the  lower 
end  communicates  with  the  vagina. 

This  viscus  is  directed  forwards,  so  that  its  position  is  oblique  in  the 
cavity  of  the  pelvis ;  and  a  line  through  its  centre  would  correspond  with 
the  axis  of  the  inlet  of  the  pelvic  cavity. 

Fig.  175. 


Side  View  of  the  Female  Pelvis.     (Illustratioas  of  Dissections.) 


Muscles  and  Viscera : 

Arteries  : 

A.  Pyriformis  muscle,  cut. 

a.  External  iliac. 

B.  Large  psoas,  cut. 

b.  Internal  iliac. 

c.  Gluteus  maximiis,  cut. 

c.  Middle  sacral. 

D.  Coccygeus,  and  e,  Levator  aui, 

thrown 

d.  Uterine. 

down. 

«.  Vaginal. 

F.  Sphincter  vaginae. 

/.  Upper  hsemorrhoidal. 

«.  Urethra. 

g.  Gluteal,  cut. 

H.  Urinary  bladder. 

h.  Obliterated  hypogastric. 

T.  Vagina. 

i.  Inferior  vesical. 

K.  Rectum. 

L.  Ovary  and  its  ligament. 

M.  Fallopian  tube. 

N.  Round  ligament. 

0.  Uterus. 

The  anterior  flattened  surface  is  covered  by  peritoneum,  except  in  the 
lower  fourth  where  it  is  in  contact  with  the  bladder.  The  posterior  sur- 
face, rounded,  is  invested  altogether  by  the  serous  membrane. 

The  upper  end  (fundus)  is  the  largest  part  of  the  organ,  and  is  in  con- 
tact with  the  small  intestine.  The  lower  end,  or  the  neck  (cervix)  is 
received  into  the  vagina. 

To  each  side  are  attached  the  broad  ligament  with  the  Fallopian  tube, 
the  round  ligament,  and  the  ovary. 

The  Fallopian  tube,  M,  four  inches  long,  is  contained  in  the  upper  or 
free  border  of  the  ligament.     One  end  is  connected  to  the  upper  angle  of 


512  DISSECTION    OF    THE    PELVIS. 

the  uterus,  whilst  the  other  is  loose  in  the  cavity  of  the  pelvis.  At  the 
uterine  end  the  tube  is  of  small  size,  but  at  the  opposite  extremity  it  is 
dilated  like  a  trumpet,  and  fringed,  forming  the  corpus  jimhriatmii. 

The  round  or  suspensory  ligament,  n,  is  a  fibrous  cord  about  five  inches 
long,  which  is  directed  outwards  through  the  internal  abdominal  ring  and 
the  inguinal  canal  to  end  in  the  groin.  Tiiis  cord  lies  over  the  obliterated 
hypogastric,  and  the  external  iliac  artery ;  and  it  is  surrounded  by  the 
peritoneum,  which  accompanies  it  a  siiort  way  into  the  canal. 

The  ovary,  Lj  is  placed  nearly  horizontally,  and  bulges  at  the  posterior 
aspect  of  the  broad  ligament  ;  it  is  connected  to  the  uterus  at  the  inner 
end  by  a  special  fibrous  band,  one  inch  tmd  a  half  in  length,  the  ligament 
of  the  ovary.  Its  form  is  oval,  and  its  margins  are  turned  forwards  and 
backwards.     Its  size  is  very  variable. 

The  VAGINA  (fig.  175,  ^)  is  the  tube  by  which  the  uterus  communicates 
with  the  exterior  of  the  body.  It  is  somewhat  cylindrical  in  shape, 
though  flattened  from  above  down ;  and  its  length  is  about  five  inches.  As 
it  follows  the  bend  of  the  rectum  it  is  slightly  curved  ;  and  its  axis  corre- 
sponds at  first  with  the  centre  of  the  outlet,  but  higher  up  with  that  of 
the  cavity  of  the  pelvis. 

Above  the  vagina  are  the  base  of  the  bladder,  and  the  urethra  ;  and 
beneath  or  below  it  is  the  rectum.  To  each  side  is  attached  the  recto- 
vesical fascia,  which  sends  a  sheath  along  the  lower  half  of  the  tube. 
The  upper  end  receives  the  neck  of  the  uterus  by  an  aperture  in  the  an- 
terior or  upper  wall ;  and  the  lower  end,  the  narrowest  part  of  the  canal, 
is  encircled  by  the  sphincter  vaginae  muscle.  A  large  plexus  of  veins 
surrounds  the  vagina.  In  children,  and  in  the  virgin,  the  external  aperture 
is  partly  closed  by  the  hymen. 

The  BLADDER  (Hg.  175,  ^)  is  pLiced  at  the  anterior  part  of  the  pelvis, 
above  the  vagina  and  in  contact  with  the  back  of  tlie  pubes.  Its  position 
and  connections  so  closely  resemble  those  of  the  bladder  in  the  male  body, 
as  to  render  unnecessary  any  further  description  of  them  (p.  50G).  The 
chief  differences  in  tlie  bladder  of  the  two  sexes  are  the  following. 

In  the  female  the  bladder  is  larger  than  in  the  male,  and  its  transverse 
exceeds  its  vertical  measurement.  The  base  is  of  less  extent,  and  is  in 
contact  with  the  vagina  and  the  low(;r  part  of  the  uterus  ;  and  it  does  not 
reach  below  the  orifice  of  the  urethra.  On  the  side  of  the  viscus  there 
is  not  any  vas  deferens  ;  and  the  prostate  does  not  project  around  the 
neck. 

The  ureter  has  a  longer  course  in  the  female  than  in  the  male  pelvis 
before  it  reaches  the  bladder.  After  crossing  the  internal  iliac  vessels,  it 
passes  by  the  neck  of  the  uterus  ere  it  arrives  at  its  destination. 

The  urethra  (fig.  175,  ^)  is  a  small  narrow  tube  about  one  inch  and  a 
half  long,  which  curves  slightly  below  tlie  symphysis  pubis,  the  concavity 
being  upwards.  Its  situation  is  above  the  vagina,  and  its  external  open- 
ing is  placed  within  the  vulva. 

In  its  course  to  the  surface  it  is  embedded  in  the  tissue  of  the  vaginal 
wall,  and  perforates  the  triangular  ligament  of  the  perinaeum.  It  is  sur- 
rounded by  the  muscular  fibres  of  the  constrictor  and  orbicularis  urethras 
(p.  398)  ;  and  corresponls  with  the  two  hinder  parts  (prostatic  and  mem- 
branous) of  the  male  urethra.  A  plexus  of  veins  surrounds  the  urethra 
as  well  as  the  vagina. 


VESSELS    AND    NERVES    OF    THE    PELVIS.  518 

Section  IV. 

VESSELS  AND   NERVES  OF  THE  PELVIS. 

In  the  pelvis  are  contained  the  internal  iliac  vessels,  and  their  branches 
to  the  viscera ;  the  sacral  plexus  and  its  nerves ;  and  the  sympathetic 
nerve.  This  Section  is  to  be  used  by  the  dissectors  of  both  the  male  and 
female  pelvis. 

Directions.  The  internal  iliac  vessels  are  to  be  dissected  on  the  right 
side.  But  the  air  should  be  previously  let  out  of  the  bladder  ;  and  this 
viscus  and  the  rectum,  with  the  uterus  and  the  vagina  in  the  female,  should 
be  drawn  aside  from  their  situation  in  the  centre  of  the  pelvis. 

Dissection.  The  loose  tissue  and  fat  are  to  be  removed  from  the  trunks 
of  the  vessels,  as  well  as  from  the  branches  of  the  artery  that  leave  the 
pelvis,  or  supply  the  viscera ;  and  the  obliterated  cord  of  the  hypogastric 
artery  is  to  be  traced  on  the  bladder  to  the  umbilicus. 

With  the  vessels  are  offsets  of  the  hypogastric  plexus  of  nerves,  but 
these  will  probably  not  be  seen  ;  but  in  dissecting  the  vessels  to  tlie  bladder 
and  rectum,  brandies  of  the  sacral  spinal  nerves  will  come  into  view.  The 
veins  may  be  removed  in  a  general  dissection,  to  make  clean  the  arteries. 

AVhen  the  vessels  are  prepared  the  bladder  may  be  again  distended,  and 
the  viscera  replaced. 

The  INTERNAL  ILIAC  ARTERY  (fig,  176,  g)  is  ouc  of  the  trunks  result- 
ing from  the  division  of  the  common  iliac  artery,  and  furnishes  branches 
to  the  viscera  and  wall  of  the  pelvis,  to  the  generative  and  genital  organs, 
and  to  the  limb. 

In  the  adult  the  vessel  is  a  short  trunk  of  large  capacity,  wliich  meas- 
ures about  an  inch  and  a  half  in  length.  Directed  downwards  as  far  as  the 
sacro-sciatic  notch,  the  artery  terminates  generally  in  two  large  pieces, 
from  which  the  several  offsets  are  furnished.  From  the  extremity  a  partly 
obliterated  vessel  (hypogastric)  extends  forwards  to  the  bladder. 

In  entering  the  pelvis  the  artery  lies  in  front  of  the  lumbo-sacral  nerve. 
It  is  accompanied  by  the  internal  iliac  vein,  which  is  posterior  to  it,  and 
somewhat  to  the  outer  part  on  the  right  side. 

The  branches  of  the  artery  are  numerous,  and  arise  usually  in  the  fol- 
lowing manner:  From  the  posterior  piece  of  the  trunk  three  arise,  viz., 
the  ilio-lumbar,  lateral  sacral,  and  gluteal.  And  from  the  anterior  portion 
come  the  vesical  (upper  and  lower),  haemorrhoidal,  obturator,  sciatic,  and 
pudic:  in  the  female  there  are  in  addition  the  uterine  and  vaginal 
branches. 

Artery  in  the  foetus.  In  the  foetus  the  hypogastric  artery  takes  the 
place  of  the  internal  iliac,  and  leaves  the  abdomen  by  the  umbilicus.  At 
that  time  it  is  larger  than  the  external  iliac  artery ;  and,  entering  but 
slightly  into  the  cavity  of  the  pelvis,  it  is  directed  forwards  to  the  back  of 
the  bladder,  and  along  the  side  of  that  viscus  to  the  apex. 

Beyond  the  bladder  the  artery  ascends  along  the  posterior  aspect  of  the 
abdominal  wall  with  the  urachus,  converging  to  its  fellow.  Finally  at 
the  umbilicus  the  vessels  of  opposite  sides  come  in  contact  with  the  um- 
bilical vein,  and  passing  from  the  abdomen  through  the  aperture  at  that 
spot,  enter  into  the  placental  cord,  and  receive  the  name  umbilical. 

In  the  foetus,  branches  similar  to  those  in  the  adult  are  furnished  by  the 
artery,  though  their  relative  size  at  the  two  periods  is  very  different. 
33 


514 


DISSECTION    OF    THE    PELVIS, 


Change  to  adult  state.  When  uterine  life  has  ceased  the  hypogastric 
artery  diminishes  in  consequence  of  the  arrest  of  the  current  of  blood 
through  it,  and  finally  becomes  obliterated,  more  or  less  completely,  as 
far  back  as  an  inch  and  a  half  of  its  commencement.  The  part  of  the 
trunk  which  is  unobliterated  becomes  the  internal  iliac  ;  and  commonly  a 
portion  of  the  vessel  remains  pervious  as  far  as  the  upper  part  of  the  blad- 
der, and  gives  origin  to  the  vesical  arteries. 

Peculiarities.  The  length  of  the  internal  iliac  arteries  varies  from  half  an  inch  to 
three  inches,  its  extreme  measurements  ;  but  in  two-thirds  of  a  certain  number 
of  bodies  (Quain)  it  ranged  from  an  inch  to  an  inch  and  a  half. 

Size.  When  the  femoral  trunk  is  derived  from  the  internal  iliac,  and  is  placed 
at  the  back  of  the  thigh,  the  parent  vessel  is  larger  than  the  external  iliac. 

Fig.  176. 


Dissection  of  the  Inteknai,  Iliac  Artery  (Tiedemann). 


A. 

Bladder. 

d.  External,  and  g,  internal  iliac  trunk  con- 

O. 

Vas  deferens. 

tinued  by  an  impervious  part  along  the 

H 

Vesicula  seminalis. 

bladder. 

B. 

Lower  end  of  the  rectum. 

e.  Epigastric,  and/,  circumflex  iliac. 

0. 

Levator  ani. 

h.  Ilio  lumbar. 

D. 

Pnoas  magnus. 

i.  Lateral  sacral. 

E. 

Psoas  parvus. 

/.  Middle  haemorrhoidal. 

F. 

en 

IliacuP. 
es: 

k.  Obturator. 
in.  Gluteal. 

a. 

Aorta  splitting  into  the  common  iliacs. 

n.  Sciatic. 

h. 

Middle  sacral  branch. 

o.  Pudic. 

c. 

Common  iliac. 

Nerves  : 
1,  2,  3,  4.     Four  highest  sacral  nerves,    o.  Ob- 
turator. 

A.  The  three  branches  arising  from  the  posterior  portion  of  the  internal 
iliac  may  be  first  examined. 

The  ilio'lumbar  branch  (fig.  176,  h)  passes  outwards  beneath  the  psoas 


BRANCHES    OF    INTERNAL    ILIAC.  615 

muscle  and  the  obturator  nerve,  but  in  front  of  the  lumbo-sacral  nerve, 
and  divides  into  an  ascending  and  a  transverse  branch  in  the  iliac  fossa  : — 

The  ascending  or  lumbar  branch,  which  is  beneath  the  psoas,  supplies 
that  muscle  and  the  quadratus  lumborum,  and  anastomoses  with  the  last 
lumbar  artery  :  it  sends  a  small  spinal  branch  through  the  foramen  be- 
tween the  sacrum  and  the  last  lumbar  vertebra. 

The  transverse  or  iliac  offset  divides  into  branches  that  ramify  in  the 
iliacus  muscle,  some  running  over  and  some  beneath  it.  At  the  iliac  crest 
these  branches  anastomose  with  the  lumbar  and  circumflex  iliac  arteries ; 
and  some  deep  twigs  communicate  with  the  obturator  artery,  and  enter 
the  innominate  bone. 

The  lateral  sacral  arteries  (fig.  176,  i)  are  two  in  number,  superior 
and  inferior,  but  the  upper  is  the  larger  ;  they  correspond  in  situation  with 
the  lumbar  arteries,  and  form  a  chain  of  anastomoses  by  the  side  of  the 
apertures  in  the  sacrum.  These  arteries  supply  the  pyriformis  and  coccy- 
geus  muscles,  and  anastomose  with  each  other,  as  well  as  with  the  middle 
sacral.     A  small  spinal  branch  enters  each  aperture  in  the  sacrum. 

The  gluteal  artery  (fig.  176,  rn)  is  a  short  thick  trunk,  which  appears 
to  be  the  continuation  of  the  posterior  division  of  the  internal  iliac.  Its 
destination  is  to  the  gluteal  muscles  on  the  dorsum  of  the  hip  bone  ;  and 
it  is  transmitted  from  the  pelvis  above  the  pyriformis  muscle,  with  its 
accompanying  vein,  and  the  superior  gluteal  nerve.  In  the  pelvis  the 
artery  gives  small  branches  to  the  contiguous  muscles,  viz.,  iliacus,  pyri- 
formis, and  obturator,  and  a  nutritious  artery  to  the  hip  bone. 

B.  The  branches  of  the  anterior  portion  of  the  internal  iliac  artery  are 
the  following : — 

The  vesical  arteries,  superior  and  inferior,  are  distributed  to  the  upper 
and  lower  parts  of  the  bladder. 

The  upper,  three  or  four  in  number,  arise  at  intervals  from  the  partly 
obliterated  hypogastric  trunk ;  the  lowest  of  these  is  sometimes  called 
middle  vesical  branch.  Offsets  are  furnished  from  those  branches  to  all 
the  body  and  upper  part  of  the  bladder. 

The  lower  artery  arises  from  the  internal  iliac  in  common  with  a 
branch  to  the  rectum,  or  witli  one  to  the  vagina  in  the  female.  It  is  dis- 
tributed to  the  base  of  the  bladder,  the  vesiculas  seminales,  and  the  pros- 
tate. A  small  offset  from  this  artery  or  from  the  upper  vesical  is  furnished 
to  the  vas  deferens. 

Tiie  branch  to  the  rectum  (middle  haemorrhoidal)  is  commonly  supplied 
by  the  inferior  vesical.  It  is  spent  on  the  anterior  and  lower  part  of  the 
rectum,  and  on  the  vagina  in  the  female,  and  anastomoses  with  the  hsemor- 
rhoidal  arteries. 

The  obturator  artery  (fig.  176,  k).  The  branch  is  directed  forwards 
below  the  brim  of  the  pelvis  to  the  aperture  in  the  upper  part  of  the  thy- 
roid foramen  ;  passing  through  that  opening  it  ends  in  two  branches, 
which  ramify  on  the  membrane  closing  the  thyroid  foramen,  and  lie  be- 
neath the  muscle  in  that  situation.  In  the  pelvis  the  artery  has  its  com- 
panion nerve  above,  and  vein  below  it ;  and  it  gives  origin  to  the  following 
small  branches. 

Jliac  branch :  this  small  offset  enters  the  iliac  fossa  to  supply  the  bone 
and  the  iliacus  muscle ;  it  anastomoses  with  the  ilio-lumbar  artery. 

The  pubic  branch  (fig.  141,/)  ascends  on  the  posterior  aspect  of  the 
pubes,  and  communicates  with  the  corresponding  branch  of  the  opposite 
side,  and  with  an  offset  from  the  epigastric  artery. 


516  DISSECTION    OF    THE    PELVIS. 

Sometimes  the  obturator  may  take  origin  from  the  external  iliac  artery. 

The  sciatic  artery  (fig.  176,  n)  is  the  next  largest  branch  to  the  gluteal, 
and  is  continued  over  the  pyritormis  muscle  and  the  sacral  plexus  to  the 
lower  part  of  the  sacro-sciatic  notch,  where  it  issues  between  the  pyriformis 
and  the  coccygeus.  External  to  the  pelvis  it  divides  into  branches  beneath 
the  gluteus  maximus,  and  is  distributed  to  the  buttock  :  in  the  pelvis  it 
supplies  the  pyriformis  and  coccygeus  muscles. 

The  pudic  artery  (tig.  176,  o)  supplies  the  perina^um  and  the  genital 
organs,  and  has  nearly  the  same  connections  in  the  pelvis  as  the  sciatic, 
from  which  it  often  springs.  It  accompanies  the  sciatic,  though  external 
to  it,  and  leaves  the  pelvis  between  the  pyriformis  and  coccygeus.  At  the 
back  of  the  pelvis  it  winds  over  the  ischial  spine  of  the  hip  bone,  and 
enters  the  perinaeal  space  (p.  390).  The  artery  gives  some  unimportant 
offsets  in  the  pelvis,  and  frequently  the  middle  hcemorrhoidal  branch  arises 
from  it. 

Accessory  pudic  (Quain).  The  pudic  artery  is  sometimes  smaller  than 
usual,  and  fails  to  supply  some  of  its  ordinary  perimeal  branches,  esj)ecially 
the  terminal  for  the  penis.  In  those  cases  the  deficient  branches  are  de- 
rived from  an  accessory  artery,  which  takes  origin  from  the  internal  iliac 
(mostly  from  the  trunk  of  the  pudic),  and  courses  forwards  on  the  side  of 
the  bladder  and  the  prostate  gland,  to  perforate  the  triangular  perinatal 
ligament.  It  furnishes  branches  to  the  penis  to  supply  the  place  of  those 
that  are  wanting. 

c.  The  branches  of  the  internal  iliac  artery  which  are  peculiar  to  the 
female  are  two,  the  uterine  and  vaginal. 

The  uterine  artery  (fig.  lib,  d)  passes  inwards  between  the  layers  of 
the  broad  ligament  to  the  neck  of  the  uterus,  where  the  vessel  changes  its 
direction,  and  ascends  to  the  fundus.  Numerous  branches  enter  the  sub- 
stance of  the  uterus,  and,  ramifying  in  it,  are  remarkable  for  their  tortuous 
condition. 

At  the  neck  of  the.  uterus  some  small  twigs  are  supplied  to  the  vagina 
and  the  bladder ;  and  opposite  the  ovary  a  branch  bends  outwards  to  anas- 
tomose with  the  ovarian  artery  (spermatic)  of  the  aorta. 

The  vaginal  artery  (fig.  1  75,  e)  seldom  arises  separately  from  the  inter- 
nal iliac.  Combined  with  the  preceding,  or  with  the  branch  to  the  rectum, 
this  artery  extends  along  the  vagina,  and  ramifies  in  its  wall  as  low  as  the 
outer  orifice. 

Other  arteries  in  the  pelvis.  The  remaining  arteries  in  the  pelvis,  which 
are  not  derived  from  the  internal  iliac,  are  the  ovarian,  superior  hiemor- 
rhoidal,  and  middle  sacral. 

The  ovarian  artery  (p.  490),  after  passing  the  brim  of  the  pelvis,  be- 
comes tortuous,  and  enters  the  broad  ligament  to  be  distril)uted  to  the 
ovary  :  it  supplies  an  offset  to  the  Fallopian  tube,  and  another  to  the  round 
ligament ;  and  a  large  branch  anastomoses  internally  with  the  uterine 
artery. 

The  superior  hcemorrhoidal  artery,  the  continuation  behind  the  rectum 
of  the  inferior  mesenteric  (p.  441),  divides  into  two  branches  near  the 
middle  of  the  sacrum.  From  the  point  of  division  the  branches  are  con- 
tinued along  the  rectum,  one  on  each  side,  and  each  ends  finally  in  about 
three  branches,  which  pierce  the  layer  of  the  gut  three  inches  from  the 
anus  ;  they  terminate  opposite  the  inner  sphincter  in  anastomotic  loops 
beneath  the  mucous  membrane,  and  anastomose  with  the  middle  and  in- 
ferior haemorrhoidal  arteries. 


VEINS    OF    THE    PELVIS.  617 

The  middle  sacral  artery  of  the  aorta  (p.  489),  (fig.  176,  h)  descends 
along  the  middle  of  the  last  lumbar  vertebra,  the  sacrum,  and  the  coccyx. 
Tlie  artery  gives  small  branches  laterally,  opposite  each  piece  of  the 
sacrum,  to  anastomose  with  the  lateral  sacral  arteries,  and  to  supply  the 
nerves,  and  the  bones  with  the  periosteum.  Sometimes  a  small  branch  is 
furnished  by  it  to  the  low^er  end  of  the  rectum,  to  take  the  place  of  the 
middle  ha^morrhoidal  artery. 

The  INTERNAL  ILIAC  VEIN  rcceives  the  blood  from  the  wall  of  the  pel- 
vis, and  the  pelvic  viscera,  by  branches  corresponding  for  the  most  part 
witli  tliose  of  the  arteries.  The  vein  is  a  short  thick  trunk,  which  is 
situate  at  first  on  the  inner  side  of  the  internal  iliac  artery;  but  as  it 
ascends  to  join  the  external  iliac,  it  passes  behind,  and  to  the  outer  aspect 
of  its  companion  artery  on  the  right  side 

Branches.  Most  of  the  branches  entering  the  trunk  of  the  internal 
iliac  vein,  have  the  same  anatomy  as  the  arteries ;  but  the  following  vis- 
ceral branches — the  pudic  and  dorsal  of  the  penis,  the  vesical  and  haemor- 
rhoidal,  the  uterine  and  vaginal,  have  some  peculiarities. 

The  pudic  vein  receives  roots  corresponding  with  the  branches  of  the 
pudic  artery  in  the  perina^um,  but  not  those  corresponding  with  the  offsets 
of  the  artery  on  the  dorsum  of  the  penis. 

The  dorsal  vein  of  the  penis  receives  veins  from  the  corpora  cavernosa 
and  corpus  spongiosum  of  the  penis,  and  piercing  the  triangular  ligament 
of  the  urethra,  divides  into  two,  a  right  and  a  left  branch,  which  enter  a 
plexus  around  the  prostate. 

Tlie  superior  hcemorrhoidal  vein  commences  in  a  large  plexus  (hoemor- 
rhoidal)  around  the  lower  end  of  the  rectum  beneath  the  mucous  mem- 
brane (p.  533). 

The  vesical  veins  begin  in  a  plexus  about  the  lower  part  of  the  bladder, 
and  anstomose  with  the  prostatic  and  hasmorrhoidal  veins. 

The  uterine  veins  are  numerous,  and  form  a  plexus  in  and  by  the  side 
of  the  uterus :  this  plexus  inosculates  above  with  the  ovarian  plexus,  and 
below  with  one  on  the  vagina. 

TRe  vaginal  veins  surround  their  tube  with  a  large  vascular  plexus. 

Parietal  veins  of  the  pelvis.  Three  veins  of  the  wall  of  the  pelvis,  viz., 
ilio-lumbar,  lateral  sacral,  and  middle  sacral,  open  into  the  common  iliac 
vein. 

Dissection  (fig.  177).  To  dissect  the  nerves  of  the  pelvis,  on  the  right 
side,  it  will  be  necessary  to  detach  the  triangular  ligament  with  tlie 
urethra  from  the  arch  of  the  pubes  ;  and  to  cut  through,  on  the  right  side, 
the  recto-vesical  fav^icia  and  the  levator  ani,  together  with  tlie  visceral  arte- 
ries, in  order  that  the  viscera  may  be  drawn  somewhat  from  the  side  of 
the  pelvis.     If  the  bladder  is  distended  let  the  air  escape  from  it. 

By  means  of  the  foregoing  dissection  the  sacral  nerves  may  be  found  as 
they  issue  from  the  sacral  foramina.  The  dissector  sliould  follow  the  first 
four  into  the  sacral  plexus,  and  some  branches  from  the  fourth  to  the  vis- 
cera. The  last  sacral  and  the  coccygeal  nerve  are  of  small  size,  and  will 
be  detected  coming  through  the  coccygeus  muscle,  close  to  the  coccyx  ; 
these  are  to  be  dissected  with  care;  and  the  student  will  succeed  best  by 
tracing  the  connecting  filaments  which  pass  from  one  to  another,  beginning 
above  with  the  offset  from  the  fourth  nerve. 

Opposite  the  lower  part  of  the  rectum,  bladder,  and  vagina  is  a  large 
plexus  of  the  sympathetic  (pelvic  plexus),  which  sends  branches  to  the 
viscera  along  the  arteries.     This  plexus  is  generally  destroyed  in  the  pre- 


518  DESSECTION    OF    THE    PELVIS. 

vious  dissections  ;  but  if  any  of  it  remains  the  student  may  trace  the 
offsets  distributed  from  it,  and  its  communicating  branches  with  the  spinal 
nerves. 

Sacral  Spinal  Nerves  (fig.  177).  The  anterior  primary  branches 
of  the  sacral  nerves  are  five  in  number,  and  decrease  suddenly  in  size 
from  above  downwards.  Issuing  by  the  apertures  in  the  front  of  the 
sacrum  (the  fifth  nerve  excepted)  they  receive  short  filaments  of  commu- 
nication from  the  gangliated  cord  of  the  sympathetic.  The  first  three 
nerves  and  part  of  the  fourth  enter  the  sacral  plexus,  but  the  fifth  ends  on 
the  back  of  the  coccyx. 

The  coccygeal  nerve,  and  the  peculiarities  of  the  fourth  and  fifth  sacral, 
will  be  noticed  before  the  plexus  is  described. 

The  fourth  nerve  (4  ^S)  divides  into  two  parts : — one  communicates 
with  the  sacral  plexus ;  the  other  joins  the  fifth  nerve  and  distributes  the 
following  branches  to  the  viscera  and  the  surrounding  muscles  : — 

The  visceral  branches  (3)  supply  the  bladder  and  the  vagina,  and  com- 
municate with  the  sympathetic  nerve  to  form  the  pelvic  plexus.  Some- 
times these  branches  come  from  the  third  sacral  nerve. 

The  muscular  branches  are  three  in  number.  One  (2)  rather  long 
branch  enters  the  levator  ani  on  the  visceral  aspect ;  another  (4)  supplies 
the  coccygeus  ;  and  the  third  (5)  reaches  the  perinneum  by  piercing  the 
levator  ani  muscle  (p.  391). 

The  fifth  nerve  (5  S)  comes  forwards  between  the  sacrum  and  coccyx, 
and  receives  the  communicating  branch  from  the  fourth  nerve  ;  it  is  then 
directed  downwards  in  front  of  the  coccygeus,  where  it  is  joined  by  the 
coccygeal  nerve,  and  perforates  that  muscle,  the  sacro-sciatic  ligament, 
and  the  gluteus  maximus,  to  end  on  the  posterior  surface  of  the  coccyx. 

The  coccygeal  nerve  (1  c)  after  issuing  by  the  lower  aperture  of  tlie 
spinal  canal,  appears  through  the  coccygeus  muscle,  and  joins  the  fifth 
sacral  nerve  as  above  stated. 

Sacral  Plexus  (fig.  177).  This  plexus  is  formed  by  the  lumbo-sacral 
cord,  the  first  three  sacral  nerves,  and  part  of  the  fourth  sacral.  It  is 
situate  on  the  pyriformis  muscle,  beneath  the  sciatic  and  pudic  brailches 
of  tlie  internal  iliac  artery ;  and  the  nerves  entering  it  converge  towards 
the  large  sacro-sciatic  notch,  to  unite  in  a  flat  band.  From  that  spot  the 
plexus  becomes  gradually  smaller  towards  the  outer  end  ;  and,  leaving  the 
pelvis  below  the  pyriformis,  terminates  in  branches  for  the  limb  at  the 
lower  border  of  that  muscle. 

Branches.  Most  of  the  branches  arise  outside  the  pelvis,  and  are  dis- 
tributed to  the  back  of  the  lower  limb ;  for,  only  two  internal  pelvic 
muscles  (pyriformis  and  obturator  internus)  receive  nerves  from  it. 

The  nerve  of  the  obturator  internus  springs  from  the  part  of  the  plexus 
formed  by  the  union  of  the  lumbo-sacral  with  the  first  sacral  nerve  ;  it 
leaves  the  pelvis  with  the  pudic  artery,  and  winding  over  the  ischial  spine 
of  tiie  hip  bone  and  through  the  small  sacro-sciatic  notch,  enters  the 
muscle  on  the  perinieal  surface. 

Tlie  nerves  of  the  pyriformis  are  commonly  two  in  numl^er,  and  arise 
from  separate  parts  of  the  plexus  :  they  enter  the  muscle  at  its  visceral 
aspect. 

T\\Q  pudic  nerve,  like  the  artery  of  the  same  name,  supplies  the  ])arts  in 
the  perinaium,  and  the  genital  organs.  The  nerve  arises  in  the  lower  part 
of  the  plexus,  and  courses  over  the  small  sacro-sciatic  ligament,  to  accom- 
pany its  artery  through  the  small  sacro-sciatic  notch. 


NERVES    OF    THE    PELVIS 


519 


The  remaining  branches  of  the  plexus,  viz.,  the  small  and  great  sciatic 
nerves,  and  muscular  offsets  to  the  gluteus,  gemelli,  and  quadratus  femoris, 
are  described  with  the  lower  limb.     (Dissection  of  the  Buttock.) 

Dissection.  The  gangliated  cord  of  the  sympathetic  that  lies  in  front 
of  the  sacrum  may  be  examined  now  :  its  several  ganglia  (three  or  four), 
and  their  brandies,  will  come  into  view  on  the  removal  of  the  areolar 
tissue. 

Fig.  177. 


a.  Urinary  bladder. 

b.  Rectum. 

c.  Levator  aui. 

d.  Coccygeus. 
Nerves  : 

4Zand5  ^,  the  last  two  lumbar  nerves, 
wbich  form  by  their  union  the 
lumbo-sacral  cord. 

\  S  iobS,  the  five  sacral  nerves,  form- 
ing the  sacral  plexus. 

1  c.  Coccygeal  nerve. 

1.  Upper  gluteal  nerve. 

2.  Branch  of  levator  ani. 

3.  Branch  to  the  bladder. 

4.  Branch  of  sphincter  ani. 

5.  Branch  of  coccygeus. 

6.  Common  branch  of  4  S,  n  S,  and  1 
c,  for  the  back  of  the  coccyx. 


Dissection  of  the  Sacral  Nerves  and  Plexus  (altered  from  Henle). 


Sympathetic  Nerve.  In  the  pelvis  the  sympathetic  nerve  consists  of 
a  gangliated  cord,  and  of  a  plexus  on  each  side. 

The  Gangliated  Cord  (fig.  177)  lies  on  the  front  of  the  sacrum  and 
internal  to  the  series  of  apertures  in  that  bone.  Inferiorly  it  converges  to 
its  fellow,  and  is  united  with  it  by  a  loop  in  front  of  the  coccyx,  on  which 
is  situate  a  single  median  ganglion  {gang,  impar).  Each  cord  is  marked 
by  ganglia  at  intervals,  the  number  varying  from  three  to  five  :  from  them 
branches  of  communication  pass  outwards  to  the  spinal  nerves,  and  some 
filaments  are  directed  inwards  in  front  of  the  sacrum. 

The  connecting  branches  are  two  to  each  ganglion,  gray  and  white,  and 
are  very  short :  tlie  gray  cord  unites  the  ganglion  with  the  spinal  nerve, 
but  the  white  one  is  continued  over  the  ganglion  to  the  visceral  plexus 
(Beck). 

The  internal  branches  are  small,  and  communicate  around  the  middle 
sacral  artery  with  the  brandies  of  the  opposite  side.  From  the  first,  or 
first  two  ganglia,  some  filaments  are  furnished  to  the  hypogastric  plexus  ; 
and  from  the  terminal  connecting  branches,  and  from  the  ganglion  in  front 
of  the  coccyx,  offsets  descend  over  tliat  bone. 

The  PELVIC  PLEXUSES  (lateral  inferior  hypogastric)  are  two  in  number, 
right  and  left,  and  are  continuous  with  the  lateral  prolongations  of  the 


620  DISSECTION    OP    THE    PELVIS. 

hypogastric  plexus  (p.  444).  Each  is  situate  by  the  side  of  the  blackier 
and  rectum  in  the  male,  and  by  the  side  of  the  uterus  and  vagina  in  tlie 
female,  and  is  united  with  offsets  of  the  third  and  fourth  sacral  nerves. 
Numerous  ganglia  are  found  in  the  plexus,  especially  at  the  points  of  union 
of  the  spinal  and  sympathetic  nerves. 

Offsets.  From  each  plexus  offsets  are  furnished  along  the  branches  of 
the  internal  iliac  artery  to  the  viscera  of  the  pelvis,  and  the  genital  organs  ; 
these  form  secondary  plexuses,  and  have  the  same  name  as  the  vessels  on 
which  tliey  are  placed. 

The  inferior  hcemorrhoidal  plexus  is  an  offset  from  the  back  of  the 
plexus  to  the  rectum,  and  joins  the  sympathetic  on  the  superior  haimor- 
rhoidal  artery. 

The  vesical  plexus  contains  large  offsets,  with  many  wliite  tibred  or 
spinal  nerves,  and  passes  forwards  to  the  side  and  lower  part  of  the  bladder. 
It  gives  one  plexus  to  the  vesicula  seminalis,  and  another  to  the  vas 
deferens. 

The  prostatic  plexus  leaves  the  lower  part  of  the  pelvic  plexus,  and  is 
distributed  to  the  substance  of  the  prostate.  At  tlie  front  of  the  prostate 
an  offset  (cavernous)  is  continued  onwards  to  the  dorsum  of  the  penis,  to 
supply  the  cavernous  structure.  On  the  penis  the  cavernous  nerves  join 
the  pudic  nerve. 

In  the  female  there  are  the  following  additional  plexuses  for  the  supply 
of  the  viscera  peculiar  to  that  sex: — 

Ovarian  plexus.  Tlie  chief  nerves  to  the  ovary  are  derived  from  the 
renal  and  aortic  plexuses,  and  accompany  the  artery  of  that  body  ;  but  the 
uterine  nerves  supply  some  filaments  to  it. 

Vaginal  plexus.  The  nerves  of  the  vagina  are  large,  and  are  not  plexi- 
form,  but  consist  in  greater  part  of  spinal  nerve  fibres ;  they  end  in  the 
lower  part  of  the  tube. 

Tlie  uterine  nerves  are  furnished  to  the  uterus  without  direct  admixture 
with  the  spinal  nerves :  they  ascend  along  the  side  of  the  uterus,  and  are, 
for  the  most  part,  long  slender  filaments  witliout  ganglia  or  communica- 
tions.    The  Fallopian  tube  receives  its  branches  from  the  uterine  nerves. 

Some  few  nerves  surrounding  the  arteries  of  the  uterus  are  plexiform 
and  ganglionic. 

The  lymphatic  glands  of  the  pelvis  form  one  cliain  in  front  of  the 
sacrum,  and  another  along  the  internal  iliac  artery:  their  efferent  ducts 
join  the  lumbar  glands.  Into  these  glands  the  deep  lymphatics  of  the 
penis,  those  of  the  genital  organs  in  the  female,  and  the  lymphatics  of  the 
viscera  and  wall  of  the  pelvis  are  collected. 


Section  V. 

ANATOMY  OF  THE  VISCERA  OF  THE  MALE  PELVIS. 

Directions.  The  bladder  and  the  parts  at  its  base,  viz.,  the  vesiculae 
serainales,  and  tlie  prostate  gland,  are  to  be  taken  first  for  examination. 

Dissection.  To  study  the  form  and  structure  of  the  viscera,  it  will  be 
necessary  to  remove  them  from  tlie  pelvis.  For  this  purpose  the  student 
should  carry  the  scalpel  around  the  pelvic  outlet,  close  to  the  osseous 


STRUCTURE  OF  PROSTATE.  521 

boundary,  so  as  to  detach  the  crus  of  the  penis  from  the  bone,  and  the 
end  of  the  rectum  from  the  parts  around.  When  the  viscera  are  removed, 
tlie  rectum  is  to  be  separated  from  the  other  organs;  but  the  bladder,  the 
penis,  and  the  urethra  are  to  remain  united. 

After  tlie  bladder  has  been  distended  with  air,  the  areolar  tissue  is  to 
be  removed  from  the  muscular  fibres.  The  prostate  gland  and  the  vesiculae 
seminales  are  to  be  then  cleaned ;  and  the  duct  of  the  latter,  with  the  vas 
deferens,  is  to  be  followed  to  the  gland. 

If  any  of  the  integument  has  been  left  on  the  penis  and  the  urethra  it  is 
to  be  taken  away. 

THE  PROSTATE  GLAND  AND  SEMINAL  VESICLES. 

Prostate  gland  (fig.  178).  This  is  a  firm  muscular  body,  with  glands 
in  it  secreting  a  special  fluid,  which  surrounds  the  neck  of  the  bladder 
and  the  beginning  of  the  urethra.  Its  connections  with  parts  around 
have  been  enumerated  (p.  507). 

The  prostate  is  conical  in  form  like  a  chestnut,  with  the  base  or  larger 
end  directed  backwards.  Its  dimensions  in  different  directions  are  the 
following  :— Transversely  at  the  base  it  measures  about  an  inch  and  a  half; 
from  apex  to  base  an  inch  and  a  quarter;  and  in  depth  about  three-quarters 
of  an  inch  or  an  inch :  so  that  an  incision  directed  obliquely  outwards  and 
backwards  laterally,  from  the  apex  to  the  base,  will  be  the  longest  that 
can  be  practised  in  the  half  of  this  body.  Its  weight  is  about  an  ounce, 
but  in  this  respect  it  varies  greatly. 

The  upper  surface  of  the  prostate  is  narrow  and  rounded.  The  under 
suiface,  which  is  larger  and  flatter,  is  marked  by  a  median  hollow  which 
indicates  the  division  into  lateral  lobes. 

The  posterior  part,  or  the  base,  is  thick,  and  in  its  centre  is  a  notch 
which  receives  the  common  seminal  ducts.  The  forepart  or  apex  is 
pierced  by  the  urethra. 

Three  lobes  are  described  in  the  prostate,  viz.,  a  middle  and  two  lateral, 
though  there  is  no  fissure  in  the  firm  mass.  The  lateral  parts  or  lobes 
(fig.  178,  h,  c)  are  similar  on  both  sides,  and  are  separated  only  by  the 
hollow  on  the  under  surface ;  they  form  the  chief  part  of  the  prostate, 
and  are  prolonged  back,  on  each  side,  beyond  the  notch  in  the  base.  The 
middle  lobe  (d)  will  be  brought  into  view  by  detaching  the  vesicular  semi- 
nales and  the  vasa  deferentia  from  the  bladder;  it  is  the  piece  of  tlie  gland 
between  the  neck  of  the  bladder  and  the  seminal  ducts,  which  extends 
across  between  the  lateral  lobes.  Oftentimes  the  middle  lobe  is  enlarged 
in  old  people,  and  projects  upwards  into  the  bladder,  so  as  to  interfere 
with  the  flow  of  the  urine  from  that  viscus,  or  the  passage  of  a  catheter 
into  it. 

The  urethra  and  the  two  common  seminal  ducts  are  contained  in  the 
substance  of  the  prostate  (fig.  180).  The  former  is  transmitted  through 
the  gland  from  base  to  apex;  and  the  latter  perforate  it  obliquely  to  ter- 
minate in  the  urethral  canal. 

Structure.  On  a  section  the  gland  appears  reddish  gray  in  color,  is 
very  firm  to  the  feel,  and  is  scarcely  lacerable.  It  is  made  up  of  a  mass 
of  unstriated  muscular  and  fibrous  tissues,  with  interspersed  glandular 
structure;  and  the  whole  is  enveloped  by  a  fibrous  coat. 

FibroKS  covering.  This  forms  a  thin  investment  for  the  gland,  and 
sends  offsets  into  the  interior.     It  is  quite  distinct  from  the  denser  sheath 


522  DISSECTION  OF  THE  PELVIS. 

derived  from  the  pelvic  fascia,  and  is  separated  from  that  slieath  by  a 
plexus  of  veins. 

Muscular  tissue.  The  firm  part  of  the  gland  consists  of  involuntary- 
muscular  fibres,  intermixed  with  elastic  and  fibrous  tissues.  The  muscular 
fibres  are  arranged  circularly  around  the  tube  of  the  urethra :  they  are 
continuous  behind  with  the  annular  fibres  of  the  bladder,  and  in  front 
wuth  a  thin  layer  of  circular  fibres  around  the  membranous  part  of  the 
urethra. 

At  the  lower  and  outer  parts  the  texture  is  looser  and  more  spongy, 
especially  where  the  glands  are  situate,  and  the  larger  vessels  enter  (Roy. 
Med.  Chir.  Trans.,  1856).  This  arrangement  will  be  better  seen  when 
the  urethra  has  been  opened. 

Glandular  struchu^e.  Small  branched  glands  project  from  the  tube  of 
the  urethra  amongst  the  muscular  fibres;  they  form  but  a  small  part  of 
the  prostate,  and  are  most  numerous  in  the  middle  lobe.  The  final  radicles 
of  the  ducts  are  surrounded  by  small  sessile  vesicles :  on  the  exterior  of 
the  vesicles  and  ducts  the  bloodvessels  ramify.  Lining  the  interior  of  the 
tube^  is  an  epithelium  of  the  columnar  kind.  Tlie  ducts  of  the  glands 
vary  in  number  from  twelve  to  twenty,  and  open  into  the  prostatic  part  of 
the  urethra  (p.  527). 

Bloodvessels.  The  arteries  are  rather  small,  and  are  furnished  by  the 
inferior  vesical  and  middle  haemorrhoidal  (p.  515).  The  veins  form  a 
plexus  around  the  gland,  which  communicates  in  front  with  the  dorsal 
vein  of  the  penis,  and  behind  with  the  venous  plexus  at  the  base  of  the 
bladder.  In  old  men  this  vascular  intercommunication  gives  rise  to  con- 
siderable hemorrhage  in  the  operation  of  lithotomy. 

The  nerves  are  supplied  by  the  hypogastric  plexus.  The  lymphatics 
of  this  body  and  of  the  vesicula3  seminales  are  received  into  the  glands 
placed  along  the  internal  iliac  artery. 

Vesicul^  Seminales  (fig.  178,  e).  These  vesicles  are  two  membra- 
nous sacs,  which  secrete  a  fluid  to  mix  with  the  semen.  They  are  placed 
on  the  under  part  of  tlie  bladder  behind  the  prostate,  and  diverge  from 
one  another  so  as  to  limit  laterally  a  triangular  s})ace  in  that  situation  : 
their  form  and  connections  have  been  already  described  (p.  507).  Tiiough 
sacculated  and  bulged  behind,  the  vesicula  becomes  straight  and  narrowed 
in  front  (duct  d)  ;  and  at  the  base  of  the  prostate  it  blends  with  the  vas 
deferens  to  form  the  common  seminal  or  ejaculatory  duct  {g^. 

The  vesicula  seminalis  consists,  like  the  epididymis,  of  a  tube  bent  into 
a  zigzag  form,  so  as  to  produce  lateral  sacs  or  ])Ouches,  whose  bends  are 
bound  together  by  fibrous  tissue  ;  this  cell  structure  will  be  shown  by 
means  of  a  cut  into  it.  When  the  bends  of  the  vesicle  are  undone,  its 
formative  tube,  which  is  about  the  size  of  a  quill,  measures  from  four  to 
six  inches,  and  ends  posteriorly  in  a  closed  extremity  :  connected  with  the 
tube  at  intervals,  are  lateral  cajcal  a[)pendages  (fig.  178). 

Structure.  The  wall  of  the  seminal  vesicle  has  the  same  number  of 
layers  as  the  vas  deferens  (p.  483)  ;  but  the  muscular  coat  is  thinner. 

Within  the  casing  of  the  recto-vesical  fascia,  the  vesicuhii  and  vasa 
deferentia  are  covered  by  a  layer  of  transverse  and  longitudinal  plain 
muscular  fibres.  The  transverse  are  the  more  superficial  (the  base  of  the 
bladder  being  upwards),  are  strongest  near  the  prostate,  and  act  most  on 
the  vasa  deferentia.  The  longitudinal  fibres,  placed  chiefly  on  the  sides  of 
the  vesicular,  are  continued  forwards  with  the  common  seminal  ducts  to 
the  urethra.     (Med.  Chir.  Trans.  1850.) 


ANATOMY    OF    VESICULA    SEMINALIS 


523 


The  mucous  membrane  is  thrown  into  ridges  by  the  bending  of  the  tube, 
and  presents  an  areolar  or  honeycomb  appearance  ;  it  is  provided  with 
tubular  glands,  as  in  the  vas  deferens,  and  is  covered  by  a  flattened  epi- 
thelium. 

End  of  vas  deferens  (tig.  178).  Opposite  the  vesicula  the  vas  deferens 
is  increased  in  capacity,  and  is  rather  sacculated  like  the  contiguous  vesi- 
cle :  but  before  it  joins  the  tube  of  that  body  to  form  the  common  seminal 
duct,  it  diminishes  in  size,  and  becomes  straight.  In  the  mucous  lining 
are  numerous  tubular  glands  like  those  of  the  intestine  (Henle)  ;  and  the 
epithelium  is  columnar  as  in  the  rest  of  the  tube. 

Fig.  178. 


n.  Bladder. 

''  and  e,  right  and  left  lateral  lobes  of  the 
prostate. 

<l.  Middle  lobe. 

e.  Vesicula  seminalis,  the  right  oue  un- 
ravelled. 

/.  Vas  deferens. 

g.  Common  seminal  duct,  formed  by  the 
union  of  the  vas  deferens  with  the 
duct  of  the  vesicula. 

h.  Ureter. 


View  of  the  Under  Part  of  the  Bladder  with  the  Vesiculje  Seminales  asd 
Vasa  Deferentia  (Slightly  altered  from  Haller). 


Common  seminal  ducts  (fig.  180,/).  These  tubes  (right  and  left)  are 
formed  by  the  junction  of  the  narrowed  part  or  duct  of  the  vesicula  semi- 
nalis with  the  vas  deferens  of  the  same  side.  They  begin  opposite  the 
base  of  the  prostate,  and  are  directed  upwards  and  forwards  through  an 
aperture  in  the  circular  prostatic  fibres,  and  along  the  sides  of  a  hollow 
(vesicula  prostatica),  to  open  into  the  urethral  tube.  Their  length  is 
rather  less  than  an  inch,  and  their  course  is  convergent  to  their  termina- 
tion close  to  each  other  in  the  floor  of  the  urethra  (p.  527). 

Structure  The  wall  of  the  common  duct  is  thinner  than  that  of  the 
vesicula  seminalis  ;  but  it  possesses  similar  coats.  It  is  surrounded  by 
longitudinal  involuntary  muscular  fibres,  which  blend  in  the  urethra  with 
the  submucous  stratum.  It  possesses  the  same  glands  and  epithelium  as 
the  dilated  part  of  the  vas  deferens;  but  at  the  end  of  the  tube  the 
mucous  membrane  wants  glands  and  is  smooth  (Henle). 


524 


DISSECTION    OF    THE    PELVIS, 


THE    BLADDER. 

After  the  bladder  has  been  separated  from  the  surrounding  parts  its 
form  and  the  extent  of  its  different  regions  can  be  more  conveniently 
studied. 

Whilst  the  bladder  is  in  the  body,  it  is   conical  in  shape,  and  rather 

flattened  from  before  backwards  ;  but 
out  of  the  body  it  is  more  circular  than 
when  in  its  natural  position,  and  it  loses 
that  arched  form  by  which  it  adapts  it- 
self in  distension  to  the  curve  of  the 
pelvis. 

If  this  viscus  is  moderately  dilated, 
it  measures  about  five  inches  in  length, 
and  three  inches  across  (Huschke).  Its 
capacity  is  greatly  influenced  by  the  age 
and  sex,  and  by  the  habits  of  the  indi- 
vidual. Ordinarily  the  bladder  holds 
about  a  pint  without  inconvenience  dur- 
ing life,  though  it  can  contain  much 
more  when  distended.  As  a  general 
rule  it  is  larger  in  the  female  than  in 
the  male. 

Structure.  A  muscular  and  a  mu- 
cous coat,  with  an  intervening  flbrous 
layer,  exist  in  the  wall  of  the  bladder  : 
at  certain  parts  the  peritoneum  may  be 
also  enumerated  as  a  constituent  of  the 
wall.  The  vessels  and  nerves  are 
large. 

The  imperfect  covering  o{  'peritoneum 
has  been  described  (p.  504). 

Tlie  muscular  coat  is  formed  of  thin 
layers  of  unstriated  muscular  fibres,  viz., 
an  external  or  longitudinal,  a  middle  or 
circular,  and  an  internal  or  submucous. 
The  longitudinal  fibres  (fig.  179,  ') 
form  a  continuous  covering,  with  the 
usual  plexiform  disposition  of  the  mus- 
cular bundles,  and  extend  from  apex  to 
base.  Above,  some  are  connected  with 
the  urachus,  and  the  subperitoneal 
fibrous  tissue.  Below,  the  posterior 
and  lateral  fibres  enter  the  prostate  ; 
whilst  the  anterior  are  attached  to  the 
fascia  covering  the  ])ro8tate,  with  the 
exception  of  a  fasciculus  on  each  side, 
which  is  united  to  the  back  of  the  ])ul)es 
through  the  anterior  true  ligament  of  tiie  bladder.  On  the  front  and  back 
of  tlie  bladder  tlui  muscular  layer  is  stronger,  and  its  fibres  more  vertical 
than  on  the  lateral  parts.  Sometimes  this  outer  layer  of  fibres  is  called 
detrusor  urines  from  its  action  in  the  expulsion  of  the  urine. 

The  cArcidar  fibres  (fig.  179,  ^)  are  thin  and  scattered  on  the  body  of 


MfscuLAR  Fibres  of  the  Bladder,  Pros- 
tate, AND  Urethra. 

1.  External  or  longituninal  fibres  of  the 

bladder. 

2.  Circular  fibres  oT  the  middle  coat. 

3.  Submucous  layer. 

4.  Muscular  layer  around  the  urethra. 

.5.  Circular  fibres  of  the  prostate  and  ure- 
thra continuous  with  the  circular  of 
the  bladder. 

6,  7.  Septum  of  the  corpus  spongiosum. 

8.  Corpus  spongiosum. 

9.  Corpus  cavernosum. 

10.  Ureter. 


URINARY    BLADDER.  525 

the  bladder ;  but  around  the  cervix  they  are  collected  into  a  thick  bundle, 
the  sphincter  vesicae^  and  are  continuous  before  with  the  fibres  of  the  pros- 
tate. When  the  fibres  are  hypertrophied,  they  project  into  the  interior  of 
the  organ,  forming  the  fasciculated  bladder;  aixl  in  some  bodies  the  mucous 
coat  may  be  forced  outwards  here  and  there  between  them,  in  the  form  of 
sacs,  producing  the  sacculated  bladder. 

The  submucous  stratum  (fig.  179,^)  forms  a  continuous  layer  over  the 
lower  half  of  the  bladdei",  but  its  fibres  are  scattered  above.  In  the  lower 
third  of  the  viscus  the  fibres  are  longitudinal,  and  are  continued  around 
the  urethra,  but  they  become  oblique  above  that  point.  At  the  back  of 
the  bladder  the  layer  is  increased  in  strength  by  the  longitudinal  fibres  of 
the  ureters  blending  with  it.  The  projection  of  the  uvula  vesicae  is  due 
to  this  submucous  stratum. 

The  muscular  strata  communicate  freely,  so  that  one  cannot  be  sepa- 
rated from  another  without  division  of  the  connecting  bundles  of  fibres. 
In  both  sexes  the  disposition  of  the  fibres  is  similar  (Med.  Chir.  Trans., 
1856). 

Fibrous  coat.  A  fibrous  layer  is  placed  between  the  muscular  and 
mucous  strata,  and  is  enumerated  as  one  of  the  coats  of  the  bladder ;  it  is 
composed  of  areolar  and  elastic  tissues  as  in  other  hollow  viscera,  in  which 
the  vessels  and  nerves  ramify. 

Dissection.  The  bladder  is  now  to  be  opened  by  an  incision  down  the 
front ;  and  the  cut  is  to  be  continued  along  the  upper  part  of  the  prostate 
gland. 

The  mucous  membrane  of  the  bladder  is  continuous  posteriorly  with  the 
lining  of  the  ureters,  and  anteriorly  with  that  of  the  urethra.  It  is  very 
slightly  united  to  the  muscular  layer ;  and  it  is  thrown  into  numerous  folds 
in  the  flaccid  state  of  the  viscus,  except  over  a  small  triangular  surface 
behind  the  urethral  opening. 

The  membrane  is  of  a  pale  rose  color  in  the  healthy  state  soon  after 
death.  Its  surface  is  studded  with  mucous  follicles  and  branched  glands, 
particularly  towards  the  neck  of  the  bladder.  In  the  epithelium  covering 
the  surface  are  three  kinds  of  cells  :  the  superficial  are  roundish  and  flat- 
tened ;  the  middle  are  pyriform;  and  the  deeper  are  conical  and  cylindrical. 

Objects  inside  the  bladder.  Within  the  bladder  are  the  following  named 
parts,  viz.,  the  orifices  of  the  ureters  and  uretlira,  with  the  triangular  sur- 
face (fig.  179). 

Orifices.  At  the  anterior  part  of  the  bladder  is  the  orifice  of  the  urethra, 
surrounded  by  the  prostate  gland.  The  mucous  membrane  presents  here 
some  longitudinal  folds  ;  and  the  aperture  is  partly  closed  by  a  small  pro- 
minence below,  uvula  vesicce,  occasioned  by  a  thickening  of  the  submucous 
muscular  and  fibrous  layer.  This  eminence  is  placed  in  front  of  the  middle 
lobe  of  the  prostate  ;  and  from  its  anterior  part  a  slight  ridge  is  continued 
on  the  floor  of  the  urethra. 

About  an  inch  and  a  half  behind  the  orifice  of  the  urethra,  and  rather 
more  than  that  distance  apart,  are  the  two  narrow^  openings  of  the  ureters 
(fig.  181).  These  excretory  tubes  for  the  urine  perforate  the  wall  of  the 
bladder  obliquely,  lying  in  it  for  the  distance  of  one-third  of  an  inch,  so 
that  the  reflux  of  fluid  through  them  towards  the  kidney  is  prevented  as 
the  bladder  is  distended.  Each  terminates  by  a  slit-like  opening  in  a 
prominence  formed  by  subjacent  muscular  fibres. 

Trimigular  surface.  Immediately  behind  the  orifice  of  the  urethra  is  a 
smooth  triangular  surface,  which  is  named  trigone  (trigonum  vesicaj).     Its 


526  DISSECTION    OF    THE    PELVIS. 

apex  reaches  the  prostate,  and  its  base  the  ureters.  Its  boundaries  may 
be  marked  out  by  a  line  on  each  side  from  the  urethra  to  the  ureter,  and 
by  a  transverse  one,  behind,  between  the  openings  of  the  ureters.  This 
surface  corresponds  with  the  triangular  space  externally  at  the  base  of  the 
bladder,  between  the  prostate  in  front  and  tlie  vesiculie  and  vasa  deferentia 
on  the  sides.  Over  it  the  mucous  coat  is  more  closely  united  to  the  fibrous 
and  muscular,  so  as  to  prevent  the  accidental  folds  occurring  in  the  other 
parts  of  the  empty  bladder. 

Dissection.  The  arrangement  of  the  fleshy  fibres  of  the  ureters  will 
come  into  view  on  the  removal  of  the  mucous  membrane  from  the  lower 
third  of  the  bladder. 

Ending  of  the  fibres  of  the  vreters.  As  soon  as  the  ureter  pierces  the 
outer  and  middle  coats  of  the  bladder,  its  longitudinal  fibres  are  thus  dis- 
posed : — the  more  internal  and  strongest  are  directed  transversely,  and 
join  the  corresponding  fibres  of  the  other  urine  tube  ;  whilst  the  remainder 
are  continued  down  over  the  triangular  surface,  and  blend  with  the  sub- 
mucous layer. 

Bloodvessels  and  nerves.  The  source  of  the  vesical  arteries,  and  the 
termination  of  the  veins  have  been  detailed  (p.  515).  The  vessels  are 
disposed  in  greatest  number  about  the  base  and  neck  of  the  bladder. 
Most  of  the  7ierves  distributed  to  the  bladder,  though  supplied  from  the 
pelvic  plexus  of  the  sympathetic  (p.  519),  are  derived  directly  from  the 
spinal  nerves.  The  lymphatics  enter  the  glands  by  the  side  of  the  internal 
iliac  artery. 

THE  URETHRA  AND  PENIS. 

Urethra  (fig.  181).  The  tube  of  the  urethra  extends  from  the  neck 
of  the  bladder  to  the  end  of  the  penis,  and  has  an  average  length  of  about 
eight  inches  ;  but  it  is  shorter  by  one  inch  during  life  (Thompson).  It  is 
supported  by  the  prostate,  the  triangular  ligament,  and  the  spongy  struc- 
ture of  the  penis.  The  tube  is  divided,  as  before  said  (p.  508),  into  a 
prostatic,  a  membranous,  and  a  spongy  part. 

Dissection.  To  open  the  urethra,  let  the  incision  through  the  upper 
part  of  the  prostate  be  continued  onwards  to  the  extremity  along  the  line 
of  union  of  the  urethral  canal  with  the  body  of  the  penis. 

Tha  prostatic  part  (fig.  181)  is  nearer  the  upper  than  the  lower  surface 
of  the  muscular  mass  surrounding  it.  It  is  one  inch  and  a  quarter  in 
length,  and  is  altogether  the  widest  portion  of  the  urethral  canal.  Its 
form  is  spindle-shaped,  for  it  is  larger  in  the  middle  than  at  either  end. 
Its  transverse  measurement  at  the  neck  of  the  bladder  is  a  quarter  of  an 
inch  ;  at  its  centre  a  line  or  two  more  ;  and  at  the  front  rather  less  than 
at  the  back. 

Separating  this  part  of  the  passage  from  the  bladder  is  the  eminence  of 
the  uvula  vesicae  with  its  slight  ridge.  In  front  of  this  is  a  central  longi- 
tudinal eminence  of  the  mucous  lining  (rf),  about  three-quarters  of  an  inch 
•in  length,  and  larger  behind  tiian  before,  which  is  prolonged  anteriorly 
towards  the  membranous  part  of  the  canal,  and  is  named  crest  of  the 
urethra  (veru  montanum,  caput  gallinaginis)  :  it  is  formed  like  the  uvula 
by  a  bundle  of  the  submucous  muscular  and  fibrous  tissue.  In  that  crest 
of  the  mucous  membrane,  near  its  posterior  extremity,  is  a  slight  hollow 
(e)  named  vesicnla  prostatica  or  sinus  pocularis. 

The  vesi cilia  prostatica  or  utricle  (fig.  180,  g)   is  directed  backwards 


URETHRA. 


527 


and  downwards  in  the  prostate,  for  a  quarter  of  an  inch,  passing  beneath 
the  middle  and  between  the  lateral  lobes.  Its  orifice  in  the  urethra  is 
about  a  line  wide,  and  its  closed  extremity  is  about  as  large  again.  Along 
the  wall,  on  each  side,  is  placed  the  common  seminal  duct  (/),  which  ter- 
minates on  or  within  the  margin  of  the  mouth  of  the  sac  ;  and  if  bristles 
are  introduced  into  the  common  seminal  duct  behind  the  prostate,  they 
will  render  evident  the  apertures.  Small  glands  open  on  the  surface  of  the 
mucous  membrane  lining  the  utricle.  The  vesicula  is  the  remains  of  the 
united  lower  ends  of  the  ducts  of  Miiller  in  the  foetus,  and  represents  the 
uterus  in  the  female. 

Fig.  180. 


a.  Bladder. 

h.  Prostate,  and  c,  prostatic  part  of  the 
urethra. 

d.  Vesicula  seminalis. 

e.  Vas  deferens. 

/.  Common  ejaculatory  duct. 
g.  Vesicula  prostatica. 


Skction  through  the  Blapdrr,  Prostate,  and  Urethra,  to  show  the  vesicula  prostatica 
and  the  common  seminal  duct. 


On  each  side  of  the  central  crest  is  an  excavation,  which  is  named  the 
prostatic  sinus  (fig.  181,/).  Into  this  hollow  the  greater  number  of  the 
ducts  in  the  prostate  open  ;  but  the  apertures  of  some  are  seen  at  the 
posterior  part  of  the  central  eminence. 

The  membranous  part  of  the  urethra  (fig.  181,  g)  is  three-quarters  of 
an  inch  in  length,  and  intervenes  between  the  apex  of  the  prostate  gland 
and  the  bulb  {k)  of  the  corpus  spongiosum  urethrae.  In  its  interior  are 
slight  longitudinal  folds.  This  is  the  narrowest  portion  of  the  whole  tube, 
with  the  exception  of  the  outer  orifice,  and  measures  rather  less  than  a 
quarter  of  an  inch  across.  It  is  the  weakest  of  the  three  portions  of  the 
canal,  and  is  supported  by  a  thin  stratum  of  erectile  tissue,  by  a  thin  layer 
of  unstriated  circular  fibres  (p.  397),  and  outside  all  by  the  constrictor 
urethrae  muscle. 

The  spongy  part  (fig.  181,  i)  reaches  to  the  end  of  the  penis.  It  is 
about  six  inches  in  length.  And  its  strength  depends  upon  a  surrounding 
material  named  corpus  spongiosum  urethrne. 

The  average  size  of  the  canal  is  about  a  quarter  of  an  inch  in  diameter, 
though  at  the  vertical  slit  (meatus  urinarius),  by  which  it  terminates  on 
the  glans  penis,  the  tube  is  smaller  than  elsewhere.  On  a  cross  section  it 
appears  as  a  transverse  slit,  but  in  the  glans,  as  a  vertical  interval.  Two 
dilatations  exist  in  the  fioor  of  the  spongy  portion  :  One  is  close  to  the 
triangular  ligament,  being  contained  in  the  bulb  or  bulbous  part  of  the 


528 


DISSECTION    OF    THE    PELVIS. 


urethra,  and  is  named  sinus  of  the  bulb  ;  tlie  other  is  an  elongated  hollow, 
situate  in  the  glans  penis,  which  has  been  called  fossa  navicular  is  (n) 
from  its  shape. 

Fig.  181. 


a.  Triangular  surface  of  the  blad- 
der. 
6.  Openings  of  the  ureters. 

c.  Prostate,  cut. 

d.  Caput  gallinaginis. 

e.  Sinus  pocularis. 

/.  Prostatic  sinus,  with  openings 
of  the  glands  of  the  prostate. 

g.  Membranous  part  of  the  ure- 
thra. 

h.  Cowper's  glands,  a  duct  from 
each  opening  into  the  urethra. 

i.  Spongy  part  of  the  urethra. 

fr.  Bulb  of  the  urethra. 

Z.  Glans  penis,  and  n,  fossa  navi- 
cularis. 

o.  Openings  of  lacunse  and  glands, 

r.  Corpus  cavernosum  of  the  penis. 


VxBw  OF  THE  Lower  Part  op  the  Bladder  and  of  the  Urethra  Laid  Open. 


There  are  many  small  pouches  or  lacunae  {o)  in  the  canal,  as  far  back 
as  the  membranous  part,  which  have  their  apertures  turned  towards  the 
outer  orifice  of  the  urethra.  One  of  these,  larger  than  the  rest,  lacuna 
maffua^  is  placed,  generally,  on  the  upper  boundary  or  roof  of  the  urethra, 
op])osite  the  fossa  navicularis. 

The  ducts   of  Cowper's  glands  (fig.   181,  K)   are   two  in   number,  and 


CORPORA    CAVERNOSA    PENIS. 


529 


terminate,  one  on  each  side,  on  the  floor  of  the  urethra  near  the  front  of 
the  bulb,  but  they  are  generally  too  small  to  be  recognized. 

MucoKS  lining  of  the  urethra.  The  mucous  membnme  of  the  urethra 
is  continued  into  tlie  bladder,  as  well  as  into  the  ducts  opening  into  the 
canal,  and  joins  in  front  the  tegumentary  covering  of  the  glans  penis.  It 
is  of  a  reddish  color  in  the  sj)ongy  and  membranous  portions,  but  in  the 
prostate  it  becomes  whiter.  In  the  spongy  and  membranous  parts  it  is 
thrown  into  longitudinal  folds  during  the  contracted  state  of  the  penis. 

Its  surface  is  studded  throughout  with  follicles,  and  with  the  apertures 
of  branched  glands,  which  are  lodged  in  the  submucous  tissue,  and  whose 
ducts  are  inclined  obliquely  forwards ;  and  it  is  provided  with  papilla3  to- 
wards the  external  orifice.  Its  epithelial  covering  is  of  the  columnar  kind, 
but  near  the  meatus  it  becomes  laminar. 

Submucous  tissue.  Beneath  the  mucous  lining  of  the  urethra  is  a 
stratum  of  longitudinal  unstriated  muscular  fibres,  mixed  with  elastic  and 
fibrous  tissues.  It  is  continuous  behind  with  the  submucous  fibres  of  the 
bladder,  and  is  joined  in  the  prostate  by  the  muscular  fibres  accompanying 
the  common  seminal  ducts.  The  stratum  differs  along  the  canal : — It  is 
most  developed  in  the  prostate,  where  it  forms  the  projection  of  the  crest  ; 
in  the  membranous  {)ortion  the  muscular  structure  is  less  abundant ;  and 
in  the  spongy  part  fibrous  tissue  forms  the  greater  portion  of  the  submucous 
layer. 

In  the  prostatic  and  membranous  divisions  of  the  urethra  there  is,  in 
addition,  a  thin  enveloping  layer  of  vascular  or  erectile  tissue,  which  is 
continued  backwards  from  the  corpus  spongiosum  urethrae  to  the  neck  of 
the  bladder. 

Structure  of  the  Pexis.  The  form  and  the  connections  of  the  penis 
having  been  described   in  page   508,  tlie  tissues  of  which  it  is  com})osed 


Fig.  182. 


ViRW  OP  THE  Fibres  of  thb  Case  of  the  Corpcs  Cavernosum. 
h.  The  external  or  longitudiual  layer.  1.  The  pectiniform  sepfim. 

a.  Inner  or  circular  fibres. 


remain  to  be  noticed.     If  a  section  is  made  along  one  side  of  the  pen's,  it 
will  show  this  body  to  be  composed  of  two  masses  of  spongy  and   vascu^u" 
tissue  (corpora  cavernosa)  incased  in  a  fibrous  covering,  with  an  imperfect 
septum  between  them. 
34 


530 


DISSECTION    OF    TUE    PELVIS. 


Fig.  183. 


Corpora  cavernosa  (fig.  181,  r).  These  bodies  form  the  bulk  of  the 
penis,  and  are  two  dense  cylindrical  tubes  of  fibrous  tissue,  containing 
erectile  structure.  Each  is  fixed  behind  by  a  pointed  process,  cms  penis, 
to  the  upper  part  of  the  pubic  arch  for  about  an  inch  ;  and  blends  with  its 
fellow  in  the  body  of  the  penis,  after  a  distance  of  an  inch  and  a  half. 
There  is  a  slight  swelling  on  the  crus,  called  the  bulb  of  the  corpus  caver- 
nosum  (Kobelt). 

Each  corpus  cavernosum  is  composed  of  a  fibrous  case  with  a  cavernous 
or  trabecular  structure  inside,  with  vessels  in  the  intervals  of  the  spongy 
mass.     An  incomplete  median  septum  exists  along  the  body  of  the  penis. 

The  Jibrous  case  is  a  white,  strong,  elastic  covering  (fig.   182),  from 
half  a  line  to  a  line  in  thickness.     Along  the  middle  of  the  penis  a  septal 
process  is  sent  inwards  from  it ;    and  numerous 
other  finer  threads, — the  trabeculse  of  the  spongy 
structure,  are  connected  with  its  inner  surface. 

It  is  formed  of  white  shining  fibres  which  are 
disposed  in  two  layers,  outer  and  inner.  The 
outer  stratum  (fig.  182,  h)  is  formed  of  longitu- 
dinal fibres  with  close  meshes.  The  inner  stra- 
tum (fig.  182,  a)  consists  of  circular  fibres,  with 
a  like  plexiform  disposition  ;  and  the  circular 
fibres  of  each  cavernous  body  meeting  in  the  mid- 
dle line  give  rise  to  the  septum  penis.  Both 
strata  are  inseparably  united  by  communicating 
bundles. 

The  septal  process  (fig.  183)  is  placed  verti- 
cally along  the  body  of  the  penis,  and  is  thicker 
and  more  perfect  behind  than  in  front.  Near 
the  junction  of  the  crura  this  partition  divides  the 
inclosed  cavity  into  two  parts  ;  but  as  it  reaches 
forwards  it  becomes  less  strong,  and  is  pierced  by 
elongated  apertures,  which  give  it  the  appearance 
of  a  comb,  from  which  the  name  septum  pectini- 
forme  is  derived.  Tiirough  the  intervals  in  the 
septum  the  vessels  in  the  corpora  cavernosa  com- 
municate. It  is  formed  by  the  circular  fibres  of 
the  fibrous  case. 

The  cavernous  or  trabecular  structure  is  a  net- 
work of  fine  threads,  which  fills  the  interior  or 
the  corpora  cavernosa.  Its  processes  are  thinner 
towards  the  centre  than  at  the  circumference  ; 
and  the  areolar  spaces  are  larger  in  the  middle 
and  at  the  fore  part  of  the  contained  cavity, 
than  at  the  circumference  or  in  the  crura  of  the  penis.  In  addition  to 
white  fibrous  tissue,  the  trabecuL-e  contain  eUstic  fibres,  and  unstriated 
muscular  fibres  (Miiller).  The  spongy  structure  may  be  demonstrated 
by  sections  of  the  penis,  after  it  has  been  distended  with  air  and  dried. 
Bloodvessels.     The  bloodvessels  of  the  penis  are  large  in  size,  and  serve 


Pectiniform  Septum  of  the 
Penis. 

a.  Apertures  in  the  partition. 

h.  Separate  fibrous  processes 
like  the  teeth  of  a  comb, 
which  are  formed  by  the 
circular  fibres. 


to   nourish  as  well  as  to  minister  to  the  function  of 


the  organ. 


Havinor 


entered  the  cavernous  mass,  they  ramify  in  the  trabecular  structure. 

The  arteries  of  the  corpora  cavernosa  are  oflTsets  of  the  pudic  :  the  chief 
branch  (art.  corp.  cavernosi)  enters  at  tiie  crus,  and  runs  forwards  through 


CORPUS    SPONGIOSUM    URETHRA. 


531 


and  the  rest 


I 


the  middle  of  the  cavernous  structure,  distributing  offsets 
pierce  the  fibrous  case  along  the  dorsum  of  the  penis. 

In  the  anterior  they  divide  into  branches,  which  ramify  in  the  trabeculae 
(fig.  184,  a),  becoming  finer,  until  they  terminate  in  very  minute  branches, 
which  open  into  the  veins  in  the  intertrabecular  spaces  without  an  inter- 
vention of  capillaries.  Some  of  the  finest  twigs  end  in  tufts  of  short, 
slightly  curled  and  dilated  vessels — the  helicine  arteries  of  Miiller  (fig. 
184,  e),  which  project  into  the  intertrabecular  spaces,  and  are  imbedded 
in  the  thin  coat  of  the  veins  (/)  :  with  the  extremities  of  these  twisted 
vascular  bodies  fine  fibrous  processes  are  connected.  The  helicine  arteries 
exist  in  greatest  number  at  the  posterior  part  of  each  corpus  cavernosum. 

The  veins  fill  the  interstices  of  the  areolar  structure,  and  anastomose 
freely  together  to  form  venous  plexuses ;  and  into  them  the  terminal 
branches  of  the  arteries  pour  their  contents.     By  means  of  the  apertures 


Fig.  184. 


Magnified  view  of  the  Trabecular  Strccture  akd  Arterirs  of  the  Penis. 

a.  Branch  of  an  artery  and  its  ramifications         e.  A  tuft  of  the  twisted  or  helicine  arteries, 
in  the  bands  of  the  spongy  structure  of  The  dark  shadowing,/,  represents  a  vein 

the  penis,  b.      ,  incasing  the  bundle  of  vessels  (Miiller). 

e.  Trabecular  structure. 


in  the  septum  the  veins  of  opposite  sides  communicate  freely.  The  erec- 
tile condition  of  tlie  corpus  cavernosum  is  produced  by  the  distension  of 
the  plexuses. 

The  chief  veins  of  the  corpus  cavernosum  escape  at  the  crus  penis  with 
the  artery,  and  join  the  pudic  vein ;  but  others  issue  along  the  upper  and 
under  aspects,  to  end  in  the  dorsal  vein  and  the  prostatic  plexus. 

Corpus  spongiosum  urethrce  (fig.  179).  This  constituent  part  of  the 
penis  surrounds  the  urethra,  but  not  equally  on  all  sides;  for  at  the  bulb 
only  a  thin  stratum  is  above  the  canal,  whilst  at  the  glans  penis  (fig.  181, 
/)  it  is  placed  chiefly  above  the  urethral  tube.  Posteriorly  an  offset  of 
the  corpus  spongiosum  is  continued  beyond  the  bulb  around  the  urethra 

Structure.  The  tissue  of  the  corpus  spongiosum  is  similar  to  that  of  the 
corpus  cavernosum :  thus  it  consists  of  a  fibrous  tunic  inclosing  a  trabecu-. 
lar  structure  and  bloodvessels. 

The  fibrous  covering  is  less  dense  and  strong  than  in  the  corpora  cav- 
ernosa, and  consists  only  of  circular  fibres.  A  septal  piece  (fig.  179,  ") 
projects  inwards  from  it  in  the  middle  line,  opposite  the  tube  of  the  urethra ; 


532  DISSECTION    OF    THE    PELVIS. 

this  is  best  marked  for  a  short  distance  in  front  of  the  bulb,  and  assists  in 
dividing  that  part  into  two  lobes.  The  trabecular  bands  are  much  finer, 
and  more  uniform  in  size  than  in  the  corpora  cavernosa. 

Bloodvessels.  The  arrangement  of  the  bloodvessels  in  the  erectile 
structure  of  the  corpus  spongiosum  is  similar  in  tlie  bulb  to  that  in  the 
corpora  cavernosa;  but  in  the  rest  of  the  spongy  substance  the  arteries 
are  said  to  end  in  capillaries  in  the  usual  way.  The  helicine  terminations 
of  the  arteries  are  absent  from  the  glans  penis,  where  the  veins  form  a 
very  close  and  regular  plexus. 

The  arteries  are  derived  from  the  pudic  on  each  side  : — one,  arteries  of 
the  bulb,  enters  the  bulb  behind  ;  and  several  in  front,  offsets  of  tlie  dorsal 
artery,  penetrate  into  the  glans.  Kobelt  describes  another  branch  to  the 
bulb  at  the  upper  aspect. 

Most  of  the  veins,  including  those  of  the  glans,  end  in  the  large  dorsal 
vein  of  the  penis,  some  communicating  with  veins  of  the  cavernous  body ; 
others  issue  from  the  bulb,  and  terminate  in  the  pudic  vein. 

Nerves  and  lymphatics.  The  nerves  of  the  penis  are  large  and  are 
supplied  by  both  the  spinal  and  sympathetic  nerves :  on  the  glans  penis 
they  are  furnished  with  Pacinian  bodies.  The  superficial  lymphatics  of 
the  integuments,  and  those  beneath  the  mucous  membrane  of  the  urethra, ' 
join  the  inguinal  glands;  the  deep  accompany  the  veins  beneath  the  arch 
of  the  pubes,  to  end  in  the  lymphatic  glands  in  the  pelvis. 

THE  RECTUM. 

Dissection.  Tlie  rectum  is  to  be  washed  out,  and  then  distended  with 
tow ;  and  the  peritoneum  and  the  loose  fat  are  to  be  removed  from  it. 

The  lower  end  of  the  large  intestine,  wliich  is  contained  in  the  pelvis, 
is  not  sacculated  like  the  colon,  but  is  smooth  on  the  surface,  the  longitudi- 
nal bands  of  the  colon  being  absent  from  it. 

It  is  about  eight  inches  in  length ;  and  its  average  diameter  is  that  of 
the  sigmoid  flexure  of  the  colon.  Its  size  is  uniform  as  far  as  the  lower 
extremity,  where  it  is  dilated,  particularly  in  old  people;  but  at  the  aper- 
ture of  termination  in  the  anus  the  gut  is  smaller  than  elsewhere. 

Structure.  The  rectum  contains  in  its  wall  a  peritoneal,  a  muscular,  a 
mucous,  and  a  submucous  stratum ;  and  the  muscular  and  mucous  layers 
have  certain  characters  which  distinguish  this  part  of  the  intestinal  tube. 

The  peritoneum  forms  but  an  incomplete  covering,  and  its  arrangement 
is  referred  to  in  the  description  of  the  connections  of  the  pelvic  viscera 
(p.  505). 

The  muscular  coat  consists  of  two  planes  of  pale  or  unstriated  fibres, 
viz.,  a  superficial  or  longitudinal,  and  a  deep  or  circular.  The  longitudi- 
nal, continuous  with  those  in  the  bands  on  the  colon,  are  here  diffused  to 
form  a  stratum  around  the  gut.  The  circular  describe  arches  around  the 
intestine,  and  become  thicker  and  stronger  towards  the  anus,  where  they 
are  collected  in  the  band  of  tlie  internal  sphincter  muscle. 

The  mucous  coat  is  more  movable  than  in  the  colon,  and  resembles  in 
this  respect  the  lining  of  the  cesophagus ;  it  is  also  thicker  and  more  vas- 
cular than  in  the  rest  of  the  large  intestine. 

When  the  bowel  is  contracted  the  mucous  lining  is  thrown  into  numer- 
ous accidental  folds ;  but  some  near  the  anus  are  longitudinal,  inclosing 
submucous  muscular  fibres,  and  form  the  columns  of  Morgagni.  There 
are  other  three  permanent  folds  (Houston)  which  are  half  an  inch  or  less 


ANATOMY    OF    FEMALE    VISCERA.  533 

in  depth,  and  contain  circular  fibres  of  the  gut.  The  most  constant  of 
these  is  about  three  inches  from  the  anus,  on  the  front  of  the  rectum, 
opposite  the  base  of  the  bladder ;  another  is  placed  on  the  right  side  of 
the  intestine,  towards  the  top ;  and  the  third  is  on  the  left  side,  midway 
between  the  other  two.  These  folds  will  be  seen  by  laying  open  the  gut 
along  the  side,  provided  it  is  tolerably  fresh. 

The  mucous  membrane  has  the  same  general  structure  as  in  the  colon, 
but  towards  the  anus  the  secretory  apparatus  gradually  disappears. 

Bloodvessels.  The  arteries  are  supplied  from  three  different  sources, 
viz.,  superior  hnemorrhoidal  of  the  inferior  mesenteric,  middle  haemorrhoidal 
of  the  internal  iliac,  and  inferior  haemorrhoidal  of  the  internal  pudic.  All 
three  sets  anastomose  on  the  lower  end  of  the  gut,  and  only  the  upper 
hcemorrhoidal,  which  is  the  largest,  requires  further  notice.  The  final 
branches  of  this  artery  (p.  51G),  about  six  in  number,  pierce  the  muscular 
layer  three  inches  from  the  anus,  and  descend  between  the  mucous  and 
muscular  coats  as  far  as  the  internal  sphincter,  where  they  unite  in  loops 
just  within  the  anus. 

The  veins  are  deficient  in  valves,  and  communicate  freely,  like  the 
arteries,  in  a  plexus  between  the  muscular  and  mucous  coats,  around  the 
lower  end  of  the  gut.  Above,  they  join  the  inferior  mesenteric  vein,  and 
through  it  reach  the  vena  portas ;  and,  posteriorly,  they  pour  some  blood 
into  the  internal  iliac  vein  by  the  middle  hiemorrhoidal  branch. 

Nerves  and  lymphatics.  The  nerves  of  the  intestine  are  obtained  from 
the  sympathetic ;  and  those  of  tlie  sphincter  come  from  the  spinal  cord. 
The  lymphatics  terminate  in  the  chain  of  glands  on  the  sacrum. 


Section  VI. 

ANATOMY  OF  THE  FEMALE  VISCERA. 

In  the  pelvis  are  contained  the  viscera,  alike  in  both  sexes,  viz.,  the 
bladder,  urethra,  and  rectum  ;  and  those  special  to  the  female,  or  the 
organs  of  generation. 

Dissection.  The  contents  of  the  pelvis  are  to  be  removed,  together 
with  the  genital  organs.  For  this  purpose  the  student  should  keep  the 
scalpel  close  to  the  osseous  boundary  of  the  pelvic  outlet,  to  avoid  injuring 
the  end  of  the  rectum ;  and  he  should  also  detach  the  crus  of  the  clitoris 
from  the  bone. 

After  the  parts  are  taken  from  the  body,  the  rectum  is  to  be  separated 
from  the  uterus  and  vagina,  but  the  rest  of  the  viscera  may  remain  united 
until  after  the  genital  organs  are  examined.  The  bladder  and  rectum  may 
be  moderately  distended  ;  and  the  fat  and  areolar  tissue  are  to  be  removed 
from  the  viscera. 

GENITAL  ORGANS. 

The  genital  organs  consist  of  the  following  parts :  the  mons  Veneris 
and  external  labia,  the  clitoris  and  internal  labia,  and  the  vestibule  with 
the  meatus  urinarius.  Within  the  external  labia  is  the  aperture  of  the 
vagina,  with  the  hymen.  Sometimes  the  term  vulva  or  pudendum  is 
applied  to  these  parts  as  a  whole. 


534 


DISSECTION    OF    THE    PELVIS 


Mons  Veneris  and  labia  pndendi.  In  front  of  the  pubes  the  intepjument 
is  covered  with  hair,  tind  is  raised  into  a  sliglit  eminence — mons  Veneris, 
by  a  layer  of  subjacent  fat. 

Extending  downwards  from  the  prominence  are  two  folds  of  integument, 
the  labia  pudendi  (labia  majora),  which  correspond  with  the  scrotum  in 
the  male.  Above  and  below,  the  labia  are  united,  the  points  of  junction 
being  named  commissures ;  and  between  them  is  an  interval  called  rima. 
The  labia  decrease  in  thickness  interiorly  ;  they  are  covered  externally 
with  a  few  hairs,  but  are  lined  internally  with  raucous  membrane.  In 
them  is  a  dartoid  tissue  resembling  that  in  the  male  scrotum. 

Within  the  lower  commissure  of  the  labia  is  a  small  thin  transverse  fold 
of  integuments  wdiaQ^  fourchette  ov  frcenulum  ;  and  between  this  fold  and 
the  lower  commissure  is  an  interval — i\iQ  fossa  navicular  is. 

Clitoris  and  nymphce.  Beneath  the  upper  commissure  of  the  labia 
majora  is  the  projection  of  the  clitoris,  with  the  nympluB  or  smaller  labia 
descending  from  it. 

Dissection.  To  see  the  clitoris,  the  integuments  forming  the  upper 
commissure  must  be  removed  ;  and,  after  the  body  of  the  organ  has  been 
laid  bare,  the  crura,  one  on  each  side,  are  to  be  followed  outwards. 

The  clitoris  (fig.  185  b)  is  a  small  erectile  body,  and  is  the  representa- 
tive of  the  penis.  It  has  the  same  composition  as  the  penis,  except  that 
the  urethra  is  not  continued  below  it.  Its  anterior  extremity  is  terminated 
by  a  rounded  part  or  glans  (<?),  and  is  covered  by  a  fold  of  the  skin  corre- 
sponding with  the  prepuce  of  the  male. 


Rkpresentation  of  the  Clitoris. 
a.  Cms,  and  6,  body  of  the  corpus  cavernosam. 

c.  GlaoH  clitoridis.   The  lower  figure  shows  the  structure  ou  a  vertical  section  ;  the  same  letters 
refer  to  like  parts. 

In  its  structure  this  organ  resembles  the  penis  in  the  following  particu- 
lars :  it  consists  of  corpora  cavernosa,  which  are  attached  by  crura  (one 
on  each  side  (a)  )  to  the  pubic  arch,  and  are  blended  in  the  body.  Along 
the  middle  is  an  imperfect  pectiniform  septum.  Further,  it  possesses  a 
portion  of  corpus  spongiosum,  but  this  structure  is  limited  to  the  glans 
clitoridis  (c). 


I 


THE    VAGINA.  535 

Structure.  The  outer  fibrous  casing  and  the  septum  are  alike  in  both 
penis  and  clitoris  ;  and  in  the  interior  of  the  clitoris  is  an  erectile  tissue, 
like  tliat  in  the  male  organ  (p.  533). 

Tlie  bloodvessels  of  the  corpus  cavernosum  are  like  those  of  the  penis  ; 
and  the  glans  receives  the  ending  of  the  dorsal  artery  (p.  408). 

The  nymphce  (fig.  186,  ^)  (labia  minora)  are  two  folds  of  mucous  mem- 
brane, which  descend  from  the  end  of  the  clitoris,  one  on  each  side  of  the 
orifice  of  the  vagina  ;  they  are  continuous  above  witli  the  preputial  cover- 
ing of  the  glans,  and  extend  down  about  one  inch  and  a  half.  Tiie  inner 
surface  is  continuous  with  the  lining  of  the  vestibular  space  and  vagina, 
and  the  outer,  with  the  external  labium.  Bloodvessels  are  contained  in 
each  fold. 

Vestibule  and  orifice  of  the  urethra.  Within  the  nymphce,  between 
the  clitoris  above  and  the  vagina  below,  is  an  interval,  about  one  inch  and 
a  half  deep,  which  is  called  the  vestibule.  In  the  middle  line  of  the  ves- 
tibular space  is  the  round  orifice  of  the  urethra,  which  is  placed  in  a  median 
eminence  about  one  inch  below  the  clitoris,  and  near  the  aperture  of  the 
vagina. 

Orifice  of  the  vagina  (fig.  186),  and  the  hymen.  The  aperture  of  the 
vagina  is  close  below  the  meatus  urinarius,  and  varies  much  in  size.  In 
the  child,  and  in  the  virgin,  it  is  partly  closed  below  by  a  thin  semilunar 
fold  of  mucous  membrane,  named  the  hymen.  After  the  destruction  of 
that  membrane  small  irregularly-shaped  projections,  carunculce  myrti- 
formes.,  exist  around  the  opening  of  the  vagina. 

Mucous  membrane.  The  mucous  covering  of  the  external  genitals  is 
furnished  throughout  with  papillae,  but  these  are  largest  on  the  labia  minora 
and  the  clitoris.     Its  epithelium  is  laminar. 

Sebaceous  glands  open  on  the  contiguous  surfaces  of  the  labia  majora 
and  minora,  and  beneath  the  prepuce  ;  and  mucous  glands  and  follicles 
exist  on  the  vestibule  and  the  inner  surface  of  the  nympha^. 

GENERATIVE  ORGANS. 

The  generative  organs  are  the  uterus  and  vagina,  and  the  ovaries  with 
the  Fallopian  tubes. 

Dissection.  The  viscera  are  now  to  be  separated,  so  that  the  bladder 
and  the  urethra  may  be  together,  and  the  vagina  and  the  uterus  remain 
united.  The  bladder  is  to  be  set  aside  for  subsequent  use.  The  surface 
of  the  vagina  and  the  lower  part  of  the  uterus  should  be  cleaned  ;  but  tlie 
peritoneal  investment  of  the  latter  is  to  be  left  untouched  for  the  present. 

THE  VAGINA. 

The  tube  of  the  vagina  is  connected  with  the  uterus  at  one  end,  and 
with  the  vulva  at  the  other  (fig.  175,  ^).  It  has  a  curved  course  between 
the  two  points  mentioned  ;  and  the  anterior  and  posterior  walls  are  not 
equal  in  length,  for  the  former  measures  about  four  inches,  and  the  latter 
five  or  six. 

In  the  body  the  vagina  is  flattened  from  above  downwards,  so  that  the 
opposite  surfaces  may  be  in  contact,  but  the  upper  end  is  rounded  where 
it  is  joined  to  the  uterus.  Its  size  varies  at  different  spots  :  thus  the  ex- 
ternal orifice  which  is  surrounded  by  the  constrictor  vaginte  muscle  is  the 
narrowest  part ;  the  middle  portion  is  the  largest ;  and  the  upper  end  is 
intermediate  in  dimensions  between  the  other  two. 


536 


DISSECTION    OF    THE    PELVIS 


After  the  vagina  has  been  laid  open  by  an  incision  ahmg  tlie  upper  wall, 
the  position  of  the  uterus  in  that  wall,  instead  of  the  extremity  of  the 
passage,  may  be  remarked  ;  and  the  tube  may  be  seen  to  extend  higher 
on  the  posterior  than  the  anterior  aspect  of  the  cervix  uteri.  On  the  inner 
surface,  towards  the  lower  part,  is  a  slight  longitudinal  ridge  both  in  front 
and  behind,  named  columns  of  the  vagina.  Before  the  tissue  of  the  vagina 
has  been  distended,  other  transverse  ridges  or  rugas  pass  between  the 
columns.  The  wall  of  the  vagina  is  thicker  anteriorly  around  the  urethra 
than  at  any  other  part  of  tiie  canal. 

Structure.  The  vaginal  wall  is  formed  by  a  spongy  erectile  tissue, 
covered  externally  by  a  layer  of  unstriated  muscle,  and  lined  by  mucous 
membrane.  At  its  lower  end  the  tube  is  surrounded  by  a  band  of  the 
fibres  of  the  sphincter  vagince  muscle  (p.  402). 

The  erectile  tissue  is  more  abundant  at  the  ends  than  the  middle  of  the 
vagina,  and  is  greatest  in  quantity  below  wliere  it  gives  increased  thick- 
ness to  the  wall.  Two  masses,  one  on  each  side  of  the  opening  of  the 
vagina,  have  been  described  as  the  semi-bulbs  by  Taylor  (bulbi  vestibidi, 
Kobelt,  fig.  18G,  a).  These  are  elongated  bundles  of  plexiform  veins, 
inclosed  in  tibrous  membrane  ;  they  are  about  an  inch  in  length  from  above 
down,  and  are  situate  one  on  each  side  of  the  vestibule,  where  they  are 
covered  on  the  outer  side  by  the  constrictor  vagintB  (a).  At  the  upper 
end  each  is  pointed,  and  communicates  with  the  vessels  of  the  clitoris  : 
and  at  the  lower  rounded  extremity  it  joins  the  venous  plexus  of  the 
vagina. 

These  bodies  would  answer  to  the  divided  bulb  of  the  corpus  spongiosum 
urethral  in  the  male,  eacli  lateral  half  being  thrust  aside  in  the  female 
towards  the  crus  clitoridis  by  the  large  aperture  of  tlie  vagina. 

Fijr.  186. 


A.  Sphincter  vaginse  muscle. 

B.  Clitoris, 
c.  Nymphse. 

n.  Semi-bulbs  or  bulbi  vestibuli. 

b.  Venous  plexus  coutinuous  with  veins 

of   the   clitoris    (pars   intermodia, 
Kobelt). 

c.  Dorsal  vein  of  the  clitoris. 


Vbxods  Plexuses  of  the  Genital  Oruans  and  Opening  of  the  Vagina  (Kobelt). 


The  mucous  membrane  is  continued  through  the  lower  aperture  to  join 
the  integument  on  tlie  labia  majora,  and  tlirough  the  os  uteri,  at  the  oj)po- 
site  end,  to  the  interior  of  the  uterus.  Many  mucij)arous  glands  and  fol- 
licles open  on  the  surface,  but  these  are  in  greatest  abundance  at  the  up- 
per part.  Conical  and  filiform  papilhc  exist  on  the  membrane  ;  and  a 
laminar  epithelium  gives  a  covering  to  it. 

The  muscular  layer  is  outside  the  erectile  structure,  and  consists  of  lon- 
gitudinal fibres.     Some  reach  all  along  the  vagina;  others,  and  these  are 


I 


ANATOMY    OF    UTERUS.  537 

the  stronp^est,  only  as  far  upwards  as  the  recto-vesical  fascia,  to  which  they 
are  attached  on  each  side.  Above  they  end  in  the  superficial  layer  of  the 
uterus,  and  in  the  subperitoneal  fibrgus  tissue ;  and  below  in  the  sub- 
dermic  tissue. 

Bloodvessels  and  nerves.  The  arteries  are  derived  from  the  vaginal, 
uterine,  and  vesical  branches  of  the  internal  iliac.  The  veins  form  a 
plexus  around  the  vagina,  as  well  as  in  the  genital  organs,  and  o[)en  into 
the  internal  iliac  vein.     For  a  description  of  the  nerves,  see  page  520. 

Tiie  lymphatics  accompany  the  bloodvessels  to  the  glands  by  the  side 
of  the  internal  iliac  artery. 

Glands  of  Bartholin.  On  the  outer  part  of  the  vagina,  near  the  lower 
end,  are  two  small  yellowish  glandular  bodies,  one  on  each  side,  w^hich 
represent  Cov>^per's  glands  in  the  male.  Each  is  about  as  large  as  a  small 
bean  ;  and  its  duct  is  directed  forwards  to  open  on  the  inner  aspect  of  the 
nympha  of  the  same  side.  Tlie  duct  resembles  that  of  Cowper's  gland  in 
its  structure  (p.  398). 

THE    UTERUS. 

The  uterus  or  womb  is  formed  chiefly  of  unstriated  muscular  fibres. 
Its  office  is  to  receive  the  ovum,  and  to  retain  for  a  fixed  period  the  de- 
veloping foetus. 

This  viscus  in  the  virgin  state  is  somewhat  pear  shaped,  the  body 
being  flattened  (fig.  187),  and  possesses  inferiorly  a  rounded  narrow  part 
or  neck. 

Before  impregnation  the  uterus  measures  about  three  inches  in  length, 
two  in  breadth  at  the  upper  part,  and  an  inch  in  greatest  thickness.  Its 
weight  varies  from  an  ounce  to  an  ounce  and  a  half.  But  after  gestation 
its  size  and  volume  exceed  always  the  measurements  here  given. 

The  upper  end  is  convex,  and  is  covered  by  peritoneum  :  the  term 
fundus  is  applied  to  the  part  of  the  organ  above  the  attachment  of  the 
Fallopian  tube  (e). 

The  loiver  end  is  small  and  rounded,  and  in  it  is  a  transverse  aperture 
of  communication  between  the  uterus  and  the  vagina,  named  os  uteri  (os 
tincce) :  its  margins  or  lips  (labia)  are  smootli,  and  anterior  and  posterior 
in  situation,  but  the  hinder  one  is  the  longest.  Towards  the  lower  part 
tiie  uterus  is  constricted,  and  this  diminished  portion  is  called  the  neck 
(6)  of  the  uterus  (cervix  uteri)  ;  it  is  surrounded  by  the  vagina,  and  is 
covered  by  tiiis  tube  to  a  greater  extent  behind  than  in  front.  The  neck 
is  about  lialf  an  inch  in  length,  and  gradually  tapers  towards  the  ex- 
tremity. 

The  body  (a)  of  the  uterus  is  more  convex  posteriorly  than  anteriorly, 
and  decreases  in  size  down  to  the  neck.  It  is  covered  on  botii  aspects  by 
the  peritoneum,  except  at  the  lower  part  in  front  (about  half  an  inch), 
where  it  is  connected  to  tlie  bladder.  To  each  side,  which  is  straight,  the 
parts  contained  in  tlie  broad  fold  of  the  peritoneum  are  attached  (fig. 
175): — viz.,  the  Fallopian  tube  at  the  top  (m)  ;  the  round  ligament  (x), 
rather  below  and  before  it;  and  tiie  ovary  (l),  and  its  ligament  below 
and  behind  the  others. 

Dissection.  To  examine  the  interior  of  the  uterus,  a  cut  is  to  be  made 
along  the  anterior  wall  from  the  fundus  to  the  os  uteri ;  and  tiien  some  of 
the  thick  wall  is  to  be  removed  on  each  side  of  the  middle  line  to  show 
the  contained  artery. 


638  DISSECTION    OF    THE    PELVIS. 

The  tluckness  of  the  uterine  wall  is  greatest  opposite  the  middle  of  the 
body.  It  is  greater  at  the  centre  than  at  the  angles  of  the  fundus  (fig. 
187),  the  wall  becoming  thinner  towards  the  attachment  of  the  Fallopian 
tubes. 

Interior  of  the  vterus  (fig.  187).  Within  the  uterus  is  a  small  space, 
which  is  divided  artificially  into  two — that  of  the  body,  and  that  of  the 
neck. 

The  space  occupying  the  body  of  the  viscus  (c)  is  triangular  in  form, 
and  is  larger  than  the  other.  Its  base  is  at  the  fundus,  where  it  is  convex 
towards  the  cavity,  and  tlie  angles  are  prolonged  towards  the  Fallopian 
tubes.  The  apex  is  directed  downwards,  and  joins  the  cavity  in  tiie  cer- 
vix by  a  narrowed  circular  part,  isthmus,  which  may  be  narrower  than 
the  opening  of  the  uterus  into  the  vagina. 

The  space  within  the  neck  (ri)  terminates  inferiorly  at  the  os  uteri,  and 
is  continuous  above  with  the  space  within  the  body.  It  is  larger  at  the 
middle  than  at  either  end,  being  spindle-shaped,  and  is  somewhat  flattened 

Fig.  187. 


Interior  of  the  Utercs,  with  a  Posterior  View  of  the  Broad  Ligament  and  the 
Uterine  Appendages. 
a.  Body,  and  6,  neck  of  the  uterus.  g.  The  fimbria  attached  to  the  ovary. 

c.  Cavity  of  the  body,  and  d,  of  the  neck.  h.  Ovary,  and  i,  ligament  of  the  ovary. 

e.  Fallopian  tube,  and  /,  its  trumpet-shaped        k.  Parovarium. 
end. 

like  the  cavity  of  the  body.  Along  both  the  anterior  and  the  posterior 
wall  is  a  longitudinal  ridge  ;  and  the  other  ridges  {rugce)  are  directed  ob- 
liquely from  these  on  each  side  :  this  appearance  has  been  named  arbor 
vitce  uterinus.  In  the  intervals  between  the  rugte  are  mucous  follicles, 
which  sometimes  become  distended  with  fluid,  and  give  rise  to  rounded 
clear  sacs. 

Structure.  The  dense  wall  of  the  uterus  is  composed  of  layers  of 
unstriated  muscular  fibre,  intermixed  with  areolar  and  elastic  tissues,  and 
large  bloodvessels.  On  the  exterior  is  the  peritoneum  ;  and  lining  the 
interior  is  a  thin  mucous  membrane. 

The  muscular  fibres  can  be  demonstrated  at  the  full  period  of  gestation 
to  form  three  strata  in  the  wall  of  the  uterus,  viz.,  external,  internal,  and 
middle  : — 

The  external  layer  contains  fibres  which  are  mostly  transverse  ;  but  at 
the  fundus  and  sides  they  are  oblique,  and  are   more   marked  than  along 


I 


OVARTES    AND    FALLOPIAN    TUBES.  539 

the  middle  of  the  organ.  At  the  sides  the  fibres  converge  towards  the 
broad  ligament ;  some  are  inserted  into  the  subperitoneal  fibrous  tissue ; 
and  others  are  continued  into  the  Fallopian  tube,  the  round  ligament,  and 
the  ligament  of  the. ovary. 

The  internal  fibres  describe  circles  around  the  openings  of  the  Fallopian 
tubes,  and  spread  from  these  apertures  till  they  meet  at  the  middle  line. 
At  the  neck  of  the  uterus  they  are  arranged  in  a  transverse  direction. 

The  middle  or  intervening  set  of  fibres  are  more  indistinct  than  the 
others,  and  have  a  less  determinate  direction. 

The  mucous  lining  of  the  uterus  is  continued  into  the  vagina  at  one 
end,  and  into  the  Fallopian  tubes  at  the  other. 

In  the  body  of  the  uterus  it  is  of  a  reddish-white  color,  and  is  thin, 
smooth,  and  adherent,  but  without  papillae.  Like  the  mucous  membrane 
of  the  intestine,  it  possesses  tubular  glands^  which  may  be  either  straight 
and  simple,  or  twisted  and  branched  ;  they  are  lined  by  ciliated  epithe- 
lium, and  their  minute  apertures  are  scattered  over  the  surface. 

In  the  cervix  uteri,  between  the  rugae,  muaou^  follicles  and  glands  are 
collected,  and  near  the  outer  opening  are  papillae. 

The  epithelial  covering  of  the  mucous  membrane  consists  of  a  single 
layer  of  cells,  which  are  columnar  and  ciliated  throughout  the  cavity  of 
the  uterus. 

The  bloodvessel s  of  the  uterus  are  large  and  tortuous  and  occupy  canals 
in  the  uterine  substance,  in  which  they  communicate  freely  together.  The 
arteries  are  furnished  from  the  uterine  and  ovarian  branches  (p.  516). 

The  veins  correspond  with  the  arteries  :  they  are  large  in  size,  and  form 
plexuses  in  the  uterus. 

The  nerves  are  derived  from  the  sympathetic  (p.  519),  and  are  very 
small  in  proportion  to  the  size  of  the  uterus  :  in  the  cervix  they  are  traced 
to  the  papilla?. 

Lymphatics.  One  set  accompanies  the  uterine  vessels  to  the  glands  on 
the  iliac  artery.  Another  set  issues  from  the  fundus,  enters  the  broad 
ligament,  and  accompanies  the  ovarian  artery  to  the  glands  on  the  aorta  : 
the  last  are  joined  by  lymphatics  of  the  ovary  and  Fallopian  tube. 

Bound  ligame7it  of  the  uterus  (fig.  175,  n).  Tliis  firm  cord  supports 
the  uterus,  and  is  contained  partly  in  the  broad  ligament,  and  partly  in 
the  inguinal  canal.  It  is  about  five  inches  in  length,  and  is  attached  to 
the  upper  part  of  the  uterus  close  below,  and  anterior  to  the  Fallopian 
tube.  A  process  of  the  peritoneum  accompanies  it  in  the  inguinal  canal, 
and  remains  pervious  sometimes  for  a  short  distance. 

Tiie  ligament  is  comjjosed  of  unstriated  muscular  fibres,  derived  from 
the  uterus,  together  with  vessels  and  areolar  tissue. 

OVARIES    AND    FALLOPIAN    TUBES. 

Ovary  (fig.  187).  The  ovaries  are  two  bodies,  corresponding  with  the 
testes  of  the  male.  They  are  contained  in  the  broad  ligaments  of  tlie 
uterus,  one  in  each. 

Each  ovary  is  of  an  elongated  form,  and  somewhat  flattened  from  above 
down.  It  is  of  a  whitish  color,  with  either  a  smootii  or  a  scarred  surface. 
Its  volume  is  variable  ;  but  in  the  virgin  state  it  is  about  one  inch  and  a 
half  in  length,  half  that  size  in  width,  and  a  third  of  an  inch  in  thickness. 
Its  weight  varies  from  one  to  two  drachms. 

The  ovary  is  placed  at  the  back  of  the  broad  ligament,  and  is  connected 


540 


DISSECTION    OF    THE    PELVIS. 


Fig.  188. 


with  tliat  membrane  by  its  anterior  margin,  where  the  vessels  enter  the 
stroma.  Its  outer  end  (^)  is  rounded  and  is  connected  with  one  of  the 
fimbriie  at  the  mouth  of  the  Fallopian  tube.  The  inner  extremity  is  nar- 
rowed, and  is  attached  to  the  side  of  the  uterus  by  a  fibrous  cord  (i) — the 
ligament  of  the  ovary,  below  the  level  of  the  Fallopian  tube  and  round 
ligament. 

Structure.  The  ovary  consists  of  a  stroma  of  areolar  tissue  containing 
small  sacs  named  Graafian,  and  the  whole  is  inclosed  within  a  fibrous  tunic. 
The  peritoneum  surrounds  it  except  at  the  attached  margin. 

The  fibrous  coat  is  adherent  to  the  contained  stroma.  Along  the  at- 
tached margin  of  the  ovary  is  a  slit,  by  which  the  vessels  and  nerves  enter. 
Sometimes  a  yellow  spot  (corpus  luteum),  or  some  cicatrices,  may  be  seen 
in  this  covering. 

Stroma  (fig.  188).  The  substance  of  the  ovary  is  spongy,  vascular, 
and  fibrous.  At  the  centre  the  fibres  radiate  from  the  hilum  towards  the 
circumference.  But  at  the  exterior  is  a  granular  material  (cortical  layer) 
which  contains  very  many  small  cells,  about  ^^jythof  an  inch  in  size — the 
nascent  Graafian  vesicles. 

The  Graafian  vesicles  or  ovisacs  (fig.  188)  are  round  and  transparent 
cells,  scattered  through  the  stroma  of  the  ovary  below  the  cortical  layer. 
During  the  child-bearing  period  some  are  larger  than  the  rest  (a)  ;  and  of 
this  larger  set  ten  to  thirty,  or  more,  may  be  counted  at  the  same  time ; 

these  vary  in  size  from  a  pin's  head  to  a 
pea.  The  largest  are  situate  at  the  circum- 
ference of  the  organ,  and  sometimes  they 
may  be  seen  projecting  through  the  fibrous 
coat. 

Each  consists  of  a  transparent  coat  with 
a  fluid  inside.  The  coat  of  the  vesicle 
named  ovi-capsule  (tunica  fibrosa),  is  formed 
of  fine  areolar  tissue,  and  is  united  to  the 
stroma  of  the  ovary  by  bloodvessels,  which 
ramify  in  the  wall.  Lining  it  is  a  layer  of 
nucleated  granular  cells  —  the  membrana 
granulosa,  whicli  is  thickened  at  one  spot, 
and  surrounds  the  ovum  at  the  discus  pro- 
ligerus  (Von  Baer),  fixing  it  to  the  wall. 
Ths  fluid  in  the  interior  is  transparent  and 
albuminous  ;  it  contains  the  minute  ovum, 
to"rether  with  molecular  granules. 

When  the  Graafian  vesicle  is  matured  it 
bursts  on  the  surface  of  the  ovary,  and  the  contained  ovum  escapes  into 
the  Fallo[)ian  tube.  After  the  shedding  of  the  ovum  the  ruptured  vesicle 
gives  origin  to  a  yellow  substance,  corpus  lateum,  which  finally  clianges 
into  a  cicatrix  (&). 

Bloodvessels  and  nerves.  The  ovarian  artery  pierces  the  ovary  at  the 
anterior  or  attached  border,  and  its  branches  run  in  zigzag  lines  through 
the  stroma,  to  which  and  the  Graafian  vesicles  they  are  distributed.  The 
veins  ])egin  in  the  vesicles  and  the  texture  of  the  ovary,  and  after  escaping 
from  its  substance,  form  a  plexus  {pam-piniform)  within  the  fold  of  tlie 
broad  ligament.  The  nerves  are  derived  from  the  sympathetic  on  tiie 
ovarian  and  uterine  vessels. 

Appendage  to  the  ovary  (fig.   187,  k)   (Parovarium,  Organ  of  Rosen- 


OVARY  DURING  THE  ChII.D-BEABINO 

Period  laid  open. 
a.  Graaflau    vesicles    in    diflfereat 

stages  of  growth. 
h.  Plicated    body    remainiag    after 

the  escape  of  the  ovum  (Farre). 


BLADDER  AND  URETHRA  IN  FEMALE.         541 

miiller).  On  holding  up  the  broad  ligament  of  the  uterus  to  the  light,  a 
collection  of  small  tortuous  tubules  will  be  seen  between  the  ovary  and  the 
Fallopian  tube.  This  is  the  remnant  of  the  upper  part  of  the  Wolffian 
body  of  the  foetus  ;  it  is  about  one  inch  broad,  with  its  base  to  the  Fallo- 
pian tube,  and  apex  to  the  attached  part  of  the  ovary.  The  small  tubes  are 
from  twelve  to  twenty  in  number  ;  at  the  wider  end  they  are  joined  more 
or  less  perfectly  by  a  tube  crossing  the  rest,  which  is  prolonged  sometimes 
a  short  way  into  the  broad  ligament.  Each  tube  is  a  closed  fibrous  capsule 
with  a  clear  fluid  within,  and  with  a  lining  of  epithelium. 

Fallopian  Tubes  (fig.  187,  e).  Two  in  number,  one  on  each  side, 
they  convey  the  ova  from  the  ovaries  to  the  uterus,  and  correspond  in 
their  office  with  the  vasa  deferentia  in  the  male. 

Each  is  about  four  inches  in  length  :  cord-like  at  the  inner  end,  where 
it  is  attached  to  the  upper  part  of  the  uterus,  it  increases  in  size  towards 
the  outer  end,  and  terminates  in  a  wide  extremity  (/),  like  the  mouth  of 
a  trumpet.  This  dilated  end  is  fringed,  and  the  pieces  are  called  Jim bri'cR. 
When  the  fimbriated  end  is  floated  out  in  water,  one  of  the  processes  (g) 
may  be  seen  to  be  connected  with  the  outer  end  of  the  ovary.  In  the  centre 
of  the  fimbrise  is  a  groove  leading  to  the  orifice  of  the  Fallopian  tube. 

On  opening  the  tube  with  care,  the  size  of  the  contained  space,  and  its 
small  aperture  into  the  uterus  can  be  observed.  Its  canal  varies  in  size  at 
different  spots:  the  narrowest  part  is  at  the  orifice  into  the  uterus  (ostium 
uterinum),  where  it  scarcely  gives  passage  to  a  fine  bristle;  towards  the 
outer  end  it  increases  a  little,  but  it  is  rather  diminished  in  diameter  at 
the  outer  aperture  (ostium  abdominale). 

Structure.  This  excretory  tube  has  the  same  structure  as  the  uterus 
with  which  it  is  connected,  viz.,  a  muscular  layer  covered  externally  by 
peritoneum,  and  lined  by  mucous  membrane. 

The  muscular  coat  is  formed  of  an  external  or  longitudinal,  and  an  in- 
ternal or  circular  layer ;  both  these  are  continuous  with  similar  strata  in 
the  wall  of  the  uterus. 

The  mucous  membraiie  forms  some  longitudinal  folds,  particularly  at  the 
outer  end.  At  the  inner  extremity  of  the  canal  it  is  continued  into  the 
mucous  lining  of  tlie  uterus,  but  at  the  outer  end  it  joins  the  peritoneum. 
A  columnar  and  ciliated  epithelium  covers  tlie  surface,  as  in  the  uterus, 
and  is  said  by  Henle  to  be  detected  on  the  outer  surface  of  the  fimbriie. 

The  bloodvessels  and  nerves  are  furnished  from  those  supplied  to  the 
ovary  and  uterus. 

THE  BLADDER,  URETHRA,  AND  RECTUM. 

Bladder.  The  peculiarities  in  the  form  and  size  of  the  female  bladder 
have  been  detailed  in  the  description  of  the  connections  of  the  viscera  of 
the  female  pelvis  (p.  513).  For  a  notice  of  its  structure,  the  anatomy  of 
the  male  bladder  is  to  be  referred  to  (p.  524). 

Dissection.  To  prepare  the  bladder,  distend  it  with  air,  and  remove 
the  peritoneal  covering  and  the  loose  tissue  from  the  muscular  fibres. 

After  the  external  anatomy  of  the  bladder,  and  urethra  has  been  learnt, 
they  are  to  be  slit  open  along  the  upper  part. 

Urethra.  The  length  and  the  connections  of  the  excretory  tube  are 
given  in  page  512. 

The  average  diameter  of  the  uretlira  is  rather  more  than  a  quarter  of  an 
inch,  and  the  canal  is  enlarged  and  funnel-shaped  towards  the  neck  of  the 


642  DISSECTION    OF    THE    PELVIS.. 

bladder  ;  near  the  external  aperture  is  a  hollow  in  the  floor.  In  conse- 
quence of  not  being  surrounded  by  resistant  structures,  the  female  urethra 
is  much  more  dilatable  than  the  corresponding  passage  in  the  male. 

Structure.  Like  the  urethra  of  the  male,  it  consists  of  a  mucous  coat, 
which  is  enveloped  by  a  plexus  of  bloodvessels,  and  by  muscular  fibre. 

The  muscular  layer  extends  the  whole  length  of  the  urethra.  Its  fibres 
are  circular,  corresponding  with  the  prostatic  enlargement  in  the  other  sex, 
and  continuous  behind  with  the  middle  layer  of  the  bladder.  In  the  peri- 
neal ligament  this  stratum  is  covered  by  the  constrictor  urethras  as  in  tlie 
male  (p.  403). 

The  mucous  coat  is  pale  except  near  the  outer  orifice.  It  is  marked  by 
longitudinal  folds;  and  one  of  these,  in  the  floor  of  the  canal,  resembles 
the  median  crest  in  the  male  urethra  (p.  526).  Around  the  outer  orifice 
are  some  mucous  follicles ;  and  towards  the  inner  end  are  tubular  mucous 
glands^  whose  apertures  are  arranged  in  lines  between  the  folds  of  the 
membrane.  A  laminar  epithelium  is  spread  over  the  surface,  and  beneath 
it  are  deeper  conical  cells  as  in  the  bladder. 

A  submucous  stratum  of  longitudinal  elastic  and  muscular  tissues  lies 
close  beneath  the  mucous  membrane,  as  in  the  male. 

Dissection.  The  rectum  may  be  prepared  for  examination  by  distend- 
ing it  with  tow,  and  by  removing  the  peritoneal  covering  and  the  areolar 
tissue  from  its  surface. 

Rectum.  The  structure  of  the  rectum  is  similar  in  the  two  sexes  ;  and 
the  student  may  use  the  description  in  the  Section  on  the  viscera  of  the 
male  pelvis  (p.  522). 


Section  YII. 

INTERNAL  MUSCLES  OF  THE  PELVIS. 

Two  muscles,  the  pyriformis  and  obturator  internus,  liave  their  origin 
within  the  cavity  of  the  pelvis. 

Dissection.  Take  away  any  fascia  or  areolar  tissue  which  may  remain 
on  the  muscles  ;  and  define  their  exit  from  the  pelvis,  the  pyriformis  pass- 
ing through  the  great  sacro-sciatic  notch,  and  the  obturator  through  the 
small  notch  of  the  same  name.  On  the  right  side  the  dissector  may  look 
to  the  attachment  of  the  levator  ani  muscle  to  the  pubic  part  of  the  hip- 
bone. 

Tlie  PYRIFORMIS  MUSCLE  is  directed  outwards  through  the  great  sacro- 
sciatic  notch  to  the  great  trochanter  of  the  femur.  The  muscle  has  re- 
ceived its  name  from  its  form. 

In  the  pelvis  the  pyriformis  arises  by  three  slips  from  the  second, 
third,  and  fourth  pieces  of  the  sacrum,  between  the  anterior  aperture.*, 
and  from  the  lateral  part  of  the  bone  external  to  those  iioles  ;  as  it  passes 
from  the  pelvis,  it  takes  origin  also  from  the  surface  of  the  hip-bone  form- 
ing the  upper  part  of  the  large  sacro-sciatic  notch,  and  from  the  great 
sacro-sciatic  ligament.  From  this  origin  the  fibres  converge  to  the  ten- 
don o^  insertion  into  the  trochanter.     (Dissection  of  the  B.ittock.) 

The  anterior  surface  is  in  contact  with  the  rectum  on  tlie  left  side,  with 
the  sacral  plexus,  and  with  the  sciatic  and  pudic  branches  of  the  internal 


I 


LIGAMENTS  OF  PELVIC  BONES.  543 

iliac  vessels.  The  opposite  surface  rests  on  the  sacrum,  and  is  covered 
by  the  great  gluteal  muFcle  outside  the  pelvis.  The  upper  border  is  near 
the  hip-bone,  tlie  gluteal  vessels  and  the  superior  gluteal  nerve  being  be- 
tween :  and  the  lower  border  is  contiguous  to  the  coccygeus  muscle,  the 
sacral  plexus,  and  the  sciatic  and  pudic  vessels  intervening. 

Action.  The  pyriformis  belongs  to  the  group  of  external  rotators  of  the 
hip-joint;  and  its  use  will  be  given  with  the  description  of  the  rest  of  the 
muscle  in  the  dissection  of  the  Buttock. 

The  OBTURATOR  INTERNUS  MUSCLE  has  its  Origin  in  the  pelvis,  and 
insertion  at  the  great  trochanter  of  the  femur,  like  tlie  preceding ;  but  the 
part  outside  is  almost  parallel  in  direction  with  that  inside  the  pelvis. 

The  muscle  arises  by  a  broad  fleshy  attachment  from  the  obturator  mem- 
brane, except  a  small  part  behind  ;  i'rom  the  pelvic  fascia  covering  its  sur- 
face ;  slightly  from  the  bone  anterior  to  the  thyroid  hole,  but  from  all  the 
smooth  inclined  surface  of  the  pelvis  behind  and  above  that  aperture, 
though  opposite  the  small  sacro-sciatic  foramen  a  thin  layer  of  fat  separates 
the  fleshy  fibres  from  the  bone.  The  fibres  are  directed  backwards  and 
somewhat  downwards,  and  end  in  three  or  four  tendinous  pieces,  which 
turn  over  the  sharp  edge  of  the  hip-bone  corresponding  with  the  small 
sacro-sciatic  notch.  Outside  the  pelvis  the  tendons  blend  into  one,  which 
is  inserted  into  the  great  trochanter. 

The  muscle  is  in  contact  by  one  surface  with  the  wall  of  the  pelvis  and 
the  obturator  membrane;  by  the  other  surface  with  the  pelvic  fascia,  and 
towards  its  lower  border  with  the  [)udic  vessels  and  nerve. 

Action.  The  muscle  draws  the  trochanter  towards  the  back  of  the  hip- 
bone over  which  it  bends,  and  rotates  out  the  hip  joint.  For  further  no- 
tice of  its  use,  see  the  dissection  of  the  Buttock. 

CoccYGEus  Muscle.  The  position  and  the  connections  of  this  muscle 
may  be  studied  with  advantage  in  the  interior  of  the  pelvis.  The  muscle 
is  described  at  p.  501. 

LIGAMENTS  OF  THE  PELVIS. 

The  following  are  the  articulations  between  the  bones  of  the  pelvis : — 
The  several  pieces  of  the  sacrum  and  coccyx  are  united  with  one  another. 
The  sacrum  is  joined  at  its  base  to  the  last  lumbar  vertebra,  at  its  apex  to 
the  coccyx,  and  laterally  to  the  two  innominate  bones.  And  the  innomi- 
nate bones  are  connected  together  in  front,  as  well  as  to  the  sacrum  and 
the  spinal  column  posteriorly. 

Union  of  Pieces  of  Sacrum  and  Coccyx.  Whilst  the  pieces  of 
the  sacrum  and  coccyx  remain  separate  they  are  articulated  as  in  the 
other  vertebrae  by  an  anterior  and  posterior  common  ligament,  with  a  disk 
of  intervertebral  substance  for  the  bodies;  and  by  other  ligaments  for  the 
neural  arch  and  processes  (p.  346). 

After  the  sacral  vertebrap-  have  coalesced,  only  rudiments  of  the  liga- 
ments of  the  bodies  are  to  be  recognized  ;  but  when  the  pieces  of  tlie  coccyx 
unite  by  bone,  those  ligaments  disappear  in  the  adult  male. 

Sacro-vertebral  Articulation.  The  base  of  the  sacrum  is  articu- 
lated with  the  last  lumbar  vertebra  by  ligaments  similar  to  those  uniting 
one  vertebra  to  another  (p.  346) ;  and  by  one  special  ligament — the  sacro- 
vertebral. 

Dissection.     For  the  best  manner  of  bringing  these  different  ligaments 


544:  DISSECTION    OF    THE    PELVIS. 

into  view,  the  dissector  may  consult  the  directions  already  given  for  the 
dissection  of  the  ligaments  of  the  vertebras  (p.  346). 

The  common  ligaments  for  the  bodies  of  the  two  bones  are  an  anterior 
and  a  posterior,  with  an  intervening  fibro-cartilaginous  substance.  Be- 
tween the  neural  arches  lie  the  ligamenta  subflava;  and  between  the 
spines  the  supra  and  interspinous  bands  are  situate.  The  articular  pro- 
cesses are  united  by  capsular  ligaments  with  synovial  membranes. 

The  sacro-vertehral  ligament  is  a  rather  strong  bundle  of  fibres,  which 
reaches  from  the  under  suH'ace  of  the  tip  of  the  transverse  process  of  the 
last  lumbar  vertebra  to  the  lateral  part  of  the  base  of  the  sacrum.  Widen- 
ing as  it  descends,  the  ligament  joins  the  fibres  in  front  of  the  articulation 
between  the  sacrum  and  the  innominate  bone. 

Sacro-coccygeal  Articulation.  The  sacrum  and  coccyx  are 
united  at  the  centre  by  a  fibro-cartilage,  and  by  an  anterior  and  posterior 
common  ligament.  And  there  is  a  separate  articulation  for  the  cornua  of 
the  bones. 

Dissection.  Little  dissection  is  needed  for  these  ligaments.  When 
the  areolar  tissue  has  been  removed  altogether  from  the  bones,  the  liga- 
ments will  be  apparent. 

The  anterior  ligament  (sacro-coccygeal)  consists  of  a  few  fibres  that 
pass  between  the  bones  in  front  of  the  fibro-cartilage. 

The  posterior  ligament  is  wide  at  its  attachment  to  the  last  piece  of  the 
sacrum,  but  narrows  as  it  descends  to  be  inserted  into  the  coccyx. 

.  The  Jibro-cartilage  resembles  that  between  the  bodies  of  the  other  ver- 
tebrae, and  is  attached  to  the  surfaces  of  the  bones. 

Articulatioji  of  the  cornua.  The  cornua  of  the  first  piece  of  the  coccyx 
are  united  with  the  cornua  of  the  last  sacral  vertebra  by  ligamentous  bands, 
and  not  by  joints  as  in  tlie  articular  processes  of  the  otlier  vertebrae. 

Movement.  Whilst  the  coccyx  remains  separate  from  the  sacrum,  a 
slight  antero-posterior  movement  will  take  place  between  them. 

Sacro-iliac  Articulation.  The  irregular  surfaces  by  which  the 
sacrum  and  the  innominate  bone  articulate,  are  united  by  cartilage  (syn- 
chondrosis), and  are  maintained  in  contact  by  anterior  and  posterior  sacro- 
iliac ligaments.  Inferiorly  the  bones  are  further  connected,  without  being 
in  contact,  by  the  strong  sacro-sciatic  ligaments. 

Dissection.  To  see  the  posterior  ligaments,  the  mass  of  muscle  at  the 
back  of  the  sacrum  is  to  be  removed  on  the  side  on  which  the  innominate 
bone  remains.  The  anterior  bands  will  be  visible  on  the  removal  of  some 
areolar  tissue.  The  small  sacro-sciatic  ligament  will  be  brought  into  view 
by  removing  the  coccygeus;  and  the  large  ligament  is  dissected  with  the 
lower  limb. 

The  anterior  sacro-iliac  ligament  consists  of  a  few  thin  scattered  fibres 
between  the  bones,  near  their  articular  surfaces. 

The  posterior  ligaments  (sacro-iliac)  are  much  stronger  than  the  ante- 
rior, and  the  fibres  are  collected  into  bundles:  these  ligaments  pass  from 
the  rough  inner  surface,  at  the  posterior  end  of  the  innominate  bone,  to 
the  first  two  pieces  of  the  sacrum.  One  bundle,  which  is  distinct  from 
the  others,  and  more  superficial,  is  named  the  oblique  or  long  posterior 
ligament;  it  is  attached  to  the  posterior  upper  iliac  spinous  process,  and 
descends  almost  vertically  to  the  third  piece  of  the  sacrum. 

Articular  cartilage.  Between  the  irregular  surfaces  of  the  bones  is  a 
thin  uneven  layer  of  cartilage  (fig.  189,  a).  It  fits  into  the  inequalities 
of  the  osseous  surfaces,  uniting  them  very  firmly  together.     On  separating 


SACRO-SCTATIC    LIGAMENTS. 


545 


the  bones  after  the  other  ligaments  are  examined,  the  cartilage  may  be 
detached  with  a  knife. 

Movement.  There  is  scarcely  any  appreciable  motion  in  the  sacro-iliac 
articulation,  even  when  the  hip-bone  is  seized  by  the  hand,  and  forcibly 
pulled  in  different  directions.  The  articulation  seems  designed  for  se- 
curity and  little  movement,  inasmuch  as  the  surfaces  are  not  in  contact, 
are  very  irregular,  and  have  a  firm  and  inextensible  piece  of  cartilage 
interposed  between  them.  In  some  instances,  and  especially  during. preg- 
nancy, there  is  a  greater  degree  of  motion  perceptible. 

Two  sacro-sciatic  ligaments  pass  from  the  lateral  part  of  the  sacrum 
and  coccyx  to  the  hinder  border  of  the  os  innominatum,  across  the  space 
between  the  bones  at  the  back  of  the  pelvis  :  they  are  named  large  and 
small. 

The  large  ligament  (fig.  190,  a)  reaches  from  the  back  of  the  hip  bone, 
and  the  side  of  the  sacrum  and  coccyx  to  the  ischial  tuberosity.     As  this 


Fig.  190. 


This  figure  shows  the  irregular  piece  of  carti- 
lage (a)  in  the  sacro-iliac  articulation. 


Sacro-sciatic  Ligamknts. 
a.  Large  or  posterior  ligament. 
h.  Small  or  anterior  ligament. 


may  have  been  cut  in  the  examination  of  the  gluteal  region,  no  further 
notice  is  given  here  ;  but  if  it  remains  entire,  see  Dissection  of  the  But- 
tock for  its  description. 

The  small  ligament  (fig.  190,  h)  is  attached  internally  by  a  wide  piece 
to  the  border  of  the  sacrum  and  coccyx,  where  it  is  united  with  the  origin 
of  the  preceding  band.  The  fibres  are  directed  outwards,  and  are  inserted 
by  a  narrowed  part  into  the  ischial  spine  of  the  hip  bone.  Its  pelvic  sur- 
face is  covered  by  the  coccygeus  muscle ;  and  by  tie  opposite  surface  it 
is  in  contact  with  the  great  sacro-sciatic  ligament.  Above  it  is  the  large 
sacro-sciatic  foramen  ;  and  below  it  is  the  small  foramen  of  the  same  name, 
which  is  bounded  by  the  two  ligaments. 

By  their  position  these  ligaments  convert  into  two  foramina  (sacro- 
sciatic),  the  large   sacro-sciatic  excavation  in  the  dried  bones  :  the  open- 
ings, and  the  parts  they  give  passage  to,  are  described  with  the  Buttock. 
35 


546 


DISSECTION    OF    THE    PELVIS, 


Ligaments  of  the  Innominate  Bones  (fig.  191).  The  innominate 
bones  are  united  in  front,  at  the  pubic  symphysis,  by  an  interposed  piece 
of  cartilage  and  special  ligaments ;  and  behind,  each  is  connected  with 
the  transverse  process  of  the  last  lumbar  vertebra  by  a  separate  band  (ilio- 
lumbar). In  the  centre  of  the  bone  is  a  membranous  structure  closing  the 
thyroid  aperture. 

The  ilio-lumhar  or  ilio-vertehral  ligament  is  triangular  in  form  and  is 
divided  into  fasciculi.  Internally  it  is  attached  to  the  tip  of  the  trans- 
verse process  of  the  last  lumbar  vertebra  ;  externally  the  fibres  spread  out, 


Anterior  ligament  of  the  symphysis  ;  d, 
inferior,  and  c,  cartilage  of  the  sym- 
physis, with  a  slit  in  the  middle. 

Obturator  membrane. 

Surface  of  the  acetabulum  covered  with 
cartilage. 

Fatty  substance  in  the  acetabulum. 

Cotyloid  ligament,  which  is  cut  where 
it  forms  part  of  the  transverse  band 
over  the  notch. 

Deep  part  of  the  ligament  over  the  coty- 
loid notch. 


Ligaments  of  the  Symphysis  Pubis,  Thyroid  Hole,  and  Acetabulum. 


and  are  inserted  into  the  iliac-crest  for  about  an  inch,  opposite  the  poste- 
rior part  of  the  iliac  fossa.  To  the  upper  border  of  the  ligament  the  fascia 
lumborum  is  attached;  its  posterior  surface  is  covered  by  the  quadratus 
lumborum,  and  its  anterior  by  the  iliacus  muscles. 

Tlie  thin  obturator  membrane  (fig.  191,  h)  closes  almost  entirely  the 
thyroid  foramen,  and  is  composed  of  fibres  crossing  in  different  directions. 
It  is  attached  to  the  bony  margin  of  the  foramen,  except  above  where  the 
obturator  vessels  pass  through  ;  and  towards  the  lower  part  of  the  aperture 
it  is  connected  to  the  pelvic  aspect  of  the  hip-bone.  The  surfaces  of  the 
ligament  give  attachment  to  the  obturator  muscles.  Branches  of  the  ob- 
turator vessels  and  nerve  perforate  it. 

Pubic  Articulation  (fig.  191,  a)  (symphysis  pubis).  The  oval  pubic 
surfaces  of  the  hip  bones  are  united  by  cartilage,  and  by  fibres  in  front 
of,  and  above  the  bones  :  they  are  also  connected  by  a  strong  subpubic 
ligament. 

The  anterior  pubic  ligament  (fig.  191,  a)  is  very  strong  and  is  formed 
of  difierent  layers  of  fibres.  The  superficial  are  oblique,  and  cross  one 
another,  joining  with  the  aponeurosis  of  the  external  oblique  muscle  of 


SYMPHYSIS    PUBIS.  547 

the  abdomen  ;  but  the  deeper  fibres  are  transverse  between  the  surfaces 
of  the  bones.     Some  of  the  deepest  fibres  contain  cartilage  cells. 

There  is  not  any  strong  posterior  band  ;  but  beneath  the  periosteum  are 
a  few  scattered  fibres  in  contact  with  the  articular  cartilage. 

The  superior  ligamentous  fibres  fill  the  interval  between  the  bones 
above  the  cartilage. 

The  subpubic  ligament  (fig.  191,  d)  (ligam.  arcuatum)  is  a  strong  tri- 
angularly-shaped band  below  the  symphysis,  and  occupies  the  upper  part 
of  the  pubic  arch.  The  apex  of  the  ligament  touches  the  articular  carti- 
lage, and  the  base,  contained  within  the  triangular  perinaeal  ligament,  is 
turned  towards  the  membranous  part  of  the  urethra. 

Dissection.  The  cartilage  will  be  best  seen  by  a  transverse  section  of 
the  pubes,  which  will  show  the  disposition  of  the  anterior  ligament  of  the 
articulation,  and  the  thickness  of  the  cartilage,  with  its  toothed  mode  of 
insertion  into  the  bone  ;  but  when  opportunity  offers,  a  vertical  section 
may  be  made. 

Cartilage  (fig.  191,  c).  The  cartilage  is  firmly  fixed  to  the  ridged  bony 
surfaces  of  the  symphysis  :  it  is  wider  above  than  below,  and  is  generally 
as  thick  again  before  as  behind.  Variations  in  its  size  depend  on  the 
shape  of  the  bones. 

Towards  the  posterior  part  of  the  cartilage  there  is  a  narrow  fissure 
with  uneven  walls  ;  and  a  fibrous  structure  with  large  interspersed  com- 
pound cells  is  to  be  recognized  in  the  wall.  It  extends  usually  the  whole 
depth  of  the  cartilage  and  through  a  half  or  a  third  of  the  thickness  :  it 
is  said  to  increase  in  pregnancy.  In  some  bodies  it  reaches  through  the 
cartilage  so  as  to  divide  this  into  two  collateral  pieces. 

Movement.  As  the  bones  are  not  in  contact  in  the  pubic  symphysis,  but 
are  united  by  an  intermediate  cartilage,  the  motion  is  usually  very  slight. 
The  kind  of  movement  of  the  hip  bone  is  inward  and  outward,  so  as  to 
increase  or  diminish  the  pelvic  cavity. 

When  the  pubic  cartilage  is  divided  into  two  by  a  larger  central  space 
than  usual,  greater  freedom  of  motion  is  present  in  the  symphysis  ;  and 
in  pregnancy  the  looseness  of  the  innominate  bone  is  sometimes  so  great 
as  to  interfere  seriously  with  locomotion. 


518 


ARTERIES    OF    THE    ABDOMEN. 


TABLE  OF  THE  ARTERIES  OF  THE  ABDOMEN. 


f  1.  Phrenic. 


o 


2.  Cocliac  axis* 


3.  superior 
lueseuteric* 


4.  middle  capsu- 
lar 


renal 
spermatic 


inferior 
mesenteric* 


Coronary 


hepatic 


(^  splenic 


r  Pancreatic 
I   intestinal 
~{    ileo-colic 
I    right  colic 
middle  colic 


Left  colic 
sigmoid 
superior 
hasmorrhoidal 


(Esophageal 
gastric. 

Superior  pyloric 
gastro-epiploic 

left  hepatic 

branch 
right  hepatic 

blanch 

pancreatic 
va*<a  brevia 
fplenic 
left  gastio- 
L      epiploic 


Inferior  pyloric 
pancreatico-duodenal. 


\  Cystic. 


8.  lumbar 

9.  middle  sacral* 


External  iliac 


(  Epigastric   .     .     .  < 
(  circumflex  iliac 


Pubic  branch 

anastomotic 

cremasteric. 


1^  10.  common  iliac.  ■{ 


r  Parietal 
branches 


Ilio-lumbar 

latei'al  sacral 

Superficial 
deep. 


gluteal 


internal  iliac 


["Coccygeal 
•   fi.,         J  comes  uervi 
sciatic      .  ^      i^ehiadici 
l_rauscular. 


'Visceral 
inferior  hajmor- 

rhoidal 
superficial  peri- 

naeal 
transverse  peri- 

nseal 
artery  of  the 

bull, 
to  corpus  caver- 

no«um 
dorsal  art«>'y. 


pudic 


.  visceral 
branches 


obturator      Articular, 

Middle  hamorrhoidal 

vesical 

uterine 

vaginal. 


»  The  branches  marked  with  an  asterisk  are  single. 


VEINS    OF    THE    ABDOMEN. 


549 


TABLE  OF  THE  VEINS  OF  THE  ABDOMEN. 


Visceral 
branches 


Internal  iliac  ■< 


fl.  Common  iliac.     .^ 


Vertebro-lumbar 

right  spermatic 

renal 

right  capsular 

diaphragmatic 

hepatic  veins 
which  bring 
blood  from  the 
vena  portse. 


f  Splenic 


external  iliac 

ilio-lumbar 
lateral  sacral 
middle  sacral 
into  the  left. 


Eight 
left    , 


(  Epigasti 
}  circumfl 
(      iliac 


trie 
ex 


capsular 
spermatic 


Vena  portje 


Splenic 

branches 
vasa  brevia 
pancreatic 
left  gastro- 
epiploic 


inferior 
mesenteric 


'  Intestinal 
ileo-colic 
right  colic 
middle  colic 
superior  mesenteric  -^   right  gastro- 
epiploic 


pancreatic 
pancreatico- 
duodenal 


coronary 
t.  cystic 


'  Hsemorrhoidal 
plexus 

r  Vesical 
vesico-prostatic  j  dorsal  of  the  penis 
plexus  1  deep  veius  of  the 

i_      penig. 
uterine 

_  vaginal. 


Obturator 


pudic    . 


parietal  , 

branches    "^ 


^  gluteal. 


r  Left  coli( 

sigmoid 
<|    superior 


hseraor- 
rhoidal. 


'  Veius  of  corpus  ca- 
vernosum 
of  the  bulb 
transverse  perinsoal 
superficial  peripseal 
inferior  hajmor- 
rhoidal. 


r  coccygeal 
J  comes  nervi 
i       dici 
muscular. 


ichia- 


550 


SPINAL    NERVES    OF    THE    ABDOMEN. 


TABLE  OF  THE  SPINAL  NERVES  IN  THE   ABDOMEN. 


f  Posterior  branches 


Lumbar 

SPINAL 
NERVES 

divide 
into  .    . 


Anterior  branches :  of 
these  the  four  first 
end  in  the  Lumbar  ^ 
PLEXUS,*   which 
supplies      .     .     . 


Internal 
external 


Ilio-hypogastric 


ilio-inguinal 

external  cuta- 
neous   .     . 

genito-crural   , 


anterior  crural 


obturator 


Muscular 

<  Ml 
(  cu 


Muscular 
taneous. 


Cutaneous  of  the 

ilium 
hypogastric  branch. 

(  To  integuments  of 
(       tlie  groin. 

J  To  integuments  of 
(       the  thigh. 

J   Genital  branch 
I  crural  branch. 

Branches  inside  the 
pelvis 


Branches   outside 
the  pelvis    .     . 


Accessory 


To  the  iliacus 
muscle. 

To  the  femoral 
artery. 

are  noticed  in 
thigh. 

Other  offsets 
are  described 
in  the  thigh. 


*  The  lumbo-sacral  gives  off  the  superior  gluteal  nerve. 


Sacral 

SPINAL 
NRRVES 

divide 
into  .     . 


'  Posterior  branches 
unite  together  and 
give  off    ...    . 


The  anterior  branches 
of  the  four  superior 
unite  with  the  lum- 
bo-sacral in  the  sa- 
cral PLEXUS,!  and 
furnish 


Muscular  and 
cutaneous 
filaments. 


Branches  inside 
the  pelvis 


branches  outside 
the  pelvis     .    . 


Visceral 

to  levator  ani 

to  ol)turator  internus 

to  the  pyriformis 


f  pudic 


inferior   hsemor- 
rhoidal  (sometimes). 

to  the  gluteus  maxi- 
mus 

to  the  superior  ge- 
mellus 

to  the  inferior  ge- 
mellus and  the 
quadratus 

articular 

small  sciatic 
1^  great  sciatic. 


f  Inferior 

hajmorrhoidal 
superficial 
perinseal  (an- 
terior and 
posterior) 
muscular 
to  the  bulb 
dorsal  of  the 
penis. 


these  are  de- 
scribed in  the 
Thigh. 


t  The  other  sacral  nerves  are  described  at  p.  518. 


NERVES  OF  THE  ABDOMEN 


551 


TABLE  OP  SYMPATHETIC  NERVE  OP  THE  ABDOMEN. 


!XFs*   or  pre- 
centre  of  the 
furnishes  the  " 
plexuses  : 


Diaphragmatic 


coeliac 


Coronary  plexus 
hepatic    ... 


Pyloric 

right  gastro-epiploic 

pancreatico-duodenal 

cystic. 


Left  gastro-epiploic 
pancreatic. 


superior  mesenteric 
suprarenal 

renal 

aortic Hypogastric. 

spermatic 

*-  inferior  mesenteric 


^  splenic     .    .     . 
Offsets  to  small  and  large  intestine 


Spermatic  plexus,  filaments  to  the. 


Offsets  to  the  large  intestine 
Superior  hsemorrhoidal. 


*  This  receives 


(  Great  splanchnic  nerves. 

.     .     .  <  part  of  small  splanchnic 

(  offset  of  pneumogastric. 


Hypogastric  Plexus-j- 
ends   in   the   pelvic 
plexus   on   each   side, 
which  gives  the  follow- 
ing plexuses    .     .     .     . 


inferior  hsemorrhoidal 


uterine 
vaginal 


Prostatic 

cavernous 

deferential 

to  vesiculse  seminales. 


External  branches 


Ganqltated  cord  of  the 
sympathetic  in  the  ab- 
domen supplies     .     .     . 


internal 


t  This  is  joined  above  by 


To  the  lumbar  and  sacral  spinal  nerves. 

To  aortic  plexus 
to  hypogastric  plexus 
to  join  I'ound  middle  sacral  artery 
between  the  cords  on  the  coccyx,  in  the 
ganglion  impar. 


The  aortic  plexus 

filaments  from  the  lumbar  ganglia. 


PNEUMOGASTRIC  NERVE  IN  THE  ABDOMEN 

r  Right   . 


Pneumogastric 


<  Coronary  branches  to  the  back  of  the  stomach 
•  \  filaments  to  join  the  cooliac  and  splenic  plexuses. 


jgf.  <  Coronary  branches  to  the  front  of  the  stomach,  and 
\      to  the  hepatic  plexus. 


652  DISSECTION    OF    THE    THIGH. 


CHAPTER  IX. 

DISSECTION  OF  THE  LOWER  LIMB. 


Section  I. 

THE  FRONT  OF  THE  THIGH. 

All  the  parts  described  in  Section  I.  are  to  be  examined  before  the 
time  for  turning  the  body  arrives. 

Position.  During  the  dissection  of  the  front  of  the  thigh  the  body  lies 
on  the  back,  with  the  buttocks  resting  on  the  edge  of  the  table,  and  with 
a  block  of  suitable  size  beneath  the  loins.  The  lower  limb  should  be  sup- 
ported in  a  half-bent  position  by  a  stool  beneath  the  foot,  and  should  be 
rotated  outwards  to  make  evident  a  hollow  at  the  upper  part  of  the  thigh. 

Surface  marking.  Before  any  of  the  integument  is  removed  from  the 
limb,  the  student  is  to  observe  the  chief  eminences  and  hollows  on  the 
surface  of  the  thigh. 

The  limit  between  the  thigh  and  abdomen  is  marked,  in  front,  by  the 
firm  band  of  Poupart's  ligament  reaching  from  the  crest  of  the  hip  bone 
to  the  pubes.  On  the  outer  side,  the  separation  is  indicated  by  the  con- 
vexity of  the  iliac  crest  of  the  hip  bone,  which  subsides  behind  in  the 
sacrum  and  coccyx.  On  the  inner  side  is  the  projection  of  the  pubes, 
from  which  a  line  of  bone  (pubic  arch)  may  be  traced  backwards  along 
the  inner  and  upper  parts  of  the  limb  to  the  ischial  tuberosity. 

On  the  anterior  aspect  of  the  thigh,  and  close  to  Poupart's  ligament,  is 
a  sliglit  hollow,  corresponding  with  the  triangular  space  of  Scarpa,  in 
which  the  larger  vessels  of  the  limb  are  contained  ;  and  extending  thence 
obliquely  towards  the  inner  side  of  the  limb,  is  a  slight  depression  mark- 
ing the  situation  of  the  femoral  artery  beneath.  The  position  of  the 
arterial  trunk  may  be  ascertained  by  a  line  from  the  centre  of  the  interval 
between  the  symphysis  pubis  and  the  crest  of  the  hip  bone,  to  the  inner 
condyle  of  the  femur. 

At  the  outer  side  of  the^high,  about  four  inches  below  and  behind  the 
anterior  part  of  the  iliac  crest,  the  well-marked  projection  of  the  great 
trochanter  of  the  femur  will  be  recognized.  In  a  thin  body  the  head  of 
the  femur  may  be  felt  by  rotating  the  limb  inwards  and  outwards,  whilvSt 
tlie  thumb  of  one  hand  is  placed  in  the  hollow  below  Poupart's  ligament, 
or  tlie  fingers  behind  the  great  trochanter. 

At  the  knee  tlie  outline  of  the  several  bones  entering  into  the  formation 
of  the  joint  may  be  traced  with  ease.  In  front  of  the  joint,  wlien  it  is 
half-bent,  tlie  rounded  prominent  patella  may  be  perceived  ;  this  bone  is 
firmly  fixed  whilst  the  limb  is  kept  in  the  same  position,  but  is  moved 
with  great  freedom  when  the  joint  is  extended,  so  as  to  relax  the  muscles 


I 


ANATOMY    OF    SUPERFICIAL    PARTS.  653 

inserted  into  it.  On  each  side  of  the  patella  is  the  projection  of  the  con- 
dyle of  tlie  femur,  but  that  on  the  inner  side  is  the  largest.  If  the  fingers 
are  passed  along  the  sides  of  the  patella  whilst  tlie  joint  is  half-bent,  they 
will  be  conducted  to  the  tuberosities  of  the  head  of  the  tibia,  and  to  a 
slight  hollow  between  the  bones. 

Behind  the  joint  is  a  slight  dspression  over  the  situation  of  the  ham  or 
popliteal  space ;  and  on  its  sides  are  firm  boundaries,  which  are  formed  by 
the  tendons  (hamstrings)  of  the  flexor  muscles  of  the  leg. 

Dissection.  With  tlie  position  of  the  limb  the  same  as  before  directed, 
the  student  begins  the  dissection  with  the  examination  of  the  subcutaneous 
fatty  tissue  with  its  nerves  and  vessels. 

At  first  the  integument  is  to  be  reflected  only  from  the  hollow  on  the 
front  of  the  thigh  close  below  Poupart's  ligament.  To  raise  the  skin 
from  this  part,  an  incision  about  four  inches  in  length,  and  only  skin  deep, 
is  to  be  made  from  the  pubes  along  the  inner  border  of  the  thigh.  At  the 
lower  end  of  the  first  incision,  another  cut  is  to  be  directed  outwards 
across  the  front  of  the  limb  to  the  outer  aspect ;  and  at  the  upper  end  the 
knife  is  to  be  carried  along  the  line  of  Poupart's  ligament  as  far  as  the 
crest  of  the  hip  bone.  The  piece  of  skin  included  by  these  incisions  is 
to  be  raised  and  turned  outwards,  without  taking  with  it  the  subcutaneous 
flxt. 

The  subcutaneous  fatty  tissue,  or  the  superficial  fascia,  forms  a  general 
investment  for  the  limb,  and  is  constructed  of  a  network  of  areolar  tissue, 
with  fat  or  adipose  substance  amongst  the  meshes.  As  a  part  of  the  com- 
mon covering  of  the  body,  it  is  continuous  with  that  of  the  neighboring 
regions,  consequently  it  may  be  followed  inwards  to  the  scrotum  or  labium, 
and  upwards  on  the  abdomen. 

Its  thickness  varies  in  different  bodies,  according  to  the  quantity  of  fat 
in  it ;  and  at  the  upper  part  of  the  thigh  it  is  divisible  into  two  strata 
(superficial  and  deep)  by  some  cutaneous  vessels  and  inguinal  glands. 
The  superficial  of  the  two  layers  is  apparent  after  the  removal  of  the  skin, 
but  its  connections  will  be  made  more  evident  by  the  following  dissection. 

Dissection.  To  reflect  the  superficial  stratum  of  the  fascia,  incisions 
similar  to  those  in  the  skin  are  to  be  employed,  though  the  transverse  one 
is  not  to  reach  so  low  on  the  thigh  by  a  couple  of  inches ;  and  the  separa- 
tion from  the  subjacent  structures  is  to  be  begun  at  the  lower  part,  where 
the  large  saphenous  vein,  and  a  condensed  or  membranous  appearance  on 
the  under  sui-face,  will  mark  the  depth  of  the  stratum.  This  layer  of  the 
fat  may  be  thrown  upwards  readily,  by  a  few  touches  of  the  knife  along 
the  middle  line  of  the  limb;  but  where  vessels  and  glands  are  not  found, 
viz.,  along  the  outer  and  inner  borders  of  the  thigh,  the  separation  of  the 
superficial  fascia  into  two  layers  cannot  be  easily  made. 

The  subcutaneous  layer  of  the  fat  decreases  in  thickness  near  Poupart's 
ligament,  becoming  more  fibrous  at  the  same  spot ;  and  at  its  under  aspect 
is  a  smooth  and  membranous  surface.  It  conceals  the  superficial  vessels 
and  the  inguinal  glands,  and  is  separated  by  these  from  Poupart's  liga- 
ment. 

Dissection  (fig.  193).  The  inguinal  glands  and  the  superficial  vessels 
are  to  be  next  laid  bare  by  the  removal  of  the  surrounding  fat ;  but  the 
student  is  to  be  careful  not  to  destroy  the  deeper,  very  thin  layer  of  the 
superficial  fascia,  which  is  beneath  them,  and  is  visible  chiefly  on  the 
inner  side  of  the  centre  of  the  limb.  Three  sets  of  vessels  are  to  be  dis- 
sected out : — One  set  (artery  and  vein)  is  directed  inwards  to  the  pubes, 


554  DISSECTION    OF    THE    THIGH. 

and  is  named  external  pudic ;  another,  superficial  epigastric,  ascends  over 
Poupart's  ligament ;  and  the  third,  or  the  superficial  circumflex  iliac, 
appears  at  the  outer  border  of  the  limb.  The  large  vein  in  the  middle 
line  of  the  thigh  to  which  the  branches  converge,  is  the  internal  saphenous. 

Some  of  the  small  lymphatic  vessels  may  be  traced  from  one  inguinal 
gland  to  another. 

A  small  nerve,  the  ilio-inguinal,  is  to  be  sought  on  the  inner  side  of  the 
saphenous  vein,  close  to  the  pubes ;  and  the  branch  of  the  genito-crural 
nerve,  or  an  offset  of  it,  may  be  found  a  little  outside  the  vein. 

Superficial  Vessels.  The  small  cutaneous  arteries  at  the  top  of  the 
thigh  are  the  first  branches  of  the  femoral  trunk  ;  they  pierce  the  deep 
fascia  (fascia  lata),  and  are  distributed  to  the  integuments  and  the  glands 
of  the  groin. 

The  external  pudic  artery  (h)  (superior)  crosses  the  spermatic  cord  in 
its  course  inwards,  and  ends  in  the  integuments  of  the  penis  and  scrotum, 
where  it  anastomoses  with  offsets  of  the  internal  pudic  artery. 

Another  external  pudic  branch  (inferior,  p.  565)  pierces  the  fascia  lata 
at  the  inner  border  of  the  thigh,  and  ramifies  also  in  the  scrotum.  In 
the  female  both  branches  supply  the  labium  pudendi. 

The  superficial  epigastric  artery  (c)  passes  over  Poupart's  ligament  to 
the  lower  part  of  the  abdomen  (p.  407),  and  communicates  with  branches 
of  the  deep  epigastric  artery. 

The  superficial  circumflex  iliac  artery  (c?)  is  the  smallest  of  the  three 
branches :  appearing  as  two  or  more  pieces  on  the  outer  border  of  the 
thigh  near  the  iliac  crest,  it  is  distributed  in  the  integuments :  it  supplies 
an  offset  with  the  external  cutaneous  nerve. 

A  vein  accompanies  each  artery,  having  the  same  name  as  its  companion 
vessel ;  and  ends  in  the  upper  part  of  the  saphenous  vein,  with  the  excep- 
tion of  that  with  the  inferior  pudic  artery  :  but  the  description  of  these 
veins  will  be  given  in  a  subsequent  page. 

The  superficial  inguinal  glands  (e)  are  ari'anged  in  two  lines.  One 
set  lies  across  the  thigh,  near  Poupart's  ligament;  and  the  other  is  situate 
along  the  side  of  the  saphenous  vein.  In  the  lower  or  femoral  group  the 
glands  are  larger  than  in  the  upper,  and  the  lymphatic  vessels  from  the 
surface  of  the  lower  limb  enter  them.  The  upper  or  abdominal  group  is 
joined  by  the  lymphatics  of  the  penis,  by  those  of  the  lower  part  of  the 
abdomen,  and  by  those  of  the  buttock.  Tlie  glands  vary  much  in  number 
and  size ;  and  not  unfrequently  the  longitudinal  set  by  the  side  of  the  vein 
are  blended  together. 

Dissection.  The  deeper  layer  of  the  superficial  fascia  is  to  be  detached 
from  the  subjacent  fascia  lata.  Internal  to  the  saphenous  vein  a  thin 
membrane  can  be  raised  by  transverse  cuts  above  and  below,  and  by  a 
longitudinal  one  on  the  inner  side  of  the  thigh  ;  but  external  to  that  vessel 
there  exists  scarcely  a  continuous  layer.  The  handle  of  the  scalpel  may 
be  employed  in  the  separation ;  and  the  dissector  is  to  avoid  injuring  the 
nerves  and  vessels.  In  reflecting  the  stratum  the  margin  of  an  aperture 
(saphenous)  in  the  fascia  lata  will  become  apparent. 

The  deeper  layer  of  the  superficial  fascia  is  a  very  thin  membraniform 
stratum,  which  is  most  evident  near  Poupart's  ligament,  and  on  the  inner 
side  of  the  saphenous  vein.  About  one  inch  below  the  ligament  it  conceals 
the  large  saphenous  opening  in  the  fascia  lata;  and  as  it  stretches  across 
the  aperture  it  is  attached  to  the  circumference — internally  by  loose  areolar 


CUTANEOUS    VEINS    AND    NERVES.  555 

tissue,  but  externally  by  firm  fibrous  bands ;  it  is  also  connected  with  the 
loose  crural  sheath  of  the  subjacent  vessels  in  the  aperture. 

The  part  of  the  stratum  over  the  saphenous  opening  is  perforated  by 
many  small  apertures  for  the  transmission  of  the  lymphatics ;  and  it  has 
been  named  cribriform  fascia  from  its  sieve-like  appearance.  In  a  hernial 
protrusion  through  tliat  opening  the  cribriform  portion  is  projected  forwards 
by  the  tumor,  and  forms  one  of  the  coverings. 

Dissection.  Now  the  student  has  observed  the  disposition  of  the  super- 
ficial fascia  near  Poupart's  ligament,  he  may  proceed  to  examine  the 
remainder  of  the  subcutaneous  covering  of  the  thigh,  together  with  the 
vessels  and  nerves  in  it. 

To  raise  the  skin  from  the  front  of  the  thigh,  a  cut  is  to  be  carried 
along  the  centre  of  the  limb,  over  the  knee  joint,  to  rather  below  the  tu- 
bercle of  the  tibia.  At  the  extremity  a  transverse  incision  is  to  be  made 
across  the  front  of  the  leg,  but  this  is  to  reach  farthest  on  the  inner  side. 
The  skin  may  be  reflected  in  flaps  inwards  and  outwards ;  and  as  it  is 
raised  from  the  front  of  the  knee  a  superficial  bursa  between  it  and  the 
patella  will  be  opened. 

The  saphenous  vein  is  first  to  be  traced  out  in  the  fat  as  far  as  the  skin 
is  reflected,  but  in  removing  the  tissue  from  it  the  student  should  be  care- 
ful of  branches  of  the  internal  cutaneous  nerve. 

The  cutaneous  nerves  of  the  front  of  the  thigh  (fig.  192)  are  to  be 
sought  in  the  fat,  Mnth  small  cutaneous  arteries,  in  the  following  positions : 
On  the  outer  margin,  below  the  upper  third,  is  placed  the  external  cuta- 
neous nerve.  In  the  middle  of  tlie  limb,  below  the  upper  third,  lie  the 
two  branches  of  the  middle  cutaneous  nerve.  At  the  inner  margin  are  the 
ramifications  of  the  internal  cutaneous  nerve — one  small  offset  appearing 
near  the  upper  part  of  the  thigh  ;  one  or  more  about  half  way  down  ;  and 
one  of  the  terminal  branches  (anterior)  about  the  lower  third. 

On  the  inner  side  of  the  knee  three  other  cutaneous  nerves  are  to  be 
looked  for :  One,  a  branch  of  the  great  saphenous,  is  directed  outwards 
over  the  middle  of  the  patella.  Another,  the  trunk  of  the  great  saphenous 
nerve,  lies  by  the  side  of  the  vein  of  the  same  name,  close  to  the  lower 
part  of  the  surface  now  dissected.  And  the  third  is  a  terminal  branch 
(inner)  of  the  internal  cutaneous  nerve,  which  is  close  behind  the  pre- 
ceding, and  communicates  with  it. 

Vessels.  All  the  cutaneous  veins  on  *he  anterior  and  inner  aspects  of 
the  thigh  are  collected  into  one ;  and  this  trunk  is  named  saphenous  from 
its  manifest  appearance  on  the  surface. 

The  internal  saphenous  vein  (fig.  193,  a)  is  the  cutaneous  vessel  of  the 
inner  side  of  the  lower  limb,  and  extends  from  the  foot  to  the  upper  part 
of  the  thigh.  In  the  part  of  its  course  now  dissected,  the  vessel  lies  infe- 
riorly  somewhat  behind  tlie  knee-joint ;  but  as  it  ascends  to  its  termina- 
tion, it  is  directed  along  the  inner  side  and  the  front  of  the  thigh.  Near 
Poupart's  ligament  it  pierces  the  fascia  lata  by  a  special  opening  named 
saphenous,  and  enters  the  deep  vein  (femoral)  of  the  limb. 

Superficial  branches  join  it  both  externally  and  internally  ;  and  near 
Poupart's  ligament  the  three  veins  corresponding  with  the  arteries  in  that 
situation,  viz.,  external  pudic  (6),  superficial  epigastric  (c),and  circumflex 
iliac  (c?),  terminate  in  it.  Towards  the  upper  part  of  the  limb  the  veins 
of  the  inner  side  and  back  of  the  thigh  are  most  frequently  united  into  one 
branch,  which  enters  the  saphenous  trunk  near  the  aperture  in  the  fascia 
lata ;  and  sometimes  those  on  the  outer  side  of  the  thigh  are  collected  to- 


556 


DISSECTION    OF    THE    THIGH, 


Fig.  192. 


gether  in  a  similar  way.  When  this  arrangement  exists  three  large  veins 
will  be  present  on  the  front  of  the  thigh,  near  the  saphenous  opening.  On 
the  side  of  the  knee  the  vein  receives  a  deep  branch  from  the  joint. 

Some  unnamed  cutaneous  arteries  are  distributed  to  the  integuments 
along  with  the  nerves  ;  and  the  superficial  branch  of  the  anastomotic  artery 
(p.  568)  accompanies  the  saphenous  nerve  and  its  branches  near  the  knee. 
Nerves.  The  cutaneous  nerves  of  the  thigh  are  derived  from  branches 
of  the  lumbar  plexus,  and  are  distributed  in  greater  number  on  the  inner 
than  the  outer  side. 

llio-inguinal.  This  nerve  (p.  497)  is  small  in  size,  and  reaches  the 
surface  by  passing  through  the  external  ab- 
dominal ring  (fig.  192,  ^) ;  it  supplies  the 
scrotum,  and  ends  in  the  contiguous  part  of 
the  thigh,  internal  to  the  saphenous  vein. 

The  Genito-crural.  The  crural  branch  of 
this  nerve  (p.  497)  pierces  the  fascia  lata 
near  Poupart's  ligament  (fig.  192,  ^),  rather 
external  to  the  line  of  the  femoral  artery. 
After  or  before  the  nerve  has  become  super- 
ficial it  communicates  with  the  middle  cuta- 
neous nerve  ;  and  it  extends  on  the  anterior 
aspect  of  the  thigh  as  far  as  midway  between 
the  knee  and  the  pelvis. 

Occasionally  this  branch  is  of  large  size, 
and  takes  the  place  of  the  external  cutaneous 
nerve  on  the  outer  side  of  the  limb.     • 

The  external  cutaneous  nerve  (p.  497) 
ramifies  on  the  outer  aspect  of  the  limb  (fig. 
192,  ^).  At  first  it  is  contained  in  a  promi- 
nent ridge  of  the  fascia  lata  on  the  outer  mar- 
gin of  the  thigh,  where  it  divides  into  an  an- 
terior and  a  posterior  branch. 

The  posterior  branch  subdivides  into  two 
or  three  others,  which  arch  backwards  to 
supply  the  integuments  of  the  outer  part  of 
the  thigh  as  low  as  the  middle. 

The  anterior  branch  appears  on  the  sur- 
face of  the  fascia  lata  about  four  inches  from 
Poupart's  ligament,  and  is  continued  to  the 
knee  ;  it  distributes  branches  laterally,  but 
those  towards  the  posterior  surface  are  the 
most  numerous,  and  the  largest  in  size. 

Middle  cutaneous  (fig.  192,  ^).  The  nerve 
of  the  centre  of  the  thigh  is  a  cutaneous  offset 
of  the  anterior  crural  (p.  497),  and  divides 
into  two  branches.  It  is  transmitted  through 
the  fascia  lata  about  three  inches  from  Pou- 
part's ligament,  and  its  branches  are  con- 
tinued to  the  knee.  In  the  fat  this  nerve  is 
united  with  the  genito-crural  and  internal 
cutaneous  nerves. 

Internal  cutaneous.     Derived  from  the  an- 
furnished  to  all  the  inner  side  of  the 


Cutaneous  Nerveson  the  Front 
OF  THE  Thigh. 
External  cutaneous. 
Middle  cutaneouH. 
Internal  cutaneous. 
Internal  saphenous. 
Patellar  branch  of  saphenous. 

6.  Genito-crural. 

7.  llio-inguinal. 
S.  Ilio-hypogastric  on  the  belly. 


terior  crural  trunk,  this  nerve 


CUTANEOUS    NERVES    OF    THIGH.  557 

thigh.     It  is  divided  into  two  branches  (anterior  and  inner),  which  perfo- 
rate the  fascia  in  separate  places. 

The  anterior  branch  becomes  cutaneous  in  the  lower  third  of  the  thigh, 
in  the  line  of  the  inner  intermuscular  septum  (fig.  192,  ^),  along  which  it 
is  continued  to  the  knee.  This  branch  is  distributed  in  the  lower  third 
of  the  thigh,  as  well  as  over  the  patella  and  the  inner  side  of  the  knee- 
joint,  and  is  united  with  the  patellar  branch  of  the  internal  saphenous 
nerve. 

The  inner  branch  (fig.  207,  ®)  perforates  the  fascia  at  the  inner  side  of 
the  knee  behind  the  internal  saphenous  nerve,  with  which  it  communi- 
cates ;  it  furnishes  offsets  to  the  inside  of  the  knee,  and  to  the  upper  half 
of  the  leg  on  the  inner  surface. 

Other  small  offsets  of  the  nerve  supply  the  inner  side  of  the  thigh,  and 
appear  by  the  side  of  the  saphenous  vein.  One  or  two  come  into  view 
near  the  upper  part  of  the  vein,  and  reach  as  far  as  the  middle  of  the 
thigh ;  and  one,  larger  in  size  than  the  rest,  becomes  cutaneous  where  the 
others  cease,  and  extends  as  far  as  the  knee. 

The  internal  saphenous  (fig.  192,  *),  a  branch  of  the  anterior  crural,  is 
continued  to  the  foot,  but  only  a  small  part  of  it  is  now  visible.  The 
nerve  pierces  the  fascia  on  the  inner  side  of  the  knee;  and,  after  commu- 
nicating with  the  inner  branch  of  the  internal  cutaneous,  gives  forwards 
some  offsets  over  the  knee-joint.  Finally  it  accompanies  the  saphenous 
vein  to  the  leg  and  foot. 

Its  patellar  branch  (fig.  192,  ^)  appears  on  the  inner  side  of  the  knee 
above  the  preceding,  and  is  soon  joined  by  the  internal  cutaneous  nerve. 
It  ends  in  many  branches  over  the  patella  ;  these  communicate  with  offsets 
from  the  middle  and  external  cutaneous  nerves,  and  form  an  interlace- 
ment— plexus  patellce — over  the  joint. 

Dissection.  Let  the  fat  and  the  inguinal  glands  be  now  removed  from 
the  surface  of  the  fascia  lata,  the  cutaneous  nerves  being  thrown  aside  to 
be  traced  afterwards  to  their  trunks. 

At  the  upper  part  of  the  thigh  the  student  is  to  define  the  saphenous 
opening  in  the  fascia  lata  by  detaching  the  superficial  fascia.  The  inner 
side  is  easily  shown.  But  the  outer  border  is  blended  with  the  superficial 
fascia  and  with  the  subjacent  crural  sheath ;  and  it  is  only  after  the 
uniting  fibrous  bands  are  broken  or  cut  through  that  its  semilunar  edge 
comes  into  view.  • 

The  fascia  lata  is  the  deep  aponeurosis  of  the  thigh.  It  surrounds  the 
limb  with  a  firm  sheath,  and  sends  inwards  septa  between  the  different 
muscles.  This  membranous  investment  is  of  a  bluish-white  color,  but  in 
fat  bodies  is  sometimes  so  slight  as  to  be  taken  away  with  the  subcu- 
taneous fat. 

It  is  much  stronger  on  the  outer  than  the  inner  aspect  of  the  limb  where 
it  receives  the  insertion  of  the  tensor  vaginae  femoris,  and  the  greater  part 
of  the  gluteus  maximus  muscle.  This  thickened  part  (ilio-tibial  band)  is 
attached  above  to  the  hip-bone  and  below  to  the  bones  of  the  leg,  and 
helps  the  extensor  muscle  to  keep  the  knee-joint  straight  in  standing. 

Numerous  apertures  exist  in  the  fascia  for  the  transmission  of  the  cuta- 
neous nerves  and  vessels  ;  and  the  largest  hole  is  near  Poupart's  ligament, 
to  permit  the  passage  of  the  internal  saphenous  vein. 

Processes  prolonged  from  the  under  surface  form  septa  between,  and 
fibrous  sheaths  around  the  several  muscles.  Two  of  the  processes  are 
larger  than  the  rest,  and  are  named  outer  and  inner  intermuscular  septa  of 


558 


DISSECTION    OF    THE    THIGH. 


the  thigh  :  they  are  fixed  to  the  femur,  so  as  to  limit  on  the  sides  the 
extensor  of  the  knee.  The  position  of  these  partitions  is  marked  on  the 
surface  by  white  lines. 

At  the  top  of  the  thigh  the  fascia  is  fixed  to  the  prominent  borders  of 
the  pelvis.  Thus  it  is  connected  externally  with  the  iliac  crest,  and  inter- 
nally with  the  pubes  and  the  pubic  arch.  In  the  middle  line  behind  it  is 
joined  to  the  lower  end  of  the  sacrum  and  coccyx  ;  and  in  front,  to  Pou- 
part's  ligament  between  the  pubes  and  the  iliac  crest.  Behind  the  knee- 
joint  the  fascia  passes  uninterruptedly  to  the  leg ;  but  in  front  of  the  ar- 
ticulation it  blends  with  an  expansion  from  the  extensor  muscle,  an^d  is 
continued  over  the  joint  and  the  patella,  though  separated  from  that  bone 
by  a  bursa,  to  be  inserted  into  the  heads  of  the  tibia  and  fibula. 

On  each  side  of  the  patella  is  a  band  of  almost  transverse  fibres  (reti- 
naculum) which  is  attached  to  and  supports  the  knee-cap.     The  outer. 

Fig.  193. 


Vessels  : 
a.  Saphenous  vein. 
6.  Superficial  pudic. 
c   Superficial  epigastric. 

d.  Superficial   circumflex 

iliac. 

e.  Inguinal  glands. 

/.  Saphenous  opening. 

Nerves: 

1.  Ilio-inguinal. 

2.  External  cutaneous. 

3.  Genito-crural. 

4.  Middle  cutaneous. 
Small    unnamed    vessels 

accompany  the  different 
nerves  to  the  teguments. 


Dissection  of  the  Superficial  parts  of  the  Thigh  (Illustrations  of  Dissections). 


thick  and  strong,  is  continuous  externally  with  the  ilio-tibial  band,  and 
joins  the  insertion  of  the  vastus  externus  at  its  attachment  to  the  upper 
part  of  the  patella:  it  guides  the  patella  outwards  when  the  joint  is  bent. 
The  inner  band,  of  slight  strength,  is  fixed  to  the  patella  lower  than  the 
other,  and  unites  with  the  insertion  of  the  inner  vastus. 

Directions.     The  flaps  of  skin  wliich  were  removed  from  the  front  of 
the  thigh,  to  follow   the  cutaneous  vessels  and   nerves,   are  to  be  now 


PARTS    CONCERNED    IN    FEMORAL    HERNIA.  559 

itched  together  to  keep  moist  the  subjacent  parts ;  and  the  saphenous 
opening  is  to  be  learnt. 

The  saphoneous  opening  in  the  fascia  lata  (fig.  193,/)  is  a  narrow  semi- 
lunar slit,  which  is  situate  rather  to  the  inner  side  of  the  middle  line  of  the 
thigh.  It  measures  about  a  third  of  an  inch  in  width,  and  one  inch  and  a 
half  in  length.  Its  upper  extremity  (superior  cornu)  is  at  Pou part's  liga- 
ment; and  its  lower  extremity  (inferior  cornu)  is  distant  from  that  struc- 
ture about  one  inch  and  a  half,  and  presents  a  well-defined  margin. 

The  inner  part  of  the  opening  is  posterior  to  the  level  of  the  femoral 
vessels,  and  is  flattened  over  the  subjacent  muscle  (pectineus) ;  but  it  is 
marked  below  by  a  thin  and  sharp  border. 

The  outer  boundary  is  much  stronger,  and  has  a  semilunar  border  when 
detached,  whose  concavity  is  turned  downwards  and  inwards.  This  edge 
is  named  from  its  shape  ya/c?y<9rm  margin  of  the  saphenous  opening  (falci- 
form process  of  Burns) ;  it  is  superficial  to  the  femoral  vessels,  and  is  con- 
nected by  fibrous  bands  to  the  crural  sheath,  and  to  the  deeper  layer  of 
the  superficial  fascia.  Traced  upwards,  the  outer  edge  blends  with  the 
base  of  Gimbernat's  ligament  (part  of  Poupart) :  the  upper  end  of  this 
border,  where  it  is  internal  to  the  subjacent  femoral  vein,  has  been  named 
the  femoral  ligament. 

The  rigidity  of  the  margin  of  the  opening  is  much  influenced  by  the 
position  of  the  limb;  for  with  the  finger  beneath  the  upper  part  of  the 
falciform  border,  whilst  the  thigh  is  moved  in  difl'erent  directions,  this 
band  will  be  perceived  to  be  most  unyielding  when  the  limb  is  extended 
and  rotated  out,  and  most  relaxed  when  the  thigh  is  bent  and  turned  in 
the  opposite  direction. 

Through  the  lower  part  of  the  opening  the  saphenous  vein  is  transmit- 
ted :  and  through  the  upper  part,  close  to  the  falciform  edge,  a  femoral 
hernia  projects.  Lymphatics  and  one  or  two  superficial  vessels  also  pass 
through  it. 

PARTS   CONCERNED  IN  FEMORAL  HERNIA. 

To  obtain  a  knowledge  of  the  hernial  protrusion  in  the  thigh,  the  dis- 
sector has  to  study  the  undermentioned  parts,  viz.,  the  crural  arch  and 
Gimbernat's  ligament,  the  crural  sheath  with  its  crural  canal  and  ring, 
together  with  a  partition  (septum  crurale)  between  the  tliigh  and  the 
abdomen. 

Dissection  (fig.  194).  To  examine  Poupart's  ligament  and  a  loose 
membranous  sheath  around  the  femoral  vessels,  the  piece  of  the  fascia  lata 
outside  the  saphenous  opening  is  to  be  reflected  inwards  by  the  following 
incisions:  One  cut  is  to  be  begun  near  the  edge  of  the  falciform  border, 
and  to  be  carried  outwards  for  one  inch  and  a  half,  parallel  and  close  to 
Poupart's  ligament.  Another  is  to  be  directed  obliquely  downwards  and 
inwards  from  the  termination  of  the  first,  to  a  little  below  the  inferior 
cornu  of  the  opening.  When  the  fascia  marked  out  by  those  incisions  has 
been  raised  and  turned  inwards,  and  the  fat  removed,  the  tube  on  the  ves- 
sels (crural  sheath)  will  be  brought  into  view  as  it  descends  beneath  Pou- 
part's ligament. 

With  the  handle  of  the  scalpel  the  crural  sheath  is  to  be  separated 
carefully  from  the  fascia  lata  beneath,  from  Poupart's  ligament  in  front, 
and  from  Gimbernat's  ligament  on  the  inner  side. 

Pouparfs  ligament  (fig.  194,  ^j,  or  the  crural  arch,  is  the  firm  band  of 


560  DISSECTION    OF    THE    THIGH. 

the  aponeurosis  of  the  external  oblique  muscle  of  the  abdomen,  which 
stretches  from  the  front  of  the  iliac  crest  to  the  pubes  (p.  411).  When 
viewed  on  the  surface,  the  arch  is  curved  downwards  towards  the  limb, 
whilst  the  fascia  lata  remains  on  the  thigh.  The  outer  half  is  oblique. 
But  the  inner  half  is  almost  horizontal,  and  widens  as  it  approaches  the 
pubes,  where  it  is  inserted  into  the  pubic  spine  and  pectineal  line  of  the 
hip  bone,  forming  Gimbernat's  ligament. 

The  space  between  the  crural  arch  and  the  innominate  bone  is  larger  in 
the  female  than  in  the  male,  and  is  closed  by  parts  passing  from  the  abdo- 
men to  the  thigh.  The  outer  half  of  the  interval  is  filled  by  the  fleshy 
psoas  and  iliacus  muscles,  to  which  the  arch  is  closely  bound  by  fascia ; 
and  the  inner  half  is  occupied  by  the  femoral  vessels  and  their  sheath. 

Gimhernafs  ligament^  or  the  part  of  the"tendon  of  the  external  oblique 
muscle  which  is  inserted  into  the  pectineal  line,  is  about  three-fourtlis  of 
an  inch  in  length,  and  is  triangular  in  shape.  Its  apex  is  at  the  pubic 
spine  ;  whilst  its  base  is  in  contact  with  the  crural  sheath,  and  is  joined 
by  the  fascia  lata.  By  one  margin  (anterior)  it  is  continuous  with  the 
crural  arch,  and  by  the  opposite  it  is  fixed  to  the  pectineal  line.  In  the 
erect  position  of  the  body  the  lio^ament  is  almost  horizontal. 

The  crural  sheath  (fig.  194,  ^)  is  a  loose  tube  of  membrane  around  the 
femoral  vessels.  It  has  the  form  of  a  funnel,  sloped  unequally  on  the  sides. 
The  wide  part  or  base  of  the  tube  is  upwards ;  and  the  narrow  part  ceases 
about  two  inches  below  Pou part's  ligament,  by  blending  with  the  common 
areolar  sheath  of  the  bloodvessels.  Its  outer  border  is  nearly  straight,  and 
is  perforated  by  the  genito-crural  nerve  (^).  Its  inner  border  is  oblique, 
and  is  pierced  by  lymphatics,  superficial  vessels,  and  the  saphenous  vein(/)  ; 
this  part  of  the  sheath  appears  in  the  saphenous  opening,  and  is  connected 
to  the  falciform  margin  and  the  superficial  fascia.  In  front  of  the  crural 
sheath  and  behind  it  is  the  fascia  lata  of  the  thigh. 

The  sheath  is  continuous  with  the  fascia?  lining  the  abdomen  in  this 
way ;  the  anterior  part  is  prolonged  beneath  Poupart's  ligament  into  the 
fascia  transversalis,  and  the  posterior  half  is  continued  into  the  fascia 
iliaca  (p.  428). 

Crossing  the  front  of  the  sheath  beneath  the  arch  of  Poupart's  ligament, 
is  a  fibrous  band,  the  deep  crural  arch.  A  notice  of  it  is  included  in  the 
description  of  the  fascia  transversalis  (p.  419). 

Dissection  (fig.  194).  The  student  is  to  open  the  sheath  by  an  incision 
across  the  front,  and  to  raise  the  loose  anterior  part  with  hooks.  Inside 
the  tube  are  contained  the  femoral  vessels,  each  surrounded  by  its  covering 
of  areolar  tissue,  together  with  an  inguinal  gland  ;  and  if  a  piece  of  the 
areolar  casing  be  cut  out  over  both  the  artery  and  the  vein,  there  will  be 
an  appearance  of  two  thin  partitions,  the  one  being  situate  on  the  inner 
side  of  the  vein,  separating  this  vessel  from  the  gland,  and  the  other  (J) 
between  the  vein  and  the  artery.  A  fatty  stratum  stretches  over  the  upper 
aperture  of  the  sheath,  closing  it  towards  the  abdomen. 

Interior  of  the  crural  sheath  (fig.  194).  The  sheath  is  said  be  be  divided 
into  three  compartments  by  two  partitions  ;  and  the  position  of  the  so- 
called  septa  has  been  before  referred  to — one  being  internal  to  the  femoral 
vein,  and  the  other  between  the  two  large  vessels.  In  the  outer  compart- 
ment is  contained  the  femoral  artery  (a),  lying  close  to  the  side  of  the 
sheath  ;  in  the  middle  one  is  placed  the  femoral  vein  (b)  ;  and  in  the  inner 
space  (crural  canal)  only  a  lymphatic  gland  (c)  is  situate. 

The  crural  canal  (fig.  192)  is  the  innermost  space  in  the  interior  of  the 


ANATOMY    OF    FEMORAL    HERNIA 


561 


crural  sheath  :  Its  length  is  about  a  third  of  an  inch,  and  it  reaches  from 
the  base  of  Gimbernat's  ligament  to  the  upper  part  of  the  sapenous  opening. 
It  decreases  rapidly  in  size  from  above  down,  and  is  closed  below.  The 
aperture  by  which  the  space  communicates  with  the  cavity  of  the  abdomen 
is  named  in  the  crural  ring. 

Fig.  194. 


A.  Fascia  lata  reflected. 

B.  Crural  sheath  opened, 
c.  Poupart's  ligament. 

D.  Fascia  late  of  the  thigh  in  place. 
X  Two  septa  dividing  the  space  of 
the  crural  sheath  into  three  com- 
partments. 
Vessels  : 

a.  Femoral  artery. 

b.  Femoral  vein  ;  and 

c.  A  lymphatic  gland,  all  in  the 

crural  sheath. 

d.  Superficial  circumflex  iliac. 

e.  Superficial  pudic. 
/.  Saphenous  vein. 

Nerves : 

1.  Genito-crural. 

2.  Ilio-inguinal. 

4.  External  cutaneous. 


Dissection  of  the  Crural  Sheath  (Illustrations  of  Dissections). 

Anterior  to  the  canal,  are  Poupart's  ligament  and  the  upper  end  of  the 
falciform  margin  of  the  saphenous  opening ;  whilst  behind  it  is  the  pecti- 
neus  muscle,  covered  by  fascia  lata.  On  the  outer  side  of  the  canal,  but 
in  the  sheath,  is  the  femoral  vein.  Through  this  channel  the  intestine  passes 
from  the  abdomen  in  femoral  hernia. 

The  crural  ring^  is  the  upper  opening  of  the  crural  canal.  It  is  on  a 
level  with  the  base  of  Gimbernat's  ligament  (fig.  142,  ^),  and  is  larger  in 
the  female  than  in  the  male.  Oval  in  shape,  its  greatest  measurement  is 
from  side  to  side,  in  which  direction  it  equals  about  half  an  inch ;  and  it 
is  filled  by  a  lymphatic  gland. 

The  structures  around  the  ring,  outside  the  crural  sheath,  are  similar  to 
those  bounding  the  canal,  viz.,  in  front  the  superficial  and  the  deep  crural 
arch,  and  behind,  the  pubes  covered  by  the  pectineus  muscle  iand  the  fascia 
lata.  Internally  is  Gimbernat's  ligament  with  the  conjoined  tendon  ;  and 
externally  (but  within  the  sheath)  is  the  femoral  vein.  The  position  of 
vessels  on  the  several  sides  of  the  ring  is  stated  at  page  429. 

Septum  crurale.  That  part  of  the  subperitoneal  fatty  layer  which  is 
placed  over  the  opening  of  the  crural  ring,  has  been  named  crural  septum 
from  its  position  between  the  thigh  and  abdomen  (Cloquet).     The  situa- 

'  Gimbernat  used  tlie  name  crural  ring,  and  Mr.  Lawrence  proposes  to  call  it 
femoral  aperture.     Might  not  the  nomenclature  be  made  to  resemble  more  that 
used  in  describing  inguinal  hernia,  by  calling  this  opening  the  internal  crural 
aperture,  and  the  saphenous  opening  the  external  crural  aperture  ? 
36 


562  DISSECTION    OF    THE    THIGH. 

tion  of  the  septum  is  now  visible,  but  its  characters  are  ascertained  in  the 
dissection  of  the  abdomen  (p.  428). 

Femoral  Hernia.  In  this  kind  of  hernia  there  is  a  protrusion  of  in- 
testine into  the  thigh  beneath  Pou part's  ligament.  And  tlie  gut  descends 
in  the  crural  sheath,  being  placed  on  tin;  inner  side  of  the  vein. 

Course.  At  first  the  intestine  takes  a  vertical  direction  in  its  progress 
from  the  abdomen,  and  passes  through  the  crural  ring,  and  along  the  crural 
canal  as  far  as  the  saphenous  opening.  At  this  spot  it  changes  its  course, 
and  is  directed  forwards  to  the  surface  of  the  thigh,  where  it  becomes 
elongated  transversely;  and  should  the  gut  protrude  still  farther,  the  tumor 
ascends  on  the  abdomen,  in  consequence  of  the  resistance  being  less  in  this 
direction  than  on  the  front  of  the  thigh. 

The  winding  course  of  the  hernia  may  suggest  to  the  dissector  the  direc- 
tion in  which  attempts  should  be  made  to  replace  the  intestine  in  the  ab- 
dominal cavity.  With  the  view  of  making  the  bowel  retrace  its  course, 
it  will  be  necessary  if  the  protrusion  is  small  to  direct  it  backwards  and 
upwards ;  but  if  the  hernia  is  large  it  must  be  pressed  down  first  to  the 
saphenous  opening,  and  afterwards  backwards  and  upwards  towards  the 
crural  canal  and  ring. 

During  the  manipulation  to  return  the  intest'ne  to  its  cavity  the  thigh 
is  to  be  raised  and  rotated  inwards,  in  order  tliat  the  margin  of  the  saphe- 
nous opening  and  the  other  structures  may  be  relaxed. 

Coverings.  As  the  intestine  protrudes  it  is  clothed  by  the  following 
layers,  which  are  elongated  and  pushed  before  it  from  within  outwards. 
First  is  a  covering  of  the  peritoneum  lining  the  abdomen,  which  forms  the 
hernial  sac.  Next  one  from  the  septum  crurale  across  the  crural  ring. 
Afterwards  comes  a  stratum  from  the  crural  sheath,  unless  the  hernia 
bursts  through  an  aperture  in  the  side.  Over  this  is  spread  a  layer  of  the 
cribriform  fascia.  And,  lastly,  there  is  an  investment  of  the  superficial 
fat  or  fascia,  together  with  the  skin. 

The  coverings  may  vary,  or  may  be  conjoined  in  different  degrees  ac- 
cording to  the  condition  of  the  hernia.  In  some  instances  the  prolonga- 
tion from  the  crural  sheath  is  wanting.  Further,  in  an  old  hernia  the 
covering  derived  from  the  septum  crurale  is  united  usually  with  that  from 
the  crural  sheath,  so  as  to  form  one  layer,  the  fascia  propria  (Cooper). 
In  general,  in  an  operation  for  the  relief  of  the  strangulated  bowel,  the 
surgeon,  after  dividing  the  subcutaneous  fat,  can  recognize  but  little  of  the 
coverings  enumerated  by  anatomists  until  he  meets  with  that  of  the  sub- 
peritoneal fat  or  septum  crurale. 

Diagnosis.  This  hernial  tumor  is  generally  smaller  than  inguinal,  and 
does  not  extend  into  the  scrotum  in  the  male,  or  the  labium  in  the  female ; 
and  if  its  neck  can  be  traced  below  Poupart's  ligament,  it  can  be  distin- 
guished certainly  from  an  inguinal  hernia. 

Seat  of  stricture  and  division  of  it.  The  strangulation  of  a  femoral 
hernia  may  be  situate  either  outside  or  inside  the  neck  of  the  sac. 

The  external  stricture  may  be  found  opposite  the  margin  of  the  saphe- 
nous opening,  or  deeper  in,  opposite  Poupart's  ligament.  It  may  be  re- 
moved by  cutting  down  on  the  neck  of  tiie  tumor  at  the  inner  side,  and 
dividing  the  constricting  band  arching  over  the  neck  of  the  hernia  in  this 
situation,  witliout  opening  the  sac. 

The  stricture  inside  the  neck  of  the  sac  is  occasioned  by  the  thickening 
of  the  peritoneum.  For  its  relief  the  neck  of  the  sac  is  to  be  laid  bare, 
as  if  there  was  an  external  stricture  ;  and  if  the  intestine  cannot  be  passed 


SCARPA'S    TRIANGULAR    SPACE 


563 


into  the  abdomen  after  division  of  all  constricting  bands  on  the  exterior 
of  tlie  neck,  the  sac  of  the  peritoneum  is  to  be  opened ;  and  a  director 
having  been  introduced  through  the  constriction,  a  cut  is  made  horizontally 
inwards  for  the  extent  of  one  or  two  lines.  The  several  vessels  that  may 
be  wounded  in  attempting  to  relieve  the  deep  stricture  are  enumerated  at 
page  429. 

Scarpa's  triangular  space. 

This  hollow  is  situate  at  the  upper  part  of  the  thigh,  and  lies  beneath 
the  depression  observable  near  Poupart's  ligament.  It  corresponds  with 
the  axilla  in  the  upper  limb. 

Dissection  (fig.  195).  The  space  will  appear  on  removing  the  fascia 
lata  near  Poupart's  ligament.  The  muscular  boundaries  on  the  sides  may 
be  first  dissected,  and  the  muscle  on  the  outer  side  (sartorius)  should  be 
fixed  in  place  with  stitches.     Afterwards,  the  remains  of  the  crural  sheath 


Fi?.  195. 


Muscles: 

A. 

Sartorius. 

B. 

Iliacus. 

C. 

Tensor  fasciae  latse. 

D. 

Rectus  feraoris. 

E. 

Pectineus, 

F 

Adductor  longus. 

a. 

Gracilis. 

/ 


Vessels  : 
a.  Femoral  artery. 
6.  Superficial  circumflex  iliac. 
('.  Superficial  epigastric. 
e.  Superficial  pudic  (inferior) ,  and 
z,  the  accompanying  veins. 

Deep  circumflex  iliac. 

Deep  epigastric. 

Femoral  veiu. 

Inferior  external  pudic  vein. 

Saphenous  vein. 

Nerves  : 

The  large  anterior  craral  is  close 
outside  the  artery. 

2.  Oflfset  from  the    same    to    the 

pectineus. 

3.  Middle  cutaneous. 

4.  Internal  cutaneous. 

5.  Genito-crural. 

6.  External  cutaneous. 


Dissection  on  Scarpa's  Triangular  Space  (Illustrations  of  Dissections). 

are  to  be  taken  away;  and  the  femoral  vessels  are  to  be  followed  down- 
wards as  far  as  the  sartorius  muscle.  On  the  outer  side  of  the  vessels 
clean  the  divisions  of  the  anterior  crural  nerve,  together  with  the  branches 
of  an  artery  (profunda)  whicli  are  buried  in  the  fat.  In  removing  the  fat 
from  beneath  the  femoral  artery,  the  student  is  to  look  for  one  or  two  small 
nerves  to  the  pectineus  muscle. 

This  intermuscular  space  (fig.  195)  contains  the   trunks  of  the  blood- 
vessels of  the  thigh,  and  the  anterior  crural   nerve,  with  lymphatics  and 


564  DISSECTION    OF    THE    THIGH. 

fat.  It  measures  commonly  three  inches  from  above  down  ;  but  the 
length  varies  with  the  breadth  of  the  sartorius,  and  the  height  at  which 
this  muscle  crosses  inwards. 

The  base  of  the  space  is  at  Poupart's  ligament  ;  and  the  apex  is  at  the 
meeting  of  the  sartorius  with  the  adductor  longus  muscle. 

Towards  the  surface  it  is  covered  by  the  fascia  lata,  and  by  the  teo;u- 
ments  with  inguinal  glands  and  superficial  vessels.  The  floor  slopes  to- 
wards the  middle,  where  it  is  deepest ;  it  is  constructed  externally  by  the 
sartorius.  A,  and  by  the  conjoined  psoas  and  iliacus,  b,  for  about  two 
inches ;  and  internally  by  the  pectineus  and  adductor  longus  muscle,  e 
and  F,  and  between  and  beneath  these  near  the  large  vessels,  is  a  small 
piece  of  the  adductor  brevis. 

The  femoral  artery  runs  through  the  centre  of  the  hollow,  and  supplies 
small  cutaneous  offsets,  as  well  as  a  large  deep  branch,  the  profunda:  a 
small  offset  (external  pudic)  is  directed  from  it  to  the  scrotum  across  the 
inner  boundary.  On  the  inner  side  of  the  artery  and  close  to  it  is  placed 
the  femoral  vein,  which  is  here  joined  by  the  saphenous  and  profunda 
branches.  About  a  third  of  an  inch  external  to  the  vessel  is  situate  the 
large  anterior  crural  nerve,  which  lies  deeply  at  first  between  the  iliacus 
and  psoas,  but  becomes  afterwards  more  superficial  and  divides  into 
branches. 

Deep  lymphatics  accompany  the  femoral  vessels,  and  are  continued 
into  the  iliac  glands  in  the  abdomen  ;  they  are  joined  by  the  superficial 
lymphatics. 

Femoral  Artery  (fig.  197.)  This  vessel  is  a  continuation  of  the  ex- 
ternal iliac,  and  reaches  from  the  lower  of  Poupart's  ligament  to  the 
margin  of  the  opening  in  the  adductor  magnus  muscle ;  at  that  spot  it 
passes  into  the  ham,  and  takes  the  name  popliteal.  Occupying  two-thirds 
of  the  thigh,  the  course  of  the  vessel  will  be  indicated,  during  rotation 
outwards  of  the  limb  with  the  knee-joint  half  bent,  by  a  line  drawn  from 
a  point  midway  between  the  symphysis  pubis  and  the  front  of  the  iliac 
crest,  to  the  inside  of  the  inner  condyle  of  the  femur. 

In  the  upper  part  of  its  course  the  artery  lies  rather  internal  to  the 
head  of  the  femur,  and  is  comparatively  superficial,  being  uncovered  by 
muscle  ;  but,  in  the  lower  part,  it  is  placed  along  the  inner  side  of  the 
shaft  of  that  bone,  and  is  beneath  the  sartorius  muscle.  This  difference 
in  its  connections  allows  of  a  division  of  the  arterial  trunk  into  two  por- 
tions, superficial  and  deep. 

The  superficial  part  of  the  artery  (fig.  195,  a),  which  is  now  laid  bare, 
is  contained  in  Scarpa's  triangular  space,  and  is  about  three  inches  long. 
Its  position  in  that  hollow  may  be  ascertained  by  the  line  before  men- 
tioned. 

Incased  at  first  in  the  crural  sheath  for  about  two  inches,  it  is  covered 
by  the  skin  and  the  superficial  fascia,  and  by  the  fascia  lata  and  some  in- 
guinal glands.  At  its  beginning  the  artery  rests  on  the  psoas  muscle  ; 
and  it  is  subsequently  placed  over  tlie  pectineus,  e,  though  at  some  dis- 
tance from  it  in  this  position  of  the  limb,  and  separated  from  it  by  fat, 
and  the  profunda  and  femoral  veins. 

Its  companion  vein  (A)  is  on  the  inner  side  and  close  to  it  at  the  pubes, 
but  is  placed  behind  the  artery  at  the  apex  of  the  space. 

The  anterior  crural  nerve  lies  on  the  outer  side,  being  distant  about  a 
third  of  an  inch  near  Poupart's  ligament ;  and  the  internal  cutaneous 
branch  of  the  nerve  approaches  the  artery,  or  lies  on  it,  near  the  apex  of 


UPPER    PART    OF    FEMORAL    VESSELS.  565 

the  containing  space.     Crossing  beneath  the  vessels  is  the  nerve  of  the 
pectineus  Q. 

Unusual  position.  Four  examples  of  transference  of  the  main  artery  of  the  limb 
from  the  front  to  the  back  of  the  thigh  have  been  recorded.  In  these  cases  the 
vessel  passed  from  the  pelvis  through  the  great  sacro-sciatic  notch,  and  accom- 
panied the  great  sciatic  nerve  to  the  popliteal  space. 

The  branches  of  the  first  part  of  the  artery  are  the  superficial  epigastric 
and  circumflex  iliac,  two  external  pudic,  and  the  deep  femoral  branch. 
The  cutaneous  offsets  have  been  seen  (p.  554),  with  the  exception  of  the 
following,  which  lies  at  first  beneath  the  fascia  lata. 

The  inferior  external  pudic  artery  (fig.  195,  e)  arises  separately  from, 
or  in  common  with  the  other  pudic  branch  (superior).  It  courses  inwards 
over  the  pectineus  muscle  to  end  in  the  teguments  of  the  scrotum  or  the 
labium  pudendi,  according  to  the  sex,  and  it  perforates  the  fascia  lata  at 
the  inner  border  of  the  thigh  to  reach  its  destination  :  in  the  fat  it  anasto- 
moses with  branches  of  the  superficial  perinasal  artery. 

The  deep  femoral  branch  (fig.  197,  ^)  or  the  profunda^  is  the  largest 
offset  of  the  femoral  artery,  and  arises  from  the  outer  part  of  that  trunk 
one  to  two  inches  (Quain)  below  Poupart's  ligament.  It  is  consumed  in 
the  muscles  of  the  thigh,  and  its  distribution  will  be  afterwards  ascertained. 
In  the  present  dissection  it  may  be  seen  to  lie  over  the  iliacus  muscle, 
where  it  gives  the  external  circumflex  artery  to  the  outer  part  of  tlie 
thigh  ;  and  then  to  turn,  with  a  large  vein,  beneath  the  trunks  of  the 
femoral  vessels  to  the  inner  side  of  the  limb.^ 

Variation  in  origin.  The  origin  of  the  profunda  may  approach  nearer  to  Pou- 
part's ligament  until  it  arrives  opposite  that  band  ;  or  may  even  go  beyond,  and 
be  fixed  to  the  external  iliac  artery  (one  example,  Quain).  And  the  branch  may 
recede  farther  and  farther  from  the  ligament,  till  it  leaves  the  parent  trunk  at  the 
distance  of  four  inches  from  the  commencement  ;  but  in  this  case  the  circumflex 
branches  usually  arise  separately  from  the  femoral.  In  applying  a  ligature  to 
the  femoral  artery  in  the  upper  part  of  the  thigh,  the  thread  should  be  placed 
four  inches  below  Poupart's  ligament,  in  order  that  the  spot  chosen  may  be  free 
from  the  disturbing  influence  of  so  large  an  ofl'set. 

Femoral  Vein  (fig.  195,  K).  The  principal  vein  of  the  limb,  whilst 
in  the  triangular  space,  has  almost  the  same  relative  anatomy  as  the 
artery  :  its  position  to  that  vessel,  however,  is  not  the  same  througliout. 
Beneath  Poupart's  ligament  it  is  on  the  inner  side  of  the  arterial  trunk, 
and  on  the  same  level,  and  is  supported  on  the  pubes  between  the  psoas 
and  pectineus  muscles  ;  but  it  soon  winds  beneath  the  artery,  and  appears 
on  the  outer  side  opposite  the  upper  border  of  the  adductor  longus  muscle. 
Occasionally  it  is  inside  the  artery  throughout.  In  this  space  it  receives 
the  internal  saphenous  and  deep  femoral  veins,  and  a  small  branch  (/) 
with  the  inferior  external  pudic  artery. 

DEEP  PARTS  OF  THE  FRONT  OF  THE  THIGH. 

The  muscles  on  the  front  of  the  thigh  are  to  be  learnt  next :  they  are 
the  sartorius,  and  the  extensor  of  the  knee  ;  and  at  the  top  of  the  thigh 
is  the  small  tensor  of  the  fascia  lata.  Three  muscles  are  combined  in  the 
extensor,  viz.,  rectus,  vastus  externus,  and  vastus  internus. 

'  Sometimes  the  term  common  femoral  is  applied  to  the  part  of  the  trunk  above 
the  origin  of  the  profunda,  and  the  names  superficial  and  deep  femoral  to  the 
nearly  equal  parts  into  which  it  divides. 


666  DISSECTION    OF    THE    THIGH. 

The  external  circumflex  branch  of  the  profunda  artery  lies  amongst  the 
muscles  and  supplies  them  with  branches ;  and  a  large  nerve,  the  anterior 
crural,  furnishes  offsets  to  them. 

Dissection.  To  proceed  with  the  deep  dissection,  the  limb  is  to  be 
retained  in  the  same  position  as  before,  and  the  flaps  of  skin  on  the  front 
of  the  thigh  are  to  be  thrown  aside.  The  fascia  lata  i«  to  be  cut  along 
the  middle  line  of  the  thigh  and  knee,  and  to  be  reflected  to  each  side 
nearly  to  the  same  extent  as  the  skin.  Over  the  knee-joint  the  student  is 
to  note  its  attachment  to  the  edges  of  the  patella,  and  its  union  with  a 
prolongation  from  the  tendon  of  the  extensor  muscle  to  the  leg. 

In  raising  the  inner  piece  of  the  fascia  the  narroAv  muscle  appearing 
(sartorius)  should  be  followed  to  its  insertion  into  the  tibia :  and  to  pre- 
vent its  displacement,  it  should  be  fixed  with  stitches  along  both  edges. 
Care  should  be  taken  of  the  small  nerves  in  contact  with  the  sartorius  ; — 
viz.,  a  plexus  beneath  it  at  the  middle  of  the  thigh  from  the  saphenous, 
internal  cutaneous,  and  obturator ;  two  branches  of  the  internal  cutaneous 
below  its  middle, — one  crossing  the  surface,  and  the  other  lying  along  the 
inner  edge  of  the  muscle ;  and  the  trunk  of  the  great  saphenous  escaping 
from  beneath  it  near  the  knee,  with  the  patellar  branch  of  the  same  per- 
forating it  rather  higher. 

Internal  to  the  sartorius  some  strong  muscles  (adductors)  are  inclined 
downwards  from  the  pelvis  to  the  femur.  The  student  is  to  lay  bare  the 
fore  part  of  those  muscles  ;  and  beneath  the  most  superficial  (adductor 
longus),  near  where  it  touches  the  sartorius,  he  is  to  seek  a  branch  of  the 
obturator  nerve  to  the  plexus  before  mentioned  in  the  middle  of  the 
thigh.  On  the  outer  side  of  the  sartorius  is  the  large  extensor  of  the 
knee.  For  its  dissection  the  knee  is  to  be  bent,  to  make  tense  the  fibres  : 
and  an  expansion  below  from  the  common  tendon  to  the  fascia  lata  and 
the  knee-joint  is  not  to  be  removed  now, — its  arrangement  will  be  noticed 
after. 

The  little  muscle  at  the  upper  and  outer  part  of  the  thigh, — tensor  of 
the  fascia  lata,  is  to  be  cleaned ;  and  a  strip  of  the  fascia,  corresponding 
with  its  width,  should  be  left  along  the  outer  aspect  of  the  thigh.  After 
this  slip  has  been  separated,  the  rest  of  the  fascia  on  the  outer  side  of  the 
thigh  is  to  be  divided  by  one  or  two  transverse  cuts,  and  is  to  be  followed 
backwards  to  its  attachment  to  the  femur. 

The  SARTORIUS  (fig.  196,  ^)  is  the  longest  muscle  in  the  body,  and 
extends  from  the  pelvis  to  the  leg.  It  arches  over  the  front  of  the  thigh, 
passing  from  the  outer  to  the  inner  side  of  the  limb,  and  lies  in  a  hollow 
between  the  extensor  on  tlie  one  side,  and  the  adductors  on  the  other. 

Its  origin  is  tendinous  from  the  upper  anterior  iliac  spinous  process  of 
the  hip  bone,  and  from  about  half  the  interval  between  this  and  the  infe- 
rior process.  The  fibres  constitute  a  ribbon-like  muscle,  which  ends  in  a 
thin  tendon  below  the  knee,  and  is  inserted  into  the  inner  surface  of  the 
tibia — mainly  into  a  slight  depression  by  the  side  of  the  tubercle  for  an 
inch  and  a  half,  but  also,  by  its  upper  edge,  as  far  back  as  the  internal 
lateral  ligament  of  the  knee-joint. 

The  muscle  is  superficial  throughout,  and  is  perforated  by  some  cuta- 
neous nerves  and  vessels.  Its  upper  part  is  oblique,  and  forms  the  outer 
boundary  of  the  triangular  space  containing  the  femoral  artery :  it  rests 
on  the  following  muscles,  iliac  us,  b,  rectus,  d,  and  adductor  longus,  g,  as 
well  as  on  the  anterior  crural  nerve  and  the  femoral  vessels.  The  middle 
portion  is  vertical,  and  lies  in  a  hollow  between  the  vastus  internus  e,  and 


SARTORIUS    MUSCLE 


567 


the  adductor  muscles  as  low  as  the  opening  for  the  femoral  artery ;  but 
beyond  that  aperture,  where  it  bounds  the  popliteal  space,  it  is  [)laced  be- 
tween the  vastus  with  the  great  adductor  in  front,  and  the  gracilis,  ii,  with 
tlie  inner  hamstrings  behind.  The  femoral  vessels  and  their  accompany- 
ing nerves  are  concealed  by  this  portion  of  the  muscle.  The  lower  or 
tendinous  piece,  i,  rests  on  the  internal  lateral  ligament  of  the  knee-joint, 

Fis.  196. 


Mm 
A. 

-cles  : 
Sartorius. 

B. 

Iliacus. 

C. 

Tensor  fasciae  latse. 

D. 

Rectus  femoris. 

E. 

Vastus  internus. 

F. 

Pectineus. 

G. 

Adductor  longus. 

H 

Gracilis. 

I. 

Tendon,  of  Sartorius 

Vessels  : 

a. 

Femoral  artery. 

b. 

Femoral  vein. 

c. 

Saphenous  vein. 

SCRFACE  View  of  the  Front  of  the  Thioh,  the  Teguments  and  Fascia  being  removkd. 
(Illustrations  of  Dissections. 

being  superficial  to  the  tendons  of  the  gracilis  and  semi-tendinosus,  and 
separated  from  them  by  a  prolongation  of  tiieir  synovial  bursa :  from  its 
upper  border  there  is  an  aponeurotic  expansion  to  join  that  from  tlie  ex- 
tensor over  the  knee;  and  from  its  lower  border  is  given  another  which 
blends  with  the  fascia  of  the  leg.  Below  the  tendon  the  great  saphenous 
nerve  appears  with  vessels ;  and  piercing  it  is  the  patellar  branch  of  the 
same  nerve. 

Action.     The  tibia  and  femur  being  free  to  move,  the  muscle  bends  the 


568  DISSECTION    OF    THE    THIGH. 

knee  and  hip-joints  over  which  it  passes,  giving  rise  to  rotation  inwards 
of  the  tibia  ;  and  makes  tense  finally  the  fascia  of  the  thigh. 

With  the  limbs  fixed,  the  two  muscles  will  support  the  pelvis  in  stand- 
ing, and  will  assist  in  bringing  forwards  the  pelvis  in  stooping  and 
walking. 

When  standing  on  one  leg  the  muscle  will  help  to  rotate  the  body,  so  as 
to  turn  the  face  to  the  opposite  side. 

Dissection  (fig.  197).  The  sartorius  is  to  be  turned  aside,  or  cut 
through  if  it  is  necessary,  to  follow  the  remaining  part  of  the  femoral 
artery. 

Beneath  the  muscle  is  an  aponeurosis  betw^een  the  adductor  and  exten- 
sor muscles ;  this  is  thin  above,  and  when  it  is  divided  the  internal  saphe- 
nous nerve  will  come  into  view.  Parallel  to  the  upper  part  of  the  saphe- 
nous nerve,  but  outside  it,  is  the  nerve  to  the  vastus  internus  muscle, 
which  sends  an  offset  on  the  surface  of  the  vastus  to  the  knee-joint ;  this 
may  be  traced  now,  lest  it  should  be  destroyed  afterwards.  The  plexus 
of  nerves  on  the  inner  side  of  the  thigh  may  be  more  completely  dissected 
in  this  stage. 

The  femoral  vessels  and  their  branches  are  to  be  nicely  cleaned.  Where 
the  femoral  artery  passes  to  the  back  of  the  limb  its  small  anastomotic 
b:'anch  arises  :  this  branch  is  to  be  pursued  through  the  fibres  of  the  vastus 
internus,  and  in  front  of  the  adductor  magnus  tendon  to  the  knee ;  an  off- 
set of  it  is  to  be  followed  with  the  saphenous  nerve. 

Tlie  aponeurotic  covering  o\ev  the  femoral  vessels  (fig.  197,'')  exists 
only  where  these  are  covered  by  the  sartorius.  It  is  thin  above,  but  below 
it  is  formed  of  strong  fibres,  which  are  directed  transversely  between  the 
vastus  internus  and  the  tendons  of  the  adductor  muscles.  Inferiorly  the 
membranous  structure  ceases  at  the  opening  in  the  adductor  magnus  by  a 
defined  border,  beneath  which  the  saphenous  nerve  and  its  vessels  escape. 

The  deep  part  of  the  femoral  artery  (fig.  197,  ^)  lies  in  a  hollow  be- 
tween muscles  (Hunter's  canal)  until  it  reaches  the  opening  in  the  adduc- 
tor magnus.  Here  it  is  covered  by  the  sartorius  muscle  and  the  subjacent 
aponeurosis,  in  addition  to  the  integuments  and  the  superficial  and  deep 
fasciae.  Beneath  it  are  the  pectineus,  the  adductor  brevis  in  part,  the 
adductor  longus,  and  a  small  piece  of  the  adductor  magnus.  On  the  outer 
side  is  the  vastus  internus. 

External  to  the  artery  and  close  to  it  is  the  femoral  vein  ;  and  in  the 
integuments  oftentimes  an  offset  of  the  saphenous  passes  across  the  line  of 
the  arterial  trunk. 

Crossing  over  the  artery  from  the  outer  to  the  inner  side  is  the  internal 
saphenous  nerve,  which  is  beneath  the  aponeurosis  before  noticed,  but  is 
not  contained  within  the  areolar  sheath  of  the  vessels. 

Splitting  of  the  artery.  Occasionally  the  femoral  artery  is  split  into  two  below 
the  origin  of  the  profunda.  Four  examples  of  this  peculiarity  have  been  met 
with  ;  but  in  all,  the  trunks  were  blended  into  one  above  the  opening  in  the 
adductor  muscle. 

Branches.  One  named  branch,  anastomotic  and  muscular  offsets,  spring 
from  this  part  of  the  artery. 

The  anastomotic  branch  (fig.  198,  h)  (arter.  anastomotica  magna)  arises 
close  to  the  opening  in  the  adductor  muscle,  and  divides  at  once  into  two 
parts,  superficial  and  deep  : — 

The  superficial  offset  (w)  continues  with  the  saphenous  nerve  to  the 


^^  lower  bo 


LOWER    PART    OF    FEMORAL    VESSELS 


569 


lower  border  of  the  sartorius,  and  piercing  the  fascia  lata,  ramifies  in  the 
integuments. 

The  deep  branch  (/)  is  concealed  in  the  fibres  of  the  vastus  internus, 
and  descends  in  front  of  the  tendon  of  the  adductor  magnus  to  the  inner 
side  of  the  knee-joint,  where  it  anastomoses  witli  the  articular  branches  of 

Fig.  197. 


1.  Femoral  artery. 

2.  Profunda  artery. 

3.  Internal  circumflex. 

4.  External  circumflex. 

6.  Superficial  circumflex  iliac  and  epigas- 
tric branches. 

6.  External  pudic  artery. 

7.  Aponeurosis  over  tke  lower  part  of  the 

femoral  artery. 

8.  Anterior  crural  nerve. 

9.  Pectineus  muscle. 

10.  Adductor  longus. 

11.  Gracilis. 

12.  Vastus  internus. 
1.3.'  Kectus  femoris. 

14.  Sartorius  cut  across. 


Deep  part  of  the  Femoral  Artery  and  its  Branches,  with  Muscles  op  the  Thigh 
(Quain's  Arteries). 

the  popliteal  and  anterior  tibial  arteries.  A  branch  passes  outwards  from 
it  in  the  substance  of  the  vastus,  and  forms  an  arch  in  front  of  the  lower 
end  of  the  femur  with  an  offset  of  the  upper  external  articular  artery  ;  from 
this  loop  twigs  descend  to  the  joint. 

Muscular  branches.      Branches  for  the  supply  of  the  muscles   come 


670  DISSECTION    OF    THE    THIGH. 

mostly  from  the  outer  side  of  the  femoral  artery  ;  they  enter  the  sartorius, 
the  vastus  internus,  and  the  adductor  longus. 

The  FEMORAL  VEIN  Corresponds  closely  with  the  femoral  artery  in  its 
connections  with  the  parts  around,  and  in  its  branches. 

Dissection.  The  femoral  artery  and  vein  are  to  be  cut  across  below  the 
origin  of  the  profunda,  and  are  to  be  thrown  downwards  preparatory  to 
the  deeper  dissection.  Afterwards  all  the  fat,  and  all  the  veins,  are  to  be 
carefully  removed  from  amongst  the  branches  of  the  profunda  artery  and 
anterior  crural  nerve.  Unless  this  dissection  is  completed,  the  upper  part 
of  the  vastus  internus  will  not  be  prepared  for  learning. 

The  TENSOR  VAGINA  FEMORis  (fig.  198,  ^')  occupies  the  upper  third  of 
the  thigh,  and  is  the  smallest  and  most  external  of  the  outer  set  of  mus- 
cles. It  takes  origin  from  the  front  of  the  crest  of  the  hip  bone  at  tlie 
outer  aspect ;  from  the  anterior  upper  iliac  spine,  and  from  part  of  tlie 
notch  between  this  and  the  inferior  spine  as  far  as  the  attachment  of  tiie 
sartorius.  Its  fibres  form  a  fleshy  belly  about  two  inches  wide,  and  are 
inserted  into  the  fascia  lata  about  three  inches  below,  and  rather  in  front 
of  the  line  of  the  great  trochanter  of  the  femur. 

At  its  origin  the  muscle  is  situate  between  the  sartorius  and  the  gluteus 
medius.  Beneath  it  are  the  ascending  offsets  of  the  external  circumflex 
artery  ;  and  a  branch  of  the  superior  gluteal  nerve  enters  its  under  surface. 
A  strong  sheath  of  fascia  surrounds  the  muscle. 

Action.  Supposing  the  limb  movable  the  muscle  abducts  the  thigh, 
making  tense  at  the  same  time  the  fascia  lata ;  and  finally  it  will  help  in 
rotating  inwards  the  femur. 

When  the  limb  is  fixed  it  will  support  the  pelvis,  and  assist  in  balancing 
the  same  on  the  femur  in  walking. 

Dissection.  After  the  tensor  has  been  learnt,  the  slip  of  fascia  extending 
from  it  to  the  knee  may  be  cut  through  ;  and  when  it  is  detached  from 
the  muscles  around,  the  head  of  the  rectus  may  be  followed  upwards  to 
the  pelvis. 

The  TRICEPS  EXTENSOR  of  the  knee  (fig.  197)  consists  of  three  fleshy 
parts  or  heads,  outer  (vastus  externus),  inner  (vastus  internus),  and  mid- 
dle (rectus),  which  are  united  below  in  a  common  tendon. 

The  RECTUS  FEMORIS  givcs  rise  to  a  fleshy  prominence  on  the  front  of 
the  thigh  (fig.  197,  '^).  At  its  origin  from  the  pelvis  the  muscle  consists 
of  two  tendinous  pieces  :  one  arises  from  the  anterior  inferior  iliac  spinous 
process  ;  the  other  (to  be  afterwards  seen)  is  fixed  into  a  depression  on 
the  back  of  the  hip  bone,  close  above  the  acetabulum.  The  fleshy  fibres 
terminate  inferiorly  in  another  tendon,  which  joins  the  aponeurotic  parts 
of  the  other  two  muscles  in  the  common  tendon. 

The  rectus  is  larger  at  the  middle  than  at  the  ends  ;  and  its  fibres  are 
directed  from  the  centre  to  the  sides,  as  in  a  quill,  giving  rise  to  that  con- 
dition called  penniform.  It  is  subcutaneous,  except  above  where  it  is 
overlaid  by  the  sartorius.  It  conceals  branches  of  the  external  circumflex 
artery  and  anterior  crural  nerve,  and  rests  on  tlie  vasti.  The  U{)per  ten- 
don of  the  rectus  readiest  furthest  on  the  anterior  surface  where  the  sar- 
torius touches,  whilst  the  lower  tendon  is  most  extensive  on  the  posterior 
aspect,  or  towards  the  subjacent  vasti. 

Dissection.  To  see  the  remaining  muscles,  cut  across  the  rectus  near 
the  lower  end,  and  raise  it  without  injuring  the  branches  of  vessels  and 
nerves  beneath.  The  muscular  mass  on  the  front  of  the  femur  is  to  be 
divided  into  two,  above,  along  the  situation  of  some  descending  vessels  and 


TRICEPS    EXTENSOR    OF    KNEE.  671 

fnerves :  the  part  external  to  the  vessels  is  the  vastus  externus,  and  the 
larjrer  mass,  internal  to  them,  is  the  vastus  internus. 

To  make  out  the  lower  separation  of  the  two,  look  to  the  outer  aspect 
of  the  thigh  about  half  way  down,  where  the  long  and  vertical  fibres  of 
the  vastus  externus  descending  to  their  tendon,  cross  over  others  (deeper), 
which  are  continued  obliquely  inwards,  and  belong  to  the  inner  vastus. 

The  VASTUS  EXTERNUS  has  a  very  narrow  attachment  to  the  femur  in 
comparison  with  its  size.  It  takes  origin  along  the  upper  half  of  the 
femur,  by  a  piece  from  half  an  inch  to  an  inch  thick,  which  is  attached 
to  the  root  of  the  neck  of  the  femur,  and  the  fore  and  outer  parts  of  the 
root  of  the  great  trochanter  ;  to  the  line  connecting  the  trochanter  with  the 
linea  aspera  ;  and  to  the  upper  half  of  the  linea  aspera,  and  the  contiguous 
external  intermuscular  septum.  Interiorly  the  fibres  of  the  muscle  end  in 
an  aponeurosis  which  blends  with  the  tendons  of  the  rectus  and  vastus 
internus  in  the  common  tendon,  and  sends  a  slip  to  the  outer  edge  of  the 
patella. 

The  muscle  is  pointed  at  the  upper  end ;  but  enlarged  below  where  it 
produces  tlie  prominence  on  the  outer  side  of  the  thigh.  Its  cutaneous 
surface  is  aponeurotic  above,  and  is  covered  by  the  rectus,  tensor  vaginae 
femoris,  and  gluteus  muscles.  The  deep  surface  rests  on  the  vastus  inter- 
nus, and  receives  branches  of  the  external  circumflex  artery  and  anterior 
crural  nerve. 

The  VASTUS  INTERNUS  (fig.  19G,  ^)  form  the  large  head  of  the  exten- 
sor.^ The  fleshy  mass  arises  from  the  anterior  and  two  lateral  surfaces  of 
the  shaft  of  the  femur,  except  where  the  vastus  externus  is  attached,  and 
its  limits  may  be  thus  indicated  :  Upwards  it  reaches  as  far  as  the  ante- 
rior introchanteric  line ;  downwards,  in  the  middle,  to  about  two  inches 
from  the  articular  end  of  the  femur ;  and  laterally  to  both  intermuscular 
septa.  At  the  lower  end  of  the  muscle  the  fibres  terminate  in  an  aponeu- 
rosis, which  blends  in  the  common  tendon  of  insertion,  and  is  attached  to 
the  patella  lower  than  the  vastus  externus. 

The  upper  part  of  the  muscular  mass  is  buried  beneath  the  sartorius 
and  rectus  muscles  ;  but  the  lower  part  is  superficial,  and  projects  more 
than  the  vastus  externus ;  some  of  the  lowest  fibres  are  almost  transverse, 
and  will  be  able  to  draw  inwards  the  patella.  The  adductor  muscles  are 
almost  inseparably  joined  with  this  vastus  along  the  attachment  to  the 
linea  aspera. 

Dissection.  The  tendon  of  the  extensor  will  appear  by  dividing  along 
the  middle  line  of  the  patella  and  knee-joint  a  thin  aponeurotic  layer, 
which  is  derived  from  the  lower  fleshy  fibres  of  the  muscle,  and  covers  the 
joint.  On  reflecting  inwards  and  outwards  that  fibrous  layer  the  tendon 
will  be  laid  bare  to  its  insertion  into  the  tibia. 

The  tendon  of  the  extensor  muscles  of  the  leg  is  common  to  the  rectus, 
the  vastus  externus,  and  vastus  internus.  It  is  placed  in  front  of  the 
knee-joint,  to  wiiich  it  serves  the  oflice  of  an  anterior  ligament.  Wide 
above  where  the  muscular  fibres  terminate,  it  narrows  as  it  descends  over 
the  joint,  and  is  inserted  inferiorly  into  the  prominence  of  the  tubercle  of 
the  tibia,  and  into  the  bone  below  it  for  an  inch  ;  close  to  its  attachment 
to  the  tibia  a  synovial  bursa  is  beneath  it.     In  it  the  patella  is  situate, 

'  Sometimes  the  part  of  the  mass,  inside  a  line  continued  upwards  from  the 
inner  border  of  the  patella,  is  named  aureus :  naturally  there  is  not  any  separa- 
tion at  that  spot. 


572  DISSECTION    OF    THE    THIGH. 

some  few  scattered  aponeurotic  fibres  passing  over  the  cutaneous  surface, 
but  none  being  continued  over  the  articular  surface  of  the  bone.  (See 
Ligament  of  the  Patella.) 

From  the  lower  part  of  the  muscle  a  superficial  aponeurotic  expansion 
is  derived :  this  prolongation,  which  is  strongest  on  the  inner  side,  is 
united  with  the  fascia  lata  and  the  other  tendinous  offisets  to  form  a  cap- 
sule in  front  of  the  joint,  and  is  fixed  below  to  the  heads  of  the  tibia  and 
fibula. 

Suhcrureus  muscle.  Beneath  the  strong  fibres  of  the  vastus,  near  the 
knee  joint,  is  a  thin  layer  of  pale  fibres,  which  is  but  a  part  of  the  inner 
vastus,  separated  from  the  rest  by  areolar  tissue.  Attached  to  the  femur 
in  the  lower  fourth,  and  often  by  an  outer  and  inner  slip,  it  ends  in  apo- 
neurotic fibres  on  the  synovial  sac  of  the  knee  joint. 

Action.  All  three  heads  of  the  triceps  extend  the  knee  joint,  when  the 
tibia  is  movable  ;  and  the  rectus  can  flex  the  hip  joint  over  which  it  passes. 
The  fleshy  bellies  are  strong  enough  to  break  the  patella  transversely  over 
the  end  of  the  femur,  or  to  rupture  sometimes  the  common  tendon. 

When  the  tibia  is  fixed  the  vasti  will  bring  forwards  the  femur,  and 
straighten  the  knee,  as  in  walking  or  standing  ;  and  the  rectus  will  prop 
the  pelvis  on  the  femur,  or  assist  in  moving  it  forwards  in  stooping. 

The  subcrureus  contracts  in  extension  of  the  knee,  and  elevates  the 
synovial  membrane  above  the  patella. 

Intermuscular  septa.  The  processes  of  the  fascia  lata,  which  limit 
laterally  the  extensor  muscle  of  the  knee,  are  thus  named,  and  are  fixed  to 
the  linea  aspera  and  the  lines  leading  to  the  condyles  of  the  femur. 

The  external  septum  is  the  strongest,  and  reaches  from  the  outer  condyle 
of  the  femur  to  the  insertion  of  the  gluteus  maximus.  It  is  situate  between 
the  vastus  internus  and  externus  on  the  one  side,  and  the  short  head  of  the 
biceps  on  the  other,  to  which  it  gives  origin  ;  and  it  is  perforated  near  the 
outer  condyle  by  the  upper  external  articular  vessels  and  nerve. 

The  inner  partition  is  very  thin  along  the  side  of  the  vastus  internus ; 
and  its  place  is  supplied  by  the  strong  tendon  of  the  adductor  magnus  be- 
tween the  inner  condyle  and  the  linea  aspera :  the  internal  articular  ves- 
sels are  transmitted  through  it  to  the  front  of  the  knee  joint. 

The    EXTERNAL    CIRCUMFLEX    ARTERY  (fig.   197,  *)    is  the  cllicf   VCSScl 

for  the  supply  of  the  muscles  of  the  front  of  the  thigh.  It  arises  from  the 
outer  side  of  the  profunda  (deep  femoral)  artery,  but  often  from  the  femoral 
trunk.  It  is  directed  outwards  through  the  divisions  of  the  anterior  crural 
nerve,  and  beneath  the  sartorius  and  rectus  muscles  to  the  outer  part  of 
the  thigh,  where  it  ends  in  branches.  Offsets  are  given  from  it  to  the 
rectus  and  sartorius  ;  and  its  terminal  muscular  branches  consist  of  ascend- 
ing, transverse,  and  descending  : — 

The  ascending  branch  is  directed  beneath  the  tensor  vaginae  femoris  to 
the  back  of  the  hip  bone,  where  it  anastomoses  with  the  gluteal  artery, 
and  supplies  the  contiguous  muscles. 

The  transverse^  the  smallest  in  size,  divides  into  two  which  perforate 
the  vastus  externus,  and  anastomose  w^ith  arteries  on  the  back  of  the  thigh. 

The  descending  branch  is  the  largest,  and  ends  in  pieces  which  are  dis- 
tributed to  the  vasti  muscles.  One  considerable  branch  enters  the  outer 
part  of  the  vastus  internus,  and  reaching  the  knee,  anastomoses  on  this 
joint  with  the  external  articular  arteries  ;  a  small  ofi*set  courses  over  tlie 
muscle  with  a  nerve  to  the  joint. 

The  ANTERIOR  CRURAL  NERVE  (fig.  197,  ^)  of  the  lumbar  plexus  (p. 


ANTERIOR  CRURAL  NERVE.  573 

497)  supplies  the  muscles,  and  most  of  the  teguments  of  the  front  of  the 
thigh,  and  the  integuments  of  the  inner  side  of  the  leg.  Soon  after  the 
trunk  of  the  nerve  leaves  the  abdomen  it  is  flattened,  and  is  divided  into 
superficial  and  deep  parts. 

A.  The  superficial  part  ends  in  three  tegumentary  branches  :  the  mid- 
dle and  internal  cutaneous  of  the  thigh,  and  the  great  saphenous. 

The  middle  cutaneous  nerve  (fig.  192,  ^)  perforates  the  fascia  lata,  some- 
times also  the  sartorius,  about  three  inches  below  Poupart's  ligament,  and 
extends  to  the  knee  (p.  556). 

The  internal  cutaneous  nerve  (fig.  192,  ^)  sends  two  or  more  small  twigs 
through  the  fascia  lata  to  the  integument  of  the  upper  third  of  the  thigh, 
and  then  divides  in  front  of  the  femoral  artery,  or  on  the  inner  side,  into 
the  two  following  branches,  anterior  and  inner.  Sometimes  these  branches 
arise  from  the  anterior  crural  trunk  at  separate  spots : — 

The  anterior  branch  (^)  is  directed  to  the  inner  side  of  the  knee.  As 
far  as  the  middle  of  the  thigh  it  lies  over  the  sartorious,  but  it  then  pierces 
the  fascia  lata,  and  ramifies  in  the  integuments  (p.  557.) 

The  inner  branch  remains  beneath  the  fascia  lata  as  far  as  the  knee  (p. 
557).  Whilst  underneath  the  fascia  the  nerve  lies  along  the  inner  border 
of  the  sartorius,  and  joins  in  a  plexus,  about  the  middle  of  the  thigh,  with 
offsets  of  the  obturator  and,  nearer  the  knee,  with  a  branch  of  the  internal 
saphenous  nerve. 

The,  internal  saphenous  nerve  (fig.  197)  is  the  largest  of  the  three  super- 
ficial branches.  In  the  thigh  the  nerve  takes  the  course  of  the  deep  blood- 
vessels, and  is  continued  along  their  outer  side,  beneath  the  aponeurosis 
covering  the  same,  as  far  as  the  opening  in  the  adductor  magnus  muscle. 
At  that  spot  the  nerve  passes  from  beneath  the  aponeurosis,  and  is  pro- 
longed under  the  sartorius  muscle  to  the  upper  part  of  the  leg,  where  it 
becomes  cutaneous  (fig.  192,  *).  It  supplies  two  offsets  whilst  it  is  con- 
tained in  the  thigh  beneath  the  fascia  : — 

A  communicating  branch  arises  about  the  middle  of  the  thigh,  and 
crosses  inwards  beneath  the  sartorius  to  join  in  the  plexus  of  the  internal 
cutaneous  and  obturator,  or  with  the  internal  cutaneous  nearer  the  knee  : 
this  branch  is  often  absent. 

The  patellar  branch  springs  from  the  nerve  near  the  knee  joint,  and 
perforating  the  sartorius  muscle  and  the  fascia  lata,  ends  in  the  integument 
over  the  knee  (fig.  192,  ^). 

B.  The  deep  or  muscular  part  of  the  anterior  crural  nerve  (fig.  197) 
gives  branches  to  all  the  muscles  of  the  front  of  the  thigh,  except  the 
tensor  vaginne  femoris ;  and  it  supplies  also  an  offset  to  one  of  the  adduc- 
tor muscles,  viz.,  the  pectineus. 

A  slender  nerve  (fig.  195,  '^)  crosses  beneath  the  femoral  artery,  and 
enters  the  anterior  surface  of  \.\\q  pectineus :  sometimes  there  are  two. 

Branches  to  the  sartorius  are  furnished  by  the  middle,  or  by  the  inter- 
nal cutaneous  nerve,  whilst  it  is  in  contact  with  that  muscle. 

A  nerve  enters  the  under  surface  of  the  rectus  at  the  upper  part,  and 
divides  into  branches  as  it  is  about  to  penetrate  the  fibres. 

The  nerve  to  the  vastus  externus  separates  into  two  or  more  branches 
as  it  enters  the  muscle.  From  one  of  these  an  articular  filament  is  con- 
tinued downwards  to  the  knee  joint,  which  it  enters  on  the  anterior  aspect. 

The  nerve  to  the  vastus  internus  (fig.  197)  is  nearly  as  large  in  size  as 
the  internal  saphenous,  in  common  with  which  it  often  arises.     To  the 


574  DISSECTION    OF    THE    THIGH. 

upper  part  of  the  vastus  it  furnishes  one  or  more  branches,  and  is  then 
continued  as  far  as  the  middle  of  the  thigh,  where  it  ends  in  otisets  to  tlie 
muscle  and  the  knee  joint. 

Its  articular  branch  is  prolonged  on  or  in  the  vastus,  and  on  the  tendon 
of  the  adductor  magnus  to  the  inner  side  of  the  knee  joint;  and  it  is  dis- 
tributed over  the  synovial  membrane  on  the  front  of  the  articulation. 
Tliis  small  nerve  accompanies  the  deep  branch  of  the  anastomotic  artery. 

A  branch  of  nerve  to  the  tensor  vagince  femoris  is  derived  from  the 
superior  gluteal ;  it  enters  the  under  surface  of  the  muscle,  and  extends 
nearly  to  the  lower  end. 

Directions.  After  the  examination  of  the  muscles  of  the  front  of  the 
thigh,  with  their  vessels  and  nerves,  the  student  is  to  learn  the  adductor 
muscles,  and  the  vessels  and  nerves  which  belong  to  them. 

PARTS  OF  THE  INNER  SIDE  OF  THE  THIGH. 

The  muscles  in  this  position  are  the  three  adductors, — longus,  brevis, 
and  magnus,  with  the  gracilis  and  pectineus ;  these  have  the  following 
position  with  respect  to  one  another.  Internal  to  all  and  the  longest,  is 
the  gracilis.  Superficial  to  the  others,  are  the  pectineus  and  the  adductor 
longus ;  and  beneath  the  last  two  are  the  short  adductor  and  the  adductor 
magnus. 

In  connection  with  the  muscles,  and  supplying  them  are  the  profunda 
artery  (of  the  femoral)  and  its  branches,  with  the  accompanying  vein. 

Tlie  obturator  nerve  lies  amongst  the  adductor  muscles,  and  furnishes 
branches  to  them. 

Dissection.  For  the  preparation  of  the  muscles,  the  investing  fascia 
and  tissue  are  to  be  taken  away ;  and  the  two  superficial  adductors  are  to 
separated  from  one  another. 

Let  the  student  be  careful  of  the  branches  of  the  obturator  nerve  in 
connection  with  the  muscles,  viz.,  those  entering  the  muscular  fibres,  and 
one  issuing  beneath  the  adductor  longus,  to  join  the  plexus  at  the  inner 
side  of  the  thigh. 

Lastly,  should  any  fat  and  veins  be  left  with  the  profunda  and  its 
branches  they  must  be  removed. 

The  GRACILIS  reaches  from  the  pelvis  to  the  tibia  (fig.  198,  °),  and  is 
fleshy  and  ribbon-like  above,  but  tendinous  below.  The  muscle  arises  by 
a  thin  aponeurosis,  two  or  three  inclies  in  depth,  from  the  pubic  boi'der  of 
tlie  hip  bone  close  to  the  margin,  viz.,  opposite  the  lower  half  of  the  sym- 
{)hysis,  and  the  upper  part  of  the  pubic  arch.  Inferiorly  it  is  inserted  by 
a  flat  tendon,  about  one-third  of  an  inch  wide,  into  the  inner  surface  of 
the  tibia,  beneath  and  close  to  the  sartorius. 

The  muscle  is  superficial  throughout.  At  the  upper  part  of  the  thigh 
it  is  flattened  against  the  adductors  brevis  and  magnus,  so  as  to  have  its 
borders  directed  forwards  and  backwards;  and  in  the  lower  third,  it  inter- 
venes between  the  sartorius  and  semi-membranous  muscles,  and  forms 
part  of  the  inner  boundary  of  the  popliteal  space.  At  its  insertion  the 
tendon  is  nearer  the  knee  than  that  of  the  semitendinosus,  though  at  the 
same  depth  from  the  surface,  and  both  lie  over  the  internal  lateral  liga- 
ment; and  from  the  tendon  an  expansion  is  continued  to  the  fascia  of  the 
leg,  like  the  sartorius.  A  bursa  separates  the  tendon  from  the  ligament, 
and  projects  above  it  to  the  sartorius. 

Action.    It  bends  the  knee  joint  if  the  tibia  is  not  fixed,  rotating  in 


ADDUCTOR    MUSCLES    OF    HIP  JOINT, 

Fiff.  198. 


575 


Deep  Dissectton  of 


Muscles  : 

A.  Adductor  longus,  cut. 

B.  Pectineus,  cut. 
c.  Gracilis. 

D.  Adductor  brevis. 

E.  Adductor  magnus. 

F.  Obturator  externus. 
o.  Semimembranosus. 
H.  Vastus  internus. 

K.  Rectus  femoris. 
li.  Tensor  fasciae  latse. 
N.  Piece  of  the  sartorius. 
o.  Iliacus. 
p.  Psoas. 
Vessels  : 
a.  Femoral  artery,  and  6, 

/>.    Trnnk  nf   tVio    nrnfnn<1« 


THE  Adductor  McsciiEs  with  their  Vessels  and  Nerves. 
(Illustrations  of  Dissections.) 

d.  Internal,  and  e,  external  circumflex. 
/.  First,  g,  second,  and  h,  third  perforating. 
i.  Muscular  and  anastomotic  of  the  profunda. 
Tc.  Anastomotic  of  the  femoral,  with   I,  the 
articular,  and  n,  the  cutaneous  piece. 
Nerves  : 
1.  Obturator,  joined  by  the  accessory  obtu- 
rator nerve,  with  2,  the  superficial,  and 
4,  the  deep  part. 
3.  Cutaneous  branch  of  the  obturator. 

5.  Articular  branch  to  the  kee  from  the  deep 

piece. 

6.  Anterior  crural  nerve. 

7.  Internal  saphenous,  and  10,  its  patellar 

branch, 
femoral  vein.  8.  Nerve  to  the  vastus  internus,  and  9  its 


576  DISSECTION    OF    THE    TIirGII. 

that  bone ;  and  then  brings  the  movable  femur  towards  the  middle  line 
with  the  other  adductors. 

Supposing  the  foot  resting  on  the  ground  the  gracilis  will  aid  in  propping 
the  pelvis  on  the  limb. 

The  PECTiNEus  (fig.  196,  ^)  is  the  highest  of  the  muscles  directed  from 
the  pelvis  to  the  inner  side  of  the  femur.  It  has  a  fleshy  origin  from  the 
ilio-pectineal  line  of  the  hip  bone,  and  from  the  triangular  smooth  surface 
in  front  of  that  line;  and  it  is  inserted  inferiorly  by  a  tendon,  about  two 
inches  in  width,  into  the  femur  behind  the  small  trochanter,  and  into  the 
upper  part  of  the  line  which  extends  from  that  process  to  the  linea  aspera. 
The  muscle  is  twisted,  so  that  the  surfaces  which  are  directed  forwards 
and  backwards  near  the  pelvis  are  turned  inwards  and  outwards  at  the 
femur.  One  surface  is  in  contact  with  the  fascia  lata;  and  the  opposite 
touches  the  obturator  muscle  and  nerve,  and  the  adductor  brevis.  The 
pectineus  lies  between  the  psoas  and  the  adductor  longus  ;  and  the  internal 
circumflex  vessels  pass  between  its  outer  border  and  the  psoas. 

Action.  It  adducts  the  limb  and  bends  the  hip-joint.  When  the  femur 
is  fixed  it  can  support  the  pelvis  in  standing;  or  it  can  draw  forwards  the 
pelvis  in  stooping. 

The  ADDUCTOR  LONGUS  lies  below  the  pectineus  (fig.  196,  ^),  and  is 
triangular  in  form,  with  the  apex  at  the  pelvis  and  the  base  at  the  femur. 
It  arises  by  a  narrow  tendon  from  the  front  of  the  pubes  below  the  angle 
of  union  of  the  crest  and  the  symphysis ;  and  it  is  inserted  into  the  inner 
edge  of  the  linea  aspera. 

This  muscle  is  situate  between  the  gracilis  and  the  pectineus,  and  forms 
part  of  Scarpa's  triangular  space.  Its  anterior  surface  is  covered  near  the 
femur  by  the  femoral  vessels  and  the  sartorius  :  the  posterior  rests  on  the 
other  two  adductors,  on  part  of  the  obturator  nerve,  and  on  the  deep 
femoral  artery.  Aponeurotic  bands  connect  the  tendon  of  insertion  with 
the  adductor  magnus  and  vastus  internus. 

Action.  With  the  femur  movable,  it  will  flex  the  hip-joint,  and  with 
the  aid  of  the  other  adductors  will  carry  inwards  the  limb,  so  as  to  cross 
the  thigh  bones.  In  walking  it  helps  the  other  adductors  to  project  the 
limb. 

With  the  femur  fixed,  the  muscle  props  and  tilts  forwards  the  pelvis. 
Dissection.  The  adductor  brevis  muscle,  with  the  obturator  nerve  and 
the  profunda  vessels,  will  be  arrived  at  by  reflecting  the  two  last  muscles. 
On  cutting  through  the  pectineus  near  the  pubes,  and  throwing  it  down, 
the  dissector  may  find  occasionally  the  small  accessory  nerve  of  the  obtu- 
rator which  turns  beneath  the  outer  border;  if  this  is  present,  its  branches 
to  the  hip  joint  and  the  obturator  nerve  are  to  be  traced  out.  The  adductor 
longus  is  then  to  be  divided  near  its  origin,  and  raised  with  care,  so  as  not 
to  destroy  the  branches  of  the  obturator  nerve  beneath  ;  its  tendon  is  to 
be  detached  from  that  of  the  adductor  magnus  beneath  it,  to  see  the 
branches  of  the  profunda  artery. 

Now  the  adductor  brevis  will  be  laid  bare.  A  part  of  the  obturator 
nerve  crosses  over  this  muscle  to  the  femoral  artery,  and  sends  an  ofl*set 
to  the  plexus  at  the  inner  side  of  the  thigh :  a  deeper  part  of  the  same 
nerve  lies  beneath  this  adductor.  The  muscle  should  be  separated  from 
the  subjacent  adductor  magnus,  where  the  lower  branch  of  the  nerve  with 
an  artery  issues.  In  this  last  ste^)  of  the  dissection  the  student  should 
trace  on  and  in  the  fibres  of  the  adductor  magnus  a  slender  articular 
branch  of  the  obturator  nerve  to  the  knee. 


OBTURATOR    NERVE    AND    BRANCHES.  577 

The  accessory  obturator  nerv^  (Sclimidt)  is  derived  from  the  trunk  of 
the  obturator,  near  the  lumbar  plexus  (p.  497),  and  passes  from  the  abdo- 
men over  the  brim  of  the  pelvis.  In  the  thigh  it  turns  beneath  the  pecti- 
neus,  and  joins  the  superficial  part  of  the  obturator  nerve  ;  it  supplies  an 
offset  to  the  hip-joint  with  the  articular  artery,  and  occasionally  one  to 
the  under  surface  of  the  pectineus. 

The  ADDUCTOR  BREVis  (fig.  198,  ^)  has  a  thin  fleshy  and  aponeurotic 
attachment,  about  two  inches  in  depth,  to  the  front  of  the  hip-bone  with 
the  gracilis.  The  muscle  arises  from  the  pubic  border  of  the  bone  close 
to  and  outside  the  gracilis,  reaching  upwards  as  high  as  the  adductor  lon- 
gus,  and  not  quite  so  low  as  tlie  gracilis.  It  is  inserted,  behind  the  pecti- 
neus, into  all  the  line  leading  from  the  lineaaspera  to  the  small  trochanter. 

In  front  of  the  muscle  are  the  pectineus  and  the  adductor  longus,  with 
the  superficial  piece  of  the  obturator  nerve,  and  the  profunda  artery  ;  but 
it  is  gradually  uncovered  by  the  adductor  longus  below,  and  the  contiguous 
borders  of  the  two  are  side  by  side  at  their  insertion  into  the  femur.  Be- 
hind the  muscle  is  the  adductor  magnus,  with  the  deep  piece  of  the  obtu- 
rator nerve  and  a  branch  of  the  inner  circumflex  artery.  In  contact  with 
the  upper  border  is  the  obturator  externus,  f,  and  the  internal  circumflex 
artery  passes  between  the  two. 

Action.  This  muscle  adducts  the  limb  with  slight  flexion  of  the  hip- 
joint,  like  the  pectineus.  And  if  it  acts  from  the  femur  it  will  balance 
and  move  forwards  the  pelvis. 

The  OBTURATOR  NERVE  (fig.  198,  M  is  a  branch  of  the  lumbar  plexus 
(p.  497),  and  supplies  the  adductor  muscles  of  the  thigh,  as  well  as  the 
hip  and  knee  joints.  The  nerve  issues  from  the  pelvis  through  the  aper- 
ture in  the  upper  part  of  the  thyroid  foramen  ;  and  it  divides  in  that  open- 
ing into  two  pieces,  which  are  named  superficial  and  deep  from  their  posi- 
tion w4th  respect  to  the  adductor  brevis  muscle. 

A.  The  superficial  part  (^)  of  the  nerve  is  directed  over  the  adductor 
brevis,  but  beneath  the  pectineus  and  the  adductor  longus,  to  the  femoral 
artery,  on  which  it  is  distributed  ;  at  the  lower  border  of  the  last  muscle  it 
furnishes  an  offset  or  two  to  join  in  a  plexus  with  the  internal  cutaneous 
and  saphenous  nerves  (p.  573),  and  supply  the  teguments.-* 

Near  the  pelvis  or  in  the  a[)erture  of  exit,  this  piece  of  the  nerve  sends 
outwards  an  articular  twig  to  the  hip  joint  with  the  joint-artery. 

Muscular  branches  are  furnished  to  the  adductor  longus,  the  adductor 
brevis,  and  the  gracilis. 

B.  The  deep  part  (*)  of  the  obturator  nerve  pierces  the  fibres  of  the  ex- 
ternal obturator  muscle,  and  continuing  beneath  the  adductor  brevis  is  con- 
sumed chiefly  in  the  adductor  magnus.  The  following  offsets  are  supplied 
by  it : — 

Muscular  branches  enter  the  obturator  externus  as  the  nerve  pierces  it ; 
others  are  furnished  to  the  large,  and  sometimes  to  the  short  adductor. 

A  slender  articular  branch  (fig.  198,  ^)  enters  the  fibres  of  the  adductor 
magnus,  and  passes  through  it  near  the  linea  aspera  to  reach  the  popliteal 

'  This  small  nerve  is  often  absent;  it  was  found  only  four  or  live  times  in  nine 
or  ten  bodies  which  were  examined  by  its  discoverer.  The  name  given  to  it  by 
Schmidt  refers  to  this  irregularity,  viz.,  nerv.  ad  obturatorem  accessorius  incon- 
stans.     Commentarius  de  Nervis  Lumbalibus. 

2  In  some  bodies  the  superficial  part  of  the  nerve  is  of  large  size,  and  has  a  dis- 
tribution similar  to  that  of  the  inner  branch  of  the  internal  cutaneous  nerve,  whose 
place  it  takes  :  in  such  instances  it  joins  freely  in  the  plexus. 
37 


.578  DISSECTION    OF    THE    THIGH. 

artery,  by  which  it  is  conducted  to  tlie  b«ick  of  the  knee-joint :  its  termi- 
nation is  seen  in  the  dissection  of  the  popliteal  space. 

Dissection.  To  prepare  the  profunda  artery  and  its  branches,  supposing 
the  veins  and  the  fat  removed,  it  will  be  requisite  to  follow  backwards  the 
internal  circumflex  artery  above  the  upper  border  of  the  adductor  brevis, 
and  to  trace  the  perforating  branches  to  the  apertures  in  the  adductors 
near  the  femur. 

The  PROFUNDA  (fig.  198,  c)  is  the  chief  muscular  artery  of  the  thigh, 
and  arises  from  the  femoral  about  one  inch  and  a  half  below  Poupart's 
ligament  (p.  565).  At  its  origin  the  vessel  is  placed  on  the  outer  side  of 
the  parent  trunk  ;  but  it  is  soon  directed  inwards  beneath  the  femoral  ves- 
sels to  the  inner  side  of  the  femur,  and  ends  at  the  lower  third  of  the  thigh 
in  a  small  branch  that  pierces  the  adductor  magnus. 

Where  the  vessel  lies  in  the  triangular  space  of  the  thigh  it  rests  on  the 
iliacus  muscle.  But  on  the  inner  side  of  the  femur  it  is  parallel  to  the 
femoral  artery,  though  deeper  in  position  ;  and  it  is  placed  first  over  the 
pectineus  and  adductor  brevis,  and  thence  to  its  termination  between  the 
adductors  longus  and  magnus. 

Its  branches  are  numerous  to  the  surrounding  muscles  on  the  front  and 
back  of  the  thigh,  and  maintain  free  anastomoses  with  other  vessels  of  the 
thigh  and  leg ;  through  these  communications  the  blood  finds  its  way  to 
the  lower  p«rt  of  the  limb  when  the  tube  of  the  chief  artery  is  obliterated 
either  above  or  below  the  origin  of  the  profunda.  The  named  branches 
are  these : — 

The  external  circumjiex  artery  (fig.  198,  e)  has  been  described  in  the 
dissection  of  the  muscles  of  the  front  of  the  thigh  (p.  572). 

The  internal  circumflex  branch  (fig.  198,  d)  arises  from  the  inner  and 
posterior  part  of  the  profunda,  and  turns  backwards  between  the  psoas  and 
pectineus,  but  above  the  adductor  brevis  and  magnus.  Opposite  the  small 
trochanter  it  ends  in  two  branches,  which  will  be  seen  in  the  dissection  of 
the  buttock  (p.  590).  It  supplies  the  undermentioned  offsets  to  the  inner 
side  of  the  thigh  : — 

An  articular  artery  may  enter  the  hip  joint  through  the  notch  in  the 
acetabulum. 

At  the  border  of  the  adductor  brevis  two  muscular  branches  arise  :  one 
ascends  to  the  obturator  and  the  superficial  adductor  muscles;  the  other, 
which  is  larger,  descends  with  the  deep  piece  of  the  obturator  nerve  be- 
neath the  adductor  brevis,  and  ends  in  this  and  the  largest  adductor. 

The  perforating  branches,  three  in  number,  pierce  the  tendons  of  some 
of  the  adductor  muscles  close  to  the  linea  aspera  of  the  femur :  they  sup- 
ply muscles  on  the  back  of  the  thigh,  and  wind  round  tlie  thigh-bone  to 
end  in  the  vasti. 

The^rs^  (/)  begins  opposite  the  lower  border  of  the  pectineus,  and  per- 
forates the  short  and  large  adductors. 

The  second  branch  {g)  arises  below  the  middle  of  the  adductor  brevis, 
and  passes  through  the  same  muscles  as  the  preceding:  from  \i  21,  nutritious 
vessel  is  supplied  to  the  shaft  of  the  femur. 

The  third  artery  (A)  springs  from  the  deep  femoral  trunk  below  the  ad- 
ductor brevis,  and  is  transmitted  through  the  adductor  magnus. 

The  terminal  branch  of  the  profunda  (fourth  perforating)  pierces  the 
adductor  magnus  near  the  aperture  for  the  femoral  artery. 

Muscular  or  anastomotic  branches  (/)  to  the  back  of  the  thigh  (three 
or  four  in  number)  pass  through  the  adductor  magnus  at  some  distance 


ADDUCTOR    MAGNUS    MUSCLE.  579 

from  tlie  linea  aspera,  and  end  in  a  chain  of  anastomoses   in  the  ham- 
strings. 

Tlie  PROFUNDA  VEIN  results  from  the  union  of  the  different  branches 
corresponding  with  the  offsets  of  its  companion  artery.  It  accompanies 
closely  the  artery  of  the  same  name,  to  which  it  is  superficial,  and  ends 
above  in  the  femoral  vein. 

Dissection,  To  bring  into  view  the  remaining  muscles,  viz.,  adductor 
magnus,  obturator  externus,  and  the  psoas  and  iliacus  insertion,  the  ad- 
ductor brevis  is  to  be  cut  through  near  the  pelvis,  and  to  be  thrown  down. 
Then  tlie  investing  layer  of  fascia  and  areolar  tissue  is  to  be  removed 
from  each  muscle. 

After  the  adductor  magnus  has  been  learnt,  it  will  be  needful  to  detach 
a  few  of  the  upper  fibres  to  examine  the  obturator  externus. 

The  ADDUCTOR  MAGNUS  (fig.  128,  ^)  is  narrow  at  the  pelvis,  and  wide 
at  the  femur.  It  is  triangular  in  form,  with  its  base  directed  upwards, 
one  side  being  attached  to  the  femur,  and  the  other  free  at  the  inner  part 
of  the  thigh. 

The  muscle  arises  along  the  pubic  arch  of  the  innominate  bone  outside 
the  other  adductors,  reaching  from  the  symphysis  to  the  lower  part  of  the 
ischial  tuberosity.  The  anterior  fibres  diverge  from  their  origin,  being 
horizontal  above  but  more  oblique  below,  and  are  inserted  (from  above 
down)  into  the  line  from  the  great  trochanter  to  the  linea  aspera ;  into 
the  linea  aspera  ;  and  into  the  line  leading  from  that  crest  of  bone  to  the 
inner  condyle  for  about  an  inch.  The  posterior  fibres  from  the  ischial 
tuberosity  are  vertical  in  direction,  and  end  at  the  lower  third  of  the 
thigh  in  a  tendon,  which  is  inserted  into  the  inner  condyle  of  the  femur, 
and  is  connected  by  a  fibrous  expansion  to  the  inner  condyloid  ridge. 

The  muscle  consists  of  two  parts,  which  differ  in  their  characters.  The 
anterior  one,  thin  and  fleshy,  forms  a  septum  between  the  other  adductors 
and  the  muscles  on  the  back  of  the  thigh  ;  but  the  posterior  piece,  partly 
fleshy  and  partly  tendinous,  constitutes  the  inner  thick  margin  of  the 
muscle.  On  the  anterior  surface  are  tiie  other  two  adductors  and  the  pec- 
tineus,  with  the  obturator  nerve  and  the  profunda  artery.  The  posterior 
surface  touches  tlie  ham-string  muscles  and  the  great  sciatic  nerve.  In 
contact  with  the  ujjper  border  are  the  obturator  externus  and  the  quadra- 
tus  femoris,  with  the  internal  circumflex  vessels  ;  and  along  the  inner  border 
lie  the  gracilis  and  the  sartorius.  At  its  attachment  to  the  femur  the 
muscle  is  closely  united  with  the  other  adductors,  particularly  the  adduc- 
tor longus,  and  is  there  pierced  by  apertures  for  the  passage  of  the  femoral 
and  perforating  arteries. 

Action.  This  muscle  is  used  as  an  adductor,  but  chiefly  as  a  projector 
forwards  of  the  femur  in  walking  :  in  the  last  oflfice  it  receives  help  from 
the  other  adductors  internally,  and  from  the  gluteus  medius  and  minimus 
externally. 

The  femur  being  fixed  it  will  act  powerfully  in  keeping  the  pelvis  erect 
on  the  head  of  the  thigh  bone. 

The  opening  in  the  adductor  for  the  transmission  of  tlie  femoral  vessels 
into  the  popliteal  space  is  tendinous  at  the  anterior,  but  flesliy  at  the  pos- 
terior aspect.  It  is  situate  at  the  point  of  junction  of  the  middle  with  the 
lower  third  of  the  thigh,  and  is  larger  than  is  necessary  for  tlie  passage  of 
the  vessels.  On  the  outside  it  is  bounded  by  the  vastus  internus  ;  and  on 
the  inside  by  the  tendon  of  the  adductor  magnus,  with  some  fibres  added 
from  the  tendon  of  the  long  adductor. 


680  DISSECTION    OF    THE    THIGH. 

The  PSOAS  and  iliacus  (fig.  198)  arise  separately  in  the  abdomen  (p. 
493),  but  are  united  in  the  thigh — tlie  conjoined  portion  of  the  muscles 
coming  beneath  Ponpart's  ligament.  The  psoas,  f,  is  inserted  by  tendon 
into  the  small  trochanter  of  the  femur :  and  the  fleshy  iliacus,  o,  joins 
partly  the  tendon  of  the  psoas,  tut  the  rest  of  its  fibres  are  fixed  into  a 
special  triangular  surface  of  bone  in  front  of  and  below  that  trochanter. 

Beneath  the  ligament  the  muscles  occupy  the  interval  between  the  ilio- 
pectineal  eminence  and  the  anterior  s^uperior  iliac  spinous  process — the 
iliacus  resting  on  a  small  bursa  ;  and  below  the  pelvis  the  mass  covers  the 
capsule  of  the  hip  joint,  and  a  larger  intervening  bursa.  On  the  front  of 
the  psoas  is  the  femoral  artery,  and  between  the  two  muscles  lies  the  an- 
terior crural  nerve.  The  pectineus  and  the  internal  circumflex  vessels  are 
contiguous  to  the  inner  border  ;  and  the  sartorius  and  vastus  internus 
touch  the  outer  edge. 

Action.  These  muscles  act  as  flexors  of  the  hip  joint,  and  their  use  is 
given  with  the  description  of  the  part  in  the  abdomen  (p.  493). 

The  OBTURATOR  EXTERNUS  (fig.  198,  ^)  is  triangular  in  form,  with  the 
base  at  the  pelvis  and  the  apex  at  the  femur.  The  fibres  of  the  muscle 
take  origin  from  the  outer  surface  of  the  obturator  membrane  for  the  an- 
terior half ;  and  from  the  anterior  half  or  more  of  the  bony  circumference 
of  the  thyroid  foramen — the  attachment  being  an  inch  wide  opposite  the 
symphysis  pubis.  The  fibres  are  directed  obliquely  backw^ards  to  be  in- 
serted by  a  tendon  into  the  pit  at  the  root  of  the  great  trochanter. 

This  muscle  is  concealed  by  the  pectineus,  and  adductor  brevis  and 
magnus.  It  covers  the  obturator  membrane  and  vessels,  and  is  pierced  by 
part  of  the  obturator  nerve.  As  it  winds  back  it  is  in  contact  with  the 
inner  and  lower  parts  of  the  hip  joint.  The  insertion  of  the  muscle  will 
be  seen  in  the  dissection  of  the  Buttock. 

Action,  The  muscle  is  an  external  rotator  of  the  thigh  :  and  its  action 
will  be  given  in  full  with  the  other  muscles  of  the  same  grou})  in  the 
Buttock. 

Dissection  By  detaching  a  small  part  of  the  obturator  muscle  from 
the  pelvis,  the  branches  of  the  artery  and  nerve  of  the  same  name  will 
be  seen  amongst  its  fibres.  A  better  view  will  be  obtained  if  the  dissec- 
tion of  the  vessel  and  nerve  is  deferred  till  after  the  limb  is  detached. 

The  obturator  artery  is  a  branch  of  the  internal  iliac  (p.  515),  and 
enters  the  thigh  through  the  upper  part  of  the  thyroid  foramen.  In  the 
aperture  the  artery  divides  into  two  pieces,  which  form  a  circle  beneath 
the  muscle  around  the  obturator  membrane  : — 

The  upper  branch  extends  along  the  inner  half  of  the  membrane ;  and 
the  lower,  perforating  the  membrane  below  the  level  of  the  other,  turns 
downwards  and  forms  a  circle  by  uniting  with  the  upper  branch.  An 
articular  twig  to  the  hip-joint  is  supplied  fi-om  the  lower  branch. 

Muscular  oflTsets  of  tlie  artery  are  furnished  to  the  obturator  muscles, 
and  some  small  twigs  reach  the  upper  part  of  the  adductors. 

Branches  of  nerve  to  the  external  obturator  muscle  come  from  the  deep 
portion  of  the  obturator  trunk,  and  [)erforate  the  membrane  with  the  lower 
branch  of  the  artery. 


CUTANEOUS    NERVES    OVER    GLUTEUS.  681 

Section  II. 

THE  BUTTOCK.  OR  THE  GLUTEAL  REGION. 

Directions.  Both  this  Section  and  the  following  one  are  to  be  completed 
bj  the  student  in  the  time  appointed  for  the  body  to  lie  in  the  prone 
position. 

Position.  During  the  dissection  of  the  back  of  the  thigh  the  body  is 
placed  with  the  face  down  ;  and  the  pelvis  is  to  be  raised  by  blocks,  until 
the  lower  limbs  hang  almost  vertically  over  the  end  of  the  dissecting  table. 
When  the  body  is  turned,  the  points  of  bone  marking  posteriorly  the 
limit  between  the  thigh  and  the  abdomen  can  be  better  ascertained. 

Dissection.  The  integument  is  to  be  raised  from  the  buttock  by  means 
of  the  following  incisions :  One  is  to  be  made  along  the  iliac  crest  of  the 
hip  bone,  and  is  to  be  continued  in  the  middle  line  of  the  sacrum  to  the 
tip  of  the  coccyx.  Another  is  to  be  begun  where  the  first  terminates,  and 
is  to  be  carried  outwards  across  the  thigh  till  it  is  about  six  inches  below 
the  great  trochanter.  The  flap  of  skin  thus  marked  out  is  to  be  thrown 
down. 

Many  of  the  cutaneous  nerves  of  this  region  will  be  found  in  the  fat 
along  the  line  of  the  iliac  crest.  Tiius  in  front,  but  rather  below  the  crest, 
are  branches  of  the  external  cutaneous,  if  tliese  have  not  been  cut  in  the 
dissection  of  the  thigh.  Crossing  the  crest  towards  the  fore  part  is  a  large 
offset  of  the  last  dorsal  nerve  ;  and  usually  farther  back,  but  close  to  the 
bone,  a  smaller  branch  from  the  ilio-hypogastric  nerve.  In  a  line  with 
the  outer  border  of  the  erector  spinas,  are  two  or  three  branches  of  the 
lumbar  nerves. 

By  the  side  of  the  sarcum  and  coccyx  two  or  three  offsets  of  the  sacral 
nerves  are  to  be  looked  for  beneath  the  fat. 

The  remaining  cutaneous  nerves  are  derived  from  the  small  sciatic,  and 
must  be  sought  beneath  the  fat  along  the  line  of  the  lower  incision,  where 
they  come  from  underneath  the  gluteus  maximus.  A  few  turn  ui)wards 
over  that  muscle ;  the  rest  are  directed  down  the  thigh,  and  one  (inferior 
pudendal)  bends  below  the  ischial  tuberosity  to  reach  the  perinjcal  space. 

Cutaneous  arteries  accompany  all  the  nerves,  and  will  serve  as  guides 
to  their  situation. 

Cutaneous  Nerves  (fig.  199).  The  nerves  distributed  in  the  integu- 
ments of  the  buttock  are  small  but  numerous,  and  are  derived  from  the 
spinal  nerves  (posterior  primary  pieces) ;  from  branches  of  the  lumbar  and 
sacral  plexuses ;  and  from  the  last  dorsal  nerve. 

Branches  of  the  lumbar  Qierves  (^).  The  offsets  of  the  posterior  primary 
pieces  of  the  lumbar  nerves  (p.  367)  are  two  or  three  in  number,  and  cross 
the  crest  of  the  hip  bone  near  the  anterior  edge  of  the  erector  spin*  :  they 
ramify  in  the  integuments  of  the  middle  of  the  buttock,  and  some  branches 
may  be  traced  nearly  to  the  trochanter  major. 

The  branches  of  the  sacral  nerves  Q)  perforate  the  gluteus  maximus 
near  the  sacrum  and  coccyx,  and  are  then  directed  outwards  for  a  siiort 
distance  in  the  integuments  over  the  muscle.  These  offsets  are  usually 
two  in  number :  the  largest  is  opposite  the  lower  end  of  the  sacrum,  and 
the  other  by  the  side  of  the  coccyx. 

The  last  dorsal  nerve  (^)  supplies  the  buttock  by  means  of  its  lateral 


582 


DISSECTION    OF    THE    BUTTOCK, 


cutaneous  branch  (p.  416).  This  offset  peiforates  the  muscles  of  the  abdo- 
men, and  crosses  tlie  anterior  part  of  the  iliac  crest  to  be  distributed  over 
the  fore  part  of  the  gluteal  region,  as  low  as  the  great  troclianter. 

Nerves  of  the  lumbar  plexus.  Parts  of  two  nerves  of  tlie  lumbar  ])lexus 
(p.  496),  viz.  ilio-hypogastric  and  external  cutaneous,  are  si)ent  in  the 
integuments  of  this  region. 

The  iliac  branch  of  the  ilio-hypogastric  (')  crosses  the  iliac  crest  in 
front  of  the  branches  from  the  lumbar  nerves,  lying  generally  in  a  groove 
in  the  bone,  and  extends  only  a  short  distance  below  the  crest. 

Fig.  199. 


A.  Glutens  inaximus  muscle,  with 
the  gluteus  medius  projecting 
above  it. 

a.  Continuation  of  small  sciatic  ar- 
tery along  the  back  of  the  thigh. 
Nerves  and  vessels,  most  of  them 
cut  from  the  teguments  : — 

1.  Small  sciatic  nerve — the  trunk. 

2.  Its  cutaneous  thigh  branches  ;  & 

3.  Inferior  pudendal. 

4.  Small  sciatic  offsets  in  the  peri- 

njeum. 

5.  Cutaneous  of  the  sacral. 

6.  Offsets  of  the  lumbar  nerves. 

7.  Ilio-hypogastric 

8.  Branch  of  the  last  dorsal. 


SuPKRFiciAii  View  op  the  Bpttock  of  the  Lkft  Side  (Illustrations  of  Dissections). 


Offsets  of  the  external  cutaneous  nerve  of  the  thigh  bend  backwards  to 
tiie  integuments  above  the  great  trochanter,  and  cross  the  ramifications  of 
the  last  dorsal  nerve. 

Small  sciatic  (*).  This  nerve  of  the  sacral  plexus  (p.  518)  sends  super- 
ficial branches  to  the  buttock.  Its  cutaneous  offsets  appear  along  the 
lower  border  of  the  gluteus  maximus,  accompanied  by  superficial  branches 


THE  GLUTEUS  MAXIMUS.  583 

of  the  sciatic  artery  :  two  or  three  ascend  round  the  edge  of  the  muscle,  and 
are  lost  in  the  integuments  of  the  lower  part  of  the  buttock ;  tlie  remain- 
ing branches  (^)  descend  to  the  thigh,  and  will  be  afterwards  noticed  on  it. 

Dissection.  The  thin  and  unimportant  deep  fascia  of  this  region  may 
be  disregarded,  in  order  that  the  great  gluteal  muscle,  which  is  the  most 
difficult  in  the  body  to  clean,  may  be  well  displayed.  Supposing  the  stu- 
dent desirous  to  lay  bare  the  muscle,  let  him  turn  aside  the  cutaneous 
nerves,  and  adduct  and  rotate  inwards  the  limb  to  make  tense  the  muscu- 
lar fibres.  Having  cut  through  the  fat  and  fascia  from  the  origin  to  the 
insertion,  let  him  carry  the  scalpel  along  one  bundle  of  fibres  at  a  time  in 
the  direction  of  a  line  from  the  sacrum  to  the  femur,  imtil  all  the  coarse 
fasciculi  are  cleaned.  If  the  student  has  a  right  limb,  the  dissection  may 
be  begun  at  the  upper  border ;  but  if  a  left  limb,  at  the  lower  margin  of 
the  muscle. 

The  fasia  of  the  buttock  is  a  prolongation  of  that  enveloping  the  thigh, 
and  is  fixed  to  the  crest  of  the  hip  bone,  and  to  the  sacrum  and  coccyx. 
It  is  much  thicker  in  front  of,  than  on  the  gluteus  maximus,  and  gives 
attachment  anteriorly  to  the  gluteus  medius  which  it  covers.  At  the  edge 
of  the  gluteus  maximus,  the  fascia  splits  to  incase  the  muscle. 

The  GLUTEUS  MAXIMUS  (fig.  199,  ^^  is  the  most  superficial  muscle  of 
the  buttock,  and  reaches  from  the  pelvis  to  the  upper  part  of  the  femur. 
Its  origin  from  the  pelvis  is  partly  connected  with  bone  and  partly  with 
aponeurosis:  Thus,  the  muscle  is  attached,  from  above  down,  to  the  pos- 
terior third  of  the  iliac  crest,  and  to  a  special  impression  on  the  hip  bone 
below  it;  next,  to  the  aponeurosis  covering  the  multifidus  spinse  muscle; 
then  to  the  back  of  the  lowest  piece  of  the  sacrum,  and  the  back  of  the 
coccyx ;  and  lastly  to  the  great  sacro-sciatic  ligament.  From  this  exten- 
sive origin  the  fibres  are  directed  outwards  to  their  insertion:  About  two- 
thirds  of  the  upper  fibres,  and  a  few  of  the  lowest,  end  in  the  fascia  lata 
of  the  outer  part  of  the  thigh :  and  the  remainder  are  fixed  for  three 
inches  into  the  lower  part  of  the  line  leading  from  the  linea  aspera  to  the 
great  trochanter  of  the  femur. 

The  gluteus  forms  the  prominence  of  the  buttock,  and  resembles  the 
deltoid  muscle  of  the  arm  in  the  situation,  and  in  the  coarseness  of  its  tex- 
ture. Its  cutaneous  surface  is  covered  by  the  common  teguments  and  in- 
vesting fascia  of  the  limb,  and  by  the  superficial  nerves  and  vessels.  The 
parts  in  contact  with  the  under  surface  will  be  seen  when  the  muscle  is 
cut  through.  The  upper  border  overlays  the  gluteus  medius.  And  the 
lower  edge,  which  is  longer  and  thicker  than  the  upper,  forms  the  fold  of 
the  nates,  and  bounds  posteriorly  the  perinjeal  space ;  beneath  the  lower 
border  the  ham-string  muscles  and  the  sciatic  vessels  and  nerves  issue. 

Action.  With  the  femur  hanging  the  muscle  extends  tlie  hip-joint  by 
putting  back  that  bone,  and  abducts  and  rotates  out  the  limb. 

When  the  limb  is  fixed,  and  the  body  is  raised  from  a  sitting  into  a 
standing  posture,  the  gluteus  acts  as  an  extensor  of  the  articulation  by 
moving  back  the  pelvis. 

In  standing  both  muscles  assist  in  keeping  the  pelvis  balanced  on  its 
props ;  and  in  rising  from  stooping  they  are  the  active  agents  in  bringing 
upright  the  pelvis.  When  the  body  is  supported  on  one  leg  the  muscle 
can  draw  tlie  sacrum  towards  the  femur,  so  as  to  turn  the  face  to  the  oppo- 
site side. 

Dissection  (fig.  200).  The  gluteus  maximus  is  to  be  cut  across  near 
the  pelvis,  and  without  injury  to  the  subjacent  sacro-sciatic  ligament  to 


684  DISSECTION    OF    THE    BUTTOCK.. 

whicli  the  lower  fibres  are  closely  joined.  The  depth  of  the  muscle  will 
be  ascertained  by  the  fascia  and  some  vessels  beneath  it.  When  this  in- 
termuscular layer  is  arrived  at,  the  outer  part  of  the  gluteus  is  to  be 
thrown  towards  its  insertion,  and  the  sciatic  artery  and  nerves  are  to  be 
detached  from  the  under  surface,  though  the  branches  of  the  gluteal  ves- 
sels entering  the  muscle  must  be  cut. 

The  loose  fat  is  to  be  taken  away  from  the  hollow  between  the  pelvis 
and  the  trochanter,  without  injuring  the  vessels  and  nerves ;  and  the 
several  muscles  are  to  be  cleaned,  the  fibres  of  each  being  made  tense  at 
the  time  of  its  dissection  by  rotating  the  lemur.  Tlie  vessels,  nerves,  and 
muscles,  which  ar-e  to  be  defined,  may  be  ascertained  by  referring  to  the 
enumeration  below  of  the  parts  beneath  the  gluteus.  In  removing  the 
areolar  tissue  from  the  ischial  tuberosity  and  the  great  trochanter,  the 
bursa  on  each  prominence  of  bone  will  be  observed. 

Lastly  the  origin  of  the  muscle  is  to  be  removed  ;  and  the  sacral  nerves 
are  to  be  dissected  out  of  the  gluteus,  and  to  be  followed  to  the  surface  of 
the  great  sacro-sciatic  ligament,  where  they  will  be  afterwards  seen. 

Parts  beneath  the  gluteus  (fig.  200).  At  its  origin  the  gluteus  maximus 
rests  on  the  pelvis,  and  conceals  part  of  the  hip  bone,  sacrum,  and  coccyx, 
also  the  ischial  tuberosity  with  the  origin  of  the  hamstring  muscles,  l, 
and  the  great  sacro-sciatic  ligament,  k.  At  its  insertion  it  covers  the 
upper  end  of  the  femur,  with  the  great  trochanter,  and  the  origin  of  the 
vastus  externus,  i.  Between  the  muscle  and  each  prominence  of  bone, 
viz.  the  tuberosity  and  the  trochanter,  is  a  large,  loose  synovial  membrane; 
and  between  it  and  the  vastus  externus  is  another  synovial  sac. 

In  the  hollow  between  the  j^elvis  and  the  femur  the  muscle  conceals, 
from  above  downwards,  the  undermentioned  parts  : — First,  a  portion  of 
the  gluteus  medius,.  a  ;  and  below  it  the  pyriformis,  b,  with  the  superficial 
branch  (a)  of  the  gluteal  vessels  between  the  two.  Coming  from  beneath 
the  pyriformis  are  the  sciatic  vessels  (&)»  and  the  large  and  small  sciatic 
nerves  (*,  ^),  which  descend  to  the  thigh  between  the  great  trochanter  and 
the  ischial  tuberosity ;  and  internal  to  the  sciatic  iU'e  the  pudic  vessels  and 
nerve  (c?,  ^)^  and  the  nerve  to  the  obturator  internus  muscle  (*)  with  its 
vessels,  which  are  directed  inwards  through  the  small  sacro-sciatic  notch. 
Still  lower  down  is  the  tendon  of  the  obturator  internus  muscle,  d,  with  a 
fleshy  fasciculus — the  gemellus  (c  and  k)— above  and  below  it.  Next 
comes  the  thin  quadratus  femoris  muscle,  g,  with  the  upper  part  of  tlie 
adductor  magnus,  ii  :  at  the  upper  border  of  the  quadratus  is  the  tendon 
of  the  obturator  externus,  f  ;  and  at  the  lower  bonier,  between  it  and  the 
adductor^  issues  one  of  the  terminal  branches  of  the  internal  circumflex 
artery  (c)  with  its  veins. 

Dissection.  Tracing  back  the  oflTsets  of  the  sacral  nerves  which  perfo- 
rate the  gluteus,  and  removing  a  fibrous  stratum  which  covers  them,  the 
looped  arrangement  of  the  first  three  nerves  on  the  great  sacro-sciatic 
ligament  will  appear.  Finally  the  nerves  may  be  followed  inwards  beneath 
the  multifidus  spinae  to  the  posterior  sacral  foramina. 

Sacral  nerves.  The  external  pieces  of  tlie  posterior  primary  branches 
of  the  first  three  sacrjU  nerves,  after  passing  outwards  beneath  the  multi- 
fidus spina?  (p.  372),  are  joined  by  loops  on  the  surface  of  the  great  sacro- 
sciatic  ligament  (fig.  120). 

Two  or  three  cutaneous  offsets  are  derived  from  this  intercommunica- 
tion, and  pierce  the  fibres  of  the  gluteus  maximus  to  be  distributed  on  the 
surface  (p.  o81). 


GLUTEUS    MEDIUS 


585 


The  GLUTEUS  MEDIUS  (fig.  200,  ^)  is  triangular  in  form,  with  its  base 
at  the  innominate  bone,  and  apex  at  the  femur.  It  arises  from  the  outer 
surface  of  the  hip  bone  between  the  crest  and  the  superior  curved  line, 

Fig.  200. 


Second  View  of  the  Dissection  of  the  Buttock  (Illustrations  of  Dissectious) 


Muscles  : 

A.  Gluteus  medius. 

B.  Pyrifoimis. 

0.  Upper  gemellus. 

D,  Obturator  iuteruus. 
K.  Gemellus  inferior. 
F.  Obturator  externus. 
Q.  Quadratus  femoris. 
H.  Adductor  magnua. 

1.  Vastus  externus. 

J.  Gluteus  maximua,  cut. 
K.  Great  sacro   sciatic  ligament. 
L.  Hamstring  muscles. 
Arteries  : 

a.  Gluteal. 


b.  Sciatic. 

c.  Internal  circumflex. 

d.  Pudic. 

e.  Anastomotic  branch  of  sciatic. 
/.  First  perforating. 

Nerves  : 

1.  Last  dorsal. 

2.  Upper  gluteal. 

3.  Small  sciatic. 

4.  Nerve  to  the  obturator  internus. 

5.  Pudic. 

6.  Great  sciatic. 

7.  Inferior  pudendal. 

8.  Cutaneous  of  the  thigh  of  small  sciatic. 

9.  Muscular  branch  of  great  sciatic. 


except  behind  where  there  is  a  surface  of  bone  free  from  muscular  fibres  ; 
and  many  superficial  fibres  come  from  the  strong  fascia  covering  the  ante- 
rior part  of  the  muscle.     The  fibres  converge  to  a  tendon,  which  is  inserted 


586  DISSECTION    OF    THE    BUTTOCK. 

into  an  impression  across  the  outer  surface  of  the  great  trochanter,  extend- 
ing from  the  tip  behind  to  the  root  in  front. 

Tlie  superficial  surface  is  concealed  in  part  by  the  gluteus  maximus ; 
and  the  deep  is  in  contact  with  the  gluteus  minimus,  and  the  gluteal  ves- 
sels and  nerve.  The  anterior  border  lies  over  tlie  gluteus  minimus,  and 
is  in  contact  with  the  tensor  of  the  fascia  lata.  The  posterior  is  contigu- 
ous to  the  pyriformis,  only  the  gluteal  vessels  intervening.  A  small  bursa 
is  interposed  between  the  tendon  of  insertion  and  the  trochanter. 

Action.     The  wliole  muscle  abducts  the  hanging  femur;  and  the  ante- 

Of?  ' 

rior  fibres  rotate  in  the  limb.  In  walking  it  is  combined  with  the  adduc- 
tors in  moving  forwards  the  femur. 

Both  limbs  resting  on  the  ground  the  muscles  assist  in  fixing  the  pelvis. 
In  standing  on  one  leg  this  gluteus  will  aid  in  balancing  the  pelvis  on  the 
top  of  the  femur. 

Dissectio7i.  When  the  gluteus  medius  is  detached  from  the  pelvis,  and 
partly  separated  from  the  gluteus  minimus  beneath,  the  gluteal  vessels  and 
nerve  will  come  into  view.  The  two  chief  branches  of  the  artery — one 
being  near  the  iliac  crest,  and  the  other  lower  down — are  to  be  traced 
through  the  fleshy  fibres  as  the  reflection  of  the  gluteus  is  proceeded  with ; 
and  the  main  part  of  the  nerve  is  to  be  followed  at  the  same  time  to  the 
tensor  vagina  femoris  muscle.  The  branches  of  the  artery  and  nerve  to 
the  gluteus  medius  will  be  cut  in  removing  that  muscle. 

The  gluteal  artery  (fig.  200,  a)  is  the  largest  branch  of  the  internal 
iliac  (p.  513),  and  issues  from  the  pelvis  above  the  pyriform  muscle.  On 
the  dorsum  of  the  hip  bone  it  ends  in  offsets  which  supply  the  gluteal 
muscles  and  the  bone.     Its  named  branches  are  superficial  and  deep: — 

The  superjlcial  branch  supplies  offsets  to  the  integuments,  and  some 
deeper  twigs  over  the  sacrum ;  it  ends  in  the  gluteus  maximus,  which  it 
penetrates  on  the  under  surface. 

The  deep  branch  (fig.  201,  a)  is  the  continuation  of  the  artery,  and 
subdivides  into  two  pieces  which  run  between  the  two  smaller  glutei.  One 
{b)  (superior)  courses  along  the  origin  of  the  gluteus  minimus  (supplying 
mostly  the  medius)  to  the  front  of  the  iliac  crest,  where  it  anastomoses 
with  the  ascending  branch  of  the  external  circumflex  artery.  The  other 
portion  (c)  (inferior)  is  directed  forwards  over  the  middle  of  the  smallest 
gluteal  muscle,  with  the  nerve,  towards  the  anterior  lower  iliac  spine 
where  it  enters  the  tensor  of  the  fascia  lata,  and  communicates  with  the 
external  circumflex  branch  (p.  572) :  many  offsets  are  furnished  to  the 
gluteus  minimus,  and  some  pierce  that  muscle  to  supply  the  hip  joint. 

Vein.  The  companion  vein  with  the  artery  enters  the  pelvis,  and  ends 
in  the  internal  iliac  vein. 

The  superior  gluteal  nerve  (fig.  201,  ^)  is  a  branch  of  the  lumbo-sacral 
cord  (p.  495-C).  It  accompanies  the  gluteal  artery,  and  divides  into  two 
branches  for  the  supply  of  the  two  smallest  gluteal  muscles:  its  lowest 
branch  terminates  anteriorly  in  the  tensor  vagiuic  femoris,  b. 

The  GLUTEUS  MINIMUS  (fig.  201,  c)  is  triangular  in  shape,  and  arises 
from  the  dorsum  of  the  hip  bone  between  the  superior  and  inferior  curved 
lines,  extending  backwards  as  far  as  the  middle  of  the  hip  joint.  Its  ten- 
don is  inserted  into  an  impression  along  the  fore  part  of  the  great  trochan- 
ter, where  it  is  united  inferiorly  with  the  gluteus  medius:  some  fibres  are 
attached  to  the  capsule  of  the  hip  joint. 

One  surface  is  in  contact  with  the  gluteus  medius,  and  the  gluteal  ves- 
sels and  nerve;  the  other  with  the  hip  bone,  the  hip  joint,  and  the  outer 


GLUTEUS    MINIMUS    AND    PYRIFORMIS.  687 

head  of  the  rectus  femoris  muscle.  The  anterior  border  lies  by  the  side  of 
the  other  gluteus;  and  the  posterior  is  covered  by  the  pyriformis  muscle. 
A  bursa  is  placed  between  the  tendon  and  the  bone. 

Action.  It  acts  as  an  abductor  and  rotator  out  of  the  femur  when  this 
bone  is  hanging;  and  in  walking,  it  and  the  medius  will  be  employed  in 
bringing  forwards  the  limb. 

Both  legs  being  fixed,  the  muscles  are  used  in  balancing  the  pelvis.  In 
standing  on  one  leg  the  gluteus  pitches  the  pelvis  over  the  supporting 
limb  with  the  preceding  muscle. 

Dissection.  Cut  through  the  smallest  gluteus  muscle  near  the  innomi- 
nate bone,  and  define  the  tendinous  part  of  the  rectus  femoris  underneath 
it,  close  above  the  hip  joint.  Whilst  detaching  the  gluteus  from  the  parts 
underneath,  the  student  cannot  fail  to  notice  the  connection  between  its 
tendon  and  the  capsule  of  tlie  joint. 

The  deep  vessels  to  the  articulation  may  be  observed  and  followed  as 
the  muscle  is  removed. 

Tlife  outer  head  of  the  rectus  femoris  is  a  tendon  as  wide  as  the  little 
finger,  and  about  two  inches  long,  which  is  fixed  into  the  groove  above 
the  margin  of  the  acetabulum.  In  front  it  joins  the  other  tendinous  piece 
of  the  rectus,  which  is  attached  to  the  anterior  inferior  iliac  spine ;  and 
balow,  it  is  connected  with  the  capsule  of  the  hip  joint. 

The  PYRIFORMIS  (fig.  200,  ^)  arises  in  the  pelvis  from  the  front  of  the 
sacrum  (p.  542),  and  leaves  that  cavity  through  the  great  sacro-sciatic 
notch.  Outside  the  pelvis  it  ends  in  a  rounded  tendon,  which  is  inserted 
into  the  upper  edge  of  the  great  trochanter,  between  the  two  smaller 
glutei. 

As  the  muscle  passes  through  the  sacro-sciatic  notch  it  divides  that 
space  into  two  parts — the  upper  giving  passage  to  the  gluteal  vessels  and 
nerve,  and  the  lower  transmitting  the  sciatic  and  pudic  vessels  and  the 
sacral  plexus.  Its  upper  border  is  contiguous  to  the  gluteus  medius,  and 
its  lower,  to  the  gemellus  superior.  Like  the  other  rotator  muscles  in  this 
situation,  it  is  covered  by  the  gluteus  maximus,  and  by  the  gluteus  medius 
at  the  insertion ;  it  rests  on  the  gluteus  minimus,  which  separates  it  from 
the  hip  joint.  Its  tendon  is  united  by  fibrous  tissue  to  that  of  the  obturator 
and  gemelli. 

Action.  The  use  of  this  and  the  other  external  rotators  is  altered  by 
the  position  of  the  femur.  If  that  bone  hangs  the  pyriformis  rotates  it 
out ;  but  if  the  hip  joint  is  bent  the  muscle  abducts  the  limb  from  its 
fellow. 

Both  limbs  being  fixed  the  muscles  balance  the  pelvis,  and  help  to  make 
the  trunk  erect  after  stooping  to  the  ground.  In  standing  on  one  leg, 
besides  assisting  to  support  the  trunk,  the  pyriformis  turns  the  face  to  the 
opposite  side. 

Dissection  (fig.  201).  The  pyriformis  may  be  cut  across  and  raised 
towards  the  sacrum,  to  allow  tlie  dissector  to  follow  upwards  the  sciatic 
and  pudic  vessels,  and  to  trace  the  accompanying  nerves  to  tlieir  origin  in 
the  lower  part  of  the  sacral  plexus. 

Some  small  nerves  to  the  obturator  internus  (*),  the  gemellus  superior 
('),  and  the  hip  joint,  are  to  be  sought  in  the  fat  at  the  lower  part  of  the 
plexus.  A  branch  to  the  inferior  gemellus  and  the  quadratus  (*)  will  be 
found  by  raising  tlie  trunk  of  the  great  sciatic  nerve  ;  but  it  will  be  fol- 
lowed to  its  termination  after  the  muscles  it  supplies  have  been  seen. 


688  DISSECTION    OF    THE    BUTTOCK. 

Sciatic  and  Pudic  Vessels.  The  vessels  on  the  back  of  the  pelvis, 
below  the  piriformis  muscle,  are  branches  of  the  internal  iliac  (p.  513). 

The  sciatic  artery  (fig.  200,  b)  supplies  the  buttock  below  the  gluteal. 
After  escaping  from  the  pelvis  below  the  pyriformis,  it  descends  with  the 
small  sciatic  nerve  over  the  gemelli  and  obturator  muscles,  as  far  as  the 
lower  border  of  the  gluteus  maximus  :  here  the  artery  gives  off  many 
branches  with  the  superficial  offsets  of  its  companion  nerve  ;  and  mucli 
reduced  in  size,  it  is  continued  with  that  nerve  along  the  back  of  the 
thigh.     In  this  course  it  furnishes  the  following  named  branches  : — 

a.  The  coccygeal  branchy  arising  close  to  the  pelvis,  perforates  the 
great  sacro-sciatic  ligament  and  the  gluteus  maximus,  and  ramifies  in 
this  muscle,  and  on  the  back  of  the  sacrum  and  coccyx. 

b.  The  branch  to  the  great  sciatic  nerve  (comes  nervi  ischiadici)  is  very 
slender,  and  entering  the  nerve  near  the  pelvis,  ramifies  in  it  along  the 
thigh. 

c.  Muscular  branches  enter  the  gluteus  maximus,  the  upper  gemellus, 
and  obturator  internus  ;  and  by  means  of  a  branch  to  the  quadratus,  which 
passes  with  the  nerve  of  the  same  name  beneath  the  gemelli  and  obturator 
internus,  it  gives  offsets  to  the  hip  joint  and  the  inferior  gemellus. 

d.  Anastomotic  branch  (fig.  200,  e).  Varying  in  size  this  artery  is 
directed  outwards  to  the  root  of  the  great  trochanter,  where  it  anastomoses 
with  the  gluteal  and  internal  circumflex. 

The  pudic  artery  (fig.  200,  c?)  belongs  to  the  perina3um  and  the  genital 
organs;  it  is  smaller  than  the  sciatic,  internal  to  which  it  lies.  Only  the 
small  part  of  the  vessel  which  winds  over  the  ischial  spine  is  seen  on 
the  back  of  the  pelvis,  for  it  enters  the  perinieal  space  through  the  small 
sacro-sciatic  notch,  and  is  there  distributed  (p.  390). 

It  supplies  a  small  branch  over  the  back  of  the  sacrum,  which  anasto- 
moses with  the  gluteal  and  sciatic  vessels  ;  and  a  twig  from  it  accompanies 
the  nerve  to  the  obturator  internus  muscle. 

The  veins  with  the  sciatic  and  pudic  arteries  receive  contributing  twigs 
corresponding  with  the  branches  of  those  arteries  at  the  back  of  the  pelvis, 
and  open  into  the  internal  iliac  vein. 

Sciatic  and  Pudic  Nerves.  The  nerves  appearing  at  the  back  of 
the  pelvis,  below  the  pyriformis,  are  branches  of  the  sacral  plexus  to  the 
lower  limb  (p.  518) ;  they  are  furnished  mostly  to  parts  beyond  the 
gluteal  region,  but  a  few  are  distributed  to  the  muscles  at  the  back  of 
the  pelvis. 

The  small  sciatic  (fig.  200,  ^)  is  a  cutaneous  nerve  of  the  back  of  the 
thigh,  for  it  supplies  only  one  muscle  of  the  buttock.  It  springs  from  the 
lower  part  of  the  sacral  plexus,  generally  by  two  pieces,  and  takes  the 
course  of  the  sciatic  artery  as  far  as  the  lower  border  of  the  great  gluteus, 
where  it  gives  many  cutaneous  branches  :  much  diminished  in  size  at  that 
spot,  the  nerve  is  continued  along  the  back  of  the  thigh  beneath  the  fascia, 
and  ends  below  the  knee  in  the  integuments  of  the  back  of  the  leg.  The 
branches  which  are  distributed  to,  or  near  the  buttock,  are  muscular  and 
cutaneous : — 

The  muscular  branches  (inferior  gluteal)  enter  the  under  surface  of  the 
gluteus  maximus  near  the  lower  border. 

The  cutaneous  branches  are  directed  upwards  and  downwards  at  the 
border  of  the  gluteus  : — 

The  ascending  set  (fig.  199)  are  distributed  in  the  fat  over  the  lower 
third  of  the  muscle. 


THE    SUPERIOR    AND    INFERIOR    GEMELLUS.  589 

The  descending  set  (fig.  199,  '^)  supply  the  integuments  of  the  upper 
third  of  the  thigh  at  the  inner  and  posterior  aspects.  One  of  these  branches 
('),  which  is  larger  than  the 'others,  is  distributed  to  the  genital  organs, 
and  is  named  inferior  pudendal  (p.  394)  ;  as  it  courses  to  the  perina3um, 
it  turns  b^elow  the  ischial  tuberosity,  and  perforates  the  fascia  lata  at  the 
inner  part  of  the  thigh  to  end  in  the  scrotum. 

The  ffi^eat  sciatic  (fig.  200,  ^)  is  the  largest  nerve  in  the  body.  It  is 
the  source  of  all  the  muscular,  aud  most  of  the  cutaneous  branches  dis- 
tributed to  the  limb  beyond  the  knee,  as  well  as  of  the  muscular  branches 
at  the  back  of  the  thigh. 

At  its  origin  it  appears  to  be  a  prolongation  of  the  sacral  plexus.  It  is 
directed  through  the  buttock  to  the  posterior  part  of  the  thigh,  and  rests 
on  the  external  rotator  muscles  below  the  pyriformis.  Commonly  it  does 
not  supply  any  branch  to  the  buttock,  but  it  may  give  origin  to  one  or  two 
filaments  to  the  hip  joint.  Frequently  the  nerve  is  divided  into  two  large 
trunks  at  its  origin,  and  one  of  them  pierces  the  fibres  of  the  pyriformis 
muscle. 

The  pudic  nerve  (fig.  200,  °)  winds  over  the  small  sacro-sciatic  liga- 
ment by  the  side  of  its  companion  artery,  and  is  distributed  with  this 
vessel  to  the  perinaium  and  the  genital  organs  (p.  391).  No  branch  is 
supplied  to  the  buttock. 

Muscular  branches  of  the  sacral  plexus  are  furnished  to  the  gluteus 
maximus,  and  to  the  external  rotators  except  the  obturator  externus. 

Branches  of  gluteus.  One  or  more  branches  of  the  plexus  enter  the 
top  of  the  gluteus  maximus  (fig.  200). 

Two  branches  of  the  pyriformis  enter  the  under  surface,  and  are  learnt 
with  the  sacral  plexus  in  the  pelvis. 

The  nerve  to  the  obturator  internus  (fig.  201,  ^)  arises  from  the  upper 
part  of  the  plexus,  and  is  directed  to  its  muscle  through  the  small  sacro- 
sciatic  notch  with  the  pudic  nerve  :  its  termination  is  seen  in  the  dissec- 
tion of  the  pelvis. 

The  nerve  to  the  superior  gemellus  (fig.  201,  '')  is  a  very  small  twig, 
and  arises  separately  from  the  following :  it  enters  the  inner  end  of  the 
muscle  on  the  superficial  surface. 

The  7ierve  to  the  inferior  gemellus  and  the  quadratus  (fig.  201,  ^)  is  a 
slender  branch,  which  passes  with  a  companion  artery  beneatli  the  gemelli 
and  the  obturator  internus,  to  end  in  the  two  muscles  from  which  it  re- 
ceives its  designation.  This  nerve  will  be  seen  more  fully  in  a  subse- 
quent dissection,  when  articular  filaments  from  it  to  the  hip-joint  may  be 
recognized. 

Dissection.  To  see  the  remaining  small  rotator  muscles,  hook  aside  the 
great  sciatic  nerve,  and  take  away  the  branches  of  the  sciatic  artery  if  it 
is  necessary.  In  cleaning  these  muscles  the  limb  should  be  rotated  in- 
wards. The  gemelli  are  to  be  separated  from  the  tendon  of  tlie  obturator 
internus. 

The  SUPERIOR  GEMELLUS  (fig.  200,  ^)  is  the  highest  of  the  two  mus- 
cular slips  along  the  sides  of  the  tendon  of  the  obturator  muscle.  Inter- 
nally it  is  attached  to  the  outer  and  lower  part  of  the  ischial  spine,  and 
externally  it  is  inserted  with  the  obturator  into  the  great  trochanter. 
Oftentimes  the  muscle  is  absent. 

The  INFERIOR  GEMELLUS  (fig.  200,  ^)  is  larger  than  its  fellow.  Its 
origin  is  connected  with  the  upper  part  of  the  ischial  tuberosity,  along 
the  lower  edge  or  lip  of  the   hollow  for  the  obturator  internus   muscle  ; 


590  DISSECTION    OF    THE    BUTTOCK. 

and  its  insertion  is  the  same  as  that  of  the  obturator  tendon.  Tliis  mus- 
cle is  phiced  between  the  obturator  internus  and  quadratus,  but  near  the 
femur  the  tendon  of  the  obturator  externus  comes  into  contact  with  its 
lower  border. 

Action.  These  small  fleshy  slips  seem  to  be  but  accessory  pieces  of 
origin  to  the  internal  obturator,  with  which  they  combine  in  use. 

The  OBTURATOR  INTERNUS  (fig.  200,  ^)  ariscs  from  the  innominate 
bone  inside  the  pelvis  (p.  543),  and  passes  to  the  exterior  through  the 
small  sacro-sciatic  notch.  The  tendon  of  the  muscle  is  directed  outwards 
over  the  hip-joint,  and  is  inserted  with  the  gemelli  into  the  upper  part  of 
the  great  trochanter,  in  front  of  the  pyriformis,  as  well  as  into  the  con- 
tiguous portion  of  the  neck  of  the  femur. 

Outside  the  pelvis  the  obturator  is  mostly  tendinous,  and  is  embraced 
by  the  gemelli  muscles  in  the  following  way:  near  the  pelvis  the  gemelli 
meet  beneath,  but  near  the  trochanter  they  cover  the  tendon.  Beneath 
the  obturator  is  a  synovial  sac.  Crossing  the  muscle  are  the  large  and 
small  sciatic  nerves  and  the  sciatic  vessels ;  and  covering  the  whole  is  the 
gluteus  maximus.  On  cutting  through  the  tendon  and  raising  tlie  inner 
end,  it  will  be  found  divided  into  three  or  four  pieces  as  it  turns  over  the 
margin  of  the  pelvis  (fig.  201,  ") ;  at  this  spot  the  pelvis  is  marked  by 
ridges  of  fibro-cartilase,  which  correspond  with  the  intervals  between  the 
tendons,  and  the  surfaces  are  lubricated  by  a  synovial  membrane. 

Action.  Acting  from  the  hinder  border  of  the  pelvis  round  which  it 
turns,  it  rotates  out  or  abducts  the  femur  according  as  this  bone  may  be 
hanging  or  raised.  It  will  erect  the  pelvis  after  stooping,  and  will  balance 
the  same  in  standing;  and  it  will  rotate  to  the  opposite  side  the  trunk 
supported  on  one  limb. 

The  QUADRATUS  FEMORis  (fig.  200,  ^)  has  the  form  expressed  by  its 
name,  and  is  situate  between  the  inferior  gemellus  and  the  adductor  mag- 
nus.  Internally  it  arises  from  the  outer  border  of  the  tuber  ischii  for 
two  inches,  along  the  origin  of  the  semi-membranosus  and  adductor  mag- 
nus ;  externally  it  is  inserted  into  a  tubercle  in  the  posterior  intertrochan- 
teric ridge,  and  slightly  into  the  neck  of  the  femur  ;  and  into  a  line  on 
the  upper  end  of  the  bone  for  about  two  inches  above  the  attachment  of 
the  great  adductor. 

By  one  surface  it  is  in  contact  with  the  sciatic  vessels  and  nerves,  and 
the  gluteus.  By  the  other  it  rests  on  the  obturator  externus,  the  internal 
circumflex  vessels,  and  its  small  nerve  and  vessels.  Between  its  lower 
border  and  the  adductor  magnus  one  of  the  terminal  branches  of  the  inter- 
nal circumflex  artery  issues.  Between  it  and  the  small  trochanter  is  a 
bursa,  which  is  common  also  to  the  upper  part  of  the  adductor  magnus. 

Action.  Though  the  muscle  has  but  slight  power,  it  will  be  associated 
with  the  other  muscles  on  the  back  of  the  pelvis  in  rotation  out  of  the 
pendent  femur,  and  in  abduction  of  the  femur  when  tiie  hip-joint  is  bent. 

And  its  femoral  attachment  being  fixed,  it  will  help  in  supporting  the 
pelvis;  or  it  will  turn  the  face  to  the  opposite  side,  the  body  being  sup- 
ported on  one  limb. 

Dissection  (fig.  201).  The  quadratus  and  the  gemelli  muscles  may  be 
now  cut  across,  in  order  that  their  small  nerve  and  artery,  the  ending  of 
the  internal  circumflex  artery,  and  the  obturator  externus  may  be  dis- 
sected out. 

The  internal  circrnnflex  branch  (fig.  201,/)  of  the  profunda  artery  (p. 
578)  divides  finally  into  two  parts.     One  {(j)  ascends    beneath   the  quad- 


QUADRATUS    AND    OBTURATOR    EXTERNUS 


591 


ratus  (in  this  position  of  the  body)  to  the  pit  of  the  trochanter,  where  it 
anastomoses  with  the  gluteal  and  sciatic  arteries,  and  supplies  the  bone. 
The  other  (//)  passes  between  the  quadratus  and  adductor  magnus  to 
the  hamstring  muscles,  and  communicates  with  a  branch  of  the  profunda 
artery. 

The  OBTURATOR  EXTERNUS  (fig.  201,^)  has  been  dissected  at  its  origin 
in  the  front  of  the  thigh  (p.  580).  The  part  of  the  muscle  now  laid  bare, 
winds  below  the  hip-joint,  and  ascends  to  be  inserted  into  the  pit  at  the 
root  of  the  great  trochanter. 


Muscles. 

A.  GJuteus  maximus,  cut. 

B.  Tensor  fasciae  latse. 

c.  Gluteus  minimus. 
D.  Gluteus  medius,  cut. 

F.  Pyiiformis. 

G.  Gemellus  superior 
H.  Obturator  intei  nus,  cut. 
I.  Gemellus  inferior. 
K.  Quadratus  femoris,  cut. 
L.  Obturator  exteruus. 
N.  Adductor  magnus. 

0.  Hamstrings. 
p.  Great   sacro-sciatic    liga- 
ment. 

Arteries, 
a.  Gluteal. 

h.  Its  upper  and,  and  c,  its 
lower  piece. 

d.  Sciatic. 

e.  Pudic. 
/.  Internal    circumflex  ;    g, 

its  ascending,  and  h,  its 
transverse  offset. 
i.  First  perforating. 
It.  External  circumflex. 
Nerves. 

1.  Superior  gluteal. 

2.  Sacral. 

3.  Small  sciatic,  cut. 

4.  Pudic. 

5.  Nerve  to  obturator  inter- 
nus. 

6.  Nerve   to  quadratus   and 
inferior  gemellus. 

7.  Nerve  to  upper  gemellus. 

8.  Large  sciatic  nerve. 

Third  View  of  thk  Dissection  of  the  Buttock  (Illustrations  of  Dissections), 

On  the  back  of  the  pelvis  the  obturator  externus  is  covered  by  the  quad- 
ratus, except  near  the  femur  where  the  upper  border  is  in  contact  with 
the  inferior  gemellus.  As  it  turns  back  to  its  insertion  it  supports  the 
hip-joint. 

Action.  Like  the  other  muscles  of  the  same  group  it  rotates  out  the 
hanging  limb  ;  but  it  differs  from  them  in  having  the  same  action  even 
when  the  hip-joint  is  bent. 

"With  the  limb  fixed,  Theile  supposes  it  to  help  in  bending  the  hip-joint 


592  DISSECTION    OF    THE    THIGH. 

in  stooping,  instead  of  extending  it  and  raising  the  trunk  like  the  other 
external  rotator  muscles. 

The  sacko-sciatic  ligaments  pass  from  the  innominate  bone  to  the 
sacrum  and  the  coccyx  ;  they  are  two  in  number,  and  are  named  large 
and  small. 

The  large  ov  posterior  ligament  (fig.  201,  ^)  is  attached  internally  to  the 
posterior  part  of  the  hip  bone,  and  to  the  side  of  the  sacrum  and  coccyx  ; 
and  externally  it  is  inserted  into  an  impression  on  the  inner  and  anterior 
part  of  the  ischial  tuberosity,  sending  upwards  a  prolongation  along  the 
pubic  arch.  It  is  wide  next  the  sacrum,  but  is  contracted  towards  the 
middle,  and  is  expanded  again  at  the  tuberosity.  On  the  cutaneous  sur- 
face are  the  branches  of  the  sacral  nerves  ;  and  the  gluteus  maximus  con- 
ceals and  takes  origin  from  it.  Branches  of  the  gluteal  and  sciatic  arteries 
perforate  it. 

The  small  ligament  will  be  seen  on  dividing  the  other  near  the  hip  bone. 
At  the  sacrum  and  coccyx  it  is  united  with  the  large  band,  but  at  the 
opposite  end  it  is  inserted  into  the  ischial  spine.  It  is  less  strong  than  the 
superficial  ligament,  by  wMiich  it  is  concealed  ;  and  it  rests  on  the  coccy- 
geus  muscle. 

By  their  attachments  these  ligaments  convert  the  large  sacro-sciatic 
notch  of  the  dried  pelvis  into  two  apertures  or  foramina.  Between  their 
insertion  into  the  spine  and  tuberosity  of  the  innominate  bone,  is  the  small 
sacro-sciatic  foramen,  which  contains  the  internal  obturator  muscle  with 
its  nerve  and  vessels,  and  the  pudic  vessels  and  nerve.  And  above  the 
smaller  ligament  is  the  large  sacro-sciatic  foramen,  which  gives  passage  to 
the  pyriformis  muscle,  with  the  gluteal  vessels  and  the  superior  gluteal 
nerve  above  it,  and  tlie  sciatic  and  pudic  vessels  and  the  sacral  plexus 
below  it. 


Section  III. 

THE  BACK  OF  THE  THIGH. 


Directions.  The  ham  or  the  popliteal  space  may  be  taken  after  the 
buttock,  in  order  that  it  may  be  seen  in  a  less  disturbed  state  than  if  it 
was  dissected  after  the  examination  of  the  muscles  at  the  back  of  the  thigh. 
When  this  space  has  been  learnt  the  student  will  return  to  the  dissection 
of  the  thigh.   • 

Position.  The  limb  is  to  remain  in  the  same  position  as  in  the  dissec- 
tion of  the  buttock. 

Dissection  (fig.  202).  To  remove  the  skin  from  the  popliteal  region  let 
an  incision  be  made  behind  the  knee  for  the  distance  of  six  inches  above, 
and  four  inches  below  the  joint.  At  eacii  extremity  of  the  longitudinal 
cut  make  a  transverse  incision,  and  raise  the  skin  in  two  flaps,  the  one 
being  turned  outwards  and  the  other  inwards. 

In  the  fat  arc  some  small  cutaneous  nerves  and  vessels,  viz.,  one  or  two 
twigs  in  the  middle  line  of  the  limb  from  the  small  sciatic  nerve  and 
artery  beneath  the  fascia ;  and  some  otfsets  of  the  internal  cutaneous 
nerve  towards  the  inner  part.  After  the  subcutaneous  fat  is  removed, 
the  special  fascia  of  the  limb  will  be  brought  into  view. 


ANATOMY    OF    POPLITEAL    SPACE.  598 

Fascia  lata.  Where  this  fascia,  covers  the  popliteal  space  it  is  strength- 
ened by  transverse  fibres,  particularly  on  the  outer  side  ;  and  it  is  connected 
laterally  with  the  tendons  bounding  that  interval.  The  short  saphenous 
vein  perforates  it  sometimes  opposite  the  knee,  but  usually  at  a  spot  lower 
down. 

Dissection  (fig.  202).  The  fascia  over  the  ham  is  now  to  be  removed 
without  injuring  the  small  sciatic  nerve  and  artery,  and  the  short  saphe- 
nous vein,  which  are  close  beneath  it.  A  large  quantity  of  fat  may  be 
next  taken  out  of  the  space,  but  without  injury  to  the  several  small  vessels 
and  nerves  in  it. 

In  cleaning  the  space  the  student  will  come  upon  the  large  internal 
popliteal  nerve  in  tlie  middle  line  ;  and  nearer  the  outer  side,  on  the  ex- 
ternal popliteal.  Both  nerves  give  branches ;  and  the  numerous  offsets  of 
the  inner  will  be  recognized  more  certainly  by  tracing  them  from  above 
down  along  the  trunk  of  the  nerve,  than  by  proceeding  in  the  opposite 
direction  ;  in  fat  bodies  the  two  small  nerves  from  the  inner  popliteal  trunk 
to  the  knee  joint  are  difficult  to  find.  Under  cover  of  the  outer  boundary, 
and  deep  in  the  space,  is  an  articular  nerve  from  the  external  popliteal, 
which  sometimes  arises  from  the  great  sciatic. 

In  the  bottom  of  the  space  are  the  popliteal  vessels,  the  vein  being  more 
superficial  than  the  artery.  The  student  is  to  seek  an  articular  branch 
(superior),  on  each  side,  close  above  the  condyle  of  the  femur;  and  to 
clean  numerous  otlier  branches  of  the  vessels  to  the  muscles  around,  espe- 
cially to  those  of  the  leg.  On  the  upper  part  of  the  artery,  the  branch  of 
nerve  from  the  obturator  to  the  knee  joint  is  to  be  found  :  and  on  the  sides 
of  the  artery  are  three  or  four  lymphatic  glands  in  the  fat. 

After  the  ham  has  been  cleaned,  the  sartorius  and  the  gracilis  are  to  be 
replaced  in  their  natural  position  on  the  inner  side. 

The  POPLITEAL  SPACE,  or  the  ham  (fig.  202),  is  the  hollow  behind  the 
knee :  it  allows  of  the  free  flexion  of  the  joint,  and  contains  the  large  ves- 
sels of  the  limb.  When  dissected,  this  interval  has  the  form  of  a  lozenge, 
and  extends  upwards  along  one-third  of  the  femur,  and  downwards  along 
one-sixth  of  the  tibia ;  but  in  the  natural  condition  of  the  parts  the  sides 
are  approximated  by  the  fascia  of  the  limb,  and  the  space  is  limited,  ap- 
parently, almost  to  the  region  of  the  joint. 

This  hollow  is  situate  between  the  muscles  on  the  back  of  the  limb  ;  and 
the  lateral  boundaries  are  therefore  formed  by  the  muscles  of  the  thigh 
(hamstrings),  and  leg.  Thus,  on  the  outer  side,  is  the  biceps  muscle  (^)  as 
far  as  the  joint ;  and  the  plantaris  and  the  external  head  of  the  gastrocne- 
mius (^)  beyond  that  spot.  On  the  inner  side,  as  low  as  the  articulation, 
are  the  semimembranosus  (*)  and  semitendinosus  (^)  muscles,  with  the  gra- 
cilis and  sartorius  between  them  and  the  femur ;  and  beyond  the  joint  is 
the  inner  head  of  the  gastrocnemius  C).  The  upper  point  of  the  ham  is 
limited  by  the  apposition  of  the  inner  and  outer  hamstrings ;  and  at  the 
lower  point  the  heads  of  the  gastrocnemius  touch  each  other. 

Stretched  acrross  the  cavity  are  the  fascia  lata  and  teguments.  Forming 
the  deep  boundary,  or  the  floor,  are  the  following  parts — the  posterior  sur- 
face of  the  femur  included  between  the  lines  to  the  condyles,  the  posterior 
ligament  of  the  knee-joint,  and  part  of  the  popliteus  muscle  with  the  upper 
end  of  the  tibia. 

The  popliteal  space  is  widest  opposite  the  femoral  condyles,  where  the 
muscles  are  most  drawn  to  the  sides  ;  and  is  deepest  above  the  articular 
38 


594 


DISSECTION    OF    THE    THIGH. 


end  of  the  femur.    Above  and  below  it  communicates,  benetith  tlie  muscles, 
with  the  back  of  the  thigh  and  leg. 

In  the  hollow  are  contained  the  popliteal  vessels  with  their  branches, 
and  the  endingof  the  external  saphenous  vein  ; 
the  popliteal  trunks  of  the  great  sciatic  nerve, 
and  some  of  their  branches ;  together  with 
lymphatic  glands,  and  a  large  quantity  of  fat. 
The  small  sciatic  nerve  and  its  vessels  are 
placed  superficially  in  the  ham  ;  and  a  branch 
of  the  obturator  nerve  lies  on  the  artery  in 
the  bottom  of  the  space. 

I'he  POPLITEAL  ARTERY  (fig.  202,  ^)  is  the 
continuation  of  the  femoral,  and  reaches  from 
the  opening  in  the  adductor  magnus  to  the 
lower  border  of  the  popliteus  muscle,  where 
it  terminates  by  bifurcating  into  the  anterior 
and  posterior  tibial  vessels.  A  portion  of  the 
artery  lies  in  the  ham,  and  is  uncovered  by 
muscle  ;  buttlie  rest  is  beneath  the  gastrocne- 
miu«,  and  beyond  the  limits  of  the  popliteal 
space  as  above  defined.  The  description  of 
the  artery  may  be  divided  therefore  into  two 
parts,  corresponding  with  this  difference  in 
the  connections. 

In  the  ham  the  vessel  is  inclined  obliquely 
from  the  inner  side  of  the  limb  to  the  interval 
between  the  condyles  of  the  femur ;  and  is  then 
directed  along  the  middle  of  the  space  over 
the  knee-joint.  As  far  as  the  inner  condyle 
the  artery  is  overlaid  by  the  belly  of  the  semi- 
membranosus muscle  ;  but  thence  onwards  it 
is  situate  between  the  heads  of  the  gastrocne- 
mius, and  is  covered  only  by  the  fascia  lata 
and  the  integuments.  Beneath  it  is  the  femur 
with  the  posterior  ligament  of  the  knee-joint. 
In  contact  with  the  vessel,  and  somewhat 
on  the  outer  side  at  first,  lies  the  popliteal  vein, 
so  that,  on  looking  into  the  space,  the  arterial 
trunk  is  almost  covered ;  but  in  the  interval 
between  the  heads  of  the  gastrocnemius,  the 
vein  and  its  branches  conceal  altogether  the 
artery.  Below  the  knee  the  short  saphenous 
vein  (fig.  203,  i),  and  the  muscular  branches 
of  the  artery,  are  laid  over  the  popliteal  trunk. 
More  superficial  than  the  large  vessels,  and 
slightly  external  to  them  in  position,  is  placed  the  internal  poi)liteal  nerve, 
which  with  its  branches  lies  over  the  artery,  like  tlie  vein,  between  the 
heads  of  the  gastrocnemius.  In  the  bottom  of  the  hollow  the  small  obtura- 
tor nerve  runs  on  the  artery  to  the  joint. 

Dissection.  To  see  the  deep  part  of  the  artery  the  inner  head  of  the 
gastrocnemius  should  be  cut  through,  and  raised  from  the  subjacent  parts. 
On  removing  the  areolar  tissue  tlie  vessels  and  nerves  will  appear.  The 
lower  articular  branches  of  the  vessels  and  nerve  are  now  brou^jht  into 


View  of  the  Popliteal  Space 

Quaia's  Arteries). 

.  Popliteal  vessels. 

I.  Internal  popliteal  nerve. 

;.  External  popliteal  nerve. 

.  Semimembranosus  muscle. 

I.  Semitendinosus  muscle. 

1,  Biceps  muscle. 

Inner  and  outer  heads  of  the 
gastrocnemius  muscle.  The 
superficial  vein  on  the  gastroc- 
nemius is  the  short  saphenous, 
\vhich  enters  the  popliteal. 


7.  8, 


POPLITEAL    ARTEHY    AND    BRANCHES.  595 

view  ; — the  inner  artery  is  below  the  head  of  the  tibia,  and  the  outer 
higher  up  between  the  tibia  and  fibula,  each  with  a  vein,  and  the  first  has 
a  companion  nerve. 

Beyond  the  ham.  Whilst  the  artery  is  beneath  the  gastrocnemius  (fig. 
208)  it  sinks  deeply  into  the  limb ;  here  it  is  crossed  by  a  small  muscle — 
the  plantaris  c,  and  the  ending  is  concealed  by  the  soleus  b.  It  rests  on 
the  po[)liteus  muscle. 

Both  the  companion  vein  and  the  internal  popliteal  nerve  change  their 
position  to  the  artery,  and  gradually  cross  over  it,  so  as  to  lie  on  its  inner 
side  at  the  lower  border  of  the  popliteus. 

Sometimes  the  artery  is  divided  as  high  as  the  back  of  the  knee  joint ; 
and  then  the  anterior  tibial  artery  may  lie  beneath  the  popliteus  muscle. 

Branches  (fig.  203)  are  furnished  by  the  artery  to  the  surrounding  mus- 
cles, and  to  the  articulation  ; — those  that  belong  to  the  joint  are  five  in 
number,  and  are  called  articular,  viz.,  two  superior,  inner  and  outer;  two 
inferior,  also  inner  and  outer ;  and  a  central  or  azygos  branch. 

a.  The  7nusctilar  branches  are  upper  and  lower.  The  upper  set,  three 
or  four  in  number,  arise  above  the  knee,  and  end  in  the  semi-membranosus 
and  biceps  muscles,  communicating  with  the  perforating  and  muscular 
branches  of  the  profunda.  The  lower  set  (sural)  are  furnished  to  the 
muscles  of  the  calf,  viz.,  gastrocnemius,  soleus,  and  plantaris. 

b.  A  superficial  or  cutaneous  branch  arises  near  the  knee  joint,  and  ac- 
companies the  external  saphenous  nerve  over  the  muscles  of  the  leg  to  end 
in  the  teguments  (fig.  203). 

c.  The  superior  articular  arteries  arise  from  the  popliteal  trunk,  one 
from  the  inner  and  one  from  the  outer  side,  above  the  condyles  of  the 
femur ;  they  are  directed  almost  transversely  beneath  the  hamstring  mus- 
cles, and  turn  around  the  bone  to  the  front  of  the  joint. 

The  external  one  (¥)  perforates  the  intermuscular  septum,  and  divides 
in  the  substance  cf  the  vastus  internus.  Some  of  the  branches  end  in  that 
muscle,  and  anastomose  with  the  external  circumflex  (of  the  profunda)  : 
others  descend  to  the  joint ;  and  one  offset  forms  an  arch  across  the  fore 
part  of  the  bone  with  the  anastomotic  artery. 

The  internal  artery  (/),  oftentimes  very  small,  winds  beneath  the  ten- 
don of  the  adductor  magnus,  and  terminates  in  the  vastus  internus  ;  it 
supplies  this  and  the  knee  joint,  and  communicates  with  the  anastomotic 
artery. 

d.  The  inferior  articular  branches  (fig.  208)  lie  beneath  the  gastro- 
cnemius, but  are  not  on  the  same  level  on  opposite  sides  of  the  limb ;  for 
the  inner  one  descends  below  the  head  of  the  tibia,  whilst  the  outer  one 
is  placed  above  the  fibula.  Each  lies  beneath  the  lateral  ligament  of  its 
own  side. 

The  external  hv^iwoh.  (c)  supplies  she  outer  side  of  the  knee  joint,  anas- 
tomosing with  the  other  vessels  on  the  articulation,  and  with  the  recurrent 
branch  of  the  anterior  tibial  artery  :  it  sends  an  offset  beneath  the  liga- 
ment of  the  patella  to  join  a  twig  from  the  lower  internal  branch. 

The  internal  artery  (6)  ascends  at  the  anterior  border  of  the  internal 
lateral  ligament,  and  after  taking  its  share  in  the  free  anastomoses  over 
the  joint,  ends  in  offsets  for  the  articulation  and  the  head  of  the  tibia. 

e.  The  azygos  branch  enters  the  back  of  the  joint  through  the  posterior 
ligament,  and  is  distributed  to  the  ligamentous  structures,  the  fat,  and  the 
synovial  menibrane  of  the  interior. 


596  DISSECTION    OF    THE    THIGH. 

The  POPLITEAL  VEIN  (fig.  203,  h)  originates  in  the  union  of  the  vence 
comites  of  the  anterior  and  posterior  tibial  vessels,  and  has  the  same  ex- 
tent and  connections  as  the  artery  it  accompanies.  At  the  lower  border  of 
the  popliteus  muscle  the  vein  is  internal  to  the  arterial  trunk  ;  between 
the  heads  of  the  gastrocnemius  it  is  superficial  to  that  vessel  ;  and  thence 
to  the  opening  in  the  adductor  magnus  it  lies  to  the  outer  side,  and  close 
to  the  artery.  It  is  joined  by  branches  corresponding  with  those  of  the 
artery,  as  well  as  by  the  short  saphenous  vein  (fig.  203). 

The  POPLITEAL  NERVES  (fig.  202)  are  the  two  large  trunks  derived 
from  the  division  of  the  great  sciatic  in  the  thigh  ;  they  are  named  inter- 
nal and  external  from  their  relative  position.  In  the  popliteal  space  each 
furnishes  cutaneous  and  articular  offsets,  but  only  the  inner  one  supplies 
branches  to  muscles. 

The  INTERNAL  POLITEAL  NERVE  (^)  is  larger  than  the  external,  and 
occupies  the  middle  of  the  ham  :  its  connections  are  similar  to  those  of  the 
artery,  that  is  to  say,  it  is  partly  superficial  and  partly  covered  by  the  gas- 
trocnemius. Like  the  vessel  it  extends  through  the  back  of  the  leg,  and 
retains  the  name  popliteal  only  to  the  lower  border  of  the  popliteus  mus- 
cle. Its  position  to  the  vessels  has  been  already  noticed.  The  branches 
arising  from  it  here  are  the  following : — 

a.  Two  small  articular  twigs  (fig.  203,  *)  are  furnished  to  the  knee 
joint  with  the  vessels.  One  which  accompanies  the  lower  internal  articu- 
lar artery  to  the  fore  part  of  the  articulation  is  the  largest  ;  and  another 
takes  the  same  course  as  the  azygos  artery,  and  enters  the  back  of  the 
joint  with  it. 

b.  Muscular  branches  arise  from  the  nerve  between  the  heads  of  the 
gastrocnemius.  One  supplies  both  heads  of  the  gastrocnemius  and  the 
phintaris.  Another  descends  beneatli  the  gastrocnemius,  and  enters  the 
cutaneous  surface  of  the  soleus.  And  a  third  penetrates  the  popliteus  at 
the  under  aspect,  after  turning  round  the  lower  border. 

c.  The  €xter7ial  saphejious  nerve  (fig.  207,^)  (ram.  communicans  tibialis) 
is  the  largest  branch,  and  is  a  cutaneous  offset  to  the  leg  and  foot.  It  lies 
on  the  surface  of  the  gastrocnemius,  but  beneath  the  fascia,  as  far  as  the 
middle  of  the  leg,  where  it  becomes  cutaneous,  and  will  be  afterwards 
seen. 

The  EXTERNAL  POPLITEAL  NERVE  (fig.  202,  ')  (peroneal)  lies  along 
the  outer  boundary  of  the  ham  as  far  as  the  knee  joint ;  at  that  level  it 
leaves  the  space  and  follows  the  edge  of  the  biceps  muscle  for  two  inches, 
till  it  is  below  the  head  of  the  fibula.  There  it  enters  the  fibres  of  the 
peroneus  longus,  and  divides  beneath  that  muscle  into  three — musculo- 
cutaneous, anterior  tibial,  and  recurrent  articular.  Its  branches  wiiilst  in 
the  popliteal  space  are  cutaneous  and  articular. 

a.  The  articular  nerve,  arising  high  in  the  space,  runs  with  tlie  upper 
external  artery  to  the  outer  side  of  the  knee,  where  it  sends  a  twig  along 
the  lower  articular  artery  :  both  enter  the  joint. 

b.  The  peroneal  communicating  branch  (fig.  207,  *)  (ram.  communi- 
cans fibularis)  joins  the  external  saphenous  branch  of  the  internal  popli- 
teal about  the  middle  of  the  leg.  It  soon  becomes  cutaneous,  and  offsets 
are  given  by  it  to  the  back  of  the  leg. 

c.  One  or  two  cutaneous  nerves  are  furnished  by  the  extei-nal  [)Opliteal 
to  the  integument  on  the  outer  side  of  the  leg  in  the  upper  half. 

The  articular  branch  of  the  obturator  nerve  (fig.  203,  ')  perforates  the 
adductor  magnus,  and  is  conducted  by  the  popliteal  artery  to  the  back  of 


I 


UAMSTRING    MUSCLES.  5J7 

the  knee  joint.     After  supplying  filaments  to  the  vessels,  the  nerve  enters 
the  articulation  through  the  posterior  ligament. 

The  lymphatic  glands  of  the  popliteal  space  are  situate  around  the 
large  arterial  trunk.  Two  or  three  are  ranged  on  the  sides  ;  whilst  one  is 
superficial  to,  and  another  beneath  the  vessel :  they  are  joined  by  the  deep 
lymphatic  vessels,  and  by  the  superficial  set  with  the  saphenous  vein. 

THE  BACK  OF  THE  THIGH. 

Dissection  (fig.  203).  Now  the  popliteal  space  has  been  examined,  the 
student  may  proceed  with  the  dissection  of  the  back  of  the  thigh.  The 
piece  of  skin  between  the  buttock  and  the  popliteal  space  should  be  di- 
vided, and  reflected  to  the  sides.  In  the  fat  on  the  sides  of  the  limb  fine 
offsets  of  the  internal  and  external  cutaneous  nerves  of  the  front  of  the 
thigh  may  be  found ;  and  along  the  middle  line  some  filaments  from  the 
small  sciatic  nerve  pierce  the  fascia. 

Remove  the  deep  fascia  of  the  limb,  taking  care  of  the  small  sciatic 
nerve  and  its  artery.  Lastly,  clean  the  hamstring  muscles  ;  trace  out  tlie 
perforating  arteries  to  the  front  of  the  thigh,  and  clean  the  branches  of 
the  great  sciatic  nerve  and  profunda  artery  to  the  muscles. 

Muscles.  The  muscles  behind  the  femur  act  mainly  as  flexors  of  the 
knee  joint.  They  extend  from  the  pelvis  to  the  bones  of  the  leg,  and  are 
named  hamstrings  from  their  cord-like  appearance  on  the  sides  of  the  ham  : 
they  are  three  in  number,  viz.,  biceps,  semitendinosus,  and  semimembra- 
nosus. The  first  of  these  lies  on  the  outer,  and  the  others  on  the  inner 
side  of  the  popliteal  space. 

The  BICEPS  (fig.  203,  '^)  has  two  heads  of  origin,  long  and  short,  which 
are  attached  to  the  pelvis  and  the  femur.  The  long  head  arises  from  an 
impression  on  the  back  of  the  ischial  tuberosity,  in  common  with  the 
semitendinosus  muscle.  The  short  head  is  fixed  to  the  femur  below  the 
gluteus  maximus,  viz.,  to  all  the  linea  aspera,  to  nearly  the  whole  of  the 
line  leading  inferiorly  to  the  outer  condyle,  and  the  external  intermuscular 
septum.  The  fibres  end  inferiorly  in  a  tendon,  which  is  inserted  into  two 
prominences  on  tlie  head  of  the  fibula  by  slips  which  embrace  the  exter- 
nal lateral  ligament ;  and  a  slight  piece  is  prolonged  to  the  head  of  the 
tibia. 

The  muscle  is  superficial,  except  at  the  origin,  where  it  is  covered  by 
the  gluteus :  it  rests  on  the  upper  part  of  the  semimembranosus,  and  on 
the  great  sciatic  nerve  and  the  adductor  magnus  muscle.  On  the  inner 
side  is  the  semitendinosus  as  far  as  the  ham.  Its  tendon  gives  offsets  to 
the  deep  fascia  of  the  limb. 

Action.  It  can  bend  the  knee  if  the  leg-bones  are  not  fixed,  and  after- 
wards rotate  out  the  tibia;  and  the  long  head,  which  passes  upwards 
beyond  the  femur,  will  extend  the  bent  hip  joint  when  the  knee  is  straight. 

The  leg  being  supported  on  the  ground,  the  long  head  will  assist  in 
balancing  and  erecting  the  pelvis  ;  and  the  short  head  will  draw  down  the 
femur  so  as  to  bend  the  knee  in  stooping. 

The  SEMITENDINOSUS  (fig.  203,  ^)  is  a  slender  muscle  and  receives  its 
name  from  appearance.  It  arises  from  the  tuberosity  of  the  hip  bone 
with  the  long  head  of  the  biceps,  and  by  fleshy  fibres  from  the  tendon  of 
that  muscle.  Inferiorly  it  is  inserted  into  the  inner  surface  of  the  tibia, 
close  below  the  gracilis,  and  for  a  similar  extent. 

Tills  muscle,  like  the  biceps,  is  partly  covered  by  the  gluteus  maximus. 


698 


DISSECTION    OF    THE    THIGH 


About  its  middle  a  tendinous  intersection  may  be  observed.  It  rests  on 
the  semimembranosus,  and  on  the  internal  lateral  ligament  of  the  knee- 
joint.     The  outer  border  is  in  contact  with  the  biceps  tvs  far  as  tlio  i)opli- 

Fiff.  203. 


Muscles  : 

A.  Gluteus  maxiraus,  cut  below,  and  partly 

raised. 

B.  Quadratus  femoris. 
c.  Adductor  magnus. 
r>.  Biceps. 

E.  Semitendinosus. 
p.  Semimembranosus. 
G.  Outer,    and 

H.  Inner  head  of  the  gastrocnemius. 
Arteries  : 
a.  Small  sciatic,  cut. 

6.  Ending  of  internal  circumflex  to  the 

hamstrings, 
c.  First,  d,  second,  and  e,  third  perforating 

of  profiinda. 
/.  Muscular  branch  of  profunda. 
g.  Popliteal  tr'iuk. 
li.  Popliteal  vein. 
i.  Short  saphenous  vein. 
k.  Upper  external,  and  I,  upper  internal 

articular  artery. 
Nerves  : 

1.  Small  sciatic. 

2.  Large  sciatic. 

3.  Branch  to  hamstrings  from  large  sciatic. 

4.  External  popliteal ;  and 

.  5.  Communicating  peroneal. 

7.  Articular  branch  of  obturator  to  knee. 

8.  Internal  popliteal. 

9.  Articular  branch  to  knee  of  the  internal 

popliteal. 
10.  Short  saphenous. 


Dlssection  of  thb  Back  op  the  Thioh  (Illustrations  of  Dissections). 

teal  space.  As  the  tendon  turns  forwards  to  its  insertion,  an  expansion 
is  continued  from  it  to  the  fascia  of  the  leg;  and  it  is  attached,  with  the 
gracilis,  below  the  level  of  the  tubercle  of  the  tibia,  the  two  being  separated 
from  the  tendon  of  the  sartorius  by  a  bursa  (p.  567). 

Action.  If  the  leg  is  movable  the  muscle  bends  the  knee  ;  and  con- 
tinuing to  contract,  rotates  towards  the  tibia.  Supposing  the  knee-joint 
straight  but  tlie  hip-joint  bent,  the  femur  can  be  depressed,  and  the  hip 
extended  by  the  semitendinosus  and  the  other  hamstrings. 

vShould  the  limbs  be  fixed  on  the  ground,  the  muscle  will  assist  in 
balancing  the  pelvis,  or  in  erecting  the  trunk  from  a  stooping  posture. 

The  SP:MiMKMiiKANOSU8  muscle  (fig.  203,  *")  is  tendinous  at  botli  ends, 
and  its  name  is  given  from  the  membraniform  appearance  of  the  upper 


BRANCHES    OF    PROFUNDA    ARTERY.  599 

tendon.  The  muscle  is  attached  above  to  the  highest  impression  on  the 
back  of  the  tuber  ischii,  above  and  external  to  the  semitendinosus  and 
biceps  ;  and  it  is  inserted  below  into  the  hinder  and  inner  part  of  the  head 
of  the  tibia. 

The  muscle  is  thick  and  fleshy  inferiorly,  where-  it  bounds  the  popliteal 
space.  On  it  lies  the  semitendinosus,  which  is  lodged  in  a  hollow  in  the 
upper  tendon;  and  beneath  it  is  the  adductor  magnus.  Along  the  outer 
border  lie  the  great  sciatic,  and  internal  popliteal  nerves.  Between  its 
tendon  and  the  inner  head  of  the  gastrocnemius  is  a  large  bursa.  The 
insertion  of  the  muscle  will  be  dissected  with  the  knee-joint. 

Action.  This  hamstring  is  united  with  the  preceding  in  its  action,  for 
it  bends  the  knee  and  rotates  in  the  tibia ;  and  with  the  knee  straight  it 
will  limit  flexion  of  the  hip,  or  extend  this  joint  after  the  femur  has  been 
carried  forwards. 

When  the  foot  rests  on  the  ground,  the  semimembranosus  acts  altogether 
on  the  pelvis. 

The  GREAT  SCIATIC  NERVE  (fig.  203,  ^)  lics  on  the  adductor  magnus 
muscle  below  the  buttock,  and  divides  it  into  the  two  popliteal  nerves 
about  the  middle  of  the  thigh,  though  its  point  of  bifurcation  may  be  car- 
ried upwards  as  far  as  the  pelvis.  In  this  extent  the  nerve  lies  along  the 
outer  border  of  the  semimembranosus,  and  is  crossed  by  the  long  head  of 
the  biceps. 

Branches.  At  the  upper  part  of  the  thigh  it  supplies  large  branches  to 
the  flexor  muscles,  and  a  small  one  to  the  adductor  magnus. 

Small  sciatic  nerve  (fig.  203,^).  Between  the  gluteus  maximus  and 
the  ham  this  small  nerve  is  close  beneath  the  fascia ;  but  it  becomes  cuta- 
neous below  the  knee,  and  accompanies  the  external  saphenous  vein  for  a 
short  distance. 

Small  cutaneous  filaments  pierce  the  fascia  of  the  thigh  ;  and  the  largest 
of  these  arises  near  the  popliteal  space. 

Dissection.  To  see  the  posterior  surface  of  the  adductor  magnus,  and 
the  branches  of  the  perforating  and  muscular  arteries,  the  hamstring 
muscles  must  be  detached  from  the  hip  bone  and  thrown  down  ;  and  the 
branches  of  arteries  and  nerves  they  receive  are  to  be  dissected  out  with 
care.     All  the  parts  are  to  be  cleaned. 

Adductor  magnus  muscle  (fig.  203,  ^).  At  its  posterior  aspect  the 
large  adductor  is  altogether  fleshy,  even  at  the  opening  for  the  femoral 
artery ;  and  the  fibres  from  the  pubic  arch  appear  to  form  a  part  almost 
distinct  from  those  connected  with  the  tuberosity  of  the  hip  bone.  In 
contact  with  this  surface  are  the  hamstring  muscles  and  the  great  sciatic 
nerve. 

Ending  of  the  perforating  arteries  (fig.  203,  c,  c?,  e).  These  branches 
of  the  profunda  appear  through  the  adductor  magnus  close  to  the  femur, 
and  are  directed  out  through  the  short  head  of  the  biceps  and  the  outer 
intermuscular  septum  to  the  vasti  muscles ;  but  as  the  first  branch  is 
placed  higher  than  the  attachment  of  the  biceps,  it  pierces  the  gluteus 
maximus  in  its  course.  In  the  vasti  they  anastomose  together,  and  with 
the  descending  branches  of  the  external  circumflex  artery. 

Muscular  branches  are  furnished  by  the  perforating  arteries  to  the 
heads  of  the  biceps ;  and  a  cutaneous  off*set  is  given  by  each  to  the  tegu- 
ments of  the  outer  part  of  the  thigh,  along  the  line  of  the  outer  inter- 
muscular septum. 


600 


DISSECTION    OF    THE    THIGH 


Fig.  204. 


Muscular  branches  of  the  profunda  (fig.  203,/)  })ierce  the  adductor 
niagnus  internal  to  the  preceding,  and  at  some  distance  from  the  lemur. 
Three  or  four  in  number,  the  highest  appears  about  five  inches  from  the 
pelvis,  and  the  rest  in  a  line  at  intervals  of  about  two  inches  from  one 
another :  they  are  distributed  to  the  hamstring  muscles,  especially  the 
semimembranosus,  and  communicate  below  with  offsets  of  the  popliteal 
-trunk. 

The  HIP-JOINT  (fig.  204).  This  articulation  is  a  ball  and  socket  joint, 
the  head  of  the  femur  being  received  into  the  acetabulum  or  the  cup- 
shaped  hollow  of  the  innominate  bone.  Connecting  the  bones  are  the  fol- 
lowing ligaments : — one  to  deepen  the  receiving  cavity,  which  is  named 
cotyloid  ;  another  between  the  articular  surfaces  of  the  bones — the  inter- 
articular  ;  and  a  capsule  around  all. 

Dissection.  The  muscles  are  to  be  taken  away  from  the  back  of  the 
hip-joint,  and  the  upper  and  lower  attachments  of  the  capsular  ligament 
are  to  be  especially  cleared  from  areolar  tissue. 

Next,  the  front  of  the  joint   should   be  cleaned  and  examined  in  the 

same  manner,  with  the  body 
turned  over  for  a  short  time,  if 
this  change  in  position  does  not 
interfere  with  the  other  dissec- 
tions. 

In  the  capsule  itself  the  stu- 
dent has  to  define  a  wide  thick 
part  in  front,  and  a  transverse 
band  near  the  neck  of  the  femur 
behind. 

The  capsular  ligament  (fig. 
204)  is  a  thick  fibrous  case,  which 
is  strong  enough  to  check  the 
movements  of  the  joint.  Its  up- 
per margin  is  attached  to  the 
circumfererence  of  the  acetabu- 
lum at  a  short  distance  from  the 
edge,  as  well  as  to  a  transverse 
ligamentous  band  over  the  notch 
at  the  inner  side  of  the  cavity. 
Its  lower  margin  is  inserted  in 
front  into  the  anterior  intertro- 
chanteric line  (fig.  204)  ;  behind, 
by  a  very  thin  piece,  into  the 
neck  of  the  femur  about  a  finger's 
breadth  from  the  small  trochanter 
and  the  posterior  intertrochan- 
teric line  (fig.  205);  and  above, 
into  the  neck,  near  the  great  tro- 
chanter. The  capsule  differs  much  in  strength,  and  in  the  arrangement 
of  the  fibres  at  the  fore  and  hinder  surfaces. 

On  the  front  it  is  strengthened  by  a  wide  layer  of  longitudinal  fibres 
(fig.  204,  a,  6,  c).  The  central  portion — the  ilio-femoral  ligament  (a), 
is  fixed  above  by  a  narrow  piece  to  the  lower  anterior  iliac  spinous  pro- 
cess, and  below  where  it  widens,  into  the  anterior  intertrochanteric  line. 
By  its  strength  it  can  arrest  extension  of  the  joint ;  and  the  femur  being 


FOKE  PART  OF  THE  CAPSULE  OF  THE  IIlP-JOINT. 

a.  Ilio-femoral  ligament. 

b.  Pubio-femoral  edge  or  band. 

c.  Ilio-trochauteric  band. 


LIGAMENTS    OF    HIP    JOINT. 


601 


fixed,  it  will  prop  the  pelvis.  The  outer  edge  (e)  (ilio-trochanteric  band) 
extends  from  the  hip  bone  opposite  the  outer  head  of  the  rectus,  to  the 
upper  and  fore  part  of  the  great  trochanter  and  neck  of  the  femur;  its  use 
is  to  check  adduction  of  the  femur.  The  inner  edge  (b)  (pubio- femoral 
band)  is  attached  superiorly  to  the  prominent  pubic  portion  of  the  hip 
bone  inside  the  acetabulum,  and  inferiorly  to  a  roughened  surface  at  the 
lower  part  of  the  neck  of  the  femur  on  a  level  with,  and  in  front  of,  the 
small  trochanter  :  this  band  controls  the  abductory  movement  of  the  joint. 


Hinder  Part  of  thk  Hip-Joint  Capsule. 


a.  Longitudinal  fibres. 
6.  Transverse  band. 


Thiu  piece  attached  to  the  neck  of  the  femur 
about  half  way  down. 


At  the  back  of  the  capsule  close  to  the  neck  of  the  femur  is  a  band  of 
transverse  fibres  (fig.  205,  b),  about  as  wide  as  the  little  finger,  which 
arches  like  a  collar  over  the  neck  of  the  bone.  By  its  lower  edge  it  is 
united  to  the  cervix  femoris  by  a  thin  layer  (c)  of  fibrous  tissue  and  syno- 
vial membrane  ;  at  the  upper  edge  it  is  joined  by  the  longitudinal  capsular 
fibres  (a).  It  gives  insertion  to  the  longitudinal  fibres  of  the  capsule,  and 
prevents  that  restriction  of  the  swinging  movement  which  would  result 
from  their  insertion  into  the  hinder  part  of  the  neck. 

Posteriorly  the  joint  is  covered  by  the  external  rotator  muscles ;  and 
anteriorly  by  the  psoas  and  iliacus,  a  bursa  being  between  it  and  them. 
Above  is  the  gluteus  minimus,  whose  tendon  is  united  with  the  upper  and 
outer  band  of  the  capsule  ;  and  below^  is  the  obturator  externus. 

Dissection  (fig.  206).  The  capsular  ligament  is  to  be  now  divided  over 
the  prominence  of  the  head  of  the  femur,  and  this  bone  being  disarticu- 
lated but  not  detached,  the  cotyloid  and  interarticular  ligaments  inside  it 
will  appear. 

The  interarticular  or  round  ligament  is  attached  to  the  acetabulum  by 


602  DISSECTION    OF    THE    THIGH. 

two  pieces  ;  and  to  bring  these  into  view,  the  synovial  membrane  and  are- 
ohir  tissue  must  be  removed.  Tlie  transverse  ligament  over  the  notch  is 
also  to  be  defined. 

The  cotyloid  ligament  (fig.  191,  y)  is  a  narrow  band  of  fibro-cartilage, 
which  is  fixed  to  the  margin  of  the  acetabulum,  and  is  prolonged  across 
the  notch  on  the  inner  side,  so  as  to  form  part  of  the  transverse  ligament. 
Its  fibres  are  not  continued  around  the  acetabulum,  but  are  fixed  to  the 
margin  of  the  cavity,  and  cross  one  another  in  the  band.  It  is  thickest 
at  its  attachment  to  the  bone,  and  becomes  gradually  thinner  towards  the 
iree  margin,  where  it  is  applied  to  the  head  of  the  femur. 

This  ligament  fills  up  the  hollows  in  the  rim  of  the  acetabulum,  and 
deepens  the  socket  for  the  femur  in  the  same  manner  as  the  glenoid  liga- 
ment increases  the  surface  for  the  reception  of  the  head  of  the  humerus. 

The  transverse  ligament  (fig.  191,  K)  is  a  firm  but  narrow  band,  which 
reaches  across  the  upper  part  of  the  notch  at  the  inner  side  of  the  aceta- 
bulum. It  consists  partly  of  deep  special  fibres  {h)  which  are  attached  to 
the  margins  of  the  notch  ;  and  partly  of  a  superficial  bundle  from  the 
cotyloid  ligament  (y).  Beneath  it  is  an  aperture  by  which  vessels  and 
nerves  enter  the  acetabulum  to  supply  the  synovial  membrane,  and  the  fat 
in  the  bottom  of  that  hollow. 

The  inter  articular  or  round  ligament  (fig.  206,  h)  (ligam.  teres)  is  a 
slight  band  about  an  inch  long,  connecting  the  femur  with  the  innominate 
bone. 

One  extremity  is  roundish,  and  is  inserted  into  the  pit  in  the  head  of 
the  femur. 

The  other  is  flattened,  and  divides  into  two  parts  opposite  the  transverse 
ligament.  The  anterior  piece  (r)  (pubic)  is  attached  with  the  transverse 
ligament  to  the  pubic  edge  of  the  notch.  The  posterior  part  (c?)  C ischial) 
is  inserted  behind  the  transverse  ligament  into  the  ischial  border  of  the 
cotyloid  notch. 

Dissection.  To  see  its  condition  in  the  different  movements  of  the  articu- 
lation, it  should  be  examined  in  a  joint  in  which  the  capsule  is  entire,  and 
the  bottom  of  the  acetabulum  has  been  cut  out  with  a  chisel  inside  the 
pelvis. 

When  the  joint  is  in  the  extendad  state,  the  ligament  is  generally  lax, 
the  two  end  attachments  being  near  each  other  ;  but  if  the  femur  is  ad- 
ducted,  the  ischial  part  of  the  ligament  is  rendered  tight  because  the  head 
of  the  femur  rises. 

In  flexion  of  the  joint  the  ligament  is  tighter  than  in  extension,  as 
the  femoral  insertion  is  removed  from  the  acetabular ;  and  if,  in  the  bent 
state,  the  femur  be  rotated  out  or  adducted,  the  round  ligament  will  be 
most  stretched. 

A  synovial  membrane  lines  the  capsular  ligament,  and.  is  continued  along 
it  to  the  acetabulum  and  the  head  of  the  femur.  In  the  bottom  of  the 
cotyloid  cavity  it  is  reflected  over  the  fat  in  that  situation  ;  and  it  sur- 
rounds the  ligamentum  teres. 

Dissection.  To  see  the  surface  of  the  acetabulum  the  lower  limb  is  to  be 
separated  from  the  trunk  by  dividing  the  interarticular  ligament,  and  by 
cutting  through  any  parts  that  connect  it  to  the  pelvis :  at  this  stage  the 
pelvic  attachments  of  the  round  ligament  can  be  better  seen. 

Surfaces  of  hone.  The  articular  surfaces  of  the  bones  are  not  completely 
covered  with  cartilage. 


MOVEMENTS    OF    HIP    JOINT 


60S 


In  the  head  of  the  femur  is  a  pit  into  which  the  round  ligament  is  in- 
serted. 

The  acetabulum  is  coated  with  cartilage  at  its  circumference,  except 
opposite  the  notch,  and  touches  the  head  of  the  femur  by  this  part :  the 
articular  surface  is  deep  above,  but  gradually  decreases  towards  the  notch. 

Within  the  cartilage  and  close  to  the  notch,  is  a  mass  of  fat  (fig.  191, 
/)  covering  about  one  third  of  the  area  of  the  cotyloid  cavity,  which 
constitutes  the  gland  of  Plavers  : 
it  communicates  with  the  fat  of 
the  thigh  beneath  the  transverse 
ligament. 

Movement.  In  this  ball  and 
socket  joint  there  are  the  same 
kinds  of  movement  as  in  the 
shoulder,  viz.,  flexion  and  exten- 
sion, abduction  and  adduction, 
circumduction,  and  rotation. 

Flexion  and  extension.  In  the 
swinging  movement  flexion  is 
freer  than  extension,  the  thigh 
being  capable  of  such  elevation 
as  to  touch  the  belly. 

During  swinging  the  head  of 
the  femur  revolves  in  the  bottom 
of  the  acetabulum,  rotating  around 
a  line  corresponding  with  the  axis 
of  the  head  and  neck  ;  and  the 
rapidity  and  extent  of  tlie  move- 
ments do  not  endanger  the  secu- 
rity of  the  joint,  the  head  of  the 
bone  not  having  any  tendency  to 
escape. 

In  flexion,  the  back  of  the 
capsule  and  the  ilio-trochanteric 
band  are  put  on  the  stretch  ;  and 
in  extension,  the  strong  ilio  and 
pubio-femoral  bands  are  tightened. 

In  abduction  and  adduction  the  femur  is  removed  from,  or  brought 
towards  the  middle  line  of  the  body.  Of  the  two,  abduction  is  the  most 
extensive,  because  the  limb  may  soon  meet  its  fellow  when  it  is  moved 
inwards,  though,  if  it  is  carried  in  front  of  the  other,  adduction  is  con- 
siderable. 

In  both  states  the  head  moves  in  the  opposite  direction  to  the  shaft. 
Thus,  as  the  femur  is  abducted,  the  head  descends,  and  the  greater  part 
of  the  articular  surface  projects  below  the  acetabulum  ;  and  when  tlie 
limb  is  raised  to  its  utmost  the  great  trochanter  comes  to  rest  on  the 
margin  of  the  acetabulum,  so  as  to  limit  farther  motion.  As  the  limb 
descends  and  approaches  the  other,  the  head  rises  into  the  socket  of  the 
joint,  and  is  securely  lodged,  finally,  in  the  deepest  part  of  the  cavity. 

In  abduction,  the  inner  band  of  the  capsule  is  tightened  over  the  pro- 
jecting head  of  the  femur,  the  upper  part  being  relaxed.  And  in  adduc- 
tion, tlie  outer  band  of  the  capsule  is  rendered  tense  enough  to  arrest  the 
movement. 


Hip  Joint  Opened,  to  show  the  interarticular  or 
round  ligament. 

a.  Part  of  the  capsule. 

6.  Ligamentum  teres:  c,  its  pubic,  and,  d,  its 
ischial  attachment. 


604  DISSECTION    OF    THE    THIGH. 

Dislocation  may  take  place  in  both  these  lateral  movements,  the  edge 
of  the  cotyloid  cavity  serving  as  the  fulcrum  by  which  the  femur  can  be 
lifted  out  of  the  hollow  ;  in  the  one  case  (adduction)  the  neck  of  the  femur 
rests  on  the  brim  of  the  acetabulum,  and  in  the  other  (abduction)  the 
great  trochanter  is  supported  on  the  margin  of  the  joint-socket.  After  a 
dislocation  has  been  reduced,  the  state  of  adduction,  with  the  knees 
fastened  together,  is  the  securest  position  in  which  the  limb  can  be  placed, 
inasmuch  as  the  head  of  the  femur  then  occupies  the  deepest  part  of  the 
acetabulum. 

In  circumduction,  the  four  kinds  of  angular  motion  above  noticed  take 
place  in  succession,  viz.,  flexion,  abduction,  extension,  and  adduction  ;  and 
the  limb  describes  a  cone,  whose  base  is  at  its  extremity,  and  apex  at  the 
union  of  the  neck  with  the  shaft  of  the  femur.  This  movement  is  less 
free  than  in  the  shoulder-joint,  because  of  the  greater  bend  between  the 
neck  and  shaft  of  the  femur. 

There  are  two  kinds  of  rotation,  internal  and  external :  in  the  former, 
the  great  toe  is  turned  in  ;  and  in  the  latter,  the  more  extensive  of  the 
two,  it  is  moved  outwards. 

In  rotation  inwards,  the  head  of  the  femur  rolls  backwards  horizontally 
across  the  acetabulum,  the  great  trochanter  being  put  forwards  ;  and  the 
shaft  of  the  bone  revolves  around  a  line  inside  it,  which  passes  from  the 
head  to  the  inner  condyle.  During  this  movement  the  posterior  half  of 
the  capsule  is  put  on  the  stretch,  and  the  anterior  is  relaxed. 

In  rotation  out  the  head  of  the  bone  rolls  forwards  across  the  cotyloid 
cavity,  and  the  great  trochanter  is  brought  backwards,  whilst  the  shaft  of 
the  femur  moves  round  the  line  on  its  inner  side  before  noticed.  The  fore 
part  of  the  capsule  is  now  put  on  the  stretch,  and  the  hinder  is  rendered 
loose. 

The  movement  of  rotation  is  destroyed  by  fracture  of  the  neck  of  the 
bone.  Its  degree  is  proportioned  to  the  length  of  the  neck,  and  is  there- 
fore greater  in  the  femur  than  in  the  humerus. 

Use  of  bend  of  femur.  By  means  of  the  angle  at  the  union  of  the  neck 
with  the  shaft,  the  pelvis  is  more  firmly  prop[)ed  than  it  would  be  if  the 
neck  was  in  a  line  with  the  rest  of  the  femur.  It  permits  also  greater 
surface  contact  between  the  head  of  the  femur  and  the  hip  bone,  since  the 
whole  head  can  be  lodged  in  the  cotyloid  cavity  in  progression  ;  and  gives 
greater  security  to  the  joint  in  flexion  and  extension,  for  if  the  neck  and 
shaft  of  the  bone  were  in  a  line,  only  half  of  the  articular  surface  could 
enter  the  socket  of  the  innominate  bone  in  walking,  and  running.  The 
important  movement  of  rotation  is  also  duo  to  this  angle ;  and  greater 
space  is  obtained  through  it  for  the  location  of  the  a<lductor  muscles  on 
the  inner  side  of  the  femur. 

Dissection.  After  the  limb  is  removed,  the  attachments  of  all  the 
muscles  in  the  thigh  are  to  be  examined  more  minutely  before  the  dissec- 
tion of  the  leg  is  undertaken.  The  muscles  should  not  be  removed  from 
the  femur,  but  about  two  inches  of  each  should  be  left  for  after  study. 


SURFACE    MARKING    OF    LEG.  G05 

Section  IV. 

THE  BACK  OF  THE  LEG. 

Directions.  Before  the  dissection  of  tlie  leg  is  begun,  the  student  should 
make  himself  acquainted,  as  in  the  thigh,  with  the  prominences  of  bone 
and  muscle  on  the  surface,  and  with  the  markings  which  lead  to  the  posi- 
tion of  the  larger  vessels. 

Prominences  of  hone.  The  bones  of  the  leg  can  be  traced  beneath  the 
skin  from  the  knee  to  the  ankle-joint.  On  the  inner  side  is  the  tibia, 
which  is  subcutaneous  in  all  its  extent,  and  is  limited  in  front  and  behind 
by  a  sharp  ridge  :  above,  it  presents  in  front  a  prominent  tubercle  into 
which  the  ligament  of  the  patella  is  inserted  ;  and  below,  it  ends  on  the 
inner  side  of  the  ankle  in  the  internal  malleolar  projection.  On  the  outer 
side  of  the  leg  the  lower  half  of  the  fibula  may  be  felt  with  ease,  but  the 
upper  half  with  more  difficulty  in  consequence  of  the  prominence  of  the 
muscles  of  the  calf.  The  head  of  this  bone  may  be  recognized  below  the 
knee  ;  and  the  lower  end  forms  the  eminence  (malleolus)  on  the  outer  side 
of  the  ankle  joint. 

On  the  side  of  the  ankle  joint  are  the  prominent  malleoli  ;  and  when 
the  joint  is  extended^  the  head  of  the  astragalus  can  be  i'elt  below  the 
tibia. 

Muscles  and  vessels  of  the  leg.  On  the  back  of  the  leg  is  the  swell  of 
the  calf:  this  is  formed  by  the  superficial  muscles,  and  from  it  descends 
the  firm  band  of  the  tendo  Achillis,  by  which  those  muscles  are  connected 
with  the  heel.  Between  the  tendon  and  the  edge  of  the  tibia,  but  nearest 
the  former,  is  placed  the  superficial  part  of  the  posterior  tibial  artery.  In 
front  between  the  tibia  and  fibula  are  the  flexor  muscles  of  the  foot  and  the 
extensors  of  the  toes,  amongst  which  the  anterior  tibial  artery  lies  deeply  ; 
the  position  of  the  vessel  will  be  indicated  by  a  line  from  the  centre  of  the 
ankle-joint  to  the  inner  side  of  the  head  of  the  fibula. 

Prominences  of  the  foot.  At  the  inner  border  of  the  foot,  about  an  inch 
in  front  of  the  internal  malleolus,  is  the  prominent  scaphoid  bone  pointing 
out  the  spot  at  which  an  amputation  (Chopart's)  is  practised  ;  whilst  one 
inch  and  a  half  farther  forwards  is  a  slight  depression  marking  the  articu- 
lation between  the  internal  cuneiform  and  the  metatarsal  bone  of  the  great 
toe.  About  the  centre  of  the  outer  border  of  the  foot  is  the  eminence  of 
the  tarsal  end  of  the  fifth  metatarsal  bone.  A  line  over  the  dorsum  of  the 
foot,  from  the  centre  of  the  ankle  joint  to  the  interval  between  the  inner 
two  toes,  will  lie  over  the  position  of  the  main  artery. 

Position.  For  the  dissection  of  the  back  of  the  leg,  the  limb  is  to  be 
placed  on  its  front,  with  the  foot  over  the  side  of  the  dissecting-table  ;  and 
the  muscles  of  the  calf  are  to  be  put  on  the  stretch  by  fastening  the  foot. 

Dissection.  For  the  removal  of  the  skin,  one  cut  may  be  made  along 
the  middle  of  the  leg  to  the  sole  of  the  foot,  where  a  transverse  incision  is 
to  be  carried  over  the  heel.  The  two  resulting  flaps  of  skin  may  be  raised, 
the  outer  one  as  far  as  the  fibula,  and  the  other  as  far  as  the  inner  margin 
of  the  tibia. 

In  the  fat  the  cutaneous  nerves  and  vessels  are  to  be  followed.  On  the 
inner  side,  close  to  the  tibia,  is  the  internal  saphenous  vein  with  the  nerve 
of  the  same  name,  together  with  twigs  of  the  internal  cutaneous  near  the 


606  DISSECTION    OF    THE    LEG. 

knee.  In  the  centre  of  the  leg  lies  the  external  saphenous  vein,  with  the 
small  sciatic  nerve  as  its  companion  above,  and  the  external  saphenous 
nerve  below  the  middle  of  the  leg.  On  the  outer  side,  in  the  upper  third, 
cutaneous  offsets  of  the  external  popliteal  nerve  will  be  met  with. 

The  superjicial  fascia^  or  tlie  fatty  layer  of  the  back  of  the  leg,  is  least 
thick  over  the  tibia.  Over  tlie  line  of  the  superficial  vessels  it  may  be 
separated  into  two  layers. 

Superficial  Veins.  Two  veins  appear  of  the  dissection  of  the  back 
of  the  leg,  which  are  named  saphenous — inner  and  outer. 

The  internal  saphenous  vein  (fig.  208,  d)  begins  in  an  arch  on  the 
dorsum  of  the  foot.  Ascending  along  the  leg  in  front  of  the  inner  ankle, 
and  then  behind  the  inner  edge  of  the  tibia,  it  reaches  the  tliigli  (p.  5oo). 
In  the  leg  the  vein  is  joined  by  superficial  branches,  and  by  deep  roots 
from  the  tibial  veins. 

The  external  saphenous  vein  (fig.  207,  c)  begins  at  the  outer  end  of  the 
arch  on  the  dorsum  of  the  foot,  and  appears  below  the  outer  ankle.  The 
vein  tlien  courses  along  the  back  of  the  leg  to  the  ham,  where  it  ends  in 
the  popliteal  vein.  It  receives  large  branches  about  the  heel,  and  others 
on  the  back  of  the  leg,  communicating  with  the  internal  saphenous. 

Cutaneous  arteries  accompany  the  superficial  veins  and  nerves  of  the 
leg. 

Cutaneous  Nerves  (fig.  207).  The  nerves  in  the  fat  of  the  back  of 
the  leg  are  prolongations  of  branches  already  examined  in  part,  viz.  the 
internal  and  external  saphenous,  external  popliteal,  small  sciatic,  and  in- 
ternal cutaneous  of  the  thigh. 

The  internal  saphenous  nerve  (fig.  207,  '^)  accompanies  the  vein  of  the 
same  name  beyond  the  knee  (p.  573),  and  terminates  at  the  middle  of  tlie 
inner  border  of  the  foot.  In  the  leg  the  nerve  gives  off  lateral  cutaneous 
offsets,  and  the  outer  of  these  turn  over  the  tibia  to  the  anterior  aspect. 

The  external  saphenous  nerve  (207,^)  is  a  branch  of  the  internal  pop- 
liteal. Perforating  the  deep  fascia  about  the  middle  of  the  leg,  it  is  con- 
tinued with  the  external  saphenous  vein  below  the  outer  ankle,  and  is 
distributed  to  the  outer  side  of  the  foot  and  little  toe.  As  soon  as  the 
nerve  enters  the  fat  it  is  joined  by  the  communicating  branch  of  the  ex- 
ternal popliteal ;  and  near  the  heel  it  gives  large  and  long  branches  to 
the  integuments. 

Cutaneous  nerves  of  the  external  popliteal.  One  branch  of  the  external 
popliteal  trunk,  viz.,  communicating  peroneal  (fig.  207,*),  joins  the  external 
saphenous  nerve  about  the  middle  of  the  leg ;  but  not  uncommonly  this 
branch  extends  as  a  distinct  nerve  as  far  as  the  heel.  One  or  two  other 
small  cutaneous  offsets  of  the  external  popliteal  terminate  over  the  fore 
part  and  outer  side  of  the  leg  in  the  upper  half. 

The  small  sciatic  nerve  (fig.  207,^)  perforates  the  fascia  near  the  pop- 
liteal space,  and  reaches  to  about  the  middle  of  the  leg  with*  the  external 
saphenous  vein  :  it  ramifies  in  the  integuments,  and  joins  the  external 
saphenous  nerve. 

Offset  of  the  internal  cutaneous  (fig.  207,  ^).  The  inner  branch  of  the 
internal  cutaneous  of  the  thigh  (p.  ooG)  extends  to  the  middle  of  the  leg, 
and  communicates  with  the  internal  saphenous  nerve. 

Dissection.  The  deep  fascia  will  be  seen  by  removing  the  fat.  The 
superficial  vessels  and  nerves  may  be  either  cut  or  turned  aside. 

The  special  or  deep  fascia  on  the  posterior  aspect  of  the  leg  covers  the 
muscles,  and  sends  a  thick  process  between  the  deep  and  superficial  layers. 


CUTANEOUS  VEINS  AND  NERVES. 
Fig.  207.  Fig.  208. 


607 


First  View  of  the  Baci^  of  thr  Le3  (Illus- 
trations of  Dissections)  . 
Muscles  : 

A.  Gastrocnemius. 

B.  Soleus. 

c.  Semimembranosus. 

D.  Biceps. 
Vessels  : 

a.  Popliteal  artery. 

6.  Inner  saphenous  vein. 

c.  External  saphenous  vein. 
Nerves : 

1.  External,  and  2,  internal  popliteal. 

H.  Short  saphenous. 

4.  Communicating  peroneal. 

5.  Common  trunk  of  short  saphenous. 

6.  Small  sciatic. 

7.  Internal  saphenous. 

8.  Internal  cutaneous  (inner)  piece. 


Second  "V^w  op  the  Back  op  the  L'  o  (Illus- 
trations of  Dissections). 
Muscles : 

A.  Gastrocnemius,  cut. 

B.  Soleus. 

c.  Plantaris. 
D.  Semimembranosus. 
K.  Semitendinoaus. 
p.  Tendo  Achillls. 
Vessels : 
a.  Popliteal  artery. 
6.  Inner  lower  articular. 

c.  External  lower  articular. 

d.  Internal  saphenous  vein. 

e.  External  saphenous  vein. 
Nerves  : 

1.  External  popliteal. 

2.  Internal  popliteal. 

S.  Short  saphenous,  cut. 

4.  Cutaneous  plantar  branch. 


608  DISSECTION    OF    THE    LEG. 

Above,  it  is  continuous  with  the  investing  membrane  of  the  thigh,  and 
receives  offsets  from  the  tendons  about  the  knee;  and  below,  it  joins  the 
two  annular  ligaments.  Externally  it  is  continued  uninterruptedly  from 
the  one  aspect  of  the  limb  to  the  other,  but  internally  it  is  fixed  to  the 
edge  of  the  tibia.  Veins  are  transmitted  through  it  from  the  deep  to  the 
superficial  vessels. 

Dissection.  The  fascia  is  to  be  divided  along  the  centre  of  the  leg  as 
far  as  the  heel,  and  is  to  be  taken  from  the  surtace  of  the  gastrocnemius 
muscle.  By  fixing  with  a  stitch  the  inner  cut  head  of  the  gastrocnemius, 
the  fibres  of  the  muscle  will  be  more  easily  cleaned. 

Superficial  Layer,  of  Muscles.  In  the  calf  of  the  leg  there  are 
three  muscles,  gastrocnemius,  soleus,  and  plantaris,  M'hich  extend  the 
ankle.  The  two  first  are  large,  giving  rise  to  the  prominence  on  the  sur- 
face, and  end  below  by  a  common  tendon  ;  but  the  last,  inconsiderable  in 
size,  is  chiefly  tendinous. 

The  gastrocnemius  (fig.  207,  '^),  the  most  superficial  muscle,  is  ten- 
dinous along  the  middle,  and  has  above  two  distinct  pieces  or  heads,  which 
connect  it  with  tlie  condyles  of  the  femur.  The  inner  head  of  oriqin  is 
attached  by  a  large  tendon  to  an  impression  at  the  posterior  aspect  of  the 
inner  condyle,  behind  the  insertion  of  the  adductor  magnus,  and  by  fleshy 
fibres  to  the  line  above  the  condyle.  The  outer  head  is  fixed  by  tendon 
to  a  pit  on  the  outer  surface  of  the  corresponding  condyle,  above  the 
attachment  of  the  popliteus  muscle,  and  to  the  up[)er  and  back  part  of  the 
same  condyle.  The  fleshy  fibres  of  the  heads  are  united  along  the  middle 
line  by  a  narrow  thin  aponeurosis,  and  terminate  inferiorly  with  the  soleus 
in  the  common  tendon  of  insertion. 

One  surface  is  covered  by  the  fascia.  The  other  is  in  contact  with  the 
soleus  and  plantaris,  and  with  the  popliteal  vessels  and  the  internal  popli- 
teal nerve.  The  heads,  by  which  tlie  muscle  arises,  assist  to  form  the 
lateral  boundaries  of  the  popliteal  space :  and  the  fleshy  inner  head 
descends  lower  than  the  outer.  In  the  outer  head  a  piece  of  fibro-carti- 
lage  or  a  sesamoid  bone  may  exist. 

Action.  When  the  foot  is  unsupported,  the  gastrocnemius  extends  the 
ankle  ;  and  when  the  toes  rest  on  the  ground,  it  raises  the  os  calcis  and 
the  weight  of  the  body,  as  in  standing  on  the  toes,  and  iri  progression. 

Taking  its  fixed  point  at  theos  calcis,  the  muscle  draws  down  the  femur 
so  as  to  bend  the  knee  joint. 

Dissection.  To  see  the  soleus,  the  gastrocnemius  is  to  be  reflected  by 
cutting  across  the  remaining  hea  I,  and  the  vessels  and  nerves  it  receives. 
After  the  muscle  has  been  thrown  down,  the  soleus  and  plantaris  must  be 
cleaned. 

The  soleus  (fig.  208,  ^)  is  a  large  flat  muscle,  which  is  attached  to 
both  bones  of  the  leg.  It  arises  from  the  head,  and  the  upper  third  or 
half  of  the  posterior  surface  of  the  shaft  of  the  fibula ;  from  the  oblicpie 
line  across  the  tibia,  and  from  the  posterior  edge  of  this  bone  in  the 
middle  third  ;  and  between  the  bones  from  an  aponeurotic  arch  over  tlie 
large  bloodvessels.  Its  fibres  are  directed  downwards  to  the  common 
tendon. 

The  superficial  part  of  the  soleus  is  in  contact  with  the  q-astrocnemius  ; 
and  the  opposed  sui-faces  of  the  two  are  aponeurotic.  Beneath  the  soleus 
lie  the  bones  of  the  leg,  the  deep  layer  of  muscles,  and  the  vessels  and 
nerves. 


SUPERFICIAL  EXTENSORS  OF  ANKLE.         609 

Tendo  Achillis  (fig.  208,  ^).  The  common  tendon  of  the  gastro- 
cnemius and  soleus  is  one  of  the  strongest  in  the  body.  About  three 
inches  wide  above,  it  commences  at  the  middle  of  the  leg,  though  it  re- 
ceives fleshy  fibres  on  the  under  surface  nearly  to  the  lower  end  :  below  it 
is  narrowed,  and  is  inserted  into  the  lower  half  of  the  tuber  calcis  at  the 
posterior  aspect.  A  bursa  intervenes  between  it  and  the  upper  part  of 
the  tuberosity.  The  tendon  is  close  beneath  the  fascia  ;  and  lying  along 
its  outer  side,  but  superficial  to  it,  are  the  external  saphenous  vein  and 
nerve. 

Action.  In  its  action  on  the  foot  the  soleus,  like  the  gastrocnemius, 
extends  the  ankle  and  points  the  toes  when  the  foot  is  free  to  move,  and 
raises  the  heel  if  the  toes  rest  on  the  ground.  By  the  sudden  and  power- 
ful contraction  of  the  fibres  of  both  muscles,  the  common  tendon  is 
sometimes  broken  across. 

If  it  acts  from  the  os  calcis,  it  will  draw  back  the  bones  of  the  leg  into 
a.  vertical  position  over  the  foot,  as  the  body  is  raised  to  the  erect  posture 
after  stooping. 

The  PLANTARis  (fig.  208,  ^)  is  remarkable  in  having  the  longest  tendon 
in  the  body,  which  takes  the  appearance  of  a  ribbon  when  it  is  stretched 
laterally.  About  three-quarters  of  an  inch  wide,  the  muscle  arises  from 
the  line  above  the  outer  condyle  of  the  femur,  and  from  the  posterior 
ligament  of  the  knee-joint ;  and  the  tendon  is  inserted  into  the  os  calcis 
with  or  by  the  side  of  the  tendo  Achillis,  or  into  the  fascia  of  the  leg. 

The  belly  of  the  muscle,  about  three  inches  in  length,  is  concealed  by 
the  gastrocnemius,  but  the  tendon  appears  on  the  inner  side  of  the  tendo 
Achillis  about  the  middle  of  the  leg.  This  little  muscle  crosses  the  pop- 
liteal vessels,  and  lies  on  the  soleus. 

Action.  It  assists  the  gastrocnemius  to  extend  the  ankle  if  the  foot  is 
not  fixed ;  and  to  bend  the  knee-joint  if  the  foot  is  immovable. 

Dissection  (fig.  209).  The  soleus  is  to  be  detached  from  the  bones  of 
the  leg,  and  the  muscles  and  nerves  entering  it  are  to  be  divided  ;  but  in 
raising  it,  the  student  should  take  care  not  to  injure  the  thin  deep  fascia 
and  the  vessels  and  nerves  beneath.  The  superficial  muscles  may  be  next 
removed  by  cutting  through  their  tendons  near  the  os  calcis ;  and  the 
bursa  between  the  tendo  Achillis  and  the  os  calcis  should  be  opened. 

The  piece  of  fascia  between  the  muscles  of  the  superficial  and  deep 
layers  is  next  to  be  cleaned ;  and  the  integuments  between  the  inner  ankle 
and  the  heel  are  to  be  taken  away  to  lay  bare  the  annular  ligament,  but  a 
cutaneous  nerve  to  the  sole  of  the  foot,  which  pierces  the  ligament,  is  to 
be  preserved. 

Deep  part  of  the  fascia.  This  intermuscular  piece  of  the  fascia  of  the 
leg  is  fixed  to  the  tibia  and  fibula,  and  binds  down  the  deep  layer  of  flexor 
muscles.  Beneath  the  soleus  it  is  thin  and  indistinct ;  but  lower  in  the 
limb  it  is  much  stronger,  and  is  marked  by  some  transverse  fibres  near  the 
malleoli,  which  gives  it  the  appearance  and  ofiice  of  an  annular  ligament 
in  that  situation.  Inferiorly  it  joins  the  internal  annular  ligament  between 
the  heel  and  the  inner  ankle. 

Dissection.  The  deep  layer  of  muscles  (in  part),  the  posterior  tibial 
nerve,  and  the  trunk  and  offsets  of  the  posterior  tibial  vessels,  will  be  laid 
bare  by  the  removal  of  the  fascia  and  the  areolar  tissue.  A  muscle  be- 
tween the  bones  (tibialis  posticus)  is  partly  concealed  by  an  aponeurosis 
which  gives  origin  to  the  two  muscles  (flexor  communis  and  flexor  pollicis) 
39 


610  DISSECTION    OF    THE    LEG. 

on  the  sides ;  and  it  will  not  fully  appear  until  after  the  membrane  cover- 
ing it  has  been  divided  longitudinally,  and  reflected  to  tlie  sides. 

To  prepare  the  peroneal  artery,  evert  and  partly  divide  the  flexor  pollicis 
in  which  it  is  contained  ;  then  follow  branches  of  it  to  the  fore  part  of  the 
leg,  the  outer  side  of  the  foot,  and  to  join  the  posterior  tibial  artery. 

Deep  Layer  of  Muscles  (flg.  209).  The  deep  muscles  at  the  back 
of  the  leg  are  four  in  number,  viz.,  popliteus,  flexor  longus  pollicis,  flexor 
longus  digitorum,  and  tibialis  posticus.  The  first  of  these  is  close  to  the 
knee-joint ;  it  crosses  the  bones,  and  is  covered  by  a  special  aponeurosis 
The  flexors  lie  on  the  bones,  the  one  of  the  great  toe  resting  on  the  fibula, 
and  that  of  the  other  toes  on  the  tibia.  And  the  tibialis  covers  the  inter- 
osseous membrane.  With  the  exception  of  the  popliteus,  all  enter  the 
sole  of  the  foot,  and  have  a  fleshy  part  parallel  to  the  bones  of  the  leg,  and 
a  tendinous  part  beneath  the  tarsus. 

The  popliteus  (fig.  209  ^)  arises  by  tendon,  within  the  capsule  of  the 
knee-joint,  from  the  fore  part  of  an  oblong  depression  on  the  outer  surface 
of  the  external  condyle  of  the  femur ;  and  external  to  the  capsule  of  the 
joint,  some  fleshy  fibres  arise  from  the  posterior  ligament.  The  tendon 
gives  rise  to  fibres,  which  are  inserted  into  the  tibia  above  the  oblique  line 
on  the  posterior  sui-face. 

The  muscle  rests  on  the  tibia,  and  is  covered  by  a  fascia  derived  in  great 
part  from  the  tendon  of  the  semimembranosus  muscle  :  on  it  lie  the  pop- 
liteal vessels  and  nerve,  and  the  gastrocnemius  and  planCaris.  Along  the 
upper  border  are  the  lower  articular  vessels  and  nerve  of  the  inner  side  of 
the  knee ;  and  the  lower  border  corresponds  with  the  attachment  of  the 
soleus  on  the  tibia.  The  origin  will  be  seen  with  the  dissection  of  the 
ligaments  of  the  knee-joint. 

Action.  The  leg  being  free,  the  muscle  bends  the  knee-joint,  and  then 
rotates  inwards  the  tibia.  The  foot  resting  on  the  ground,  it  will  support 
the  knee.  According  to  the  view  of  Theile,  it  retracts  the  external  semi- 
lunar fibro-cartilage. 

The  FLEXOR  LONGUS  POLLICIS  {'C\g.  209,  ^)  arises  below  the  soleus  from 
the  lower  half  or  two  thirds  of  the  posterior  surface  of  the  fibula ;  from 
the  intermuscular  septum  between  it  and  the  peronei  muscles ;  and  from 
the  aponeurosis  over  the  tibialis.  Inferiorly  the  tendon  of  the  muscle 
enters  a  groove  in  the  astragalus,  and  crosses  the  sole  of  the  foot  to  its  in- 
sertion into  the  great  toe. 

In  part  the  muscle  is  covered  by  the  soleus ;  but  in  part  it  is  superficial, 
and  is  in  contact  with  the  fascia.  It  lies  on  the  fibula  and  lower  end  of 
the  tibia,  and  conceals  the  peroneal  vessels.  Along  the  inner  side  are  tlie 
posterior  tibial  nerve  and  vessels  ;  and  contiguous  to  the  outer  margin,  but 
separated  by  fascia,  are  the  peronei  muscles. 

Action.  The  foot  being  unsupported,  the  flexor  bends  the  last  phalanx 
of  the  great  toe,  and  extends  then  the  ankle. 

The  foot  resting  on  the  ground,  the  muscle  raises  the  heel ;  and  it  moves 
back  the  fibula  as  the  body  rises  from  stooping. 

The  FLEXOR  LONGUS  DIGITORUM  (fig.  209,  ^■)  (flexor  perforans)  arises 
from  the  posterior  surface  of  the  tibia,  extending  from  the  attachment  of 
the  soleus  to  about  three  inches  from  the  lower  extremity ;  and  from  the 
aponeurosis  covering  the  tibialis  posticus.  Its  tendon  enters  a  partition  in 
the  annular  ligament,  which  is  superficial  to  the  sheath  of  the  tibialis  ;  and 
it  divides  in  the  sole  of  the  foot  into  tendons  for  th(;  four  outer  toes. 

The  muscle  is  narrow  and  pointed  above,  and  is  placed  beneath  the 


DEEP    LAYER    OF    MUSCLES. 


611 


soleus ;  but  in  the  lower  half  it  is  in  contact  with  the  fascia,  and  the  pos- 
terior tibial  vessels  and  nerve  lie  on  it.  The  deep  surface  rests  on  the 
tibia  and  the  tibialis  posticus. 

Action.    The  muscle  bends  the  farthest  phalangeal  joints  of  the  four 
smaller  toes,  and  then  extends  the  ankle. 


Fig.  209. 


Mw  d 

iRr^ 

Hrjfl 

Muscles: 

IB  flL 

A.  Popliteus, 

Ifihm 

B.  Outer,  and  c,  inner  part  of  soleus,  cat. 

liH^m 

».  Tibialis  posticus. 

iijLH^^B 

E.  Flexor  digitorum. 

IHrJ^HBt 

F.  Flexor  poUicis. 

iff^HHt^ 

Q.  Peroneus  longus. 

Iwi^R^B 

H.  Peroneus  brevis. 

hH^hh 

1.    Tendo  Achillis, 

HHBh 

Arteries  : 

HHH 

a.  Popliteal, 

wl^HW 

6.  Inferior  internal,  and  c,  inferior  external  articular. 

llflHv 

d.  Anterior  tibial. 

llflHff 

e.  Posterior  tibial,  and  /,  its  communicating  branch  to 

i  win 

peroueal. 

f  JPUm 

g.  Peroneal  artery. 

flHI 

h.  Continuation  of  peroneal  to  outer  side  of  the  foot. 

'  ^Bf  1 

Nerves : 

Mtlll 

1.  Internal  popliteal. 

Wml 

2.  Muscular  branch  of  posterior  tibial. 

mSmli 

3.  Posterior  tibial. 

^^Jraff 

4.  Cutaneous  plantar. 

Deep  Dissection  of  the  Back  of  the  Lfo  (Illustrations  of  Dissections). 

If  the  toes  are  in  contact  with  the  ground,  the  flexor  helps  to  raise  the 
heel  in  walking ;  and  to  move  back  the  tibia  in  the  act  of  rising  from 
stooping. 

The  TIBIALIS  POSTICUS  (fig.  209,  ^)  occupies  the  interval  between  the 
bones  of  the  leg,  but  it  crosses  over  the  tibia  inferiorly  to  reach  the  inner 
side  of  the  foot.  The  muscle  arises  from  an  aponeurosis  superficial  to  it, 
and  from  the  interosseous  membrane,  except  about  one  inch  below  :  from 
an  impression  along  the  outer  border  of  the  tibia,  which  reaches  from  the 
head  of  the  bone  to  rather  beyond  the  attachment  of  the  flexor  longus 
digitorum  ;  and  from  the  adjacent  inner  surface  of  the  shaft  of  the  fibula 


612  DISSECTION    OF    THE    LEG. 

as  far  down  as  the  lowest  fiftli.  In  the  lower  part  of  the  leg  the  muscle  is 
directed  beneath  the  flexor  digitorum  ;  and  its  tendon,  entering  the  inner 
space  in  the  annular  ligament,  reaches  the  inner  side  of  tlie  foot  to  be  in- 
serted into  the  scaphoid  and  other  bones  (p.  625). 

The  tibialis  is  concealed  hj  the  aponeurosis  before  mentioned,  and  is 
overlapped  by  the  neighboring  muscles  ;  but  in  the  lower  part  of  the  leg  it 
is  placed  between  the  tibia  and  the  long  flexor  of  the  toes.  On  the  mus- 
cle are  the  posterior  tibial  vessels  and  nerve.  Tlie  upper  part  presents  two 
pointed  processes  of  attachment — that  to  tlie  tibia  being  the  highest — be- 
tween which  the  anterior  tibial  vessels  are  directed  forwards. 

Action.  Its  action  on  the  movable  foot  is  to  shorten  the  inner  border  by 
drawing  down  the  scaphoid  bone,  and  to  extend  the  ankle  joint.  The  toes 
resting  on  the  ground,  it  will  aid  the  muscles  of  the  calf  in  raising  the  heel 
in  the  progression  of  the  body. 

In  standing,  the  muscle  can  raise  the  inner  border  of  the  foot  with  the 
tibialis  anticus,  so  as  to  throw  the  weight  of  the  body  on  the  outer  edge. 

As  the  body  rises  from  stooping,  the  tibialis  draws  back  the  bones  of 
the  leg,  with  the  soleus. 

The  aponeurosis  covering  the  tibialis  is  attached  laterally  to  the  bones, 
but  has  a  defined  border  inferiorly  over  the  muscle.  By  one  surface  it 
gives  origin  to  the  flexors  of  the  toes,  and  by  the  other  to  the  tibialis. 

The  POSTERIOR  TIBIAL  ARTERY  (fig.  209,  e)  is  One  of  the  branches 
resulting  from  the  bifurcation  of  the  popliteal  trunk.  The  vessel  extends 
from  the  lower  border  of  the  popliteus  muscle  to  the  lower  part  of  the 
internal  annular  ligament,  where  it  ends  in  two  plantar  branches  for  the 
sole  of  the  foot. 

At  its  origin  the  artery  lies  midway  between  the  tibia  and  fibula,  but  as 
it  approaches  the  lower  part  of  the  leg  it  gradually  inclines  inwards;  and 
at  its  termination  it  is  placed  below  the  tibia,  internal  to  the  centre  of  the 
hollow  between  the  heel  and  the  inner  ankle. 

As  far  as  the  middle  (in  length)  of  the  leg  the  vessel  is  concealed  by 
two  muscles  of  the  calf,  viz.,  gastrocnemius  and  soleus ;  but  below  that 
spot,  as  it  lies  between  the  tendo  Achillis  and  the  inner  edge  of  the  tibia, 
it  is  covered  only  by  the  teguments  and  the  deep  fascia.  At  its  termina- 
tion it  is  placed  beneath  the  annular  ligament.  For  its  upper  half  the 
trunk  lies  over  the  tibialis  posticus,  but  afterwards  on  the  flexor  digitorum, 
and  on  the  lower  end  of  the  tibia  and  the  ankle-joint.  On  the  outer  side 
is  the  flexor  pollicis. 

Between  the  heel  and  the  ankle,  the  artery  is  placed  between  the  ten- 
dons of  the  common  flexor  of  the  digits  and  special  flexor  of  the  great  toe. 

Vena?  comites  closely  surround  tlie  vessel.  The  posterior  tibial  nerve 
is  at  first  internal  to  the  artery  ;  but  at  the  distance  of  one  inch  and  a  half 
it  crosses  to  the  outer  side,  and  retains  that  position  throughout. 

This  artery  supplies  branches  to  the  muscles  and  the  tibia,  and  a  large 
peroneal  trunk  to  the  outer  side  of  the  leg. 

a.  Muscular  branches  enter  the  deep  layer  of  muscles,  and  the  soleus  ; 
and  an  ofl'set  from  the  branch  to  the  soleus  pierces  the  attachment  of  that 
muscle  to  tlie  tibia,  and  ascends  to  the  knee-joint. 

b.  A  nutritious  artery  of  the  shaft  of  the  tibia  is  uncertain  in  its  place 
of  origin  ;  penetrating  the  tibialis,  it  enters  the  canal  on  the  posterior  sur- 
face of  the  bone,  and  ramifies  in  the  interior. 

c.  A  communicating  branch   (/)  arises  opposite  the  lower  end  of  the 


POSTERIOR    TIBIAL    VEINS.  613 

tibia,  and  passes  outwards  beneath  the  flexor  pollicis,  to  unite  in  an  arch 
with  a  corresponding  offset  of  the  peroneal  artery. 

d.  Articular  branches  arise  from  the  artery  opposite  the  ankle-joint, 
and  enter  the  articulation. 

e.  Cutaneous  offsets  appear  through  the  fascia  in  the  lower  half  of  the 
leg ;  the  largest  of  these  pierces  the  annular  ligament,  and  accompanies 
the  cutaneous  plantar  nerve  to  the  sole  of  the  foot. 

Peculiarities.  If  ilo-Q  posterior  tibial  artery  is  smaller  than  usual,  or  absent,  its  de- 
ficiencies in  the  foot  will  be  supplied  by  a  large  communicating  branch  from  the 
peroneal  artery,  M'hicli  is  directed  inwards  at  the  lower  end  of  the  tibia,  and  either 
joins  the  small  tibial  vessel,  or  runs  alone  to  the  sole  of  the  foot. 

The  PERONEAL  ARTERY  (fig.  209,  g)  is  often  as  large  as  the  posterior 
tibial,  and  arises  from  that  vessel  about  one  inch  and  a  half  from  the  begin- 
ning. It  takes  the  fibula  as  its  guide,  and  lying  close  to  that  bone  in  the 
fibres  of  the  flexor  pollicis,  reaches  the  lower  part  of  the  interosseous  mem- 
brane. At  this  spot  it  sends  forwards  a  branch  to  the  front  of  the  leg 
(anterior  peroneal)  ;  and  it  is  directed  onwards  over  the  articulation  be- 
tween tlie  tibia  and  fibula  (A)  to  the  outer  side  of  the  heel,  where  it  termi- 
nates in  branches,  which  anastomose  with  ofl'sets  of  the  posterior  tibial,  and 
with  the  tarsal  and  external  plantar  arteries. 

Two  companion  veins  surround  the  artery ;  and  the  nerve  to  the  flexor 
pollicis  lies  on  it  generally. 

Branches.  Besides  tlie  anterior  peroneal,  it  furnishes  muscular,  nutri- 
tious, and  communicating  offsets. 

a.  Muscular  branches  are  distributed  to  the  soleus,  tibialis  posticus,  and 
flexor  pollicis ;  and  some  turn  round  the  fibula  to  the  peronei  muscles, 
lying  in  grooves  in  the  bone. 

h.  The  nutritious  artery  is  smaller  than  that  to  the  tibia,  and  is  trans- 
mitted through  the  tibialis  posticus  to  the  aperture  about  the  middle  of 
the  fibula. 

c.  The  anterior  peroneal  branch  passes  forwards  through  an  opening 
in  the  lower  part  of  the  interosseous  membrane,  and  is  continued  to  the 
dorsum  and  outer  part  of  the  foot ;  on  the  front  of  the  leg  and  foot  it  anas- 
tomoses with  the  external  malleolar  and  tarsal  branches  of  the  anterior 
tibial  artery. 

d.  A  communicating  ofl^set  near  the  ankle  joins  in  an  arch  with  a  simi- 
lar branch  of  the  posterior  tibial.  Sometimes  there  is  a  second  arch  be- 
tween the  same  vessels. 

Peculiarities.  The  anterior  branch  of  the  peroneal  may  take  the  place  of  the 
anterior  tibial  artery  on  the  dorsum  of  the  foot. 

A  compensating  principle  may  be  observed  amongst  the  arteries  of  the  foot  as  in 
those  of  the  hand,  by  which  the  deficiency  in  one  is  supplied  by  an  enlarged  off"- 
set  of  another. 

The  POSTERIOR  TIBIAL  VEINS  begin  on  the  inner  side  of  the  foot  by  the 
union  of  the  plantar:  they  ascend  one  on  each  side  of  the  artery,  and  unite 
with  the  anterior  tibial  at  the  lower  border  of  the  popliteus  to  form  the 
large  popliteal  vein.  They  receive  the  peroneal  veins,  and  branches  cor- 
responding with  the  offsets  of  the  artery ;  branches  connect  them  with  the 
saphenous  veins. 

The  POSTERIOR  TIBIAL  NERVE  (fig.  209,  ')  a  continuation  of  the  inter- 
nal popliteal,  reaches,  like  the  artery,  from  the  lower  border  of  the  popli- 
teus muscles  to  the  interval  between  the  os  calcis  and  the  inner  malleolus. 


614  DISSECTION    OF    THE    FOOT. 

Whilst  beneath  the  annular  ligament,  or  somewhat  higher  than  it,  the 
nerve  divides  into  the  internal  and  external  plantar  branches  of*  the  foot. 

Its  connections  with  surrounding  parts  are  the  same  as  those  of  the 
artery  ;  but  its  position  to  the  vessel  changes,  for  it  lies  on  the  inner  side 
above  the  origin  of  the  peroneal  offset,  but  thence  to  the  termination,  on 
the  outer  side.     Its  branches  are  muscular  and  cutaneous. 

Muscular  branches  enter  the  deep  flexors,  and  arise  either  separately 
along  the  trunk,  or  together  from  the  upper  part  of  the  nerve.  There  is 
an  offset  for  each  of  the  muscles  except  the  popliteus ;  but  the  branch  for 
the  tibialis  is  the  largest,  and  that  for  the  flexor  poUicis  lies  on  the  pero- 
neal artery. 

A  cutaneous  nerve  of  the  sole  of  the  foot  (fig.  209,  *)  begins  above  the 
OS  calcis,  and  piercing  the  internal  annular  ligament  as  two  or  more 
pieces,  ends  in  the  integuments  of  the  inner  and  under  parts  of  the  heel ; 
this  nerve  will  be  followed  to  its  termination  in  the  dissection  of  the  foot 
(fig.  210). 

The  internal  annular  ligament  stretches  between  the  heel  and  the  inner 
ankle,  and  serves  to  confine  the  tendons  of  the  deep  layer  of  muscles  of  the 
foot  and  toes.  Attached  by  a  pointed  piece  to  the  internal  malleolus,  the 
fibres  diverge,  and  are  inserted  into  the  os  calcis.  One  border  (upper)  is 
continuous  with  the  fascia  of  the  leg ;  and  the  opposite  gives  attachment 
to  the  abductor  pollicis  muscle  of  the  foot. 

Beneath  it  are  sheaths  for  the  tendons.  The  innermost  incloses  the 
tibialis  posticus,  lodged  in  a  groove  in  the  malleolus.  Immediately  be- 
hind this  is  another  space  for  the  flexor  digitorum.  And  about  three- 
quarters  of  an  inch  nearer  the  os  calcis  is  the  interval  in  which  the  flexor 
pollicis  lies,  resting  in  a  groove  in  the  astragalus.  Each  sheath  is  lined 
by  a  synovial  membrane. 

Between  the  tendons  of  the  two  flexors  of  the  digits  are  placed  the 
tibial  vessels  and  nerve. 


Section  Y. 

SOLE  OF  the  foot. 


Position.  The  foot  is  to  be  placed  over  a  block  of  moderate  thickness 
with  the  sole  towards  the  dissector ;  and  the  part  is  to  be  made  tense  by 
fixing  the  heel  with  hooks,  and  by  separating,  and  by  fastening  apart  the 
toes. 

Dissection.  The  skin  is  to  be  raised  as  two  flaps,  inner  and  outer,  by 
means  of  one  incision  along  the  centre  of  the  sole  from  the  heel  to  the 
front ;  and  by  another  across  the  foot  at  the  root  of  the  toes.  Afterwards 
the  skin  is  to  be  removed  from  each  toe,  and  the  digital  vessels  and  nerves 
on  the  sides  are  to  be  dissected  out  at  the  sarne  time. 

In  the  fat  near  the  heel  the  student  should  follow  the  cutaneous  nerve 
of  the  sole  {supra)  ;  and  he  may  trace  out,  at  a  little  distance  from  each 
border  of  the  foot,  some  small  branches  of  the  plantar  nerves  and  arteries. 

The  subcutaneous  fat  is  very  abun  jint.  and  forms  a  thick  cushion  over 
the  parts  that  press  most  on  the  ground  in  standing,  viz.,  over  the  os 
calcis,  and  the  metatarso-phalangeal  articulations. 


PLANTAR    FASCIA.  615 

Dissection.  The  fat  should  be  now  removed,  and  the  plantar  fascia 
laid  bare.  Beginning  the  dissection  near  the  heel,  follow  forwards  the 
fascia  towards  the  toes,  to  each  of  which  a  process  is  to  be  traced.  In  the 
intervals  between  those  processes  the  digital  nerves  and  arteries  will  be 
detected  amongst  much  fatty  and  fibrous  tissues ;  but  tiie  vessels  and 
nerves  to  the  inner  side  of  the  great  toe  and  outer  side  of  the  little  toe, 
pierce  the  fascia  farther  back  than  the  rest. 

The  student  is  next  to  define  a  transverse  fibrous  band  between  the 
toes,  over  the  digital  vessels  and  nerves  ;  and  when  tliis  lias  been  dis- 
played, he  may  remove  the  superficial  fascia  from  the  toes  to  see  the 
sheaths  of  the  tendons. 

Plantar  fascia.  The  special  fascia  of  the  sole  of  the  foot  is  of  a 
pearly-white  color  and  great  strength,  and  sends  septa  between  the  mus- 
cles. Its  thickness  varies  in  different  parts  of  the  foot ;  and  from  this  cir- 
cumstance, and  the  existence  of  longitudinal  depressions  over  the  tw^o 
chief  intermuscular  septa,  the  fascia  is  divided  into  a  central  and  two 
lateral  parts. 

The  central  part,  which  is  mucli  the  thickest,  is  pointed  at  its  attach- 
ment to  the  OS  calcis,  but  widens  and  becomes  thinner  as  it  extends  for- 
wards. A  slight  depression,  corresponding  wMth  an  intermuscular  septum, 
marks  its  limit  on  each  side :  and  opposite  the  heads  of  the  metatarsal 
bones  it  divides  into  five  processes,  w^iicli  send  fibres  to  the  teguments 
near  the  web  of  the  foot,  and  are  continued  onwards  to  the  toes,  one  to 
each.  Where  the  pieces  separate  from  each  other,  the  digital  vessels  and 
nerves  and  the  lumbricales  muscles  become  superficial ;  and  transverse 
fibres  arch  over  them. 

If  one  of  the  digital  processes  be  divided  longitudinally,  and  its  parts 
reflected  to  tlie  sides,  it  will  be  seen  to  join  the  sheath  of  the  flexor  ten- 
dons, and  to  be  fixed  laterally  into  the  margins  of  the  metatarsal  bone, 
and  into  the  transverse  metatarsal  ligament. 

The  lateral  pieces  of  the  fascia  are  thinner  tlian  the  central  one.  On 
the  inner  margin  of  the  foot  the  fascia  has  but  little  strength,  and  is  con- 
tinued to  the  dorsum  ;  but  on  the  outer  side  it  is  increased  in  thickness, 
and  presents  a  strong  band  between  tlie  os  calcis  and  the  projection  of  the 
fifth  metatarsal  bone. 

Dissection.  To  examine  the  septa,  a  longitudinal  incision  may  be 
made  along  the  middle  of  the  foot  tlirough  the  central  piece  of  the  fascia, 
and  a  transverse  one  near  the  calcaneum.  On  detaching  the  fascia  from 
the  subjacent  flexor  brevis  digitorum,  by  carrying  the  scalpel  from  before 
backw^ards,  the  septal  processes  will  appear  on  the  sides  of  that  muscle. 

The  intermuscular  septa  pass  dow^n  on  the  sides  of  the  flexor  brevis 
digitorum,  and  a  piece  of  fascia  reaches  across  the  foot  from  the  one 
septum  to  the  other,  beneath  that  flexor,  so  as  to  isolate  it. 

The  inner  septum  lies  between  the  short  flexor  and  the  abductor  pol- 
licis;  and  the  internal  plantar  nerve  and  vessels,  and  the  tendon  of  the 
flexor  pollicis  longus,  pass  through  it. 

The  outer  partition  between  tlie  short  flexor  and  the  abductor  minimi 
digiti,  is  pierced  by  the  digital  nerve  and  vessels  for  the  outer  side  of  the 
little  toe. 

The  S'uperjicial  transverse  ligament  crosses  the  roots  of  the  toes,  and  is 
contained  in  the  skin  forming  the  rudimentary  web  of  the  foot.  It  is 
attached  at  the  ends  to  the  sheath  of  the  flexor  tendons  of  the  great  and 


616  DISSECTION    OF    THE    FOOT. 

little  toes,  and  is  connected  with  the  sheath  of  the  others  as  it  passes  over. 
Beneath  it  the  digital  nerves  and  vessels  issue. 

The  sheaths  of  the  flexor  tendons  (Hg.  211,  **)  are  similar  to  those  of 
the  fingers,  though  not  so  distinct,  and  serve  to  confine  the  tendons  against 
the  grooved  bones.  The  sheath  is  weak  opposite  the  articulations  between 
the  phalanges,  but  is  strong  opposite  the  centre  of  both  the  metatarsal 
and  the  next  phalanx.  Each  is  lubricated  by  a  synovial  membrane,  and 
contains  the  tendons  of  the  long  and  short  flexor  muscles. 

Dissection  (fig.  210).  In  the  sole  of  the  foot  the  muscles  are  numer- 
ous, and  have  been  arranged  in  four  layers.  To  prepare  the  first  layer 
all  the  fascia  must  be  taken  away ;  but  tliis  dissection  must  be  made  with 
some  care,  lest  the  digital  nerves  and  vessels,  which  become  supei'ficial  to 
the  central  muscle  towards  the  toes,  should  be  injured. 

The  tendons  of  the  short  flexor  muscle  are  to  be  followed  to  the  toes, 
and  one  or  more  of  the  sheaths  in  which  they  are  contained  should  be 
opened. 

First  layer  of  Muscles.  In  this  layer  are  three  muscles,  viz.,  the 
flexor  brevis  digitorum,  the  abductor  pollicis,  and  abductor  minimi  digiti. 
The  short  flexor  of  the  toes  lies  in  the  centre  of  the  foot ;  and  each  of 
the  others  is  in  a  line  with  the  toe  on  which  it  acts. 

The  ABDUCTOR  roLLicis  (fig.  210,  ^),  the  most  internal  muscle  of  the 
superficial  layer,  takes  origin  from  the  inner  part  of  the  larger  tubercle 
on  the  under  surface  of  the  os  calcis  ;  from  the  plantar  fascia ;  and  from 
the  lower  border  of  the  internal  annular  ligament,  and  the  inner  side  of 
the  foot  as  far  as  the  scaphoid  bone.  In  front  the  muscle  ends  in  a  ten- 
don, which  is  joined  by  fibres  of  the  short  flexor,  and  is  inserted  into  the 
inner  side  of  the  base  of  the  metatarsal  phalanx  of  the  great  toe. 

The  cutaneous  surface  of  the  muscle  is  in  contact  with  the  plantar 
fascia ;  and  the  other  touches  the  tendons  of  the  tibial  muscles,  the  plantar 
vessels  and  nerves,  and  the  tendons  of  the  long  flexors  of  the  toes  with  the 
accessorius  muscle. 

Action.  This  abductor  acts  chiefly  as  a  flexor  of  the  metatarso-phalan- 
geal  joint  of  the  great  toe,  but  it  will  abduct  slightly  that  toe  from  the 
others. 

The  FLEXOR  BREVTS  DIGITORUM  (fig.  210,  ^)  (flexor  perforatus)  arises 
posteriorly  by  a  pointed  process  from  the  inner  part  of  the  larger  tubercle  of 
the  OS  calcis,  and  from  the  plantar  fascia  and  tlie  septa.  About  the  centre 
of  the  foot  the  muscle  ends  in  four  small  tendons,  which  are  directed  for- 
wards over  the  tendons  of  the  long  flexor,  and  entering  the  sheaths  of  the 
four  smaller  toes,  are  inserted  into  the  middle  phalanges.  In  tlie  sheatli 
of  the  toe  the  tendon  of  this  muscle  lies  at  first  (in  this  position  of  the 
foot),  on  the  long  flexor;  opposite  the  centre  of  the  metatarsal  ])halanx  it 
is  slit  lor  the  passage  of  the  other,  and  is  attached  by  two  processes  to  the 
sides  of  the  middle  phalanx. 

The  short  flexor  of  the  toes  is  contained  in  a  sheath  of  the  plantar 
fascia,  and  occupies  tlie  middle  of  the  foot.  It  conceals  the  tendon  of  the 
long  flexor  of  the  toes,  the  accessory  muscle,  and  the  external  plantar 
vessels  and  nerve. 

Action.  It  bends  the  nearest  phalangeal  joint  of  the  four  smaller  toes, 
like  the  flexor  sublimis  in  the  upper  limb,  and  approximates  the  toes  at 
the  same  time. 

The  ABDUCTOR  MINIMI  DIGITI  (fig.  210,  ^)  has  a  wide  origin  behind 
from  the  outer  tubercle  of  the  os   calcis,  from  the  fore  part  of  the  inner 


PLANTAR    VESSELS    AND    NERVES.  617 

tubercle,  and  from  the  plantar  fascia  and  the  external  intermuscular  sep- 
tum. It  ends  anteriorly  in  a  tendon  which  is  inserted  into  the  outer  side 
of  the  base  of  the  metatarsal  phalanx  of  the  little  toe. 

The  muscle  lies  along  the  outer  border  of  the  foot,  and  conceals  the 
flexor  accessorius,  and  the  tendon  of  the  peroneus  longus.  On  its  inner 
side  are  the  external  plantar  vessels  and  nerve.  Sometimes  a  part  of  the 
muscle  is  fixed  into  the  projection  of  the  fifth  metatarsal  bone. 

Action.  Though  it  abducts  the  little  toe  from  the  others,  as  the  name 
signifies,  its  chief  use  is  to  bend  the  metatarso-phalangeal  joint. 

Dissection.  To  bring  into  view  the  second  layer  or  muscles  and  the 
plantar  vessels  and  nerves,  the  muscles  already  examined  must  be  re- 
flected. Cut  through  the  flexor  brevis  at  the  os  calcis,  and  as  it  is  raised, 
notice  a  branch  of  nerve  and  artery  to  it.  Dividing  the  abductor  minimi 
digiti  near  its  origin,  and  turning  it  to  the  outer  side  of  the  foot,  seek  its 
nerve  and  vessel  close  to  the  calcaneum.  The  abductor  pollicis  can  be 
drawn  aside  if  it  is  necessary,  but  it  may  remain  uncut  till  afterwards. 

Next  the  internal  plantar  vessels  and  nerve  are  to  be  followed  forwards 
to  their  termination,  and  backwards  to  their  origin  ;  and  the  external 
plantar  vessels  and  nerve,  the  tendons  of  the  long  flexors  of  the  toes,  the 
accessory  muscle,  and  the  small  lumbricales,  should  be  freed  from  fat. 

The  PLANTAR  ARTERIES  (fig.  210)  are  the  terminal  branches  of  the 
posterior  tibial  trunk,  and  supply  digital  offsets  to  the  toes.  They  are 
two  in  number,  and  are  named  external  and  internal  from  their  rela- 
tive position  in  the  sole  of  the  foot.  Of  the  two  the  external  is  the 
larger,  and  forms  the  plantar  arch  of  arteries. 

The  internal  artery  (b)  is  inconsiderable  in  size,  and  accompanies  the 
internal  plantar  nerve,  under  cover  of  the  abductor  pollicis,  as  far  as  the 
middle  of  the  foot,  where  it  ends  in  four  superficial  digital  branches.  (Il- 
lustrations of  Dissections,  p.  404.) 

Branches.  The  artery  furnishes  muscular  branches,  like  the  nerve,  to 
the  abductor  pollicis  and  flexor  digitorum  perforatus,  and  to  the  flexor 
brevis  pollicis  and  the  two  internal  lumbricales.  Its  superficial  digital 
branches  accompany  the  digital  nerves  of  the  internal  plantar,  and  are 
thus  disposed  of: — 

The  Jirst  is  distributed  to  the  inner  side  of  the  foot  and  great  toe ;  the 
second  lies  over  the  first  interosseous  space ;  the  third  corresponds  with 
the  second  space;  and  the  fourth  is  placed  over  the  third  space.  At  the 
root  of  the  toes  the  last  three  join  the  deeper  digital  arteries  in  those 
spaces. 

The  external  artery  (a)  takes  an  arched  course  in  the  foot,  with  the 
concavity  of  the  arch  turned  inwards.  The  vessel  is  first  directed  out- 
wards across  the  sole,  and  then  obliquely  inwards  towards  tlie  root  of  the 
great  toe,  so  that  it  crosses  the  foot  twice.  In  the  first  half  of  its  extent, 
viz.,  from  the  inner  side  of  the  calcaneum  to  the  base  of  the  metatarsal 
bone  of  the  little  toe,  the  artery  is  comparatively  superficial;  in  the  other 
half,  between  the  little  and  the  great  toe,  it  lies  deeply  in  the  foot,  and 
forms  the  plantar  arch. 

Only  the  first  part  of  the  artery  is  now  laid  bare;  the  remaining  part, 
supplying  the  digital  branches,  will  be  noticed  after  the  examination  of 
the  third  layer  of  muscles  (p.  623). 

As  far  as  the  metatarsal  bone  of  the  little  toe,  the  vessel  is  concealed  by 
the  abductor  pollicis  and  the  flexor  brevis  digitorum ;  but  for  a  short  dis- 
tance near  its  termination  it  lies  in  the  interval  between  the  last  muscle 


618 


DISSECTION    OF    THE    FOOT. 


and  the  abductor  minimi  digiti.  In  this  extent  it  is  placed  on  the  os 
calcis,  and  the  flexor  accessorius:  and  it  is  accompanied  by  vena3  comites, 
and  the  external  plantar  nerve. 


Fig.  210. 


Ficr.  211. 


First  View  of  the  Sole  op  the  Foot 
(Illustrations  of  Dissections). 
Muscles  : 

A.  Abductor  pollicis. 

B.  Flexor  brevis  dijfitorum. 
c.  Abductor  minimi  digiti. 
1).  Ligament  of  the  toes. 

Jrterip.it : 
a.  External  plantar. 
6.  Internal  plantar. 
Nerves  : 
1.  Internal  plantar,  with  its  four  branches; 

2,  3,  4  and  5,  for  three  toes  and  a  half. 
6.  Ext<^rnal  plantar  nerve,  with  two  digital 
branches  ;  7  and  8,  for  one  toe  and  a  half. 


Second  view  of  the  Sole  of  the  Foot 
(Illustrations  of  Dissections). 
Muscles  : 

A.  Musculus  accessorius. 

B.  Tendon  of  flexor  digitorum  longus. 
c.  Tendon  of  flexor  lou>,'U8  pollicis. 

D.  Marks  the  four  lumbricales  muscles,  but 

the  letters  are  put  on  the  tendons  of  the 
flexor  digitorum  perforans. 

E.  Tendon  of  flexor  perforatus. 

F.  Tendon  of  flexor  perforans. 
a.  Sheath  of  flexor  tendons. 
H.  Tendon  of  poroneus  longus. 

Arteries : 

a.  Internal  plantar. 
t).  External  plantar. 

c.  Branch  to  abductor  minimi  digiti. 

d.  Branch  to  outer  side  of  little  toe. 
Nerves : 

i.  Internal,  and  2,  external  plantar. 
4.  Branch  to  flexor  brevis  pollicis. 


It  supplies  offsets  to  the  muscles  between  which   it  lies,  and  others  to 
the  outer  side  of  the  foot  for  anastomosis  with  the  peroneal  artery. 


PLANTAR    NERVES.  619 

The  PLANTAR  NERVES  (fig.  210)  are  derived  from  the  bifurcation  of 
the  posterior  tibial  trunk  behind  the  inner  ankle.  They  are  two  in  num- 
ber, like  the  arteries,  and  have  the  same  anatomy  as  those  vessels,  for 
each  accompanies  a  plantar  artery;  but  the  larger  nerve  lies  with  the 
smaller  bloodvessel. 

The  internal  plantar  nerve  (')  courses  between  the  short  flexor  of  the 
toes  and  the  abductor  pollicis,  and  giving  but  few  muscular  offsets,  divides 
into  four  digital  branches  (^  ^,  *,  *)  for  the  supply  of  both  sides  of  the  inner 
three  toes,  and  half  the  fourth ;  it  resembles  thus  the  median  nerve  of  the 
hand  in  the  distribution  of  its  branches. 

Muscular  otfsets  are  given  by  it  to  the  short  flexor  of  the  toes  (perfo- 
ratus)  and  the  abductor  pollicis;  and  a  few  superficial  twigs  perforate  the 
fascia. 

The  four  digital  nerves  have  a  numerical  designation,  and  the  first  is 
nearest  th?  inner  border  of  the  foot.  The  branch  Q)  to  the  inner  side  of 
the  great  toe  is  undivided,  but  the  others  are  bifurcated  at  the  cleft  be- 
tween the  toes. 

Muscular  branches  are  furnished  by  these  nerves  before  they  reach  the 
toes;  thus,  the  first  (most  internal)  supplies  the  flexor  brevis  pollicis;  the 
second  gives  a  brancli  to  the  inner  lumbrical  muscle,  and  the  third,  to  the 
next  lumbricalis. 

Digital  nerves  on  the  toes.  Each  of  the  outer  three  nerves,  being 
divided  at  the  spot  mentioned,  supplies  the  contiguous  sides  of  two  toes, 
whilst  the  first  belongs  alone  to  the  inner  side  of  the  great  toe  ;  all  give 
offsets  to  the  teguments,  and  the  cutis  beneath  the  nail,  and  articular  fila- 
ments are  distributed  to  the  joints  as  in  the  fingers. 

The  external  plantar  nerve  (*)  is  spent  chiefly  in  the  deep  muscles  of 
the  sole  of  the  foot,  but  it  furnishes  digital  nerves  to  both  sides  of  the  little 
toe,  and  the  outer  side  of  the  next.  It  corresponds  in  its  distribution  with 
the  ulnar  nerve  in  the  hand. 

It  has  the  same  course  as  the  external  plantar  artery,  and  divides  at  the 
outer  margin  of  the  flexor  brevis  digitorum  into  a  superficial  and  a  deep 
portion  : — the  former  gives  origin  to  two  digital  nerves  ;  but  the  latter 
accompanies  the  arch  of  the  plantar  artery  into  the  foot,  and  will  be  dis- 
sected afterwards. 

AVhilst  the  external  plantar  nerve  is  concealed  by  the  short  flexor  of 
the  toes,  it  gives  muscular  branches  to  the  abductor  minimi  digiti  and  the 
flexor  accessorius. 

The  digital  branches  of  the  external  plantar  nerve  (^  ^)  are  two.  One 
C^)  is  undivided  ;  it  is  distributed  to  the  outer  side  of  the  little  toe,  and 
gives  offsets  to  the  flexor  brevis  minimi  digiti,  and  oftentimes  to  the  inter- 
osseous muscles  of  the  fourth  space.  The  other  (^)  bifurcates  at  the  cleft 
between  the  outer  two  toes,  and  supplies  their  collateral  surfaces :  this 
nerve  communicates  in  the  foot  with  the  last  digital  branch  of  the  internal 
plantar  nerve. 

On  the  sides  of  the  toes  the  digital  nerves  have  the  same  distribution 
as  those  from  the  other  plantar  trunk,  and  end  like  them  in  a  tuft  of  fine 
branches  at  the  extremity  of  the  digit. 

Dissection  (fig.  211).  To  complete  the  preparation  of  the  second  layer 
of  muscles,  the  origin  of  the  abductor  pollicis  should  be  detached  from  the 
OS  calcis,  and  the  muscle  should  be  turned  inwards.  The  internal  plantar 
nerve  and  artery,  and  the  superficial  portion  of  the  external  plantar  nerve, 
are  to  be  cut  across  and  thrown  forwards ;  but  the  external  plantar  artery 


620  DISSECTION    OF    THE    FOOT. 

and  tlie  nerve  with  it  are  not  to  be  injured.     All  the  fat,  and  the  loose 
tissue  and  fascia,  are  then  to  be  taken  away  near  the  toes. 

Second  layer  of  muscles  (fig.  211).  In  this  layer  are  the  tendons 
of  the  two  flexor  muscles  at  the  back  of  the  leg,  viz.,  flexor  longus  digi- 
torum  and  flexor  longus  poUicis,  which  cross  one  another.  Connected  with 
the  former,  soon  after  it  enters  the  foot,  is  an  accessory  muscle ;  and  at  its 
division  into  pieces  four  fleshy  slips  (lumbricales)  are  added  to  it. 

The  tendon  of  the  flexor  longus  digitorum  (fig.  211,®),  whilst 
entering  the  foot  beneath  the  annular  ligament,  lies  on  tiie  internal  lateral 
ligament  of  the  ankle  joint.  In  the  foot  it  is  directed  obliquely  towards 
the  centre,  where  it  is  joined  by  the  tendon  of  the  flexor  longus  pollicis 
and  the  accessory  muscle,  and  divides  into  tendons  for  the  four  outer  toes. 

Each  tendon  enters  the  sheath  of  the  toe  with,  and  beneath  a  tendon 
from  the  flexor  brevis,  e.  About  the  centre  of  the  metatjirsal  phalanx 
the  tendon  of  the  long  flexor,  f,  is  transmitted  through  the  other,  and 
passes  onwards  to  be  inserted  into  the  base  of  the  ungual  phalanx.  Uniting 
the  flexor  tendons  with  the  two  nearest  phalanges  of  the  toes  are  liga- 
mentous bands  (lig.  brevia),  one  to  each,  as  in  the  hand;  and  the  one 
fixing  the  flexor  perforans  is  anterior  (p.  277). 

Action.  It  flexes  the  last  phalangeal  joint,  and  combines  with  the  short 
flexor  in  bending  the  metacarpo-phalangeal  joint.  If  it  acted  by  itself  it 
would  tend  to  bring  the  toes  somewhat  inwards,  in  consequence  of  its  ob- 
lique position  in  the  foot. 

The  lumhricales  (fig.  211,  ^)  are  four  small  muscles  between  the  tendons 
of  the  flexor  longus  digitorum.  Each  arises  from  two  tendons,  with  the 
exception  of  the  most  internal,  and  this  is  connected  with  the  inner  side  of 
the  tendon  to  the  second  toe.  Each  is  inserted  by  a  slip  into  the  tibial 
side  of  the  base  of  the  metatarsal  phalanx  in  the  four  outer  toes,  and  sends 
an  expansion  to  the  aponeurotic  covering  on  the  dorsum  of  the  phalanx. 
Thfe  muscles  decrease  in  size  from  the  inner  to  the  outer  side  of  the  foot. 

Actio7i.  These  small  muscles  will  assist  the  flexors  in  bending  the 
metatarso-phalangeal  joint  of  the  four  outer  toes  ;  and  through  their  union 
with  the  long  extensor  tendon  they  will  aid  that  muscle  in  straightening 
the  two  phlangeal  joints. 

The  accessorius  muscle  (fig.  211  ^)  has  two  heads' of  origin: — One  is 
mostly  tendinous,  and  is  attached  to  the  under  or  the  outer  surface  of  the 
OS  calcis,  and  to  the  ligamentum  longum  phmtoe ;  the  other  is  large  and 
fleshy,  and  springs  from  the  inner  or  concave  surface  of  the  calcaneum. 
The  fibres  end  in  aponeurotic  bands,  which  join  the  tendon  of  the  flexor 
longus  digitorum  about  the  centre  of  the  foot,  and  contribute  slips  to  the 
pieces  of  that  tendon  going  to  the  second,  tliird,  and  fourth  digits  (Turner). 

The  muscle  is  bifurcated  behind,  and  the  heads  of  origin  are  separated 
by  the  long  plantar  ligament.  On  it  lie  the  external  plantar  vessels  and 
nerve  ;  and  the  flexor  brevis  digitorum  conceals  it. 

Action.  By  means  of  its  offsets  to  the  tendons  of  certain  digits  the 
muscle  helps  to  bend  those  toes. 

And  from  its  position  on  the  outer  side  and  behind  the  long  flexor  to 
which  it  is  united,  it  will  oppose  the  inward  action  of  that  muscle,  and  will 
assist  the  other  flexors  in  bending  the  toes  directly  back. 

The  tendon  of  the  flexor  longus  pollicis  (fig.  211,  ^)  is  deeper  in 
the  sole  of  the  foot  than  the  flexor  longus  digitorum  ;  and,  directed  to  the 
root  of  the  great  toe,  it  enters  the  digital  slieath,  to  be  inserted  into  the 
base  of  the  ungual  phalanx.     It  is  united  to  the  long  flexor  tendon  by  a 


THIRD    LAYER    OF    MUSCLES.  621 

strong  tendinous  process  which,  joined  by  bands  of  the  accessorius,  is  con- 
tinued into  the  pieces  of  that  tendon  belonging  to  the  second  and  third 
toes  (Turner). 

Between  the  calcEineum  and  the  internal  malleolus  this  tendon  lies  in  a 
groove  in  the  astragalus ;  and  in  the  foot  it  occupies  a  hollow  below  the 
inner  projection  (sustentaculum  tali)  of  the  os  calcis,  being  enveloped  by 
a  synovial  membrane. 

Action.  For  the  action  of  this  mnscle  on  the  great  toe,  see  page  610. 
Through  the  slip  that  it  gives  to  the  tendons  of  the  flexor  longus  going  to 
the  second  and  third  toes,  it  may  bend  those  digits  with  the  great  toe. 

Dissection  (fig.  212).  For  the  dissection  of  the  third  layer  of  muscles, 
the  accessorius  and  the  tendons  of  the  long  flexor  are  to  be  cut  through 
near  the  calcaneum,  and  turned  towards  the  toes.  Whilst  raising  the 
tendons  the  external  plantar  nerve  and  artery  are  not  to  be  interfered 
with ;  and  two  small  nerves  and  vessels  to  the  outer  two  lumbricales  are 
to  be  looked  for.  Afterwards  the  areolar  tissue  is  to  be  taken  from  the 
muscles  now  brought  into  view. 

Third  layer  of  muscles  (fig.  212).  Only  the  short  muscle  of  the 
great  and  little  toes  enter  into  this  layer.  On  the  metatarsal  bone  of  the 
great  toe  the  flexor  brevis  pollicis  lies,  and  external  to  it  is  the  adductor 
pollicis  ;  on  the  metatarsal  bone  of  the  little  toe  is  placed  the  flexor  brevis 
minimi  digiti.  Crossing  the  heads  of  the  metatarsal  bones  is  the  trans- 
versals pedis  muscle. 

The  fleshy  mass  between  the  adductor  pollicis  and  the  short  flexor  of 
the  little  toe  consists  of  the  interossei  muscles  of  the  next  layer. 

The  FLEXOR  BREVIS  POLLICIS  musclc  (fig.  212,  ^)  is  tendinous  and 
pointed  posteriorly,  but  bifurcated  in  front.  It  is  attached  behind  to  the 
inner  part  of  the  under  surface  of  the  cuboid  bene,  and  to  a  prolongation 
from  the  tendon  of  the  tibialis  posticus.  Near  the  front  of  the  metatarsal 
bone  of  the  great  toe  it  divides  into  two  heads,  which  are  inserted  into  the 
sides  of  the  base  of  the  metatarsal  phalanx. 

Resting  on  the  muscle  at  one  part,  and  in  the  interval  between  the 
heads  at  another,  is  the  tendon  of  the  flexor  longus  pollicis.  The  inner 
head  joins  the  abductor,  and  the  outer  is  united  with  the  adductor  pollicis. 
A  sesamoid  bone  is  developed  in  the  tendon  connected  with  each  head. 

Action.  By  its  attachment  to  the  first  phalanx  it  flexes  the  metatarso- 
phalangeal joint  of  the  great  toe. 

The  ADDUCTOR  roLLicis  (fig.  212,  ^),  which  is  larger  than  the  pre- 
ceding muscle  and  external  to  it,  arises  from  the  sheath  of  the  tendon  of 
the  peroneus  longus,  and  from  the  bases  of  the  second,  third,  and  fourth 
metatarsal  bones.  Anteriorly  the  muscle  is  united  with  the  outer  head  of 
the  short  flexor,  and  is  inserted  with  it  into  the  base  of  the  metatarsal 
phalanx  of  the  great  toe. 

To  the  inner  side  is  the  flexor  brevis  ;  and  beneath  the  outer  the  exter- 
nal plantar  vessels  and  nerve  are  directed  inwards. 

Action.  Its  first  action  will  be  to  adduct  the  great  toe  to  the  others,  and 
it  will  help  afterwards  in  bending  the  matatarso-phalangeal  joint  of  the  toe. 

The  TRANSVERSALis  PEDIS  (fig.  212,  °)  is  placed  transversely  over  the 
heads  of  the  metatarsal  bones.  Its  origin  is  by  fleshy  bundles  from  the 
capsule  of  the  metatarso-phalangeal  articulations  of  the  four  outer  toes 
(frequently  not  from  the  little  toe),  and  from  the  fascia  covering  the  inter- 
ossei muscles.  Its  insertion  into  the  great  toe  is  united  with  that  of  the 
adductor  pollicis. 


622 


DISSECTION    OF    THE    FOOT. 
Fig.  212.  Fig   213. 


Third  View  of  thk  Sole  op  the  Foot. 
(Illustrations  of  Dissections.) 

Muscles  : 

A.  Flexor  brevis  pollicis. 

B.  Adductor  pollicis. 

c.  Flexor  brevis  minimi  digiti. 

D.  Transversalis  pedis. 
Arteries : 

a.  Internal  plantar,  cnt. 

h.   External  plantar  ;  and 

c.   Its  four  digital  branches. 
Nerves : 

1.  Internal  plantar. 

2.  External  plantar. 

3.  Its  superficial  part,  cut. 

4.  The  deep  part,  with  the  plantar  arch. 

5.  Two  offsets  to  the  outer  two  lumbricales 

muscles. 


FouKTH  View  of  the  Soi-k  of  the  Foot. 
(Illustrations  of  Disseciious.) 

Muscles : 

0.  Three  plantar  interossei. 

1.  Four  dorsal  interossei. 
Arteries  : 

a.  Internal  plantar,  cut. 

b.  External  plantar. 

c.  Its  four  digital  branches. 

d.  Plantar  arch. 

€.  Anteiior  tibial  entering  the  sole. 
/.   Arteria  magna  pollicis 
Q  .  Branch  to  inner  side  of  great  toe. 
h.  Branch  for  the  supply  of  great  toe  and  the 
next. 
Nerves  : 

1.  Internal  plantar,  cut. 

2.  External  plitntar. 

3.  Its  superficial;  and 

4.  its  deep  part,  both  cut ;  the  latter  supply- 

ing offsets  to  the  interossei  muscles. 


The  cutaneous  surface  is  covered  by  the  tendons,  and  the  nerves  of  the 
toes  ;  and  the  opposite  surface  is  in  contact  witli  the  interossei  muscles  and 
the  digital  vessels. 

Action.     It  will  adduct  the  great  toe  to  the  others,  and  then  approxi- 


mate the  remaining  toes. 


PLANTAR    ARCH    OF    VESSELS.  623 

The  FLEXOR  BREVis  MINIMI  DiGiTi  (fig.  212,  °)  is  a  Small  narrow- 
muscle  on  the  metatarsal  bone  of  the  little  toe,  and  resembles  one  of  the 
interossei.  Arising  behind  from  the  metatarsal  bone  and  the  sheath  of 
the  peroneiis  longus,  it  blends  with  the  inferior  ligament  of  the  metatarso- 
phalangeal articulation,  and  is  inserted  into  the  base  of  the  metatarsal 
phalanx  of  the  toe;  it  is  united  also  by  fleshy  fibres  with  the  fore  part  of 
the  metatarsal  bone. 

Action.  Firstly  it  bends  the  metatarso-phalangeal  joint,  and  nextly  it 
draws  down  and  adducts  the  fore  part  of  the  fifth  metatarsal  bone. 

Dissection  (fig.  2*  3).  In  order  that  the  deep  vessels  and  nerves  may 
be  seen,  the  flexor  brevis  and  adductor  pollicis  are  to  be  cut  through  at 
the  posterior  part,  and  tlirown  towards  the  toes ;  but  the  nerves  supplying 
them  are  to  be  preserved.  Beneath  the  adductor  lie  the  plantar  arch,  and 
the  external  plantar  nerve,  with  their  branches;  and  in  the  first  interos- 
seous space  is  the  part  of  the  dorsal  artery  of  the  foot  that  enters  the  sole. 
All  these  vessels  and  nerves  with  their  branches  require  careful  cleaning. 

The  muscles  projecting  between  the  metatarsal  bones  are  the  interossei ; 
the  fascia  covering  them  should  be  removed. 

The  PLANTAR  ARCH  (fig.  213,  d)  is  the  part  of  the  external  plantar 
artery  which  reaches  from  the  base  of  the  metatarsal  bone  of  the  little  toe 
to  the  back  of  the  first  interosseous  space :  internally  the  arch  is  completed 
by  a  communicating  branch  from  the  dorsal  artery  of  the  foot  (e)  (p.  624). 
It  is  placed  across  the  tarsal  ends  of  the  metatarsal  bones,  in  contact  w^ith 
the  interossei,  but  under  the  flexor  tendons,  and  the  adductor  pollicis  to 
which  it  gives  many  branches. 

Venae  comites  lie  on  the  sides  of  the  artery,  and  the  external  plantar 
nerve  accompanies  it. 

From  the  front  or  convexity  of  the  arch  the  digital  branches  are  sup- 
plied, and  from  the  opposite  side  small  nutritive  branches  arise. 

Three  small  arteries,  the  posterior  perforating^  leiwe  the  under  part: 
these  pass  to  the  dorsum  of  the  foot  through  the  three  outer  metatarsal 
spaces,  and  anastomose  with  the  dorsal  interosseous  branches  of  the  ante- 
rior tibial  artery. 

The  digital  branches  (c)  are  four  in  number,  and  supply  both  sides  of 
the  three  outer  toes,  and  half  the  next.  One  to  the  outer  side  of  the  little 
toe  is  single;  but  the  others  lie  over  the  interossei  in  the  outer  three 
metatarsal  spaces,  but  beneath  the  transversalis  pedis  (fig.  212),  and  bi- 
furcate in  front  to  supply  the  contiguous  sides  of  two  toes.  They  give  fine 
oflsets  (fig.  212)  to  the  interossei,  to  some  lumbricales,  and  the  transver- 
salis pedis;  and  at  the  point  of  division  they  send  small  communicating 
branches — anterior  perforating,  to  join  the  interosseous  arteries  on  the 
dorsum  of  the  foot. 

The  first  digital  runs  on  the  outer  side  of  the  little  toe,  supplying  the 
flexor  brevis  minimi  digiti,  and  distributes  small  arteries  to  the  teguments 
of  the  outer  border  of  tlie  foot. 

The  second  belongs  to  the  sides  of  the  fifth  and  fourth  toes,  and  fur- 
nishes a  branch  to  the  outer  lumbrical  muscle. 

The  third  is  distributed  to  the  contiguous  sides  of  the  fourth  and  third 
toes,  and  emits  a  branch  to  the  third  lumbricalis. 

The  fourth,  or  most  internal,  corresponds  with  the  second  interosseous 
space,  and  ends  like  the  others  on  the  third  and  second  digits ;  it  may 
assist  in  supplying  the  third  lumbricalis. 


624  DISSECTION    OF    THE    FOOT. 

The  last  two  digital  are  joined  by  superficial  digitalis  branches  of  the 
internal  plantar  at  the  root  of  the  toes. 

On  tlie  sides  of  tlie  toes  the  disposition  of  the  arteries  is  like  that  of  the 
digital  in  the  hand.  They  extend  to  the  end,  where  tliey  unite  in  an 
arch,  and  give  offsets  to  the  sides  and  ball  of  the  toe :  and  the  artery  on 
the  second  digit  anastomoses  with  a  branch  from  the  anterior  tibial  artery. 
Near  the  front  of  both  the  metatarsal  and  the  next  phalanx,  they  form 
anastomotic  loops  beneath  the  flexor  tendons,  from  which  the  phalangeal 
articulations  are  supplied. 

The  DORSAL  ARTERY  OF  THE  FOOT  (fig.  213,  e)  enters  the  sole  at  the 
posterior  part  of  the  first  (inner)  metatarsal  space,  and  ends  by  inoscu- 
lating with  the  plantar  arch.  By  a  large  digital  artery  it  furnishes 
branches  to  both  sides  of  the  great  toe  and  half  the  next,  in  the  same  man- 
ner as  the  radial  artery  in  the  hand  is  distributed  to  one  digit  and  a  half. 

The  digital  branch  (^f)  (art.  magna  pollicis)  extends  to  the  front  of  the 
first  interosseous  space,  and  divides  into  collateral  branches  (//)  for  the 
contiguous  sides  of  the  great  toe  and  the  next;  near  the  head  of  the  meta- 
tarsal bone  it  sends  inwards,  beneath  the  flexor  muscles,  a  digital  branch 
{g)  for  the  inner  side  of  the  great  toe. 

These  arteries  have  the  same  arrangement  along  the  toes  as  the  other 
digital  branches;  and  that  to  the  second  digit  anastomoses  at  the  end  of 
the  toe  with  a  branch  of  the  plantar  arch. 

External  plantar  nerve  (fig.  213,  ^).  The  deep  branch  (*)  of  this 
nerve  accompanies  the  arch  of  the  artery,  and  ends  internally  in  the  ad- 
ductor pollicis.  It  furnishes  branches  to  all  the  interossei ;  to  the  trans- 
versalis  pedis;  and  to  the  two  external  lumbrical  muscles.  The  nerve 
corresponds  with  the  deep  portion  of  the  ulnar  nerve  in  the  hand. 

Dissection.  It  will  be  needful  to  remove  the  transversalis  pedis  muscle, 
to  see  a  ligament  across  the  heads  of  the  metatarsal  bones. 

The  transverse  metatarsal  ligament  is  a  strong  fibrous  band,  like  that 
in  the  hand  (p.  280),  which  connects  together  all  the  metatarsal  bones  at 
their  anterior  extremity.  A  thin  fascia  covering  the  interossei  muscles  is 
connected  to  its  hinder  edge.  It  is  concealed  by  the  transversalis  pedis, 
and  by  the  tendons,  vessels,  and  nerves  of  the  toes. 

Dissection.  To  complete  the  dissection  of  the  last  layer  of  muscles,  the 
flexor  brevis  minimi  digiti  may  be  detached  and  thrown  forwards.  Di- 
viding then  the  metatarsal  ligament  between  the  bones,  the  knife  is  to  be 
carried  directly  backwards  for  a  short  distance  in  the  centre  of  each  inter- 
osseous space,  exce{)t  the  first,  in  order  that  the  two  interossei  muscles 
may  be  separated  from  each  other.  All  the  interossei  are  visible  in  the 
sole  of  the  foot. 

The  fascia  covering  the  muscles  should  be  taken  away  if  any  remains, 
and  the  branches  of  the  external  plantar  nerve  to  tiiem  should  be  dissected 
out. 

Fourth  layer  of  muscles  (fig.  213).  In  the  fourth  and  last  layer 
of  the  foot  are  contained  the  interossei,  and  the  tendons  of  the  tibialis  pos- 
ticus and  peroneus  longus. 

The  interossei  muscles  (fig.  213)  are  situate  in  the  intervals  between 
the  metatiirsal  bones  :  they  consist  of  two  sets,  plantar  and  dorsal,  like  the 
interossei  in  the  hand.  Seven  in  number,  there  are  three  plantar  and  four 
dorsal ;  and  two  are  found  in  each  space,  except  the  innermost. 

The  plantar  interossei^  o,  belong  to  three  outer  metatarsal  bones  (fig. 
213),  and  are  slender  fleshy  slips.     They  arise  from  the  under  and  inner 


FOURTH    LAYER    OP    MUSCLES.  625 

surfaces  of  those  bones ;  and  are  inserted  partly  into  the  tibial  side  of  the 
base  of  the  metatarsal  phalanx  of  the  same  toes,  and  partly  by  an  expan- 
sion from  each  to  the  extensor  tendons  on  the  dorsum  of  the  phalanx. 
These  muscles  are  smaller  than  the  dorsal,  and  are  placed  more  in  the 
sole  of  the  foot. 

The  dorsal  interossei,  i,  one  in  each  space,  arise  by  two  heads  from  the 
lateral  surfaces  of  the  bones  between  which  they  lie  ;  and  are  inserted  like 
the  others  into  the  side,  and  on  the  dorsum  of  the  metatarsal  phalanx  of 
certain  toes  :  Thus,  the  inner  two  muscles  belong  to  the  second  toe,  one  to 
each  side  ;  the  next  appertains  to  the  outer  side  of  the  third  toe ;  and  the 
remaining  one  to  the  outer  side  of  the  fourth  toe. 

The  interossei  are  crossed  by  the  external  plantar  artery  and  nerve,  and 
their  digital  branches,  and  lie  beneath  the  transversalis  pedis  and  the  meta- 
tarsal ligament.  The  posterior  perforating  arteries  pierce  the  hinder  ex- 
tremities of  the  dorsal  set. 

Action.  Like  the  interossei  of  the  hand  (p.  281)  they  will  contribute  to 
the  bending  of  the  metatarso-phalangeal  joints  by  the  flexors,  and  will  help 
the  extensors  to  straighten  the  last  two  phalangeal  joints. 

They  can  act  also  as  abductors  and  adductors  of  the  toes.  Thus  the 
plantar  set  will  bring  the  three  outer  towards  the  second  toe ;  and  the 
dorsal  muscles  will  abduct  from  the  middle  line  of  the  second  toe — the  two 
attached  to  that  digit  moving  it  to  the  right  and  left  of  the  said  line. 

Dissection.  Following  the  tendon  of  the  tibialis  posticus  muscle  from 
its  position  behind  the  inner  malleolus  to  its  insertion  into  the  scaphoid 
bone,  trace  the  numerous  processes  that  it  sends  forwards  and  outwards. 
Open  also  the  fibrous  sheath  of  the  tendon  of  the  peroneus  longus,  which 
crosses  from  the  outer  to  the  inner  side  of  the  foot. 

The  tendon  of  the  tibialis  posticus  is  continued  forwards  over  the 
internal  lateral  ligament  of  the  ankle  joint,  and  over  the  astragalo  scaphoid 
articulation  to  be  inserted  into  the  prominence  of  the  scaphoid  bone. 
From  its  insertion  processes  are  continued  to  many  of  the  other  bones  of 
the  foot :  One  is  directed  backwards  to  the  margin  of  the  groove  in  the  os 
calcis  for  the  tendon  of  the  flexor  longus  pollicis.  Two  offsets  are  directed 
forwards  ;  one  to  the  internal  cuneiform  bone ;  the  other,  much  the  largest, 
is  attached  to  the  middle  and  outer  cuneiform,  to  the  os  cuboides,  and  to 
the  bases  of  the  second,  third,  and  fourth  metatarsal  bones.  In  other  words, 
pieces  are  fixed  into  all  the  tarsal  bones  except  one  (astragalus)  ;  and  into 
all  the  metatarsal  bones  except  two  (first  and  fifth). 

Where  the  tendon  is  placed  beneath  the  articulation  of  the  astragalus, 
it  contains  a  sesamoid  bone,  or  fibro-cartilage. 

The  tendon  of  the  peroneus  longus  muscle  winds  round  the  cuboid 
bone,  and  is  continued  inwards  in  the  groove  on  the  under  surface,  to  be 
inserted  into  the  internal  cuneiform  bone,  and  the  base  of  the  metatarsal 
bone  of  the  great  toe  ;  and  sometimes  by  a  slip  into  the  base  of  the  second 
metatarsal  bone. 

In  the  sole  of  the  foot  (fig.  213),  it  is  contained  in  a  sheath  which  is 
crossed,  towards  the  outer  part,  by  the  fibres  of  the  long  plantar  ligament 
prolonged  to  the  tarsal  ends  of  the  third  and  fourth  metatarsal  bones  ;  but 
it  is  formed  internally  only  by  areolar  tissue.  A  separate  synovial  mem- 
brane lubricates  the  sheath. 

Where  the  tendon  turns  round  the  cuboid  bone  it  is  thickened,  and  con- 
tains fibro-cartilage  or  a  sesamoid  bone. 
40 


626  DISSECTION    OF    THE    LEG. 

Section  VI. 

THE  FRONT  OF  THE  LEG. 

Position.  The  limb  is  to  be  raised  to  a  convenient  height  by  blocks 
beneath  the  knee,  and  the  foot  is  to  be  extended  in  order  that  the  muscles 
on  the  front  of  the  leg  may  be  put  on  the  stretch. 

Dissection.  To  enable  the  dissector  to  raise  the  skin  from  the  leg  and 
foot,  one  incision  should  be  made  along  the  middle  line  from  the  knee  to 
the  toes,  and  this  should  be  intersected  by  cross  cuts  at  the  ankle  and  the 
root  of  the  toes. 

After  the  flaps  of  skin  are  reflected,  the  cutaneous  vessels  and  nerves  are 
to  be  looked  for.  At  the  upper  and  inner  part  of  the  leg  are  some  fila- 
ments from  the  great  saphenous  nerve  ;  and  at  the  outer  side  others,  still 
smaller,  from  the  external  popliteal  nerve.  Perforating  the  fascia  in  the 
lower  third,  on  the  anterior  aspect,  is  the  musculo-cutaneous  nerve,  whose 
branches  should  be  pursued  to  the  toes. 

On  the  dorsum  of  the  foot  is  a  venous  arch,  which  ends  laterally  in  the 
saphenous  veins.  On  the  outer  side  is  the  external  saphenous  nerve  ;  and 
about  the  middle  of  the  instep  the  internal  saphenous  nerve  ceases.  In  the 
interval  between  the  great  toe  and  the  next  is  the  cutaneous  part  of  the 
anterior  tibial  nerve. 

The  digital  nerves  should  be  traced  to  the  ends  of  the  toes  by  removing 
the  integuments :  and  after  the  several  vessels  and  nerves  are  dissected, 
the  fat  is  to  be  taken  away,  in  order  that  the  fascia  may  be  seen. 

The  venous  arch  on  the  dorsum  of  the  foot  has  its  convexity  turned 
forwards,  and  receives  digital  branches  from  the  toes  ;  at  its  concavity  it 
is  joined  by  small  veins  from  the  instep.  Internally  and  externally  it 
unites  with  the  saphenous  veins. 

The  internal  saphenous  vein  begins  at  tlie  inner  side  of  the  great  toe, 
and  in  the  arch.  It  ascends  along  the  inner  side  of  the  foot,  and  in  front 
of  the  inner  ankle  to  the  inside  of  the  leg  (p.  606).  Branches  enter  it 
from  the  inner  side  and  sole  of  the  foot. 

The  external  saphenous  vein  begins  on  the  outside  of  the  little  toe  and 
foot,  as  well  as  in  the  venous  arch  ;  and  it  is  continued  below  the  outer 
ankle  to  the  back  of  the  leg  (p.  606). 

Cutaneous  Nerves  (fig.  214).  Tiie  superficial  nerves  on  the  front 
of  the  leg  and  foot  are  derived  mainly  from  branches  of  the  popliteal 
trunks,  viz.,  from  the  musculo-cutaneous  and  anterior  tibial  nerves  of  the 
external  popliteal,  and  from  the  external  saphenous  nerve  of  the  internal 
popliteal.  Some  inconsiderable  offsets  ramify  on  the  sides  of  the  leg  from 
the  internal  saphenous  and  external  popliteal. 

The  musculo-cutaneous  nerve  (J)  ends  on  the  dorsum  of  the  foot  and 
toes.  Perforating  the  fascia  in  the  lower  third  of  the  leg  with  a  cutane- 
ous artery,  it  divides  into  two  principal  branches  (inner  and  outer),  which 
give  dorsal  digital  nerves  to  the  sides  of  all  the  toes,  except  the  outer  part 
of  the  little  toe  and  the  contiguous  sides  of  the  great  toe  and  the  next. 
The  branches  may  be  traced  in  the  integument  as  far  as  the  end  of  the 
last  phalanx. 

The  inner  branch  (^)  communicates  with  the  internal  saphenous  nerve, 


CUTANEOUS  NERVES  ON  THE  FRONT. 


6-27 


\    A 


h 


and  supplies  the  inner  side  of  the  foot  and  great  Fig.  214. 

toe  :  it  joins  also  the  anterior  tibial  nerve. 

The  outer  branch  (*)  divides  into  three  nerves  ; 
these  lie  over  the  three  outer  interosseous  spaces, 
and  bifurcate  at  the  web  of  the  foot  for  the  con- 
tiguous sides  of  the  four  toes  corresponding  with 
those  spaces ;  it  joins  the  external  saphenous 
nerve  on  the  outer  part  of  the  foot. 

The  anterior  tibial  7ierve  Q)  becomes  cutane- 
ous in  the  first  interosseous  space,  and  is  distri- 
buted to  that  space,  and  to  the  opposed  sides  of 
the  o-reat  toe  and  the  next.     The  musculo-cuta- 

o  ... 

neous  nerve  joins  it,  and  sometimes   assists  in 
supplying  the  same  toes. 

The  external  saphenous  nerve  (fig.  207,  ^) 
comes  from  the  back  of  the  leg  below  the  outer 
ankle,  and  is  continued  along  the  foot  to  the  out- 
side of  the  little  toe  ;  all  the  outer  margin  of  the 
foot  receives  nerves  from  it,  and  the  offsets  to- 
wards tlie  sole  are  larger  than  those  to  the  dor- 
sum. Occasionally  it  supplies  both  sides  of  the 
little  toe  and  part  of  the  next. 

Internal  saphenous  nerve  (^).  A  part  of  this 
nerve  is  continued  along  tlie  vein  of  the  same 
name  to  the  middle  of  the  instep,  where  it 
ceases  mostly  in  the  integuments,  but  some 
branches  pass  through  the  deep  fascia  to  end  in 
the  tarsus. 

T\\e  fascia  of  the  front  of  the  leg  is  thickest 
near  the  knee  joint,  where  it  gives  origin  to 
muscles.  It  is  fixed  laterally  into  the  tibia  and 
fibula.  Intermuscular  septa  are  prolonged  from 
the  deep  surface  ;  and  one  of  these,  which  is  at- 
tached to  the  fibula,  separates  the  muscles  on  the 
front  from  those  on  the  outer  side  of  the  leg. 
Superiorly  the  fascia  is  connected  to  the  heads 
of  the  leg  bones,  but  inferiorly  it  is  continued  to 
the  dorsum  of  the  foot. 

Above  and  below  the  ankle  joint  it  is  strength- 
ened by  some  transverse  fibres,  and  gives  origin 
to  the  two  parts  of  the  anterior  annular  ligament ; 
and  below  the  end  of  the  fibula  it  forms  another  band,  the  external  annular 
ligament. 

Dissection.  The  fascia  is  to  be  removed  from  the  front  of  the  leg  and 
the  dorsum  of  the  foot,  but  the  thickened  band  of  the  annular  ligament 
above  and  below  the  end  of  the  tibia  is  to  be  left.  In  separating  the 
fascia  from  the  subjacent  muscles,  let  the  edge  of  the  scalpel  be  directed 
upwards. 

In  like  manner  the  fascia  may  be  taken  from  the  peronei  muscles  on  the 
outside  of  the  fibula,  but  without  destroying  the  band  (external  annular 
ligament)  below  that  bone. 

On  the  dorsum  of  the  foot  the  dorsal  vessels  with  their  nerve  are  to  be 
displayed,  and  the  tendons  of  the  short  and  long  extensors  of  the  toes  are 


THK 
AND 


Cutaneous  Nerves  of 
Front  of  the  Leo 
Foot. 

1.  Anterior  tibial. 

2.  Muscalo-cutaneous,  with  3, 

its  inner,  and  4,  its  outer 
piece ;  the  usual  distri- 
bution is  not  shown  in 
the  cut. 

.5.  Internal  saphenous. 

6.  Offsets  of  external  popliteal. 


628  DISSECTION    OF    THE    LEG. 

to  be  traced  to  the  ends  of  the  digits.  In  the  leg  the  anterior  tibial  nerve 
and  vessels  are  to  be  followed  from  the  dorsum  into  their  intermuscular 
space,  and  are  then  to  be  cleaned  as  high  as  the  knee. 

The  anterior  annular  ligament  consists  of  two  parts,  upper  and  lower, 
which  confine  the  muscles  in  their  position  :  the  former  serving  to  bind 
the  fleshy  parts  to  the  bones  of  the  leg,  and  the  latter  to  keep  down  the 
tendons  on  the  dorsum  of  the  foot  : — 

The  upper  part  (fig.  215,  ^),  above  the  level  of  the  ankle-joint,  is  at- 
tached laterally  to  the  bones  of  the  leg ;  it  possesses  one  sheath  with 
synovial  membrane  for  the  tibialis  anticus. 

The  lower  part  is  situate  in  front  of  the  tarsal  bones.  It  is  inserted 
externally  by  a  narrow  piece  into  the  upper  surface  of  the  os  calcis,  in 
front  of  the  interosseous  ligament ;  and  internally,  where  it  is  thin  and 
widened,  into  the  plantar  fascia  and  the  inner  malleous.  In  this  piece  of 
the  ligament  there  are  three  sheaths  :  an  inner  one  for  the  tibialis  anticus  ; 
an  outer  for  the  extensor  longus  digitorum  and  peroneus  tertius  ;  and  an 
intermediate  one  for  the  extensor  pollicis.  Separate  synovial  membranes 
line  the  sheaths. 

The  external  annular  ligament  is  placed  below  the  fibula,  and  is  at- 
tached on  the  one  side  to  the  outer  malleolus,  and  on  the  other  to  the  os 
calcis.  Its  lower  edge  is  connected  by  fibrous  tissue  to  the  sheaths  of  the 
peronei  muscles  on  the  outer  side  of  the  os  calcis.  It  contains  the  two 
lateral  peronei  muscles  in  one  compartment ;  and  this  is  lined  by  a  syno- 
vial membrane,  which  sends  two  otiTsets  below  into  the  sheaths  of  the 
peronei  muscles. 

The  MUSCLES  ON  THE  FRONT  OF  THE  LEG  (fig.  215)  are  three  in  num- 
ber. The  large  muscle  next  the  tibia  is  the  tibialis  anticus ;  that  next 
the  fibula,  the  extensor  longus  digitorum  ;  whilst  a  small  muscle,  appa- 
rently the  lower  part  of  the  last,  with  a  separate  tendon  to  the  fifth  meta- 
tarsal bone,  is  the  peroneus  tertius.  The  muscle  between  the  tibialis  and 
extensor  digitorum,  in  the  lower  half  of  the  leg,  is  the  extensor  pollicis. 

On  the  dorsum  of  the  foot  only  one  muscle  appears,  the  extensor  brevis 
digitorum. 

The  TIBIALIS  ANTICUS  (fig.  215,  ')  reaches  the  tarsus  :  it  is  thick  and 
fleshy  in  the  upper,  but  tendinous  in  the  lower  part  of  the  leg.  It  arises 
from  the  outer  tuberosity  and  the  upper  half  or  more  of  the  tibia ;  from 
the  contiguous  part  of  the  interosseous  ligament ;  and  from  the  fascia  of 
the  leg  and  the  intermuscular  septum  between  it  and  the  next  muscle. 
Its  tendon  begins  below  the  middle  of  the  leg,  and  passes  through  com- 
partments in  the  pieces  of  the  annular  ligament,  to  be  inserted  into  the 
internal  cuneiform  bone,  and  the  metatarsal  bone  of  the  great  toe. 

The  muscle  is  subaponeurotic.  It  lies  at  first  outside  the  tibia,  resting 
on  the  interosseous  membrane,  but  it  is  then  placed,  successively,  over  the 
end  of  the  tibia,  the  ankle-joint,  and  the  inner  tarsal  bones.  The  outer 
border  touches  the  extensor  muscles  of  the  toes,  and  conceals  the  anterior 
tibial  vessels. 

Action.  Supposing  the  foot  not  fixed,  the  tibialis  bends  the  ankle, 
moves  the  great  toe  towards  the  middle  line  of  the  body,  and  raises  the 
inner  border  of  the  foot. 

If  the  foot  is  fixed  it  can  lift  the  inner  border  with  the  tibialis  posticus, 
and  support  the  foot  on  the  outer  edge. 

If  tiie  tibia  is  slanting  backwards,  as  when  the  advanced  limb  reaches 
the  ground  in  walking,  it  can  bring  forwards  and  make  steady  that  bone. 


FLEXORS    OF    THE    ANKLE-JOINT.  629 

The  EXTENSOR  PROPRiDS  POLLicis  (fig.  215)  IS  deeply  placed  at  its 
origin  between  the  former  muscle  and  the  extensor  long'us  digltorum,  but 
its  tendon  becoms  superficial  on  the  dorsum  of  the  foot.  The  muscle 
arises  from  the  middle  three-fifths  of  the  narrow  anterior  part  on  the  inner 
surface  of  the  fibula,  and  from  the  interosseous  ligament  for  the  same  dis- 
tance. At  the  ankle  it  ends  in  a  tendon,  which  comes  to  the  surface 
through  a  sheath  in  the  lower  piece  of  the  annular  ligament,  and  continues 
over  the  inner  part  of  the  tarsus  to  be  inserted  into  the  base  of  the  last 
phalanx  of  the  great  toe. 

The  anterior  tibial  vessels  lie  on  the  inner  side  of  the  muscle  as  low  as 
the  sheath  in  the  ligament,  but  afterwards  on  the  outer  side  of  its  tendon, 
so  that  they  are  crossed  by  it  beneath  the  ligament. 

Action.  It  straightens  the  great  toe  by  extending  the  phalangeal  joints, 
and  afterwards  bends  the  ankle. 

When  the  foot  is  fixed  on  the  ground  and  the  tibia  slants  backwards, 
the  muscle  can  draw  forwards  that  bone. 

The  EXTENSOR  LONGUS  DiGiTORUM  (fig.  215,  ^)  is  flcshy  in  the  leg, 
and  tendinous  on  the  foot,  like  the  tibial  muscle.  Its  origin  is  from  the 
head  and  three-fourths  of  the  narrow  part  of  the  inner  surface  of  the  fibula; 
from  tlie  external  tuberosity  of  tlie  tibia,  and  about  an  inch  (above)  of  the 
interosseous  membrane  ;  and  from  tlie  fascia  of  the  leg  and  the  intermus- 
cular septum  on  each  side.  The  tendon  enters  its  sheath  in  the  annular 
ligament  with  the  peroneus  tertius,  and  divides  into  four  pieces.  Below 
the  ligament  these  slips  are  continued  to  the  four  outer  toes,  and  are  in- 
serted into  the  middle  and  ungual  phalanges  : — 

On  the  metatarsal  phalanx  the  tendons  of  the  long  and  short  extensor 
join  with  prolongations  from  the  interossei  and  lumbricales  to  form  an 
aponeurosis  ;  but  a  tendon  from  tlie  short  extensor  is  not  united  to  the 
expansion  on  the  little  toe.  At  the  further  end  of  this  phalanx  the  apo- 
neurosis is  divided  into  three  parts — a  central  and  two  lateral ;  the  central 
piece  is  inserted  into  the  base  of  the  middle  phalanx,  while  the  lateral 
unite  at  the  front  of  the  middle,  and  are  fixed  into  the  ungual  phalanx. 

In  the  leg  the  muscle  is  placed  between  the  peronei  on  the  one  side, 
and  the  tibialis  anticus  and  extensor  proprius  poUicis  on  the  other.  It 
lies  on  the  fibula,  the  lower  end  of  the  tibia,  and  the  ankle-joint.  On  tlie 
foot  the  tendons  rest  on  the  extensor  brevis  digitorum ;  and  the  vessels 
and  nerve  are  internal  to  them. 

Action.  The  muscle  extends  the  joints  of  the  four  outer  toes  from  root 
to  tip,  as  in  the  fingers ;  and  still  acting,  bends  the  ankle-joint. 

If  the  tibia  is  inclined  back,  as  when  the  foot  reaches  the  ground  in 
walking,  it  will  be  moved  forwards  by  this  and  the  other  muscles  on  the 
front  of  the  leg. 

The  peroneus  tertius  is  situate  below  the  extensor  longus  digitorum, 
from  which  it  is  seldom  separate.  It  arises  from  the  lower  fourth  of  the 
narrow  part  of  the  inner  surface  of  the  fibula,  from  the  lower  end  of  the 
interosseous  ligament,  Jind  from  the  intermuscular  septum  between  it  and 
the  peroneous  brevis  muscle.  And  it  is  inserted  into  the  tarsal  end  (up- 
per surface)  of  the  metatarsal  bone  of  the  little  toe. 

This  muscle  has  the  same  connections  in  the  leg  as  the  lower  part  of 
the  long  extensor,  and  is  contained  in  the  same  space  in  the  annular 
ligament. 

Action.     The  muscle  assists  the  tibialis  in  bending  the  ankle,  and  in 


630 


DISSECTION    OF    THE    LEG 


drawing  forwards  the  fibula  when  the  leg  is  advanced  to  make  a  step  in 
walking. 

The  ANTERIOR  TIBIAL  ARTERY  (fig.  215,  *)  extends  from  the  bifurca- 
tion of  the  popliteal  trunk  to  the  front  of  the  ankle  joint.  At  this  spot  it 
becomes  the  dorsal  artery  of  the  foot. 


Fig.  215. 


.^9'.-  ,tt;''-!'':f.'ffA 


Anterior  Tibial  Vess-.l  and  Muscles  (Quain's  Arteries). 

1.  Tibialus  antlcns  muscle.  3.  Part  of  anterior  annular  ligament. 

2.  Extensor  poUicis  and  extensor  longus  digi-        4.  Anterior  tibial  artery:  the  nerve  outside  it 

torum  drawn  aside.  is  the  anterior  tibial. 


The  course  of  the  artery  is  forwards  through  the  aperture  in  the  upper 
part  of  the  interosseous  membrane,  along  the  front  of  that  membrane,  and 
over  the  tibia  to  the  foot.  A  line  from  the  inner  side  of  the  head  of  the 
fibula  to  the  centre  of  the  ankle  will  mark  the  position  of  the  vessel. 

For  a  short  distance  (about  two  inches)  the  artery  lies  bstween  the 


ANTERIOR    TIBIAL    VESSELS.  631 

tibialis  anticus  and  the  extensor  longus  digitorum ;  afterwards  it  is  placed 
between  the  tibial  muscle  and  the  extensor  proprius  pollicis  till  near  the 
lower  end,  where  the  last  muscle  becomes  superficial,  and  crosses  to  the 
inner  side.  The  vessel  rests  on  the  interosseous  membrane  in  two-thirds 
of  its  extent,  being  overlapped  by  the  fleshy  bellies  of  the  contiguous 
muscles,  so  that  it  is  at  some  depth  from  the  surface ;  but  it  is  placed  in 
front  of  the  tibia  and  the  ankle  joint  in  the  lower  third,  and  is  compara- 
tively superficial  between  the  tendons  of  the  muscles. 

VenfB  comites  entwine  around  the  artery,  covering  it  very  closely  with 
cross  branches  on  the  upper  part.  The  anterior  tibial  nerve  approaches 
the  tibial  vessels  about  the  middle  third  of  the  leg,  and  continues  with  them, 
crossing  once  or  twice :  at  the  lower  end  of  the  artery  the  nerve  lies  on 
the  outer  side. 

Branches.  In  the  leg  the  anterior  tibial  artery  furnishes  mostly  mus- 
cular offsets,  but  near  the  knee  and  ankle  the  following  named  branches 
take  origin. 

a.  Cutaneous  branches  arise  at  intervals  ;  and  the  largest  accompanies 
the  musculo-cutaneous  nerve,  and  supplies  the  contiguous  muscles. 

h.  A  recurrent  branch  arises  as  soon  as  the  trunk  appears  above  the 
interosseous  membrane,  and  ascends  in  the  tibialis  anticus  to  the  knee 
joint :  on  the  joint  it  anastomoses  w  ith  the  other  articular  arteries. 

c.  Malleolar  arteries  (internal  and  external)  spring  near  the  ankle  joint, 
and  are  distributed  over  the  ends  of  the  tibia  and  fibula.  The  internal  is 
the  least  regular  in  size  and  origin  ;  the  external  anastomoses  with  the 
anterior  peroneal  artery. 

d.  Some  small  articular  branches  are  supplied  from  the  lower  end  of 
the  artery  to  the  ankle  joint. 

The  DORSAL  ARTERY  of  the  foot  is  the  continuation  of  the  anterior  tibial, 
and  extends  from  the  front  of  the  ankle  joint  to  the  posterior  part  of  the 
first  interosseous  space :  at  this  interval  it  passes  downwards  between  the 
heads  of  the  interosseous  muscle,  to  end  in  the  sole  (p.  624). 

The  artery  is  supported  by  the  inner  row  of  the  tarsus,  viz.,  the  astra- 
galus, and  the  scaphoid  and  cuneiform  bones ;  and  it  is  covered  by  the 
integuments  and  the  deep  fascia,  and  by  the  inner  piece  of  the  extensor 
brevis  muscle.  The  tendon  of  the  extensor  pollicis  lies  on  the  inner  side, 
and  that  of  the  extensor  longus  digitorum  on  the  outer  side,  but  neither  is 
near  the  vessel. 

The  veins  have  the  same  position  with  respect  to  the  artery  as  in  the 
leg ;  and  the  nerve  is  external  to  it. 

Peculiarities.  On  the  dorsum  of  the  foot  the  artery  is  often  removed  further 
outwards  than  the  line  from  the  centre  of  the  ankle  to  the  posterior  part  of  the 
first  interosseous  space.  Further,  the  place  of  the  arter}--  may  be  taken  by  a  large 
anterior  peroneal  branch . 

Branches.  Offsets  are  given  to  the  bones  and  ligaments  of  the  foot : 
those  from  the  outer  side  of  the  vessel  are  named  tarsal  and  metatarsal 
from  their  distribution.  A  small  interosseous  brancli  is  furnished  to  the 
first  metatarsal  space. 

a.  The  tarsal  branch  arises  opposite  the  scaphoid  bone,  and  runs  be- 
neath the  extensor  brevis  digitorum  to  the  outer  side  of  the  foot,  where  it 
divides  into  twigs  that  inosculate  with  the  metatarsal,  plantar,  and  ante- 
rior peroneal  arteries  :  it  supplies  offsets  to  the  extensor  muscle  beneath 
which  it  lies. 


632  DISSECTION    OF    THE    LEG. 

b.  The  metatarsal  branch  takes  an  arched  course  to  the  outer  part  of 
the  foot,  near  the  base  of  the  metatarsal  bones  and  beneath  the  extensor 
muscle,  and  anastomoses  with  the  external  plantar  and  tarsal  arteries. 

c.  From  the  arch  of  the  metatarsal  branch  three  dorsal  interosseous 
arteries  are  furnished  to  the  three  outer  metatarsal  spaces ;  and  the  exter- 
nal of  these  sends  a  branch  to  the  outer  side  of  tlie  little  toe.  They  sup- 
ply the  interossei  muscles  and  divide  at  the  cleft  of  the  toes  into  two  small 
dorsal  digital  branches. 

At  the  fore  part  of  the  metatarsal  space  each  interosseous  branch  joins 
a  digital  artery  in  the  sole  of  the  foot  by  means  of  the  anterior  per- 
forating twig  ;  and  from  the  beginning  of  each  a  small  branch,  posterior 
perforating,  descends  to  the  plantar  arch. 

d.  The  first  interosseous  branch  (art.  dorsalis  pollicis)  arises  from  the 
trunk  of  the  artery  as  this  is  about  to  leave  the  dorsum  of  the  foot ;  it  ex- 
tends forwards  in  the  space  between  the  first  two  toes,  and  is  distributed 
by  dorsal  digital  pieces  like  the  other  dorsal  interosseous  offsets. 

The  ANTERIOR  TIBIAL  VEINS  havc  the  same  extent  and  connections  as 
the  vessel  they  accompany.  They  take  their  usual  position  along  the 
artery,  one  on  each  side,  and  form  loops  around  it  by  cross  branches ;  they 
end  in  the  popliteal  vein.  The  branches  they  receive  correspond  with 
those  of  the  artery ;  and  they  communicate  with  the  internal  saphenous 
vein. 

Dissection.  To  examine  the  extensor  brevis  digitorum  on  the  dorsum  of 
the  foot,  cut  through  the  tendons  of  the  extensor  longus  and  peroneus  ter- 
tius  below  the  annular  ligament,  and  throw  them  towards  the  toes.  The 
hinder  attachment  of  the  muscle  to  the  os  calcis  is  to  be  defined. 

The  EXTENSOR  BREVIS  DIGITORUM  arises  from  the  outer  surface  of  the 
OS  calcis  in  front  of  the  sheath  for  the  peroneus  brevis  muscle,  and  from 
the  lower  band  of  the  anterior  annular  ligament.  At  the  back  of  the  meta- 
tarsal bones  the  muscle  ends  in  four  tendons,  which  spring  from  as  many 
fleshy  bellies,  and  are  inserted  into  the  four  inner  toes.  The  tendon  of  the 
great  toe  has  a  distinct  attachment  to  the  base  of  tlie  metatarsal  phalanx  ; 
but  the  rest  are  united  to  the  outer  side  of  the  long  extensor  tendons,  and 
assist  to  form  the  expansion  on  the  metatarsal  phalanx  (p.  G29). 

The  muscle  lies  on  the  tarsus,  and  is  partly  concealed  by  the  tendons  of 
the  long  extensor.     Its  inner  belly  crosses  the  dorsal  artery  of  the  foot. 

Action.  Assisting  the  long  extensor,  it  straightens  the  four  inner  toes, 
separating  slightly  from  each  other. 

Dissection.  The  branches  of  artery  and  nerve  which  are  beneath  the 
extensor  brevis  will  be  laid  bare  by  dividing  that  muscle  near  its  front, 
and  turning  it  upwards. 

By  cutting  through  the  lower  band  of  the  annular  ligament  over  the 
tendon  of  the  extensor  pollicis,  and  throwing  outwards  the  external  half 
of  it, — the  different  sheaths  of  the  liganient,  the  attachment  to  the  os 
calcis,  and  the  origin  of  the  extensor  brevis  digitorum  from  it  may  be  ob- 
served. 

The  anterior  tibial  and  musculo-cutaneous  nerves  are  now  to  be  followed 
upwards  to  their  origin  from  the  external  popliteal  :  and  a  small  branch  to 
the  knee-joint  from  the  same  source  is  to  be  traced  through  the  tibialis 
anticus. 

Nerves  to  the  front  of  the  leg.  Between  the  fibula  and  the  pero- 
neus longus  muscle  the  external  popliteal  nerve  divides  into  recurrent 
articular,  musculo-cutaneous,  and  anterior  tibial  branches. 


PERONEI    MUSCLES.  633 

The  recurrent  articular  branch  is  small,  and  takes  the  course  of  the 
artery  of  the  same  name  through  the  tibialis  anticus  muscle  to  the  knee 
joint. 

The  musculo-cutaneous  nerve  is  continued  between  the  extensor  longus 
digitorum  and  the  peronei  muscles  to  the  lower  third  of  the  leg,  where  it 
pierces  the  fascia,  and  is  distributed  to  the  dorsum  of  the  foot  and  the  toes 
(p.  G26).  Before  the  nerve  becomes  cutaneous  it  furnishes  branches  to 
the  two  larger  peronei  muscles. 

The  anterior  t'lhial  nerve  (fig.  215)  (interosseous)  is  directed  beneath  the 
extensor  longus  digitorum,  and  reaches  the  tibial  artery  about  the  middle 
third  of  the  leg.  From  this  spot  it  takes  the  course  of  the  vessel  along 
the  foot  to  the  first  interosseous  space  (p.  627).  In  the  leg  it  crosses  the 
anterior  tibial  vessels  once  or  more,  but  on  the  foot  it  is  generally  external 
to  the  dorsal  artery. 

Branches.  In  the  leg  the  nerve  supplies  the  anterior  tibial  muscle,  the 
extensors  of  the  toes,  and  the  peroneus  tertius.  On  the  dorsum  of  the  foot 
it  furnishes  a  considerable  branch  to  the  short  extensor ;  this  is  enlarged, 
and  gives  offsets  to  the  articulations  of  the  foot. 

Muscles  on  the  outer  part  of  the  leg  (fig.  209).  Two  muscles 
occupy  this  situation,  and  are  named  peronei  from  their  attachment  to  the 
fibula ;  they  are  distinguished  by  the  terms  longus  and  brevis.  Intermus- 
cular processes  of  fascia,  which  are  attached  to  the  fibula,  isolate  these 
muscles  from  others. 

The  PERONEUS  LONGUS  (fig.  209,  ®),  the  more  superficial  of  the  two 
muscles,  passes  into  the  sole  of  the  foot  round  the  outer  border.  It  arises 
from  the  head,  and  the  anterior  surface  of  the  shaft  of  the  fibula  for  two- 
thirds  of  the  length,  gradually  tapering  downwards  ;  from  the  external 
border  nearly  to  the  malleolus  ;  and  from  the  fascia  and  the  intermuscular 
septa.  Inferiorly  it  ends  in  a  tendon  which  is  continued  through  the  ex- 
ternal annular  ligament,  with  the  peroneus  brevis,  lying  in  the  groove  at 
the  back  of  the  external  malleolus  ;  and  it  passes  finally  in  a  separate 
sheath,  below  the  peroneus  brevis  along  the  side  of  the  calcis  and  through 
the  groove  in  the  outer  border  of  the  cuboid  bone,  to  the  sole  of  the  foot. 
Its  position  in  the  foot,  and  its  insertion  are  described  before  (p.  625). 

In  the  leg  the  muscle  is  immediately  beneath  the  fascia,  and  lies  on  the 
peroneus  brevis.  Beneath  the  annular  ligament  it  is  placed  over  the 
middle  piece  of  the  external  lateral  ligament  of  the  ankle  with  the  peroneus 
brevis,  and  is  surrounded  by  a  single  synovial  membrane  common  to  both. 
The  extensor  longus  digitorum  and  the  soleus  are  fixed  to  the  fibula  late- 
rally with  respect  to  it,  one  being  on  each  side. 

Action.  With  the  foot  free  the  muscle  extends  the  ankle  :  then  it  can 
depress  the  inner,  and  raise  the  outer  border  of  the  foot  in  the  movement 
of  eversion. 

When  the  foot  rests  on  the  ground  it  assists  to  lift  the  os  calcis,  and  the 
w^eight  of  the  body  as  in  standing  on  the  toes,  or  in  walking.  And  in 
rising  from  a  stooping  posture  it  draws  back  the  fibula. 

The  PERONEUS  BREVIS  (fig.  209,  ^)  reaches  the  outer  side  of  the  foot, 
and  is  smaller  than  the  preceding  muscle,  and  inferior  in  position  to  it. 
It  arises  from  the  anterior  surface  of  the  shaft  of  the  fibula  for  about  the 
lower  two-thirds,  extending  upwards  by  a  pointed  piece  internal  to  tlie 
other  peroneus  ;  and  from  the  intermuscular  septum  in  front.  Its  tendon 
passes  with  that  of  the  peroneus  longus  through  the  external  annular  liga- 
ment, and  is  placed  next  the  fibula  as  it  turns  below  this  bone.    Escaped 


634  DISSECTION    OF    THE    LEG. 

from  the  ligament,  the  tendon  enters  a  distinct  fibrous  sheath,  which  con- 
ducts it  along  the  tarsus  to  its  insertion  into  the  projection  at  the  base  of 
the  metatarsal  bone  of  the  little  toe. 

In  the  leg  the  muscle  reaches  in  front  of  the  peroneus  longus.  On  the 
outer  side  of  the  os  calcis  it  is  contained  in  a  sheath  above  the  tendon  of 
the  former  muscle  ;  and  each  sheath  is  lined  by  a  prolongation  from  the 
common  synovial  membrane  behind  the  outer  ankle. 

Action.  If  the  foot  is  unsupported  this  peroneus  extends  the  ankle, 
and  moves  the  foot  upwards  and  outwards  in  eversion. 

Like  the  long  muscle,  it  is  able  if  the  foot  is  supported  to  raise  the  heel, 
and  to  bring  back  the  fibula  as  the  body  rises  from  stooping. 


Section  VII. 

LIGAMENTS  OF  THE  KNEE,  ANKLE,  AND  FOOT. 

Directions.  In  examining  the  remaining  articulations  of  the  limb,  the 
student  may  take  first  the  knee-joint,  unless  this  has  become  dry  ;  in  that 
case  the  ligaments  of  the  leg,  ankle-joint,  and  foot  may  be  dissected  whilst 
the  knee  is  being  moistened. 

Dissection.  For  the  preparation  of  the  ligaments  of  each  articulation, 
it  is  sufiicient  to  detach  the  muscles  and  tendons  from  around  it,  and  to 
remove  the  areolar  tissue  or  fibrous  structure  which  may  obscure  or  con- 
ceal the  ligamentous  bands.  In  the  knee  a  kind  of  aponeurotic  capsule  is 
to  be  defined  on  the  front  of  the  joint. 

Some  tendons,  namely,  those  of  the  biceps,  popliteus,  adductor  magnus, 
and  semimembranosus,  are  to  be  followed  to  their  insertion,  and  a  part  of 
each  is  to  be  left. 

Articulations  of  the  knee.  The  knee  is  the  largest  hinge  joint 
in  the  body,  and  is  formed  by  the  contiguous  ends  of  the  tibia  and  femur, 
with  the  patella.  The  articular  surfaces  of  the  bones  are  covered  with 
cartilage,  and  are  maintained  in  apposition  by  strong  and  numerous  liga- 
ments. 

The  capsule  (fig.  216)  is  an  aponeurotic  covering  on  the  front  of  the 
joint,  which  closes  the  wide  intervals  between  the  anterior  and  tlie  lateral 
ligaments ;  and  is  derived  from  the  fascia  lata  united  with  fibrous  offsets 
of  the  extensor  and  flexor  muscles.  It  covers  the  anterior  and  tlie  exter- 
nal lateral  ligament,  being  inserted  below  into  the  heads  of  the  tibia  and 
fibula ;  and  it  blends  on  the  inner  side  with  the  internal  lateral  ligament. 
It  is  not  closely  applied  to  the  synovial  membrane,  but  it  is  united  below 
with  the  interarticular  fibro-cartilages. 

Dissection.  Four  external  ligaments,  anterior  and  posterior,  internal 
and  external,  are  situate  at  opposite  points  of  the  articulation.  The  poste- 
rior and  the  internal  lateral  ligament  will  appear  on  the  removal  of  the 
areolar  tissue  from  their  surfaces ;  but  the  anterior  and  the  external  lateral 
are  covered  by  the  aponeurosis  on  the  fore  part  of  the  joint,  and  will  not 
be  laid  bare  till  this  has  been  cut  through.  If  there  is  a  second  external 
lateral  band  present,  it  is  not  concealed  by  the  aponeurosis. 

Tlie  external  lateral  ligament  (fig.  216,  ^)  is  round  and  cord-like.  It  is 
attached  to  the  outer  condyle  of  the  femur  below  the  tendon  of  the  gas- 


LIGAMENTS    OF    KNEE, 


635 


m 

^Bocnemius,  and  descends  vertically  between  two  pieces  of  the  tendon  of 
^the  biceps  to  a  depression  on  the  upper  and  outer  part  of  the  head  of  the 

fibula.     Beneath  the  ligament  are  the  tendon  of  the  popliteus,  and  the 

external  lower  articular  vessels  and  nerve. 


Fig.  216. 


Fiff.  217. 


ExTKRNAL  Ligament  of  the  Knee-joint. 
(Bourgery). 

1.  Anterior  ligament. 

2.  External  lateral  ligament. 
.3.  Interosseous  ligament. 

4.  Part  of  the  capsule. 


Internal  Ligament  of  the  Knee-joint. 
(Bourgery.) 
1.  Tendon  of  the  extensor  muscle  endiug  below 
in  the  ligament  of  the  patella,  2. 

3.  Internal  lateral  ligament. 

4.  Lateral  part  of  the  capsule. 


A  second  fasciculus  is  sometimes  present  behind  the  other,  but  it  is  not 
attached  to  the  femur :  it  is  connected  above  with  the  gastrocnemius,  and 
below  with  the  posterior  prominence  of  tlie  head  of  the  fibula. 

The  tendon  of  the  biceps  is  inserted  by  two  pieces  into  the  points  on 
the  head  of  the  fibula  ;  and  from  the  anterior  of  these  there  is  a  prolonga- 
tion to  the  head  of  the  tibia.  The  external  lateral  ligament  passes  be- 
tween the  pieces  into  which  the  tendon  is  split. 

Tiie  tendon  of  the  popliteus  may  be  followed  by  dividing  the  posterior 
ligament.  It  arises  from  the  fore  part  of  the  oblong  depression  on  the 
outer  surface  of  the  external  condyle  of  the  femur.  In  its  course  to  the 
outside  of  the  joint,  it  crosses  tiie  external  semilunar  fibro-cartilage  and 
tlie  upper  tibio-peroneal  articulation.  When  the  joint  is  bent,  the  tendon 
lies  in  the  hollow  on  the  condyle ;  but  slips  out  of  that  groove  when  the 
limb  is  extended. 

The  tendon  of  the  adductor  magnus  is  inserted  into  a  tubercle  on  the 
internal  condyle  of  the  femur,  above  the  attachment  of  the  internal  lateral 
ligament. 

Tlie  internal  lateral  ligament  (fig.  217,  ^)  is  attached  to  the  condyle  of 
the  femur,  where  it  blends  with  the  capsule  ;  but  becoming  thicker  below, 
and  separate  from  the  rest  of  the  capsule,  it  is  fixed  for  about  an  inch  into 
the  inner  surface  of  the  tibia,  below  the  level  of  the  ligamentum  patella?. 

The  tendons  of  the  sartorius,  gracilis,  and  semitendinosus  muscles  lie 
over  the  ligament ;  and  the  tendon  of  the  semimembranosus,  and  the 
internal  lower  articular  vessels  and  nerve  are  beneath  it.  To  the  posterior 
ed^e  some  fibres  of  the  tendon  of  the  semimembranosus  are  added. 


636  DISSECTION    OF    THE    LEG. 

The  tendon  of  the  semimemhranosus  muscle  is  inserted  beneath  tlie 
internal  lateral  ligament  into  an  impression  at  the  back  of  the  inner  tuber- 
osity of  the  head  of  the  tibia :  between  it  and  the  bone  is  a  synovial 
bursa.  The  tendon  sends  some  fibres  to  the  internal  lateral  ligament,  a 
prolongation  to  join  the  fascia  on  the  popliteus  muscle,  and  another  to  the 
posterior  ligament  of  the  knee  joint. 

The  posterior  ligament  (ligament  of  Winslow),  wide  and  membranous, 
covers  the  back  of  the  joint  between  the  two  lateral,  and  is  joined  by 
fibres  from  the  tendon  of  the  semimembranosus,  which  are  directed  across 
the  joint  to  the  outer  side.  It  is  fixed  below  to  the  head  of  the  tibia 
behind  the  articular  surface,  and  above  to  the  femur,  but  by  strongest 
fibres  opposite  the  intercondyloid  notch.  Numerous  apertures  exist  in  it 
for  the  passage  of  the  vessels  and  nerves  to  the  interior  of  the  articulation  ; 
and  the  tendon  of  the  popliteus  pierces  it. 

The  anterior  ligament  (ligamentum  patellar)  (fig.  217,  ^),  part  of  the 
tendon  of  insertion  of  the  extensor  muscle  of  the  knee  (p.  571),  is  two 
inches  long.  Superiorly  it  is  attached  to  the  lower  part  of  the  patella, 
and  to  the  depression  on  the  inner  surface  of  the  apex  ;  and  inferiorly  it 
is  inserted  into  the  tubercle  of  the  head  of  the  tibia,  and  into  an  inch  of 
the  bone  below  it.  An  expansion  of  the  triceps  extensor  covers  it ;  and 
a  bursa  intervenes  between  it  and  the  top  of  the  tubercle  of  the  tibia. 

Dissection  (fig.  218).  To  see  the  reflections  of  the  synovial  membrane 
raise  the  knee  on  blocks,  and  open  the  joint  by  an  incision  on  each  side, 

Fiff.  218. 


The  Capsule  of  the  Knee-joint  cut  across,  and  the  Patella  thrown  down  to  show  the 

NAMED  Folds  of  the  Synovial  Sac. 

a.  Mucous  liganieat.  h.  Internal,  and  c,  external  alar  ligament. 

above  the  patella.  When  the  anterior  part  of  the  capsule  with  the  patella 
is  thrown  down,  a  fold  (mucous  ligament)  will  be  seen  extending  from  the 
intercondyloid  fossa  of  the  femur  to  a  mass  of  fat  below  the  patella.  On 
each  side  of  the  knee-{)an  is  a  similar  fold  (alar  ligament)  over  some  fat. 
The  limb  may  be  laid  flat  on  tiie  table,  and  some  of  the  posterior  liga- 


SYNOVIAL    SAC    AND    FAT    AROUND    KNEE.  637 

raent  may  be  removed,  to  show  the  pouches  of  the  synovial  membrane 
which  project  behind  over  the  condyles  of  the  femur ;  but  the  limb  is  to 
be  replaced  in  the  former  position  before  the  parts  are  learnt. 

The  synovial  membrane  (fig.  218)  lines  the  interior  of  the  capsule,  and 
is  continued  to  the  articular  ends  of  the  bones.  It  invests  the  interarticular 
cartilages  after  the  manner  of  serous  membranes,  and  sends  a  pouch  be- 
tween the  tendon  of  the  po|)liteus  and  the  external  fibro-cartilage  and  the 
head  of  the  tibia ;  it  is  also  reflected  over  the  strong  crucial  ligaments  at 
the  back  of  the  joint. 

There  are  three  named  folds  of  the  synovial  membrane.  One  in  the 
centre  of  the  joint  is  the  mucous  ligament  (a),  which  contains  small  ves- 
sels and  some  fat,  and  extends  from  the  interval  between  the  condyles  to 
the  fat  below  the  patella.  Below  and  on  each  side  of  the  patella  is  another 
fold — alar  ligament  (5  and  c),  which  is  continuous  with  the  former  below 
the  patella,  and  is  placed  over  a  mass  of  fat :  the  inner  (6)  is  prolonged 
farther  than  the  outer  by  a  semilunar  piece  of  the  serous  membrane. 

At  the  back  and  front  of  the  articulation  pouches  are  prolonged  beneath 
the  tendons  of  muscles.  Behind  there  are  two,  one  on  each  side,  between 
the  condyle  of  the  femur  and  the  tendinous  head  of  the  gastrocnemius, 
►n  the  front,  the  sac  projects  under  the  extensor  muscle  one  inch  above 
'the  articular  surface ;  and  if  it  communicates  with  the  bursa  in  that  situa- 
tion, it  will  reach  two  inches  above  the  joint  surface  of  the  femur.  When 
the  joint  is  bent  there  is  a  greater  length  of  the  serous  sac  above  the  patella. 

Fat  around  the  joint.  Two  large  masses  are  placed  above  and  below 
the  patella,  and  some  fat  is  located  around  the  crucial  ligaments. 

The  infra- patellar  mass,  the  largest  of  all,  fills  the  interval  between  the 
patella  with  its  ligament  and  the  head  of  the  tibia,  and  gives  origin  to  the 
ridges  of  the  synovial  membrane.  From  it  a  piece  is  continued  around 
the  patella :  but  it  is  larger  at  the  inner  margin  of  the  bone,  than  on  the 
outer,  and  overhangs  the  inner  perpendicular  facet.  During  extension  of 
the  joint  the  infra-patellar  pad  is  applied  to,  and  lubricates  tiie  articular 
surfaces  of  the  femur. 

The  supra-patellar  pad  is  interposed  between  the  triceps  extensor  and 
the  femur  around  the  top  of  the  synovial  sac,  and  is  greater  on  the  outer 
than  on  the  inner  side. 

Dissection  (fig.  219).  The  ligamentous  structures  within  the  capsule 
will  be  brought  into  view,  whilst  the  limb  is  still  in  the  same  position,  by 
throwing  down  the  patella  and  its  ligament,  and  clearing  away  the  fat 
behind  it.  In  this  step  the  student  must  be  careful  of  a  small  transverse 
band  which  connects  anteriorly  the  interarticular  cartilages. 

The  remains  of  the  ca[)sule  and  other  ligaments,  and  the  synovial  mem- 
brane are  next  to  be  cleared  away  from  the  front  and  back  of  the  crucial 
ligaments,  and  from  the  interarticular  cartilages.  Whilst  cleaning  the 
posterior  crucial  the  limb  is  to  be  placed  flat  on  the  table  with  the  patella 
down  ;  and  the  student  is  to  be  careful  of  a  band  before  it  from  the  exter- 
nal fibro-cartilage,  or  of  two  bands,  one  before  and  the  other  behind  it. 

Ligaments  within  the  capsule.  The  ligamentous  structures  within  the 
capsule  consist  of  the  central  crucial  ligaments,  and  of  two  plates  of  fibro- 
cartilage  on  the  head  of  the  tibia. 

The  crucial  ligaments  (fig.  219)  are  two  strong  fibrous  cords  between 
the  ends  of  the  tibia  and  femur,  which  maintain  in  contact  the  bones. 
They  cross  one  another  somewliat  like  the  legs  of  the  letter  X,  and  have 


638 


DISSECTION    OF    THE    LEG 


Fig.  219. 


received  their  name  from  that  circumstance.     One  is  much  anterior  to 
the  other  at  the  attachment  to  the  tibia. 

The  anterior  ligament  (/)  is  most  oblique  in  its  direction,  and  is  smaller 
than  the  posterior.  Inferiorly  it  is  attached  in  front  of  the  spine  of  the 
tibia,  close  to  the  inner  articular  surface,  reaching  back  to  the  inner  point 
of  the  spine:  superiorly  it  is  inserted  by  its  posterior  shorter  tibres  into 
the  back  of  the  outer  condyle  of  the  femur,  and  by  the  anterior  or  longer 
into  the  hinder  part  of  the  intercondyloid  fossa. 

The  posterior  ligament  (e)  is  almost  vertical  between  the  bones  at  the 
back  of  the  joint.  By  the  lower  end  it  is  fixed  to  the  hindermost  impres- 
sion of  the  hollow  behind  the  spine  of  the 
tibia,  near  the  margin  of  the  bone;  and 
above  its  posterior  shorter  fibres  are  in- 
serted into  the  inner  condyle  along  the  side 
of  the  oblique  curve,  whilst  the  anterior 
and  longer  reach  the  fore  part  of  the  inter- 
condyloid fossa. 

The  use  of  these  ligaments  in  the  move- 
ments of  the  joint,  after  the  external  liga- 
ments have  been  cut  through  may  now  be 
studied. 

As  lonor  as  both  lineaments  are  whole  the 
bones  cannot  be  separated  from  each  other. 
Rotation  in  of  the  tibia  is  stopped  by 
the  anterior  crucial.  Rotation  out  is  not 
checked  by  either  ligament ;  for  the  bands 
uncross  in  the  execution  of  the  movement, 
and  will  permit  the  tibia  to  be  put  hind 
foremost. 

Supposing  the  tibia  to  move,  as  in 
straightening  the  limb,  the  anterior  pre- 
vents that  bone  being  carried  too  far  for- 
wards by  the  extensor  tendon,  or  by  force  ; 
and  the  lignment  is  brought  into  action  at 
the  end  of  extension,  because  the  tibia  is 
being  put  in  front  of  the  femur.  Its  use  is 
shown  by  cutting  it  across,  and  leaving  the 
posterior  entire,  as  then  the  tibial  articulat- 
ing surfaces  can  be  placed  in  front  of  the 
femoral  in  the  half  bent  state  of  the  joint. 
The  posterior  crucial  arrests  the  too 
great  movements  backwards  of  the  tibia  by 
the  flexors  or  by  force  ;  and  it  is  stretched 
in  extreme  flexion,  in  which  the  tibia  is  being  drawn  back  from  the  femur. 
This  use  will  be  exemplified  by  cutting  across  the  posterior  (in  another 
joint  or  in  another  dissection)  and  leaving  entire  the  anterior :  when  this 
has  been  done  the  articular  surfaces  of  the  tibia  can  be  carried  nearly 
altogether  behind  the  condyles  of  the  femur. 

The  interarticular  or  semilunar  Jibro-cartilages  (fig.  220)  cover  partly 
on  each  side  the  articular  surface  of  the  tibia. 

They  are  thick  at  the  outer  margin,  where  they  are  united  by  fibres  to 
the  capsule,  and  are  thin  at  the  inner  edge  ;  they  are  hollowed  on  the 
upper  surface,  so  as  to  assist  in  giving  depth  to  the  fossjE  for  the  reception 


[ntekakticclar  Ligaments  of  the 

Kneb-Joint. 
a.  Internal,  and 
6.  External  semilunar  flbro-cartilage  ; 

the  latter  rather  displaced  by  the 

bending  of  the  joint. 
e.  Posterior  crucial  ligament,  with  rf, 

the  ascending  ligamentous   band 

of  the  external  flbro-cartilage. 
/.  Anterior  crucial  ligament. 
g.  Patellar  surface  of  the  fennur. 


INTRA-OAPSULAR    LIGAMENTS    OF    KNEE. 


639 


of  the  condyles  of  the  femur,  but  are  flattened  below.  Inserted  into  the 
tibia  at  their  extremities,  they  are  coarsely  fibrous  at  their  attachment  to 
the  bone,  like  the  crucial  ligaments  ;  and  they  become  cartilaginous  only 
where  they  lie  between  the  articular  surfaces.  The  synovial  membrane  is 
reflected  over  thom. 

The  internal  cartilage  {a)  is  ovoid  in  form,  and  is  a  segment  of  a  larger 
circle  than  the  external.  In  front  it  is  attached  by  a  pointed  part  to  the 
anterior  margin  of  the  head  of  the  tibia, 


in  front  of  the  anterior  crucial  liga- 
ment.    At  the  back,  where  it  is  much 


Fig.  220. 


View  op  the  Head  of  the  Tibia  with 
the  flsro  cartilages  attached  :  the 
crucial    ligaments    have    been    cut 

THROUGH. 

a.  Inner,  and  b,  outer  semilunar  fibro-car- 
tilage. 

c.  Transverse,  and  d,  ascending  or  poste- 
rior band  (cat)  of  the  external  carti- 
lage. 

e.  Posterior,  and  /,  anterior  crucial  liga- 
ment. 


wider,  it  is  fixed  to  the  inner  lip  of  the 
hollow  behind  the  spine  of  the  tibia, 
between  the  attachment  of  the  other 
cartilage  and  the  posterior  crucial  liga- 

•  ment. 
The  external  cartilage  (5)  is  nearly 
circular  in  form,  and  is  connected  to 
the  bone  within  the  points  of  attach- 
ment of  its  fellow.  Its  anterior  part  is 
fixed  in  front  of  the  spine  of  the  tibia, 
close  to  the  outer  articular  surface,  and 
opposite  the  anterior  crucial  ligament, 
which  it  touches ;  and  its  posterior 
extremity  is  inserted  behind  and  be- 
tween the  two  osseous  points  of  the 
spine.  This  fibro-cartilage  is  less 
closely  united  to  the  capsule  than  the 
internal,  for  the  fore  part  is  in  the  cen- 
tre of  the  joint,  and  the  tendon  of  the 
popliteus  muscle  separates  it  behind 
from  that  membrane. 

The  outer  fibro-cartilage  is  provided  with  two  accessory  bands,  one  at 
the  fore  part,  the  other  behind. 

The  anterior  or  transverse  ligament  (c)  is  a  narrow  band  of  fibres  be- 
tween the  semilunar  cartilages  at  the  front  of  the  joint.  Sometimes  it  is 
scarcely  perceptible. 

The  posterior  or  ascending  hand  (d),  thicker  and  stronger  than  the 
other,  springs  from  the  back  of  the  outer  fibro-cartilage,  and  is  inserted 
into  the  femur  as  a  single  band  (fig.  219,  d)  in  front  of  the  posterior 
crucial,  or  as  two  bands — one  being  before,  and  the  other  behind  that 
ligament. 

Use.  The  fibro-cartilages  deepen  the  sockets  of  the  tibia  for  the  recep- 
tion of  the  condyles  of  the  femur,  and  fill  the  interval  between  the  articu- 
lar surfaces  of  the  bones  at  the  circumference  of  the  joint ;  they  moderate 
the  injurious  efi^ect  of  pressure  of  the  one  bone  on  the  other;  and  cause 
the  force  of  shocks  to  be  diminished  in  transmission. 

In  flexion  and  extension  they  move  forwards  and  backwards  with  the 
tibia.  During  flexion  they  recede  somewhat  from  the  fore  part  of  the 
joint,  and  surround  the  condyles  of  the  femur;  but  in  extension  they  are 
flattened  out  on  the  surface  of  the  tibia.  Of  the  two  cartilages  the  ex- 
ternal moves  the  most  in  consequence  of  its  ends  being  less  attached  to 
the  capsule. 


640  DISSECTION    OF    THE    LEG. 

In  rotation  the  fibro-cartilages  follow  the  tibial  movements,  but  the  ex- 
ternal is  most  displaced  by  the  projecting  outer  condyle  of  the  femur. 

The  accessory  bands  in  front  and  behind  serve  to  retain  in  place  the 
least  fixed  external  fibro-cartilage  ;  thus  the  anterior  ligament  keeps  for- 
wards the  fore  part  of  that  cartilage  in  flexion,  and  the  posterior  secures 
the  back  of  the  same  from  displacement  in  rotation. 

Articular  surfaces  of  the  hones.  The  end  of  the  femur  is  marked  by  a 
patellar  and  two  tibial  surfaces. 

The  patellar  is  placed  in  the  middle  line  above  the  others ;  it  is  hol- 
lowed along  the  centre,  with  a  slanting  surface  on  each  side,  the  outer 
being  the  larger  of  the  two. 

The  surfaces  for  contact  w^ith  the  tibia,  two  in  number,  occupy  the 
ends  of  the  condyles,  and  are  separated  from  the  patellar  impression  by  an 
oblique  groove  on  each  side.  On  the  centre  of  each  is  a  somewhat  flat- 
tened part,  which  is  in  contact  with  the  tibia  in  standing ;  and  at  the 
posterior  third  is  a  more  convex  portion,  which  touches  the  tibia  in  rota- 
tion. 

The  inner  condyle  of  the  femur  is  curved  at  its  anterior  third,  the  con- 
cavity being  directed  out:  this  has  been  named  the  "oblique  curvature." 
Close  to  the  curved  part  is  a  semilunar  facet,  which  touches  the  perpen- 
dicular surface  of  the  patella  in  extreme  flexion. 

On  the  head  of  the  tibia  are  two  slight  articular  hollows,  the  inner  being 
the  deeper  and  larger,  which  rise  towards  the  middle  of  the  bone,  on  the 
points  of  the  tibial  spine. 

Tlie  joint-surface  of  the  patella  is  marked  by  the  following  impressions. 
Close  to  the  inner  edge  is  a  narrow  perpendicular  facet,  and  along  the 
lower  border  is  a  similar  transverse  mark.  Occupying  the  rest  of  the 
bone  is  a  squarish  surface,  which  is  subdivided  by  a  vertical  and  a  trans- 
verse line  into  two  pairs  of  marks — upper  and  lower.  (Goodsir,  Edinb. 
Med.  Jour.,  1855.) 

Movements  of  the  joint.  The  chief  movements  of  the  knee  are  two  in 
number,  bending  and  straightening,  like  the  elbow  ;  but  there  is,  in  addi- 
tion, rotation  of  the  tibia  when  the  joint  is  bent. 

Flexion  and  extension.  Each  of  these  movements  may  be  divided  into 
stages  for  the  purpose  of  particularizing  changes  in  its  direction. 

Inflexion  the  tibia  with  its  fibro-cartilages  moves  backwards  round  the 
end  of  the  femur ;  and  its  extent  is  limited  by  the  extensor  muscle,  and 
by  the  meeting  of  the  calf  of  the  leg  with  the  thigh. 

For  the  anterior  third  of  the  movement  the  tibia  is  directed  down  and 
in  along  the  oblique  curve  of  the  inner  condyle,  giving  rise  to  rotation 
inwards  of  that  bone  ;  but  for  the  posterior  two-thirds,  the  tibia  passes 
straight  back  over  the  condyles. 

All  the  external  ligaments  are  relaxed,  except  the  anterior ;  and  both 
crucials  are  put  on  the  stretch  towards  the  end  of  flexion. 

In  extension  the  tibia  is  carried  forwards  until  it  comes  into  a  straight 
line  with  the  femur,  when  the  uniting  ligaments  prevent  its  farther 
progress. 

In  the  hinder  two-thirds  of  the  movement  the  tibia  has  a  straight 
course  over  the  condyles  of  the  femur ;  but  in  the  anterior  third  the  leg- 
bone  is  directed  up  and  out  over  the  oblique  curve  of  the  inner  condyle, 
and  is  rotated  out. 

All  the  external  ligaments  except  the  anterior  are  tightened,  and  the 
crucial  cords  help  to  limit  extrejne  extension. 


MOVEMENTS    OF    KNEE    AND    PATELLA.  641 

Rotation.  A  half  bent  state  of  the  knee  is  necessary  for  this  movement, 
for  the  purpose  of  relaxing  the  anterior  crucial  and  the  external  ligaments ; 
and  the  foot  must  be  free.  Then,  the  tibia  with  its  fibro-cartilages  rotates 
around  a  vertical  axis,  the  great  toe  being  turned  in  and  out. 

During  rotation  in  the  inner  articular  surface  of  the  tibia  touches  the 
condyle  of  tiie  femur  and  moves  backwards;  and  the  outer  articular  sur- 
face, separated  by  a  slight  interval  from  the  thigh  bone,  passes  forwards. 

Botli  lateral  ligaments  are  loose ;  but  the  anterior  crucial  is  gradually 
tightened,  and  stops  finally  the  motion. 

In  rotation  out  the  opposite  movement  of  the  tibia  takes  place — the  in- 
ner articular  surface  being  directed  forwards,  and  the  outer  backwards. 

The  internal  lateral  ligament  controls  the  movement  by  its  fibres  being 
made  tense.     The  crucials  have  not  any  influence  on  the  motion  (p.  637). 

Movement  of  the  'patella.  When  the  knee  passes  from  flexion  to  exten- 
sion the  patella  crosses  it  obliquely  from  the  outer  to  the  inner  side,  touch- 
ing in  succession  different  parts  of  the  femoral  articular  surfaces. 

In  complete  flexion  the  knee-pan  lies  on  the  outer  side  of  the  joint 
below  the  femur,  where  it  is  scarcely  perceptible,  and  is  fixed  in  its  situa- 
tion. It  touches  the  semilunar  surface  on  the  inner  condyle  by  its  per- 
pendicular facet,  and  the  under  part  of  the  outer  condyle  by  the  upper  and 
outer  mark  on  its  square  surface. 

When  the  joint  is  passing  from  flexion  to  extension,  the  upper  pair  of 
impressions  on  the  square  surface  of  the  patella,  and  the  lower  pair  rest^ 
successively  on  the  pulley-surface  of  the  femur. 

In  complete  extension,  the  patella  is  situate  at  the  upper  and  inner 
part  of  the  knee-joint,  wiiere  it  is  very  prominent,  with  its  apex  and  the 
ligament  of  the  patella  directed  down  and  out  to  the  tibia.  For  the 
most  part  the  knee-pan  articular  surface  is  raised  above  the  trochlea 
of  the  femur,  w^hich  it  touches  only  at  the  upper  edge  by  its  lower  trans- 
verse facet. 

Peroneo-tibial  articulations.  The  tibia  and  fibula  are  united  by 
ligamentous  bands  at  the  extremities,  where  they  touch ;  and  by  an  inter- 
osseous ligament  between  the  shafts  of  the  bones. 

Dissection.  The  muscles  are  to  be  taken  away  from  the  front  and  back 
of  the  interosseous  ligament ;  and  the  loose  tissue  is  to  be  removed  from  a 
small  band  in  front  of,  and  behind  the  upper  and  lower  ends  of  the  tibia 
and  fibula. 

The  UPPER  ARTICULATION  has  very  small  movement,  and  the  structures 
between  the  ends  of  the  bones  are  two  small  bands,  anterior  and  posterior. 

The  anterior  ligament  extends  over  the  joint  from  the  outer  tuberosity 
of  the  tibia  to  the  head  of  the  fibula.  The  posterior  ligament,  thinner 
than  the  anterior,  is  attached  to  the  bones  behind  the  joint :  it  is  covered 
by  the  tendon  of  the  popliteus  muscle  and  a  prolongation  of  the  synovial 
membrane  of  the  knee-joint. 

The  articular  surfaces  are  covered  with  cartilage  :  and  a  synovial  mem- 
brane lining  the  articulation  projects  backwards  so  as  to  touch  that  of  the 
knee-joint. 

The  LOWER  ARTICULATION  posscsscs  an  anterior  and  a  posterior  band, 
together  with  an  inferior  ligament  between  the  ends  of  the  bones. 

The  anterior  ligament  reaches  obliquely  from  the  lower  end  of  the  tibia 
to  the  fibula ;  and  the  posterior  has  attachments  behind  the  articulation 
similar  to  those  of  the  band  in  front. 

The  inferior  ligament  closes  the  space  between  the  contiguous  ends  of 
41 


642 


DISSECTION    OF    THE    LEG 


the  tibia  and  fibula,  and  consists  of  transverse  yellowish  fibres  distinct 
from  the  posterior  ligament.  It  is  fixed  on  one  side  to  the  end  of  the 
fibula  above  the  pit :  and  on  the  other  it  is  inserted  into  the  contiguous 
part  of  the  tibia,  and  into  the  posterior  edge  of  the  articular  surface  so  as 
to  assist  in  deepening  the  hollow  into  which  the  astragalus  is  received. 

The  interosseous  ligament  fills  the  interval  between  the  bones  of  the 
leg,  and  serves  as  an  aponeurotic  partition  between  the  muscles  on  the 
front  and  back  of  the  leg.  Its  fibres  are  directed  downwards  for  the  most 
part  from  the  tibia  to  the  inner  surface  of  the  fibula :  but  some  few  cross 
in  the  opposite  direction. 

Internally  it  is  fixed  to  the  outer  edge  of  the  tibia :  and  externally,  to 
the  oblique  line  on  the  inner  surface  of  the  fibula  along  the  upper  three- 
fourths,  but  to  the  posterior  border  along  the  lower  fourth  of  that  bone. 

Both  superiorly  and  inferiorly  is  an  aperture  which  transmits  vessels. 
The  upper  opening,  about  an  inch  in  length,  lies  along  tlie  neck  of  the 
fibula,  and  gives  passage  to  the  anterior  tibial  vessels.  Tlie  lower  aper- 
ture is  close  to  the  fibula,  about  an  inch  above  the  lower  end,  and  is  only 
large  enough  for  the  small  anterior  peroneal  vessels. 

Some  strong  irregular  bundles  of  fibres,  the  inferior  interosseous  liga- 
ment, extend  between  the  bones  below  the  aperture  for  the  anterior  pero- 
neal artery.  It  may  be  seen  after  the  examination  of  the  ankle  joint  by 
sawing  longitudinally  the  lower  ends  of  the  leg  bones. 

Movement.  Very  little  movement  is  allowed  in  the  tibio-peroneal  articu- 
lations, as  the  chief  use  of  the  fibula  is  to  give  security  to  the  ankle  joint 
and  attachment  to  muscles  of  the  leg. 

In  the  upper  joint  there  is  a  slight  gliding  from  before  back.  In  the 
lower  articulation  the  ligaments  permit  some  yielding  of  the  fibula  to  the 
pressure  of  the  astragalus,  as  when  the  weight  of  the  body  is  thrown  on 
the  inner  side  of  the  foot ;  but  if  the  force  is  violent  the  lower  fourth  of 

that  bone  will  be  fractured  sooner 


Fig.  221. 


Internal  Lateral  Ligament  op  the  Anklb 
(altered  from  Bourgery). 

1.  Posterior  piece. 

2.  Middle  piece. 

.3.  Anterior  piece  of  the  inner  ligament. 
4.  Inferior  calcaneo-Mcaphoid  ligament. 


than  the  ligaments. 

Articulation  of  the  ankle 
(fig.  221).  Like  the  knee,  the 
ankle  is  a  ginglymoid  or  hinge  joint. 
In  this  joint  the  upper  surface  of  the 
astragalus  is  received  into  an  arch 
formed  by  the  lower  ends  of  the 
tibia  and  fibula  ;  and  the  four  liga- 
ments belonging  to  this  kind  of 
articulation  connect  together  the 
bones. 

Dissectio7i.  To  make  the  dissec- 
tion required  for  the  ligaments  of 
the  ankle  joint,  the  muscles,  and  the 
fibrous  tissue  and  vessels  must  be 
removed  from  the  front  and  back  of 
the  articulation. 

For  the  purpose  of  defining  the 
lateral  ligaments,  the  limb  must  be 
placed  first  on  one  side  and  then  on 
the  other.  The  internal  ligament 
is  wide  and  strong,  and  lies  beneath 
the  tendon  of  the  tibialis  posticus. 


LIGAMENTS    OF    ANKLE-JOINT.  643 

The  external  is  divided  into  three  separate  pieces ;  and  to  find  these  the 
peronei  muscles,  and  the  remains  of  the  annular  ligament  below  the  outer 
malleolus,  should  be  taken  away. 

The  anterior  or  tibio-tarsal  ligament  is  a  thin  fibrous  membrane,  which 
is  attached  to  the  tibia  close  to  the  articular  surface  ;  and  to  the  upper  part 
of  the  astragalus  near  the  articulation  with  the  scapiioid  bone.  In  the 
ligament  are  some  rounded  intervals  and  apertures  for  vessels.  On  the 
sides  it  joins  the  lateral  ligaments. 

The  posterior  ligament  is  thinner  internally  than  externally ;  and  it  is 
inserted  into  the  tibia  and  the  astragalus,  close  to  the  articular  surfaces  of 
the  bones.  Towards  the  outer  part  it  consists  of  transverse  fibres,  which 
are  fixed  into  the  hollow  on  the  inner  surface  of  the  external  malleolus. 

The  internal  lateral  or  deltoid  ligament  (fig.  221)  is  attached  by  its 
upper  or  pointed  part  to  the  inner  malleolus,  and  by  its  base  to  the  astraga- 
lus, the  OS  calcis,  and  the  scaphoid  bone,  by  fibres  which  radiate  to  their 
insertion  in  this  manner  : — The  posterior  (^)  are  directed  to  the  hinder  part 
of  the  inner  surface  of  the  astragalus  ;  the  middle  (^)  pass  vertically  to  the 
sustentaculum  tali  of  the  os  calcis  ;  and  the  anterior  (''),  which  are  thin  and 
oblique,  join  the  inferior  calcaneo-scaphoid  ligament  and  the  inner  side  of 
the  scaphoid  bone.  The  tendons  of  the  tibialis  posticus  and  flexor  longus 
digitorum  are  in  contact  with  this  ligament. 

The  external  lateral  ligament  (fig.  222)  consists  of  three  separate  pieces, 
anterior,  middle,  and  posterior,  which  are  attached  to  the  astragalus  and 
the  OS  calcis.  The  anterior  piece  Q)  is  a  short  flat  band,  which  is  directed 
from  the  fore  part  of  the  malleolus  to  the  side  of  the  astragalus  in  front  of 
the  lateral  articular  surface.  The  middle  portion  (^)  is  flattened  and  de- 
scends from  the  tip  of  the  malleolus  to  the  outer  surface  of  the  os  calcis, 
about  the  middle.  The  posterior  C^)  is  the  strongest,  and  is  almost  hori- 
zontal in  direction  ;  it  is  connected  externally  to  the  pit  on  the  inner  sur- 
face of  the  malleolus,  and  is  inserted  into  the  posterior  part  of  the  astraga- 
lus behind  the  upper  articular  surface,  extending  to  the  groove  for  the  flexor 
pollicis  tendon. 

The  posterior  and  middle  fasciculi  are  placed  beneath  the  peronei  mus- 
cles. The  middle  part  is  but  slightly  in  contact  above  with  the  synovial 
membrane  of  the  ankle  joint ;  and  both  it  and  the  posterior  piece  touch 
the  synovial  membrane  between  the  astragalus  and  the  os  calcis. 

Dissection.  Dividing  the  ligaments  of  the  ankle  joint,  separate  the  as- 
tragalus from  the  bones  of  the  leg,  to  see  the  osseous  surfaces  entering  into 
the  joint. 

The  synovial  membrane  of  the  joint  lines  the  capsule,  and  is  simple  in 
its  arrangement. 

Articular  surfaces.  On  the  tibia  there  are  two  articular  faces,  one  of 
which  corresponds  with  the  end  of  the  shaft,  and  the  other  with  the  mal- 
leolus. On  the  fibula  the  surface  of  the  malleohis  which  is  turned  to  the 
astragalus  is  tipped  with  cartilage. 

The  astragalus  has  a  central  articular  surface,  wider  before  than  behind 
and  trochlear-shaped,  which  touches  the  end  of  the  tibia  :  and  on  its  sides 
are  articular  impressions  for  contact  with  the  malleoli,  but  the  outer  one  is 
the  largest. 

Movement.  Only  the  movements  of  flexion  and  extension  are  permitted 
in  the  ankle  :  in  the  former  state  the  toes  are  raised  towards  the  fore  part 
of  the  leg ;  and  in  tlie  latter,  they  are  pointed  towards  the  ground. 

liijlexion  the  astragalus  moves  backwards  so  as  to  project  behind;  and 


644 


DISSECTION    OF    THE    LEG 


Fig.  222. 


all  further  motion  is  arrested  by  the  meeting  of  the  anterior  edge  of  the 
tibia  with  that  bone. 

The  posterior  ligament  is  stretched  over  the  projecting  head  of  the 
astragalus,  and  the  posterior  and  middle  parts  of  tlie  external  lateral,  and 

the    posterior   piece   of  the    internal 
lateral  ligament,  are  made  tense. 

In  extension  the  astragalus  moves 
forwards  over  the  end  of  the  tibia, 
and  projects  anteriorly.  A  limit  to 
the  movement  is  imposed  by  the  meet- 
ing behind  of  the  astragalus  with  the 
tibia. 

The  lateral  ligaments  are  partly 
made  tight  as  in  flexion,  for  instance 
the  anterior  piece  of  the  external,  and 
the  fore  and  middle  portions  of  the 
internal 

When  the  joint  is  half  extended  so 
that  the  small  hinder  part  of  the  as- 
tragalus is  brought  into  the  arch  of 
the  leg  bones,  a  slight  movement  of 
the  foot  inwards  and  outwards  may 
be  obtained  ;  but  if  the  foot  is  forcibly 
extended  the  portions  of  the  lateral 
ligaments,  attached  to  the  astragalus, 
prevent  this  lateral  movement  by 
their  tightnCvSS. 

Dissection.  The  joints  of  the  foot 
will  be  demonstrated  by  removing 
from  both  the  dorsum  and  the  sole  all 
the  soft  parts  which  have  been  examined.  Between  the  difterent  tarsal 
bones  bands  of  ligament  extend,  which  will  be  defined  by  removing  the 
areolar  tissue  from  the  intervals  between  them  (fig.  223). 

It  will  be  more  advantageous  for  the  student  to  clean  all  the  ligaments 
before  he  proceeds  to  learn  any,  than  to  prepare  only  the  bands  of  one 
articulation  at  a  time. 

Articulation  of  the  astragalus  and  os  calcis.  These  bones 
are  kept  together  by  two  joints,  and  a  strong  interosseous  ligament ;  and 
there  are  also  thin  bands  at  the  outer  side  and  behind. 

The  posterior  ligament  (fig.  223,  a)  consists  of  a  few  fibres  between 
the  bones,  where  they  are  grooved  by  the  tendon  of  the  flexor  pollicis  ; 
and  the  external  ligament  {b)  is  connected  to  the  sides  of  the  astragalus 
and  OS  calcis,  near  the  middle  piece  of  the  external  lateral  ligament  of  the 
ankle  joint. 

The  interosseous  ligament  (fig.  223,  c)  consists  of  strong  vertical  and 
oblique  fibres,  which  are  attached  above  and  below  to  tlie  depressions  on 
the  contiguous  surfaces  of  the  two  bones.  This  band  extends  across  the 
bones,  and  its  depth  is  greatest  at  the  outer  side. 

In  a  subsequent  stage  of  the  dissection  (p.  647)  articular  surfaces  will 
be  seen  between  the  bones,  viz.,  one  behind  the  interosseous  ligament,  and 
one  in  front  of  it,  with  two  synovial  membranes. 

Movement.  Under  the  influence  of  the  weight  of  the  body,  as  in  stand- 
ing,  the   astragalus   moves   down   and   in  (not   straight  forwards)   with 


External  Lateral  Ligament  of  the 
Ankle  (altered  from  Bourgery). 

1.  Anterior  part. 

2.  Posterior  part. 

3.  Middle  part  of  the  outer  ligament. 

4.  Interoaseusof  astragalus  and  os  calcis. 

5.  External  calcaneo-scaphoid  ligament. 


LIGAMENTS  OF  TARSAL  BONES. 


645 


flattening  of  the  arch  of  the  foot,  so  that  its  head  projects  against  the 
calcaneo-scaphoid  ligament.  In  this  state  the  interosseous  ligament  is 
put  on  the  stretch. 


Fig.  223. 


a.  Posterior,  &,  external,  and  c,  in- 
terosseous ligaments  between 
astragalus  and  os  calcis. 

d,  Astragalo-scaphoid. 

e.  External  calcaneo-scaphoid. 

/.  Internal,  and  g,  upper  calcaneo- 
cuboid ligaments. 

h.  Dorsal  scapho-cuboid  band. 

t,  k,  I.  Dorsal  external,  middle, 
and  internal  scapho-cuneiform 
longitudinal  bands. 

n.  Dorsal  transverse  bands  between 
the  cuneiform  and  cuboid  bones. 


View  of  the  Dorsal  Ligaments  op  the  Tarsus. 


When  the  pressure  of  the  leg  is  removed  the  astragalus  is  carried  up 
and  out  by  the  tightened  ligaments  and  muscles,  and  the  arch  of  the  foot 
is  restored. 

Astragalus  with  the  scaphoid  bone.  The  head  of  the  astragalus 
is  received  into  the  hollow  of  the  scaphoid  bone,  and  is  united  to  it  by  a 
dorsal  ligament ;  but  the  place  of  plantar  and  external  lateral  ligaments 
is  supplied  by  strong  bands  between  the  os  calcis  and  the  scaphoid  bone, 
which  will  be  noticed  below. 

The  dorsal  astragalo-scaphoid  ligament  (fig.  223,  d)  is  attached  to  the 
astragalus  close  to  the  articulation,  and  to  the  dorsal  surface  of  the  sca- 
phoid bone  :  its  attachments  will  be  better  seen  when  it  is  cut  through. 

Dissection.  The  external  ligament  of  the  articulation  may  be  seen  on 
the  dorsum  of  the  foot  in  the  hollow  between  the  os  calcis  and  the  scaphoid 
bone.  Supposing  the  tendon  of  the  tibialis  posticus  removed,  the  inferior 
ligament  will  be  detined  in  the  sole  of  the  foot  by  cutting  some  fibro-car- 
tilaginous  substance  from  it. 

The  inferior  ligament  (fig.  225,  c)  (calcaneo-scaphoid)  is  attached 
behind  to  the  fore  part  of  the  sustentaculum  tali  of  the  os  calcis,  and  in 
front,  to  the  hollow  on  the  sustentaculum  tali  of  the  os  calcis,  and  in  front, 
to  the  hollow  on  the  under  surface  of  the  scaphoid  bone.  In  the  upright 
posture  of  the  body  the  tendon  of  the  tibialis  posticus  is  beneath  it  in  the 
sole  of  the  foot ;  and  on  it  the  head  of  the  astragalus  rests. 

The  external  calcaneo-scafhoid  (fig.  223,  e)  is  placed  outside  the  head 
of  the  astragalus,  and  serves  as  a  lateral  ligament  to  the  astragalo-sca- 
phoid  articulation  ;  it  is  about  three-quarters  of  an  inch  deep.  Behind, 
it  is  fixed  to  the  upper  part  of  the  os  calcis,  between  the  articular  surfaces 
for  the  cuboid  bone  and  astragalus  ;  and  in  front  it  is  inserted  into  the 
outer  side  of  the  os  scaphoides. 

A  synovial  membrane  serves  for  this  articulation,  and  sends  back  a  pro- 
longation to  the  joint  between  the  fore  part  of  the  os  Cidcis  and  the  astra- 
galus. 

Articular  surfaces.  The  head  of  the  astragalus  has  two  articular  faces  ; 
a  smaller,  below,  for  the  os  calcis  ;  and  a  larger  one,  elongated  transversely 


646 


DISSECTION    OF    THE    LEG, 


and  larger  externally  than  internally,  for  the  scaphoid  bone.  The  sca- 
phoid bone  is  hollowed,  and  is  widest  externally. 

Movement.  The  scaphoid  moves  down  and  in  over  the  transversely 
elongated  head  of  the  astragalus,  or  up  and  out  in  the  opposite  direction. 

As  the  bone  is  forced  downwards,  the  upper  and  external  ligaments  of 
the  joint  are  made  tight ;  and  when  the  scaphoid  is  moved  in  the  opposite 
way  the  strong  inferior  ligament  is  put  on  the  stretch. 

The  OS  calcis  with  the  cuboid  bone.  The  ligaments  in  this  arti- 
culation are  plantar  and  dorsal,  the  former  being  much  the  strongest ;  and 
there  is  also  an  internal  band. 

The  dorsal  ligament  (fig.  223,  g)  (superior  calcaneo-cuboid)  is  a  rather 
thin  fasciculus  of  fibres,  wiiich  is  attached  near  to  the  contiguous  end  of 
the  OS  calcis  and  the  cuboid  bone ;  it  is  sometimes  divided  into  two  parts, 
or  it  may  be  situate  at  the  outer  border  of  the  foot. 

At  tlie  inner  side  of  the  os  cuboides  is  a  stronger  internal  hand  (fig.  223, 
f)  from  the  os  calcis,  this  is  fixed  behind  to  the  upper  part  of  the  os  calcis 
external  to  the  band  to  the  scaphoid  bone,  and  in  front  to  the  contiguous 
inner  side  of  the  os  cuboides. 


Fig.  224. 


Fiff.  225. 


Plantar  Ligaments  of  the  Foot  (Bourgery). 

1.  Long  plantar  ligament. 

2.  Deep  portion  of  the  inferior  calcaneo-cu- 

boid ligament. 

3.  Tendon  of  the  peroneus  longus  muscle. 


View  of  the  Inferior  Ligaments  of  the 
Tarsal  Bones. 
a.  Long  plantar,  cut. 

h.  Short  or  deep   inferior  calcaneo-cuboid   liga- 
ment. 

c.  Inferior  calcaneo-scaphoid. 

d.  Plantar  transverse  scapho-cuboid  ligament. 

e.  Dorsal  inner  scapho-cuneiforra  extending  into 

the  sole  of  the  foot. 
/.  Plantar  transverse  ligament  between  the  inner 

and  middle  cuneiform  bones. 
g.  Plantar  transverse  band  between  the  cuboid 

and  outer  cuneiform. 


The  inferior  calcaneo-cuhoid  ligament  in  the  sole  of  tlie  foot  (fig.  224) 
is  much  the  strongest,  and  is  divided  into  a  superficial  and  a  deep  part : — 


TRANSVERSE    TARSAL    ARTICULATION.  647 

The  superficial  portion,  ligamentum  longum  plantce  Q)  is  attached  to 
|he  under  surface  of  the  os  calcis  from  near  the  posterior  to  the  anterior 
^tubercle  :  its  fibres  pass  forwards  to  be  connected  with-  the  ridge  on  the 
under  surface  of  the  cuboid  bone ;  but  the  most  internal  are  continued 
over  the  tendon  of  the  peroneus  longus  muscle,  assisting  to  form  its  sheath, 
and  are  inserted  into  the  bases  of  the  third  and  fourth  metatarsal  bones. 

The  deep  piece  of  the  ligament  (fig.  225,  5),  seen  on  division  of  the 
superficial,  extends  from  the  tubercle  and  the  hollow  on  the  fore  part  of 
the  under  surface  of  the  os  calcis,  to  the  cuboid  bone  internal  or  posterior 
to  the  ridge. 

A  simple  synovial  membrane  belongs  to  the  articulation. 

Articular  surfaces.  Both  bones  are  flattened  towards  the  outer  part 
of  the  articulation  ;  but  at  the  inner  side  the  os  calcis  is  hollowed  from 
above  down,  and  the  os  cuboides  is  convex  to  fit  into  it. 

Movement.  In  this  joint  the  cuboid  bone  possesses  two  movements,  viz., 
an  oblique  one,  down  and  in,  and  up  and  out. 

In  the  downward  movement  the  internal  lateral  and  the  upper  ligament 
are  made  tight ;  and  in  the  upward,  the  calcaneo-cuboid  ligaments  of  the 
sole  are  stretched. 

Transverse  tarsal  articulation  (fig.  223).  The  joints  of  the 
astragalus  with  the  scaphoid,  and  os  calcis  with  the  cuboid  bone,  form  a 
transverse  articulation  across  the  foot  in  which  the  movements  of  inversion 
and  eversion  take  place. 

In  inversion  the  great  toe  is  adducted ;  the  inner  border  of  the  foot  is 
shortened,  and  is  raised  from  the  ground  so  that  the  sole  looks  inwards. 

The  scaphoid  bone  passes  down  and  in  over  the  head  of  the  astragalus, 
being  approximated  near  to  the  inner  malleolus  ;  and  the  cuboid  bone 
moves  down  and  in  on  the  os  calcis.  The  cuneiform  bones  are  raised  at 
the  same  time  and  contribute  to  the  movement  (p.  648). 

The  ligaments  connected  with  both  joints  on  the  dorsum  of  the  foot  are 
tightened. 

In  eversion  the  inner  border  of  the  foot  descends  and  lengthens,  the 
outer  border  is  raised,  and  the  great  toe  is  abducted  from  the  middle  line 
of  the  body. 

The  same  two  tarsal  bones  are  directed  up  and  out,  and  the  cuneiforms 
sink. 

The  ligaments  in  the  sole  of  the  foot  of  both  joints  now  come  into  use 
to  prevent  over  movement. 

Dissection.  Saw  through  the  astragalus  in  front  of  the  attachment  of 
the  interosseous  ligament  between  it  and  the  os  calcis;  and  remove  the 
head  of  the  bone  for  the  purpose  of  observing  the  lower  and  outer  calcaneo- 
scaphoid  ligaments. 

Tlien  the  interosseous  ligament  uniting  the  astragalus  and  the  os  calcis 
is  to  be  cut  through,  to  demonstrate  its  attachments,  the  articular  surfaces 
of  the  bones,  and  the  synovial  sacs  (p.  644). 

Articular  surfaces  of  the  two  hinder  tarsal  bones.  There  are  two 
articular  surfaces,  anterior  and  posterior,  to  both  the  astragalus  and  the  os 
calcis.  Tlie  liinder  one  of  the  os  calcis  is  convex  transversely  and  the 
anterior  is  concave  ;  but  sometimes  the  last  is  subdivided  into  two.  The 
surface  of  the  astragalus  will  liave  a  form  exactly  the  reverse  of  that  of 
the  os  calcis,  viz.,  the  hinder  one  concave  and  the  anterior  convex  ;  the 
anterior  is  seated  on  the  head  of  the  astrasralus. 


648  DISSECTION    OF    THE    LEG. 

Dissection.  The  calcaneo-cuboid  joint  may  be  opened  to  see  the  articu- 
lar surfaces:  and  the  student  is  to  keep  in  mind  tluit  all  the  other  articula- 
tions of  the  foot  are  to  be  opened  for  the  like  purpose,  even  should  directions 
not  be  given. 

Articulations  of  the  scaphoid  bone.  The  scaphoid  bone  articu- 
lates in  front  with  the  three  cuneiform  bones,  and  laterally  with  the  os 
cuboides. 

In  the  articulation  with  the  cuneiform  hones  (fig.  223)  there  are  three 
longitudinal  dorsal  ligaments  (i,  k,  /),  one  to  each  bone  ;  but  tlie  inner- 
most is  the  strongest  and  widest,  and  extends  round  the  inside  of  the 
articulation  into  the  sole  of  the  foot  (fig.  225,  e). 

The  place  of  plantar  bands  is  supplied  by  processes  of  the  tendon  of 
the  tibialis  posticus. 

A  synovial  membrane  (common  of  the  tarsus)  lines  the  articulation, 
and  sends  forwards  prolongation  between  the  cuneiform  bones. 

In  the  articulation  with  the  os  cuhoides  there  is  a  dorsal  oblique  band  of 
fibres  (fig.  223,  h)  between  the  contiguous  surfaces  of  the  bones  ;  a  plantar 
transverse  band  (fig.  225,  c?),  which  is  concealed  by  the  tendon  of  the 
tibialis  posticus  ;  and  a  strong  interosseous  ligament. 

Where  the  bones  touch,  the  surfaces  are  tipped  with  cartilage,  and  are 
furnished  with  a  prolongation  from  the  common  synovial  membrane  of  the 
tarsus. 

Articulatoins  of  the  cuneiform  bones.  These  bones  are  united 
to  one  another  by  cross  bands ;  and  the  external  one  articulates  with  the 
OS  cuboides  after  a  similar  manner. 

The  three  cuneiform  bones  are  connected  together  by  short  transverse 
dorsal  bands  (fig.  223,  7i)  between  the  upper  surfaces.  Similar  plantar 
ligaments  are  wanting,  except  one  between  the  two  innermost  (fig.  225,/). 
There  are  also  interosseous  ligaments  between  the  contiguous  surfaces  of 
the  bones.  Laterally  there  are  articular  surfaces  between  the  bones,  with 
offsets  of  the  common  synovial  membrane. 

Where  the  external  cuneiform  touches  the  cuboid  bone  the  surfaces  are 
covered  with  cartilage.  A  dorsal  ligament  (fig.  223,  n)  passes  transversely 
between  the  two  ;  and  a  plantar  ligament  (fig.  225,  g)  takes  a  similar 
direction.     Between  the  bones  there  is  also  an  interosseous  ligament. 

This  joint  is  furnished  either  with  a  distinct  synovial  sac,  or  with  a 
prolongation  of  the  common  tarsal  synovial  membrane. 

The  synovial  membrane  of  the  articulations  of  the  cuneiform  bones  is 
common  to  many  of  the  bones  of  tlie  tarsus.  Placed  between  the  scaphoid 
and  the  three  cuneiforms  it  sends  one  prolongation  forwards  between  the 
inner  and  middle  cuneiform  to  the  joints  with  the  second  and  third  meta- 
tarsal bones ;  another,  outwards,  to  the  articulation  of  the  scaphoid  with 
the  cuboid  bone  ;  and  sometimes  a  third  to  the  joint  between  the  external 
cuneiform  and  the  os  cuboides. 

Articular  snrfaces.  On  the  scaphoid  are  three  articular  faces,  the 
inner  being  rounded,  and  the  other  two  fiattened.  The  three  cuneiforms 
unite  in  a  shallow  elliptical  hollow,  which  is  most  excavated  internally. 

Movement.  The  cuneiform  bones  glide  up  and  out  on  the  scaphoid  in 
inversion  of  the  foot,  and  down  and  in  in  eversion  ;  and  the  inner  one 
moves  more  than  the  others  in  consequence  of  the  shape  of  the  articular 
surfaces,  and  the  attachment  to  it  of  the  tibialis  anticus. 

When  the  bones  pass  down  the  dorsal  ligaments  are  made  tight :  and 


LIGAMENTS    OF    TARSUS    WITH    METATARSUS. 


649 


Fig.  226. 


as  they  rise  the  interosseous  and  transverse  plantar  bands  will  keep  them 
united. 

In  standing  and  in  progression  these  bones  are  separated  somewhat  from 
each  other  with  diminution  of  the  arch  of  the  foot,  and  stretching  of  the 
transverse  ligaments  which  connect  them. 

Articulation  of  the  mktatarsal  bones.  The  bases  of  the  four 
outer  metatarsal  bones  are  connected  together  by  dorsal,  plantar,  and  in- 
terosseous ligaments  ;  and  where  their  lateral  parts 
touch,  they  are  covered  with  cartilage,  and  have 
offsets  of  a  synovial  sac. 

The  dorsal  ligaments  (fig.  22G)  are  small  trans- 
verse bands  from  the  base  of  one  metatarsal  bone 
to  the  next.  The  plantar  ligaments  (fig.  224)  are 
similar  to  the  dorsal.  The  interosseous  ligaments 
are  short,  transverse  fibres  between  the  contiguous 
rough  lateral  surfaces  :  they  may  be  afterwards 
seen  by  forcibly  separating  the  bones. 

Lateral  union.  The  four  outer  bones  touch  one 
another  laterally ;  the  second  metatarsal  lies  against 
the  internal  and  external  cuneiforms ;  and  the 
fourth  is  in  contact  internally  with  the  outer  cunei- 
form. Those  articulating  surfaces  are  covered  with 
cartilage  ;  and  are  provided  with  synovial  mem- 
brane, which  is  derived  from  the  sacs  serving  for 
the  articulation  of  the  same  four  metatarsal  with 
the  tarsal  bones. 

The  metatarsal  bone  of  the  great  toe,  like  that 
of  the  thumb,  is  not  united  to  the  others  at  its  base 
by  any  intervening  bands. 

The  digital  ends  of  the  five  metatarsal  bones  are 
united  by  the  transverse  metatarsal  ligament ;  this 
has  been  described  in  page  624. 

Tarsal  with  metatarsal  bones.  These  articulations  resemble  the 
like  parts  in  the  hand,  as  there  is  a  separate  joint  for  the  great  toe,  and  a 
common  one  for  the  four  outer  metatarsals. 

Articulation  of  the  great  toe.  The  articular  ends  of  the  bones  are  in- 
cased by  a  capsule,  and  are  provided  with  an  upper  and  a  lower  longitu- 
dinal hand  to  give  strength  to  the  joint :  the  lower  band  is  placed  between 
prolongations  from  tlie  tendons  of  the  tibialis  anticus  and  peroneus  longus. 

A  simple  synovial  membrane  serves  for  the  articulation. 

The  articular  surfaces  are  oval  from  above  down,  curved  inwards,  and 
constricted  in  the  middle  ;  that  of  the  great  toe  is  excavated,  and  the  other 
is  convex. 

Movement.  There  is  an  oblique  movement  of  the  metatarsal  bone  down 
and  in  and  up  and  out,  like  that  of  the  internal  cuneiform  with  the  sca- 
phoid bone ;  and  this  will  contribute  some  motion  to  inversion  and  ever- 
sion  of  the  foot. 

The  joint  possesses  likewise  slight  abdnctory  and  adductory  movement. 

Articulation  of  the  four  outer  toes.  The  tliree  outer  tarsal  bones  of 
the  last  row  correspond  with  four  metatarsals  ; — the  middle  cuneiform  be- 
ing opposite  the  second  metatarsal  bone,  the  external  cuneiform  touching 
that  of  the  third  toe,  and  the  os  cuboides  carrying  the  two  outer  bones. 


Dorsal  Ligaments  Uni- 
TiNQ  THE  Tarsus  to  the 
Metatarsus,  and  the  Me- 
tatarsal Bones  to  each 
other  behinu  (Bourgery). 


650  DISSECTION    OF    THE    LEG. 

The  bones  in  contact  are  tipped  with  cartilage,  and  have  longitudinal  dor- 
sal, plantar,  and  lateral  ligaments,  with  some  oblique  in  the  sole. 

The  dorsal  ligaments  (fig.  226)  are  thin  bands  of  fibres,  which  are  more 
or  less  longitudinal  as  they  extend  from  the  tarsal  to  the  metatarsal  bones. 
Each  metatarsal  bone  receives  one  ligament,  except  that  of  the  second 
toe,  to  which  there  are  three ; — the  three  bands  to  the  second  coming  from 
all  the  cuneiform  bones,  one  from  each.  The  third  bone  obtains  a  liga- 
ment from  the  external  cuneiform  ;  and  the  fourth  and  fifth  have  a  fascicu- 
lus to  each  from  the  os  cuboides. 

Plantar  ligaments  (fig.  224).  There  is  one  longitudinal  band  from  each 
of  the  two  outer  cuneiform  to  the  corresponding  metatarsal  bone  ;  but  be- 
tween the  cuboid  and  its  metatarsal  bones  there  are  only  some  scattered 
fibres. 

The  lateral  ligaments  are  longitudinal ;  they  lie  deeply  between  the 
bones,  and  are  connected  with  the  second  and  third  metatarsals  :  they  will 
be  better  seen  by  cutting  the  transverse  bands  joining  the  bases  of  the 
bones.  To  the  bone  of  the  second  toe  there  are  two  bands,  one  on  each 
side  : — the  inner  is  strong  and  is  attached  to  the  internal  cuneiform  ;  and 
the  outer  is  fixed  into  the  middle  or  the  outer  cuneiform  bone.  The  me- 
tatarsal bone  of  the  third  toe  is  provided  with  one  lateral  slip  on  its  outer 
side,  which  is  inserted  above  into  the  external  cuneiform  bone. 

Oblique  plantar  ligaments.  A  fasiculus  of  fibres  extends  across  from 
the  front  of  the  internal  cuneiform  to  the  second  and  third  metatarsals  ;  and 
from  the  external  cuneiform  there  is  another  slip  to  the  metatarsal  bone  of 
the  little  toe. 

Line  of  the  articulation.  The  line  of  the  articulation  between  the  tarsus 
and  metatarsus  is  zigzag,  in  consequence  of  the  unequal  lengths  of  the 
cuneiform  bones.  To  open  the  articulation,  the  knife  should  be  carried 
obliquely  forwards  from  the  tuberosity  of  the  fifth  to  the  base  of  the  sec- 
ond metatarsal  bone ;  then  about  two  lines  farther  back  for  the  union  of 
the  second  metatarsal  with  the  middle  cuneiform  ;  and  finally,  half  an 
inch  in  front  of  the  last  articulation,  for  the  joint  of  the  internal  cunei- 
form with  the  first  metatarsal  bone. 

Two  synovial  meinbranes  are  present  in  these  tarso-metatarsal  articula- 
tions. 

There  is  one  between  the  cuboid  and  the  two  outer  metatarsals,  which 
serves  for  the  adjacent  lateral  articular  surfaces  of  the  bones ;  this  is  not 
always  separate  from  the  following. 

The  second  is  placed  in  the  joint  between  the  external  and  middle 
cuneiforms  with  their  metatarsal  bones  (third  and  second),  and  is  an  offset 
of  the  common  synovial  membrane  belonging  to  the  articulation  of  the 
scaphoid  with  the  cuneiform  bones  (p.  G48)  :  prolongations  from  it  are 
furnished  to  the  lateral  articular  surfaces  of  the  second,  third,  and  fourth 
(inner  side)  metatarsals. 

Articular  surfaces.  The  osseous  surfaces  are  not  flat;  for  the  metatar- 
sal bones  are  undulating,  and  the  tarsal  are  uneven  to  fit  into  the  others. 

Movement.  From  tlie  wedge-shaped  form  of  the  metatarsal  bones  a 
slight  movement  from  above  down  is  obtainable;  and  this  is  greatest  in 
the  little  toe  and  the  next. 

In  the  little  toe  tliere  is  an  abductory  and  adductory  motion ;  and  a 
small  degree  of  the  same  exists  in  the  fourth  toe. 

Dissection.  All  the  superficial  ligaments  having  been  taken  away,  the 
interosseous  ligaments  of  the  tarsus  and  metatarsus  may  be  seen  by  sepa- 


METATARSO-PHALANGEAL    JOINTS.  651 

ratinoj  forcibly  the  cuneiform  bones  from  one  another  and  from  tlie  os 
cuboides ;  the  latter  bone  from  the  os  scaphoides  :  and  the  bases  of  the 
metatarsals  from  one  another.  The  dissector  will  find  that,  in  using 
force,  the  bones  will  sometimes  tear  sooner  than  the  ligaments. 

Metatarsus  with  phalanges.  These  are  condyloid  joints,  in 
which  the  head  of  the  metatarsal  bone  is  received  into  the  cavity  of  the 
phalanx. 

Each  articulation  has  two  lateral  and  an  inferior  ligament,  as  in  the 
hand;  and  the  joint  is  further  strengthened  above  by  an  expansion  derived 
from  the  tendons  of  the  extensors  of  the  toes.  A  distinct  synovial  mem- 
brane exists  in  each  joint. 

In  the  articulation  of  the  great  toe  there  are  two  sesamoid  bones,  which 
are  connected  with  the  inferior  and  lateral  ligaments. 

All  these  structures  are  better  seen  in  the  hand,  where  they  are  more 
distinct ;  and  their  anatomy  is  more  fully  described  with  the  dissection  of 
that  part.     (See  page  oOl.) 

Surfaces  of  bone.  The  metatarsal  bone  has  a  rounded  head,  which  is 
longest  from  above  down,  and  readiest  farthest  on  the  plantar  surface. 
On  the  end  of  the  phalanx  is  a  cup-shaped  cavity. 

Movement.  In  this  condyloid  joint  as  in  the  hand,  there  is  angular 
motion  in  four  different  directions,  with  circumduction. 

Flexion  and  extension.  When  the  joint  is  bent  the  phalanx  passes  un- 
der the  head  of  the  metatarsal  bone ;  and  when  it  is  extended  the  phalanx 
moves  back  beyond  a  straight  line  with  the  metatarsal  bone. 

A  limit  to  flexion  is  set  by  the  meeting  of  the  bones,  by  the  stretching 
of  the  fore  part  of  the  lateral  ligaments,  and  by  the  extensor  tendon ;  and 
to  extension,  by  the  tightness  of  the  inferior,  and  the  hinder  part  of  each 
lateral  ligament,  and  by  the  flexor  tendons. 

Lateral  movemeyit.  The  phalanx  passes  from  side  to  side  across  the  end 
of  the  metatarsal  bone.  Its  motion  is  checked  by  the  lateral  ligament  of 
the  side  from  which  it  moved,  and  by  the  contact  with  the  other  digits. 

Circumduction^  or  the  revolving  of  the  phalanx  over  the  rounded  head 
of  the  metatarsal  bone,  is  least  impeded  in  the  great  toe  joint ;  but  these 
movements  in  the  foot  are  not  so  free  as  in  the  hand. 

AiiTicuLATiONS  OF  THE  PHALANGES.  There  are  two  phalangeal 
joints  to  each  toe,  except  the  first. 

Ligaments  similar  to  those  in  the  metatarso-phalangeal  joints,  viz.,  two 
lateral  and  an  inferior,  are  to  be  recognized  in  these  articulations.  The 
joint  between  the  last  two  phalanges  is  least  distinct ;  and  oftentimes  the 
small  bones  are  immovably  united  by  osseous  substance.  These  ligaments 
receive  a  more  particular  notice  with  the  dissection  of  the  hand  (p.  302). 

A  simple  synovial  membrane  exists  in  each  phalangeal  articulation. 

Articular  surfaces.  In  both  phalangeal  joints,  the  nearest  phalanx 
presents  a  trochlear  surface ;  and  the  distal  one  is  marked  by  two  lateral 
hollows  or  cups  with  a  median  ridge. 

Movement.  Only  flexion  and  extension  are  permitted  in  the  two  pha- 
langeal joints  of  the  toes,  as  in  the  hand. 

Inflexion  the  farther  phalanx  glides  under  the  nearer;  and  in  extension 
the  two  are  brought  into  a  straight  line. 

The  bending  is  checked  by  the  lateral  ligaments  and  the  extensor  ten- 
don ;  and  the  straightening  is  limited  by  the  inferior  ligament  and  the 
flexor  tendons. 


652 


ARTERIES    OF    THE    LOWER    LIMB, 


TABLE  OF  THE  ARTERIES  OF  THE  LOWER  LIMB. 


f  External  pudic 

superficial  epi- 
gastric 

superficial  cir- 
cumflex iliac 


Profunda , 


Muscular 
Anastomotic 


Popliteal . 


Superior 
inferior. 


^  External  circumflex 


internal  circumflex 


i 


first  perforating 
second  perforating , 
third  perforating 
L  terminal  branch. 


Superficial 
deep  branch. 


f  Muscular 
upper  internal  . 
upper  external  . 
lower  internal  . 
lower  external  . 
azygos  articular 
sural. 


Arterior  tibial 


■< 


I  Posterior  tibial 


i  t, 


Ascending 

CRcending 

transverse. 

Muscular 
articular 
ascending  . 
transverse  . 


nutritious. 


final  branches. 


articular 
articular 


Recurrent 

cutaneous 

muscular 

internal  malleolar 

external  malleolar 

articular 

tarsal 

three  interos- 
seous, 
first  interosseous' 
communicating  to 
deep  arch 

'  To  great  toe  and 
half  the  next. 


metatarsal 


•^  digital 


Peroneal  . 

nutritious  to  tibia 

communicating  to 
peroneal 
-i   articular 

Internal  plantar 


external 
plantar 


Muscular 
nutritious  to  fibula 
anterior  peroneal. 


Muscular 


plantar 
arch    . 


r  Muscu 

poster! 

I       atinc 


N.  B.  The  branches  of  the  internal  iliac  artery  which  end  in  the  limb,  wi 
table  of  the  arteries  of  the  abdomen. 


Muscular 

posterior  perfor- 
■  S 

digital,  for  three 
toes  and  a  half 

anterior  perfor- 
ating. 

1  be  found  in  the 


VEINS    OF    THE    LOWER    LIMB 


663 


TABLE  OF  THE  VEINS  OF  THE  LOWER  LIMB. 


Popliteal   . 


Anastomotic 


Muscular 


Profunda 


Internal  sa- 
1^     pheuous  . 


f  Posterior  tibial 


External  plantar 


internal  plantar 
articular 
conimunicatiug 
to  saphenous 
nutritious 


Muscular 


plantar 
arch 


Posterior  per- 
forating 
digital  from 
three  toes  and 
j       a  half 
I   anterior  per- 
L      forating. 


Anterior  tibial 


External  saphenous 


sural 

articular 

muscular. 


L  peroneal 


Communicating 
to  deep  arch  . 

interosseous 

metatarsal  .     . 

tarsal 
malleolar 
communicating 
to  saphenous 
muscular 
recurrent. 


Branch  from  dor- 
sal arch  of  foot. 

plantar 

veins  from  outer 
side  of  OS  calcis 

cutaneous  in  the 
leg. 


Anterior  pero- 
neal 
muscular 
nutritious. 


Digital  from 
great  toe  and 
half  the  next. 

Three  interos- 
seous. 


Superficial 
deep  branch. 


Terminal  branch 
first  perforating 
second  perforating  . 
third  perforating 

External  circumflex 


Nutritious, 

Ascending 
transverse 
desceuing 


L  Internal  clr.uMflex;^M_j^-l^V 


Branch  from  dorsal  arch  of  the  foot 

plantar 

veins  about  os  calcis 

communicating  with  posterior  and  ante- 
rior tibial 

communicating  with  deep  veins  of  thigh 

cutaneous  from  outer  and  inner  parts  of 
thigh 

external  pudic 

superficial  epigastric 

superficial  circumflex  iliac. 


654 


NERVES    OF    THE    LOWER    LIMB. 


TABLE  OF  THE  NERVES  OF  THE  LOWER  LIMB. 


r  1.  External 
cutaneous 


C  Post 
<  an 
(      bn 


Posterior  and 

terior 

branches. 


2.  Obturator    ■< 


Accessory 


to  obturator  externus 
to  articulation 


superficial 
division 

deep  divi- 
sion    . 


(  to  obtui 
i  to  pecti 
(   to  hip  j 

jxternus 
n 

\  Muscular    . 
'  (  to  plexus  in 


rator  trunk 

iieus 

oint. 


STo  gracilis 
to  abductor  longus 
the  thigh  and  artery 


To  adductor  brevis  and  magnus 
articular. 


3.  Anterior 
crural 


Superficial 
portion     , 


deep  part 


4.  branch  )  rr„  !„*„„,, 


Muscular 


To  sartorius 
to  pectineus. 


middle  cutaneous 


interuil 
cutaueous 


Muscular 


Anterior  and  inner  branches. 

To  rectus 

to  vastus  externus — articular 

to  vastus  internus  and  crureus — articular. 


internal  S  Branch  to  plexus  over  patella  to 

saphenous   (      leg  and  fot. 


fl.  Small 
sciatic 


,  Great 
sciatic 


f  Inferior  gluteal 
-;   inferior  pudendal 
*     •    (  cutiineous  to  glute 


teal  region,  thigh,  and  leg. 


3.  To  gluteus 

4.  To  qua- 
driitiis  and 
gemelli  .     . 

6.  Superior 
gluteal 


f  Articulation  to  hip 
to  hamstrings. 


external 
popliteal 


internal 
popliteal 


Articular. 


Articular 

cutaneous 

l>eron<^al  communicating 

recurrent  articular 

musculo-        J  To  peronei 
cutaneous   (  cutaneous  to  foot  and  toes 


anterior 
tibial 


I  Muscular 

<  articular 

*  ( cutaneous 


Muscular 

18  to  two  toes. 


f  Articular 
musculiir 
short  saphenous 

f  Muscular  to  flexors 


posterior 
tibial  . 


internal  plantar 


external  plantar 


Cutaneous  of  the  sole 

mus(;nlar 

four  digital 
I  communicating  branch 
particular  to  the  toes. 


Superficial 
part   .     . 


Muscular 
two  digital 
articular 


To  glutei 

to  tensor  vagina:  femoris 


■^-pp"'  I  "rut; 


BALL    OF    THE    EYE.  655 


CHAPTER  X. 

DISSECTION  OF  THE  EYE. 

The  eyeball  is  the  organ  of  vision,  and  is  lodged  in  the  orbit.  Sup- 
ported in  tliat  hollow  on  a  mass  of  fat,  it  is  surrounded  by  muscles  which 
impart  movement  to  it ;  and  a  thin  membrane  (tunica  vaginalis  oculi) 
isolates  the  ball,  so  as  to  allow  free  movement. 

Two  lids  protect  the  eye  from  external  injury,  and  moderate  the  degree 
of  light  admitted  into  the  interior ;  and  the  anterior  or  exposed  surface  is 
covered  by  a  mucous  membrane  (conjunctiva). 

Directions.  In  the  absence  of  specimens  of  the  human  eye,  the  struc- 
ture may  be  learnt  on  the  eye  of  the  ox  or  pig.  Let  the  student  procure 
half  a  dozen  eyes  of  the  ox  for  the  purpose  of  dissection.  One  or  two 
shallow  basins  will  be  needed  ;  and  some  wax  or  tallow  in  the  bottom  of 
one,  or  in  a  deep  plate,  may  be  useful. 

Dissection.  To  see  the  general  form  of  the  ball  of  the  eye,  and  the 
outer  surface  of  the  external  coat,  the  attachments  of  the  different  muscles 
are  to  be  taken  away ;  and  the  loose  mucous  membrane  is  to  be  removed 
from  the  front. 

The  hall  of  the  eye  (fig.  227)  is  roundish  in  form  and  consists  of  two 
parts,  which  differ  in  appearance,  viz.,  an  opaque  posterior  portion,  form- 
ing five-sixths  of  the  whole,  and  a  smaller  transparent  piece  (cornea)  in 
front ;  these  two  parts  are  segments  of  different-sized  spheres,  the  an- 
terior belonging  to  the  smaller  sphere.  To  the  back  of  the  eye  the  optic 
nerve  is  attached,  rather  to  the  inner  side  of  tlie  axis  of  the  ball ;  and 
around  it  nutritive  vessels  and  the  nerves  enter. 

The  antero-posterior  diameter  of  the  ball  amounts  to  nearly  an  inch 
(■j^oths),  but  the  transverse  measures  an  inch. 

The  organ  of  vision  is  composed  of  central  transparent  parts,  with  in- 
closing membranes  or  coats.  The  coats,  posited  one  within  another,  are 
named  sclerotic,  choroid,  and  retina.  Tiie  transparent  media  in  the  in- 
terior are  likewise  three,  viz.,  the  lens,  the  aqueous  humor,  and  the  vitreous 
body. 

Dissection.  To  obtain  a  general  idea  of  the  structures  to  be  dissected, 
the  student  may  destroy  one  eyeball  by  cutting  through  it  circularly  :  he 
will  then  be  able  to  recognize  the  arrangement  of  the  parts  mentioned 
above,  with  their  strength  and  appearance  :  and  will  be  better  prepared 
to  follow  the  directions  that  are  afterwards  given. 

Fibrous  coat  of  the  eyeball.  The  outer  casing  of  the  eye  consists 
of  an  opaque  hinder  part  called  sclerotic,  and  of  an  anterior  transparent 
portion,  the  cornea. 

The  SCLEROTIC  (cornea  opaca)  is  the  firm,  whitish,  and  opaque  portion 
of  the  external  stratum  of  the  eyeball,  which  supports  the  more  delicate 
structures  within. 

Dissection.  To  examine  the  inner  and  outer  surfaces  of  this  layer  it 
will  be  necessary  to  cut  circularly  with  a  scissors  through  the  cornea  close 


656 


DISSECTIOX    OF    THE    EYE. 


to  the  sclerotic,  and  to  remove  the  cornea  from  the  front  of  the  eyeball ; 
on  piercing  the  cornea  the  aqueous  fluid  escapes  from  the  containing 
chamber.  The  outer  structures  may  be  then  abstracted  from  the  interior 
of  the  sclerotic  covering,  and  may  be  set  aside  with  the  cornea  for  subse- 
quent use. 


o.  Outer  or  sclerotic  coat,  and  d,  the 
cornea. 

6.  Middle  or  choroidal  coat. 

m.  Ciliary  ligament. 

s.  Ciliary  process. 

e.  Ciliary  muscle,  and/,  iris. 

c.  Inuer  c  at  of  retina,  continuous 
with  the  optic  nerve  behind, 
with  a  dark  layer  outside  it. 

g.  Lens. 

t.  Suspensory  ligament  of  the  lens. 

h.  Vitreous  body. 

n.  Hyaloid  membrane. 

i.  Posterior  chamber. 

0.  Canal  of  Petit 

r.  Sinus  circularis  iridis. 

1.  Optic  nerve. 

The  dotted  line  through  the  centre 
is  the  longitudinal  axis  of  the 
ball. 


Diagram  of  a  Horizontal  Section  of  the  Eyeball. 


The  sclerotic  tunic  of  the  eye  (fig.  227,  a)  is  bell-shaped,  and  extends 
from  the  entrance  of  the  optic  nerve  to  the  margin  of  the  cornea,  forming 
about  five-sixths  of  the  ball. 

At  its  back,  and  a  little  to  the  inner  side  of  the  centre  (one-tenth  of  an 
inch),  the  optic  nerve  (I)  is  transmitted  through  an  aperture  in  it:  this 
opening  decreases  in  size  from  without  inwards,  and  is  cribriform  when 
the  nerve  is  drawn  out — the  lattice-like  condition  being  due  to  the  bundles 
of  fibrous  tissue  between  the  funiculi  of  the  nerve.  Small  apertures  for 
the  passage  of  vessels  and  nerves  are  situate  around  the  optic  nerve ;  and 
there  are  others  for  vessels  at  the  front  and  centre  of  the  ball.  Anteriorly 
the  sclerotic  is  continuous  with  the  transparent  cornea. 

On  the  outer  surface  this  coat  is  smooth,  except  where  the  muscles  are 
attached  ;  on  the  inner  aspect  it  is  of  a  dark  color  with  flocculi  of  fine 
areolar  tissue  (membrana  fusca)  uniting  it  to  the  next  coat,  and  with  the 
ends  of  ruptured  vessels  and  nerves. 

The  sclerotic  covering  is  thickest  at  the  back  of  the  eyeball,  but  it  be- 
comes thinner  and  whiter  about  a  quarter  of  an  inch  from  the  cornea, 
where  it  is  visible  as  the  ''  white  of  the  eye."  Where  it  joins  the  cornea 
it  becomes  again  somewhat  thickened.  In  its  substance  near  the  union 
with  the  cornea  is  a  small  flattened  venous  space,  the  canal  of  Schlemm 
(sinus  circularis  iridis)  (fig.  235,  *■). 

Structure.  The  sclerotic  coat  is  formed  of  layers  of  white  fibrous  tissue, 
collected  into  bundles,  with  a  fine  network  of  yellow  or  elastic  fibres.     In 


STRUCTURE    OF    CORNEA. 


657 


it  are  scattered  nucleated  cells,  fusiform  in  shape,  or  possessing  rays,  and 
some  with  pigment.  Though  interlaced  with  one  another,  the  fibres  have 
rather  a  longitudinal  direction  towards  the  back  of  the  ball,  and  a  trans- 
verse one  at  the  outer  surface  near  the  cornea.  Only  a  few  vessels  ramify 
in  the  membrane,  and  end  in  capillaries  with  large  meshes.  The  presence 
of  nerves  in  it  is  a  subject  for  inquiry. 

Cornea  (fig.  227,  d).  This  firm  transparent  membrane  (cornea  pellu- 
cida)  forms  about  one-sixth  of  the  eyeball,  and  measures  about  half  an 
inch  transversely,  but  rather  less  from  above  down.  Its  shape  is  circular ; 
though,  when  viewed  in  front,  it  appears  largest  in  the  transverse  direc- 
tion, in  consequence  of  the  o{)aque  sclerotic  structure  encroaching  further 
on  it  above  and  below  than  on  the  sides. 

It  is  convex  anteriorly,  but  concave  posteriorly ;  and  it  is  ^^q^^^  *^  bV^^ 
of  an  inch  in  thickness.  Its  anterior  is  of  rather  less  extent  than  its 
posterior  surface.  At  the  circumference  it  is  thinned,  and  is  blended  with 
the  sclerotic  coat  by  continuity  of  tissue.  Supported  by  the  aqueous 
humor,  it  deflects  the  light  transmitted  to  the  eye,  and  influences  by  its 
greater  or  smaller  convexity  degrees  of  sight  at  different  distances.  After 
death  it  becomes  flaccid  from  the  transudation 
of  the  aqueous  humor ;  or,  if  the  eye  is  im- 
mersed in  water,  it  is  rendered  opaque  by 
infiltration  of  the  tissue  by  that  fluid. 

Structure  (fig.  228).  The  cornea  is  laminar 
in  texture.  It  is  constructed  of  a  special  thick 
part  called  cornea  proper :  in  front  of  this  is 
the  conjunctiva,  and  behind  is  the  membrane 
of  Demours. 

The  cornea  proper,  a  (lamellated  cornea), 
is  made  up  of  a  series  of  superposed  layers, 
about  sixty  in  number,  which  join  one  an- 
other at  numerous  points,  and  cannot  therefore 
be  detached  for  any  distance.  The  laminae 
are  formed  of  fibres,  continuous  witli  those  of 
the  sclerotic,  and  are  flattened  into  membra- 
nous layers,  arranged  one  over  another.  This 
structure  possesses  great  toughness ;  and  its 
transparency  is  destroyed  by  disturbance  of  the 
position  of  the  strata.  The  tissue  when  boiled 
gives  cliondrin. 

Between  the  corneal  layers  are  flattened 
irregular  spaces,  which  join  freely  with  one 
another ;  and  these  intervals  are  occupied  by  nu- 
cleated stellate  cells,  called  corneal  corpuscles. 

In  the  healthy  condition  bloodvessels  do  not 
permeate  it,  but  cease  in  capillary  loops  at  the 
circumference.  Nerves  ramify  in  it,  after  los- 
ing their  0{)acity  at  the  circumference  ;  they 
are  said  to  form  a  subepithelial  plexus  on  the 
anterior  surface,  from  which  varicose  fibrils  are 
prolonged  amongst  the  pieces  of  the  epithelium. 

The  membrane  at  the  back  of  the  cornea 
(fig.  228) — membrane  of  Demours — consists 
of  a  basement  layer  covered  by  epithelium. 


Vertical  Section  A  of  tub 
Cornea. 

Basement  layei-  of  cornea,  with 
d,  the  caiijuuctivH.1  epithe- 
lium on  it. 

Oblique  fibres  from  it  to  the 
layers  of  the  cornea. 

Basement  lamina,  with  /,  epi- 
thelium on  it  of  the  mem- 
brane of  Demours. 

Surface  view  of  the  epithe- 
lium of  the  membrane  of  De- 
mours. 


42 


658  DISSECTION    OF    THE    EYE. 

The  basement  layer^  E  (posterior  elastic  lamina,  Bowman),  may  be 
peeled  off  after  a  cut  has  been  made  across  the  cornea.  It  is  dense,  hard 
and  elastic,  measuring  ^^Viy^^'  *^  ^uVn^'^  ^^  ^^  \wc\\  in  thickness ;  it  is 
very  brittle,  tearing  readily  when  an  attempt  is  made  to  separate  it,  and 
curls  up  when  it  is  tree,  with  the  attached  surface  innermost.  Though 
very  elastic,  the  structure  is  destitute  of  fibres.  It  is  always  transparent, 
and  remains  so  after  boiling,  after  the  action  of  acids,  and  even  after  mace- 
ration. 

At  the  edge  of  the  cornea  this  lamina  breaks  up  into  processes  ("  pil- 
lars of  the  iris")  which  blend  with  the  outer  margin  of  the  iris,  and  with 
the  sclerotic  and  choroid  coats. 

A  laminar  epithelium,  G,  like  that  on  serous  membranes,  clothes  its  free 
surface  (fig.  228). 

The  conjunctiva  in  front  of  the  cornea  (fig.  228)  consists  chiefly  of  epi- 
thelium cells,  though  there  is  a  subjacent  basement-like  stratum. 

The  basement  layer,  b  (ant.  elastic  lamina,  Bowman),  is  transparent, 
and  only  from  ^oVo^^^  ^^  T^V^^^^  of  an  inch  thick.  It  seems  to  be  a  some- 
what hardened  piece  of  the  cornea,  without  corneal  spaces  and  corpuscles. 
From  it  fine  threads  are  prolonged  into  the  proper  corneal  layers,  as  in  the 
woodcut. 

The  epithelium,  d,  is  formed  of  three  or  four  layers  of  scales,  the  deeper 
being  columnar,  but  the  Superficial  laminar  in  form. 

Vascular  Coat  of  the  Eyeball  (fig.  231).  The  next  covering  is 
situate  within  the  sclerotic,  and  is  formed  chiefly  of  bloodvessels  and  pig- 
ment cells  :  the  muscles  in  the  interior  of  the  ball  are  connected  with  it. 

It  is  constructed  of  three  parts  :  a  posterior  (choroid)  corresponding 
with  the  sclerotic  ;  an  anterior  (iris)  opposite  the  cornea  ;  and  an  interme- 
diate ring  (ciliary  muscle)  on  a  level  with  the  union  of  the  sclerotic  and 
cornea. 

Dissectio7i.  Supposing  the  cornea  of  an  eye  cut  through  circularly,  as 
before  directed  (p.  656),  it  will  be  necessary  to  take  away  the  sclerotic 
to  lay  bare  the  choroid  coat.  With  the  point  of  the  scalpel,  or  with  a  shut 
scissors,  detach  the  fore  part  of  the  sclerotic  from  the  front  of  the  choroid 
by  breaking  through  a  soft  whitish  structure  uniting  them.  Then,  the 
eye  being  put  into  water,  the  outer  coat  is  to  be  removed  by  cutting  it 
away  piece-meal  with  a  scissors  ;  in  taking  it  off  the  slender  vessels  and 
nerves  beneath  are  to  be  preserved.  The  white  ring  around  the  eye  in 
front,  which  comes  into  view  during  the  dissection,  is  the  ciliary  muscle. 

For  the  purpose  of  obtaining  an  anterior  view  of  the  ciliary  processes, 
which  are  connected  with  the  anterior  termination  of  the  choroid  coat,  let 
the  cornea  be  removed  as  before  on  another  eyeball.  Detach  next  the 
fore  part  of  the  sclerotic  from  the  choroid  ;  and  after  two  or  three  cuts  have 
been  made  in  it  towards  the  optic  nerve,  the  resulting  flaps  may  be  pinned 
out,  so  as  to  supj)ort  the  eye  in  an  upright  position.  On  removing  with 
care  the  iris,  taking  it  away  from  the  centre  towards  the  circumference, 
the  ciliary  processes  beneath  will  be  displayed.  A  posterior  view  of  the 
processes  may  be  prepared  on  another  ball  by  cutting  through  it  circularly 
with  a  scissors,  about  one-third  of  an  inch  behind  the  cornea,  so  that  the 
anterior  can  be  removed  from  the  posterior  half;  on  taking  away  the  por- 
tion of  the  vitreous  mass  adherent  to  the  anterior  part  of  the  ball,  and 
wiping  oflT  the  pigment  from  the  back  of  the  iris,  the  small  processes  will 
be  made  manifest.  By  means  of  this  last  dissection  the  interior  of  the 
choroid  coat  may  be  seen. 


CHOROIDAL    COAT    WITH    ITS    STRUCTURE, 


659 


If  a  vertical  section  is  made  of  another  eyeball,  it  will  show  the  ciliary 
processes  in  their  natural  position,  and  will  demonstrate  the  relative  situa- 
tion of  all  the  parts.  This  section,  which  is  made  with  difficulty,  should 
be  attempted  in  water  with  a  sharp  large  knife,  and  on  a  surface  of  wax  or 
wood,  after  the  cornea  and  sclerotic  have  been  cut  with  a  scissors.  When 
the  eye  has  been  divided,  the  halves  should  remain  in  water. 

The  CHOROID  COAT  (fig.  227,  b)  is  a  thin  membrane  of  a  dark  color, 
and  extends  from  the  optic  nerve  to  the  fore  part  of  the  eyeball.  When 
viewed  on  the  eye  in  which  the  ciliary  muscle  is  entire,  it  appears  to  ter- 
minate there  ;  but  it  may  be  seen  in  the  other  dissections  to  bend  inwards 
behind  that  muscle,  and  to  end  in  a  series  of  projections  (ciliary  processes) 
behind  the  iris. 

This  coverinfj  is  rather  thicker  and  stronger  behind  than  in  front.  It 
is  supported  at  the  bottom  of  the  eyeball  by  its  close  connection  to  the 
sclerotic  coat,  and  in  front  by  the  ciliary  muscle.  Posteriorly  it  is  pierced 
by  a  round  aperture  for  the  passage  of  the  optic  nerve  ;  and  anteriorly  it 
is  united  with  the  iris. 

The  outer  surface  (fig.  231)  is  flocculent,  and  is  covered  by  the  rem- 
nants of  a  thin  membranous  layer  (membrana  fusca,  supra-choroidea)  be- 
tween it  and  the  sclerotic  coat :  on  it  may  be  seen  small  veins  arranged 
in  arches,  and  the  ciliary  arteries  and  nerves.  The  inner  surface  is  smooth, 
and  touches  the  thin  dark  pigmentary  layer  of  the  retina  (fig.  227). 


Fiff.  229. 


Fig.  230. 


Inner  Vikw  of  the  Front  op  the  Choroid 
Coat  WITH  its  Ciliary  Processes,  and  the 
Back  of  the  Iris. 

a.  Anterior  piece  of  tlie  choroid  coat 

b.  Ciliary  processes. 

c.  Iris. 

d.  Spliincterof  the  pupil. 

e.  Bundles  of  fibres  of  the  dilator  of  the  pupil. 


Pigment  Cells  of  the  Eyeball  (Kolliker). 
a.  Ramified  pis^meut  cells  of  the  choroid  coat. 
B.  Front  view  of  the  hexagonal  cells  of  the 
pigmentary  membrane. 


The  ciliary  processes  (fig.  229,  b)  are  solid  projections  on  the  inner 
surface  of  the  choroidal  coat,  and  are  arranged  in  a  circle.  About  85  in 
number,  they  lie  side  by  side,  and  consist  of  larger  and  smaller  eminences; 
at  their  inner  extremity  they  are  united  by  transverse  ridges. 

About  jV^^^  ^^  ^^  ^"^h  ^^  length,  they  increase  in  depth  internally,  and 
projecting  around  the  lens,  bound  circumferentially  by  their  free  ends  the 


660 


DISSECTION    OF    THE    EYE. 


space  (fig.  227,  t)  (posterior  chamber)  behind  the  iris.  In  front  tliey  cor- 
respond with  the  back  of  the  iris  towards  their  inner  end,  but  are  se[)a- 
rated  from  it  by  pigment ;  and  behind  tliey  are  closely  connected  with  the 
membrane  (t)  (suspensory  ligament)  on  the  front  of  the  vitreous  body, 
and  fit  into  hollows  between  eminences  on  the  anterior  surface  of  that 
membrane. 

Structure  The  choroid  coat  and  its  ciliary  processes  are  formed  prin- 
cipally of  bloodvessels.  Ramified  pigment  cells  make  up  most  of  the  rest 
of  the  coat. 

The  stroma  or  web  of  the  choroid  is  formed  by  the  outrunners  of  spe- 
cial pigment  cells  (fig.  230,  ^)  which  unite  together,  and  construct,  with 
fine  areolar  tissue,  a  fibrous  network.  Its  meshes  are  finer  towards  the 
inner  than  the  outer  surface  of  the  choroid.  On  the  exterior  and  interior 
of  the  fibrous  web  the  vessels  ramify,  with  the  following  difiference  in  their 
arrangement. 

At  the  outer  part  (fig.  231)  the  larger  branches  of  both  arteries  and 
veins  are  situate  ;  and  the  veins  (A)  form  curves  (vasa  rorticosa)  as  they 
end  in  four  or  five  chief  eflTerent  trunks.  In  the  interspaces  of  the  vessels 
are  the  ramified  pigment  cells  (fig.  230-,  ^),  which  contain  a  nucleus  and 
molecular  grains  of  dark-brown  coloring  matter.  At  the  inner  part  of 
the  choroid  the  vessels  form  a  network  of  capillaries  without  pigment 
cells,  and  with  meshes  smaller  than  elsewhere,  whose  interstices  are 
rather  less  towards  the  back  than  the  front  of  the  eyeball :  this  part  of 
the  choroidal  coat  is  described  sometimes  as  a  separate  layer  {tunica 
Ruyschianri). 

In  the  ciliary  processes  there  is  a  similar  texture  of  ramified  blood- 
vessels, though   with  larger  capillary  meshes   than   in   the   choroid  ;  and 

Fig.  231. 


a.  Sclerotic,  cut,  and  reflected. 
6.  Choroid  coat. 

c.  Iris. 

d.  Circular. 

e.  Radiating  fibres  of  ciliary  mus- 

cle. 
/.  Ciliary  nerves,  and   g,  ciliary 

arteries    Letwoen    the    two 

outer  coats. 
7t.  Veins  of  the  choroid  coat. 


View  op  the  Fro5t  of  trk  Choroidal  Coat  and  Iris— external  surface  (Zinn). 


the  intermixed   pigment  cells  lose  their  coloring  matter  towards  the  free 
ends. 

Ciliary  muscle  (fig.  231).     In  the  eye  from  which  the  sclerotic  coat 
has  been  removed,  the   white   band  of  the  ciliary  muscle  (e)   {annulus 


CILIARY    MUSCLE    AND    IRIS.  661 

ilbidfjs),   may  be  seen   in   its  natural  position  outside  the  front  of  the 
choroid  coat. 

It  consists  of  unstriated  fibres,  and  forms  a  grayish  layer,  about  j^th  of 
an  inch  wide,  on  the  surface  of  the  choroid  coat  (tig.  231,  e)  :  there  are 
two  sets  of  fibres  in  it,  radiating  and  circular: — 

The  radiating  or  superficial,  arise  in  front  from  tlie  sclerotic  coat  (fig. 
227,  «),  and  the  fibres  of  the  posterior  elastic  layer  of  the  cornea  ;  its 
fibres  are  directed  backwards,  and  are  inserted  into  the  choroid  coat  oppo- 
site to,  and  rather  behind  the  ciliary  processes.  The  nerves  to  the  iris 
pierce  it. 

The  circular  fibres  (ciliary  ligament,  fig.  231,  d)  are  internal  to  the 
radiating,  and  form  a  ring  about  4^^^^  of  inch  wide  around  the  edge  of  the 
iris  :  they  are  not  attached  to  the  sclerotic  or  the  cornea. 

Use.  The  radiating  fibres  of  the  muscle  draw  forwards  the  fore  part  of 
the  choroid  coat,  and  the  ciliary  processes,  and  thereby  relax  the  suspen- 
sory ligament  of  the  lens.  The  circular  fibres  are  said  to  compress  the 
outer  ])art  of  the  lens. 

The  IRIS  (fig.  231,  c)  is  a  vascular  and  muscular  structure,  about  half 
an  inch  in  diameter,  whose  vessels  are  continuous  with  those  of  the  cho- 
roidal coat.  Its  position  and  connections  may  be  observed  in  the  different 
dissections  that  have  been  prepared. 

Placed  w^ithin  the  ring  of  the  ciliary  muscle,  it  is  suspended  in  front  of 
the  lens  (fig.  227,/),  and  is  pierced  by  an  aperture  for  the  transmission  of 
the  light.  It  is  circular  in  form,  is  variously  colored  in  different  persons, 
and  is  immersed  in  the  aqueous  humor.  By  its  circumference  it  is  con- 
nected with  the  choroid  coat  and  the  posterior  elastic  layer  of  the  cor- 
nea. The  anterior  surface  is  free  in  the  aqueous  humor,  and  is  marked  by 
lines  converging  towards  the  pupil.  The  posterior  surface  is  covered  with 
a  thick  layer  of  the  pigment  (fig.  227),  to  which  the  term  uvea  has  been 
applied. 

The  aperture  in  it  (fig.  231 )  is  the  pupil  of  the  eye ;  this  is  slightly  in- 
ternal to  the  centre,  and  is  nearly  circular  in  form,  but  its  size  is  constantly 
varying  (from  ^^i\\  to  ^  of  an  inch)  by  the  contraction  of  the  muscular 
fibres,  according  to  the  degree  of  light  acting  on  the  optic  nerve. 

Membrane  of  the  pupil.  In  the  foetus  the  aperture  of  the  pupil  is  closed 
by  a  vascular  transparent  membrane,  wliich  is  attached  to  the  edge  of  the 
iris,  and  divides  into  two  distinct  chambers  the  space  in  which  the  iris  is 
suspended.  The  vessels  in  it  are  continuous  behind  with  those  of  the  iris 
and  the  case  of  the  lens.  About  the  eighth  month  the  vessels  become  im- 
pervious, and  at  the  time  of  birth  only  fragments  of  the  structure  remain. 

Structure  (fig.  229).  The  stroma  of  the  iris  is  composed  of  fibres  of 
areolar  tissue,  arranged  circularly  at  the  circumference,  and  as  radiating 
bundles  passing  like  rays  towards  the  pupil.  In  it  are  involuntary  mus- 
cular fibres,  both  circular  and  radiating,  together  with  pigment  cells. 
Vessels  and  nerves  ramify  through  the  tissue. 

Muscular  fibres.  The  sphincter  of  the  pupil  (fig.  229,  d)  is  a  narrow 
band  about  ^^i\i  of  an  inch  wide,  whicli  is  close  to  the  pupil,  on  the  pos- 
terior aspect  of  the  iris.  The  dilator  of  the  pupil  {e)  is  said  to  begin  at 
the  outer  border  of  the  iris,  and  to  consist  of  bundles  of  fibres  which  join 
one  another,  and  end  internally  in  the  sphincter. 

Action.  Enlargement  of  the  pupil  is  effected  by  shortening  of  the  radi- 
ating fibres  ;    and  diminution,  by  contraction   of  the  circular  ring.     The 


662 


DISSECTION    OF    THE    EYE. 


232. 


movements  of  the  iris  are  involuntary  and  regulate  the  admission  of  light 
into  the  ball. 

The  pigment  cells  are  spread  out  in  the  stroma,  and  are  disposed  also  on 
both  surfaces.  In  the  stroma  they  are  ramified  and  irregular,  as  in  the 
choroid  (fig.  230,  ^),  and  may  contain  yellow,  brown,  or  very  dark  pig- 
ment. On  the  front  they  are  ovalish  or  rounded,  but  still  ramified  ;  and 
behind,  where  there  is  a  thick  layer  (uvea),  the  cells  are  round  without 
outrunners,  and  are  filled  with  granules.  The  color  of  the  iris  is  dependent 
upon  the  tint,  and  the  position  of  the  pigment. 

The  arteries  of  the  iris  (fig.  232,  ^)  have  a  looped  arrangement :  they 
are  derived  chiefly  from  the  long  and  the  anterior  ciliary  branches  {d), 

but  some  come  from  the  vessels  of  tlie 
ciliary  processes.  On  arriving  at  the 
ciliary  muscle  the  long  ciliary  arteries 
form  a  circle  {e)  around  the  margin  of 
the  iris  ;  from  this  loop  other  anasto- 
motic branches  are  directed  towards  the 
pupil,  near  which  they  join  in  a  second 
arterial  circle  (/).  From  the  last  circle 
capillaries  run  to  the  pupil,  and  end  in 
veins. 

The  veins  resemble  the  arteries  in 
their  arrangement  in  the  iris,  and  ter- 
minate in  the  veins  of  the  choroidal 
coat. 

The  nerves  of  the  iris  (fig.  232,  a) 
divide  into  branches,  which  commu- 
nicate, and  extend  towards  the  pupil; 
they  are  without  dark  outline,  and  their 
ending  is  not  known. 

Ciliary  Vessels  and  Nerves  (fig. 
231).  Tlie  ciliary  arteries  are  offsets 
of  the  ophthalmic  (p.  56),  and  supply 
the  choroid,  the  ciliary  processes,  and 
the  iris.  They  are  classed  into  poste- 
rior and  anterior,  and  two  of  the  first 
set  are  named  long  ciliary  ;  but  they 
will  not  be  seen  without  a  special  injec- 
tion of  the  vessels  of  the  eye. 

The  posterior  ciliary  branches  {g) 
pierce  tlie  sclerotic  coat  around  and  close 
to  the  optic  nerve,  and  running  forwards  on  the  choroid,  enter  its  substance 
at  different  points. 

Two  of  this  set  (long  ciliary)  are  directed  forwards,  one  on  each  side  of 
the  eyeball,  and  form  a  circle  around  the  iris  in  the  ciliary  muscle,  as  be- 
fore explained.  In  the  ball  tiie  outer  one  lies  rather  above,  and  the  inner, 
rather  below  the  middle. 

The  anterior  c i liar g  iirteries,  five  or  six  in  number,  are  smaller  than  the 
posterior,  and  arise  at  the  front  of  the  orbit  from  muscular  branches  (p. 
56);  they  pierce  the  sclerotic  coat  about  a  line  behind  the  cornea,  su{)ply 
the  ciliary  [)rocesses,  and  join  the  circle  of  the  long  ciliary  vessels.  In 
inflammation  of  the  iris  these  vessels  are  enlarged,  and  offsets  of  them 
form  a  rinnr  around  the  cornea. 


Distribution  of  the  Nkrvks  and  Ves- 
sels OF  THE  Iris. 

A.  Half  of  the  iris  representing  the  nerves. 
a.  Nerves   entering    the    membrane,   and 

uniting  in  a  plexus,  b,  within  it  (Kiil- 
liker). 

B.  Half  of  the  iris  with  apian  of  the  ves- 

sels. 

d.  Ciliary  arteries. 

e.  Arch  of  vessels  at  the  outer  edge  of  the 

iris. 
/.    Inner  circle  of  vessels  in  the  iris. 
g.  Sphincter  of  the  iris. 


CHAMBER    OF    AQUEOUS    HUMOR.  663 

The  posterior  ciliary  veins  (fig.  231)  are  commonly  four  in  number, 
and  the  brandies  entering  these  trunks  form  arches  {h)  (vasa  vorticosa) 
on  the  surface  of  the  choroid  coat :  they  perforate  the  sclerotic  layer  at 
separate  points,  midway  between  the  cornea  and  the  optic  nerve,  and  end 
in  the  ophthalmic  vein. 

Anterior  ciliary  veins  begin  in  a  plexus  within  the  ciliary  muscle,  and 
accompany  the  arteries  through  the  sclerotic  to  end  in  the  ophthalmic: 
they  communicate  with  the  venous  space  of  the  sinus  circularis  iridis  (p. 
656). 

The  ciliary  nerves  (fig.  231,/)  are  derived  from  the  lenticular  ganglion, 
and  the  nasal  nerve  (p.  55).  Entering  the  back  of  the  eyeball  with  the 
arteries,  they  are  continued  with  the  vessels  between  the  sclerotic  and 
choroid,  nearly  as  far  as  the  ciliary  muscle:  at  this  spot  the  nerves  send 
offsets  to  the  cornea,  and  piercing  the  fibres  of  the  ciliary  muscle,  enter 
the  iris,  but  their  manner  of  ending  is  unknown.  Offsets  from  the  nerves 
supply  the  ciliary  muscle  and  the  choroid. 

Chamber  of  the  Aqueous  Humor  (fig.  227).  The  space  between 
the  cornea  in  front  and  the  lens  behind,  in  which  the  iris  is  suspended, 
contains  a  clear  fluid  named  the  aqueous  humor.  In  the  foetus  before  the 
seventh  month  this  interval  is  separated  into  two  by  the  iris  and  the  pu- 
pillary membrane,  but  in /the  adult  it  is  only  partly  divided,  for  the  two 
communicate  through  the  pupil.  The  boundaries  of  the  two  chambers 
may  be  seen  in  the  eye  on  which  a  section  has  been  made. 

The  anterior  chamber  is  the  larger  part  of  the  space;  it  is  limited  in 
front  by  the  cornea,  and  behind  by  the  iris. 

The  posterior  chamber  (?)  is  a  narrow  interval  behind  the  iris  at  the 
circumference,  which  is  bounded  in  front  by  the  iris;  behind  by  the  lens 
capsule,  and  by  a  piece  of  the  membrane  (suspensory  ligament  of  the  lens) 
on  the  front  of  the  vitreous  humor :  and  at  the  circumference  by  the 
ciliary  processes. 

The  aqueous  humor  is  quite  transparent,  and  consists  nearly  of  pure 
water.  A  small  quantity  of  chloride  of  sodium,  with  some  extractive 
matter,  is  in  solution  in  it. 

The  Retina  (fig.  227,  c).  This  layer  (tunica  nervea)  is  in  part  con- 
tinous  with  the  optic  nerve,  and  is  the  most  delicate  of  all  the  coats  of  the 
eyeball.     On  it  the  image  of  objects  is  formed  in  the  bottom  of  the  eye. 

Dissection.  The  retina  can  be  satisfactorily  examined  only  on  an  eye 
which  is  obtained  within  forty-eight  hours  after  death.  To  bring  it  into 
view  on  the  eyeball  in  which  the  choroid  coat  was  dissected,  the  choroidal 
covering  must  be  torn  away  carefully  with  two  pair  of  forceps,  whilst  the 
eye  is  immersed  in  water  or  spirit. 

The  retina  is  the  most  internal  of  the  three  concentric  strata  in  the 
globe  of  the  eye,  and  is  situate  between  the  choroid  coat  and  the  trans- 
parent mass  (vitreous)  in  the  interior.  It  is  moulded  upon,  and  supported 
by  the  vitreous  body;  and  its  form  is  that  of  a  segment  of  a  sphere,  with 
a  large  aperture  in  front.  Beginning  behind  at  the  optic  nerve  (fig.  227, 
c)  the  tliin  layer  extends  forwards  to  tlie  ciliary  processes  (their  outer  ex- 
tremities), where  it  ends  in  a  wavy  border — the  oro.  serrata. 

Where  the  retina  ceases  in  front,  a  thin  gray  layer  (ciliary  part  of  the 
retina)  composed  of  elongated  nucleated  cells,  which  are  not  nerve  ele- 
ments, is  continued  on  as  far  as  the  tips  of  the  ciliary  processes  (fig.  235, 
j)  on  which  it  ends. 

The  retina  is  of  a  pinkish  gray  color,  and  is   semitransparent  when 


664 


DISSECTION    OF    THE    EYE 


Fig.  233. 


fresh,  so  that  an  image  can  be  seen  on  it  when  the  two  external  coats  of 
the  eye  have  been  removed ;  but  it  soon  loses  this  translucency,  and  is 
moreover  rendered  opaque  by  the  action  of  water  and  other  substances. 
Its  thickness  is  greater  at  the  posterior  tlian  the  anterior  part  of  the  eye- 
ball, being  g^^th  of  an  inch  in  the  former,  and  y^o^^^  "^  ^^^^  latter  situa- 
tion. 

On  the  outer  surface  of  the  dissected  retina  are  some  fine  fragments  of 
a  structure  (Jacob's  membrane)  to  be  noticed  presently,  which  float  in  the 

fluid  in  which  the  preparation  may  be  placed. 
The  inner  surface  is  smooth ;  it  is  covered 
with  folds  in  a  preparation  of  an  eye  cut  in 
two,  but  these  are  accidental,  in  consequence 
of  the  membrane  having  lost  its  proper  sup- 
port. At  the  spot  where  the  optic  nerve  ex- 
pands (poms  opticus)  is  the  central  artery  of 
the  retina  (fig.  233). 

In  the  anterior  of  the  human  eye,  in  the 
axis  of  the  ball,  is  a  slightly  elliptical  yellow 
part  (fig.  233),  j^th  of  an  inch  in  diameter, 
which  is  named  the  yellow  spot  (limbus  luteus 
of  Sbmmerring).  Almost  in  the  centre  of  that 
spot  is  a  minute  hollow,  the  fovea  centralis^ 
which  appears  black  in  consequence  of  tlie 
thinness  of  the  wall  allowing  the  dark  pigment 
outside  to  be  seen. 

Structure  (fig.  234).  In  the  retina  are 
layers  or  strata  with  bloodvessels,  viz.,  an  in- 
ner ('),  composed  of  nerve  elements;  an  outer 
Q)  (Jacob's  membrane),  formed  of  peculiar  bodies;  and  an  intermediate 
or  granular  layer  {^)\  and  outside  all  is  a  pigmentary  stratum.  Passing 
through  the  layers  of  the  retina  except  Jacob's  and  the  pigmentary,  are 
minute  threads — fibres  of  Miiller. 

The  layer  of  nerve  substance  (^)  is  made  up  of  nerve  fibres,  and  of  a 
molecular  matrix  containing  different-sized  nerve  cells;  these  constituents 
have  the  following  arrangement : — 

The  tubules  of  the  optic  nerve  (//,),  having  become  solid  in  texture  and 
gray  in  color  from  the  absence  of  the  white  substance  of  Schwann,  radiate 
in  bundles  from  the  end  of  the  optic  trunk,  and  communicate  together  to 
construct  a  thin  web  at  the  inner  aspect  of  the  nervous  layer;  this  delicate 
network  with  lengthened  meshes  diminishes  in  strength  as  it  is  followed 
forwards. 

Outside  the  nerve  fibres  is  a  stratum  of  molecular  material  (/)  with 
large  pale  pyriform  and  roundish  nucleated  nerve  cells  (_r/)  with  offsets ; 
this  layer  begins  at  the  entrance  of  the  optic  nerve,  and  becomes  thinner 
as  it  extends  forwards.  Around  the  optic  nerve  tiie  cells  are  arranged  in 
a  layer  one  deep,  but  over  the  yellow  spot  they  are  about  six  or  eight 
deep  ;  near  the  ora  serrata  they  are  scattered  in  clusters.  An  offset  from 
eacli  cell  is  supposed  to  join  internally  the  nerve  fibres ;  and  other  oflsets 
are  prolonged  externally  into  the  molecular  material  (/)  and  seem  lost  in 
it. 

The  outer  or  columnar  stratum  (')  (Jacob's  membrane)  consists  of  two 
different  elements — rods  and  cones,  which  are  arranged  with  their  ends 
inwards  and  outwards. 


Objects  on  the  Inner  Surface 
OP  THE  Retina.  In  the  centre 
of  the  ball  is  the  yellow  limbus 
luteus,  here  represenied  by 
shading  ;  and  in  its  middle  the 
dark  spot.  To  the  inner  side  is 
the  nerve,  with  its  Hccompany- 
ing  artery.     (SOmmerring.) 


STRUCTUKE    OF    RETTNA 


665 


The  rods  (a)  are  elongated  solid  and  grooved  particles,  which  are  pointed 
at  the  inner  end,  and  are  more  numerous  than  the  other  elements  ;  from 
their  inner  ends  fine  threads  (rod-fibres)  are  prolonged  through  tlie  outer 
set  of  granules  (c),  and  are  there  connected  with  elliptical  transversely 
striated  bodies.  The  cones  (b)  are  shaped  like  a  flask  with  a  long  neck, 
and  have  the  larger  end  turned  inwards  :  tiiey  do  not  project  so  far  out  as 
the  rods.  AVhen  viewed  on  the  outer  surface,  tliey  form  large  isolated  swell- 
ings (m)  amongst  the  ends  of  the  rods,  and  at  a  deeper  level.  By  their 
inner  ends  they  are  united  with  a  pear-shaped  cell  (fig.  234)  in  the  outer 
part  of  the  granular  layer,  and  are  said  to  reach  as  far  as  the  molecular 
material  (d)  between  the  two  sets  of  granules. 

Fig.  234. 

1.  Columuar  layer  with  rods  a,  and  cones,  6. 

2.  Granular  layer  with  outer,  c,  and  inner  granules,  e,  and 
intermediate  non-granular  part,  d. 

3.  Nervous  layer  with  g,  nerve  cells,  and  7i,  nerve  fibres  ; 
outside  tho  cells  is  a  finely  granular  part,/,  and  in- 
side the  fibres  a  limiting  layer,  i,  formed  by  fibres  of 
Miiller. 

On  the  left  of  the  vertical  section  is  an  ideal  plan  of  the 
connection  of  the  several  parts.  Thus  the  nerve  cell,  ff, 
unites  internally  with  nerve  fibres,  and  externally  with 
the  inner  granular  layer ;  and  the  inner  granular  layer 
is  further  joined  by  a  thread  (fibre  of  Miiller)  to  the 
outer  granular  layer. 
k.  Microscopic  api)earanceof  the  outer  surface  of  the  retina 

over  the  yellow  spot,  where  there  are  only  cones. 
I.  Appearance  of  the  retina  near  the  yellow  spot — a  single 

circle  of  rods  surrounding  each  cone. 
rn.  Appearance  of  the  middle  of  the  retina,  a  large  number 
of  the   rods   surrou.iding   each   cone.      In   all   three 
figures  the  larger  rings  represent  the  cones,  and  the 
smaller  ones  the  rods  seen  endwise. 


Magnified  Vertical  Section  of  the  Retina  (altered  from  Kolliker). 

In  the  fresh  state  both  are  soft,  clear,  and  homogeneous,  with  a  glisten- 
ing appearance,  but  these  characters  are  soon  destroyed  by  water  and  other 
fluids  :  their  structure  is  very  uncertain. 

The  granular  layer  (^)  consists  of  innumerable  rounded  and  ovalish 
bodies  with  nuclei,  which  are  collected  into  two  sets  (c  and  e),  with  an 
intervening  fine  molecular  material  (d). 

In  the  inner  set  (e)  tliere  are  several  kinds  of  cells,  wliose  nature  is 
unknown  :  two  sets,  which  are  oval  and  nucleated,  are  said  to  have  this 
arrangement :  One  is  connected  with  the  fibres  of  Miiller  ;  and  the  other 
has  a  fibre  at  each  end,  like  a  bipolar  ganglion-cell,  wliich  is  continued 
outwards  and  inwards  into  the  molecular  material  (d  and  /). 

In  the  outer  set  (c)  two  kinds  of  nucleated  cells  are  to  be  recognized, 
which  are  connected  with  the  fibres  from  the  rods  and  cones  in  Jacob's 
layer.  The  cells  of  the  rod-fibres,  the  most  numerous,  are  elliptical,  and 
marked  by  cross  strias  (Henle)  (fig.  234).     The  cells  of  the  cone-fibres  are 


66Q  DISSECTION    OF    THE    EYE. 

pyriform  in  shape,  with  the  base  turned  to  tlie  cone,  but  are  free  from 
cross  stripes. 

The  intervening  molecular  portion  (<Z)  has  a  striated  appearance,  from 
the  passage  of  the  fibres  of  Miiller  through  it. 

The  fibres  of  Miiller  (fig.  234)  are  extremely  fine  threads,  whicli  pierce 
the  substance  of  the  retina,  supporting  and  uniting  tlie  several  layers,  as  with 
a  framework  of  areolar  tissue  ;  they  reach  from  Jacob's  layer  to  the  inner 
surface.  As  they  pass  through  the  granular  layer  they  are  connected  with 
very  fine  threads  amongst  both  set  of  granules  (c  and  e)  ;  and  in  the  inner 
set  (<?)  each  possesses  an  oval  nucleated  cell.  At  the  inner  surface  of  the 
retina  they  are  dilated  and  joined  to  each  other,  so  as  to  construct  a  bound- 
ing stratum  (/)  {membrana  limitans  interna)  ;  and  at  the  outer  part  they 
are  united  into  another  boundary  line  at  the  bases  of  the  cones  {rnembrana 
limitans  exteruo'). 

Structure  of  the  yellow  spot.  The  strata  of  the  retina  undergo  modifi- 
cations in  the  yellow  spot,  the  chief  of  which  are  the  following  :  externally, 
the  rods  of  Jacob's  layer  (^)  are  absent,  and  the  cones  become  less  bulged 
and  longer  towards  tlie  centre.  Internally,  the  nerve  cells  ((/)  of  the  layer 
(^)  are  six  to  eight  deep,  but  the  nerve  fibres  (h)  gradually  cease  at  the 
edge  of  the  central  fovea.  The  intermediate  strata  thin  gradually  towards 
the  fovea  centralis,  where  they  are  so  blended  as  to  render  diilicult  their 
identification. 

The  yellow  color  is  due  to  pigment  diffused  through  the  substance,  ex- 
cept through  Jacob's  membrane  and  the  outer  set  of  cells  (c)  of  the  granu- 
lar layer.     Water  removes  it  easily. 

Capillary  vessels  occupy  the  yellow  spot,  whilst  the  larger  branches  pass 
around  on  each  side. 

T\\Q  pigmentary  layer  (fig.  227)  covers  the  outer  surface  of  the  retina, 
and  is  connected  thereto  by  fine  processes.^  It  consists  of  a  single  stratum 
of  six-sided  nucleated  cells,  with  granular  contents  (fig.  230,  ^)  which  are 
applied  to  each  other  by  the  edges.  Each  possesses  a  nucleus  towards  the 
outer  surface,  and  much  pigment  towards  the  inner.  From  the  inner 
surface  of  the  cells  project  very  fine  threads,  which  penetrate  between 
the  rods  and  cones  of  Jacob's  layer.  The  pigmentary  layer  is  constituted 
thus  as  far  as  the  ora  serrata  of  the  retina  ;  but  in  front  of  that  line,  viz., 
on  the  ciliary  portion  of  the  retina,  the  cells  are  rounded  and  full  of  pig- 
ment, and  are  continuous  with  the  pigment  on  the  ciliary  processes  and 
back  of  the  iris. 

Vessels  of  the  retina.  The  central  artery  of  the  retina,  accompanied  by 
its  vein,  enters  the  eyeball  through  the  optic  nerve  (p.  oG).  Inside  the 
retina  the  vessel  divides  into  four  or  five  branches ;  these  pierce  the 
stratum  of  fibres  (fig.  234,  h),  and  end  in  a  network  of  capillaries  amongst 
the  ganglion  cells  (7),  and  in  the  molecular  material  outside  them  (y). 
In  the  yellow  spot  only  capillaries  exist. 

In  the  foetus  a  branch  of  the  artery  passes  through  the  centre  of  the 
vitreous  mass  to  supply  the  lens  capsule. 

Vitreous  Body.  A  transparent  mass  fills  the  greater  part  of  the 
space  within  the  coats  of  the  eyeball  (fig.  227,  /<),  which  has  been  named 
vitreous  body,  from  its  resemblance  to  glass  ;  it  consists  of  a  clear  aqueous 

'  In  the  dissection  of  the  retina  this  pifrmentary  layer  is  removed  with  tlie 
choroid  through  the  rupture  of  those  processes  ;  and  it  has  therefore  been  eoui- 
monly  described  as  part  of  the  choroid  coat. 


VITREOUS    BODY    AND    MEMBRANE, 


667 


fluid,  contained  in  a  translucent  membrane,  and  has  the   consistency  of 

jelly. 

Dissection.  The  vitreous  body  may  be  seen  on  tlie  eye  on  which  the 
retina  was  dissected,  by  taking  away  the  retina,  the  iris,  and  the  ciliary 
muscle  and  processes. 

To  obtain  a  view  of  its  anterior  part,  with  the  lens  in  situation,  an  eye- 
"ball  should  be  fixed  upright ;  the  sclerotic  and  choroid  coats  are  to  be  cut 
through  about  a  quarter  of  an  inch  behind  the  cornea  ;  and  on  removing 
carefully  the  cornea,  ciliary  muscle,  and  processes  with  the  iris,  the  vitre- 
ous body  will  be  apparent. 

The  vitreous  body  (fig.  227,  h)  is  globular  in  form,  and  fills  four-fifths 
of  the  ball,  supporting  the  retina.  In  front  it  is  slightly  hollowed,  and 
receives  the  lens  with  its  capsule  {g),  to  which  it  is  closely  united.  The 
jiuid  of  the  vitreous  body  has  nearly  the  same  composition  as  the  aqueous 
humor  with  some  salts  and  albumen.  Enveloping  the  whole  is  a  thin 
membrane  named  hyaloid. 

The  hyaloid  membrane  (ji)  is  a  fine  transparent  covering  of  the  vitreous 
body.  It  passes  continuously  over  the  surface  ;  and  in  the  foetus  it  is 
connected  with  fibres  w^hich  penetrate  the  mass.  On  the  inner  aspect  are 
a  few  delicate  nuclei. 

At  the  fore  part  it  is  joined  by  the  membrane  (f)  supporting  the  lens; 
and  it  ends  by  uniting  with  the  back  of  the  lens  capsule.  At  the  bottom 
of  the  ball  the  membrane  is  closely  connected  with  the  retina. 

Structure  of  the  vitreous  mass.  From  the  slow  escape  of  the  fluid  after 
puncture  of  the  hyaloid  membrane,  it  has  been  supposed  that  there  are 
membranous  partitions,  dividing  the  vitreous  mass  into  compartments 
which  communicate  with  each  other.  In  the  centre  of  the  vitreous  body 
is  a  fibrous  canal,  which  readies  to  the  back  of  the  lens,  and  transmits  a 
branch  from  the  central  artery  of  the  retina  to  the  lens  capsule  in  the 
foetus. 

The  vitreous  mass  and  the  hyaloid  membrane  are  extra-vascular,  and 
receive  their  nutritive  material  from  the  vessels  of  the  ciliary  processes 
and  retina. 

Suspensory  ligament  of  the  lens  (Zonule  of  Zinn).  This  is  a  transpa- 
rent membranous  structure  (fig.  285,  t),  placed  around  the  lens  capsule, 


d.  Cornea. 

e.  Ciliary  muscle. 
/.   Iris. 
g.  Lens. 

i.   Posterior  chamber. 
j.   Ciliary  part  of  the  retina. 
m.  Ciliary  ligament. 
n.  Hyaloid  membrane, 
o.  Canal  of  Petit. 
r.  Sinus  circularis  iridis, 
*.  Ciliary  process. 
t.    Suspensory  ligament  of  the  lens. 

Enlarged  Representation  of  the  Parts  of  the  Eyeball  on  one  side  opposite  the  Lens  : 
the  letters  refer  to  the  same  parts  as  in  the  woodcut,  227. 


which  joins  externally  the  hyaloid  membrane  opposite  the  anterior  termi- 
nation (ora  serrata)  of  the  retina.  After  the  ciliary  processes  of  tlie  cho- 
roid coat  are  detached  from  it,  dark  lines  of   pigment  cover  the  surface ; 


668  DISSECTION    OF    THE    EYE. 

and  when  these  are  washed  away  plaits  {ciliary  processes)  come  into  view, 
which  are  less  prominent  and  longer  tlian  the  processes  of  the  choroid 
coat,  and  do  not  quite  reach  the  lens  capsule  internally.  The  two  sets  of 
prominences  are  dovetailed  together — the  projections  of  one  being  received 
into  hollows  between  the  other.  In  this  membrane  are  stiff  longitudinal 
and  elastic  fibres.  Tlie  tenseness  or  laxness  is  influenced  by  the  state  of 
the  ciliary  muscle ;  for  during  its  contraction  the  membrane  is  rendered 
lax  by  the  drawing  forwards  of  the  ciliary  processes. 

Canal  of  Petit.  Around  the  margin  of  the  lens  capsule  is  a  small  canal 
(fig.  235,  o)  about  one-tenth  of  an  inch  across,  which  is  situate  between 
the  suspensory  ligament  and  the  front  of  the  hyaloid  menjbrane.  When 
the  canal  has  been  opened,  and  filled  with  air  by  means  of  a  blowpipe,  it 
is  sacculated  at  regular  intervals,  like  the  large  intestine,  by  the  inflation 
of  the  plaits  of  the  anterior  boundary.  The  margin  of  the  capsule  of  the 
lens  projects  into  the  space. 

Lens  and  its  capsule.  The  lens  is  situate  behind  the  pupil  of  the  eye 
(fig.  227,  g),  and  brings  to  a  focus  on  the  retina  the  light  passing  through 
that  aperture. 

The  capsule  is  a  firm  and  very  elastic  transparent  case,  which  is  per- 
meable to  fluid,  and  closely  surrounds  the  lens :  it  is  seated  in  a  hollow  on 
the  front  of  the  vitreous  body.  Tiie  anterior  part  projects  towards  the 
pupil ;  whilst  the  posterior  is  received  on  the  vitreous  mass,  to  whicli  it  is 
inse})arably  united.  The  circumference  of  the  case  corresponds  with  the 
canal  of  Petit  (o). 

Its  anterior  surface  (fig.  227)  is  free,  and  touches  the  iris  (/),  but  is 
separated  from  it  by  a  slight  space  at  the  outer  part  (posterior  chamber,  i)  ; 
it  gives  attachment  towards  the  circumference  to  the  suspensory  liga- 
ment {i). 

The  fore  part  of  the  capsule  is  four  or  five  times  thicker  than  the  poste- 
rior, as  far  outwards  as  the  attachment  of  the  suspensory  ligament,  and 
supports  itself  after  the  removal  of  the  lens ;  it  is  firm  and  quite  trans- 
parent, and  remains  clear  for  some  time  when  immersed  in  spirit,  acids, 
and  boiling  water,  like  tlie  elastic  layers  of  tlie  corneti.  The  posterior 
part  of  the  capsule  is  thin  and  membranous,  and  decreases  in  thickness 
towards  the  centre  :  it  is  joined  by  the  hyaloid  membrane  {ii)  of  the  vitre- 
ous body. 

In  the  adult  human  eye  the  capsule  of  the  lens  is  not  provided  with 
bloodvessels  ;  but  in  the  fcetus  a  branch  of  the  central  artery  of  the  retina 
supplies  it  (p.  606). 

Dissection.  The  lens  will  be  obtained  by  cutting  across  the  thin  mem- 
branous capsule  in  which  it  is  inclosed. 

The  lens  is  a  solid  and  transparent  doubly  convex  body ;  but  the  curves 
are  unequal  on  the  two  surfaces  (fig.  227,  g)^  the  posterior  being  greater 
than  tlie  anterior.  Its  margin  is  somewhat  rounded  ;  and  the  measurement 
from  side  to  side  is  one-third  of  an  inch,  but  from  before  back  about  one- 
fourth  of  an  inch.  Tlie  density  increases  from  the  circumference  to  the 
centre  ;  for  whilst  the  superficial  part  may  be  rubbed  off  with  the  finger, 
the  deeper  portion  is  firm,  and  is  named  the  nucleus. 

On  each  surface  are  three  lines  or  Stella*,  diverging  from  the  centre,  and 
reaching  towards  the  margin  ;  they  are  the  edges  of  planes  or  septa,  and 
are  so  situate  that  those  on  one  side  are  intermediate  in  position  to  those 
on  the  other.  In  the  human  eye  they  are  not  distinctly  seen,  because  th«y 
bifurcate  repeatedly  as  tliey  extend  outwards. 


LENS    AND    ITS    CAPSULE. 


669 


Covering  the  anterior  surface  of  the  lens,  and  connecting  it  with  the 
capsule,  is  a  layer  of  very  transj)arent  nucleated  polygonal  cells,  which 
can  be  recognized  only  in  a  fresh  eye  :  these  become  elongated  towards  the 
circumference  of  the  lens,  and  seem  to  pass  into  the  superficial  lens-fibres. 

Structure.  After  the  lens  has  been  hardened  by  spirit  or  boiling,  it  may 
be  demonstrated  to  consist  of  a  series  of  layers  (fig.  236)  arranged  one 
within  another,  like  those  in  an  onion.  Under  the  microscope  each  layer 
may  be  seen  to  be  constructed  of  minute  parallel  fibres.  It  consists  mostly 
of  albumen,  and  no  bloodvessels  are  found  in  its  texture. 

The  lamince  of  each  surface  have  their  apices  in  the  centre,  where  the 
septa  meet ;  they  may  be  detached  from  one  another  at  that  spot,  and  may 
be  turned  outwards  towards  the  equator  of  the  lens. 

The  constituent  fibres  of  the  lamina?  are  about  goVo*^^  ^^  ^"^  \x\q\\  in 
diameter,  solid,  and  flattened  at  the  margin  of  the  lens  ;  and  the  deeper 


Fiff.  236. 


Fig.  237. 


-^— ■< 


A  Representation  of  the  Laminae  in  a  Hardened 
Lens. 
a.  The  nucleus. 
6.  Superficial  laminae. 

fibres  are  narrowed  and  less  distinct.  In 
the  superficial  softer  fibres  are  contained 
granular  nuclei  (fig.  237,  a). 

The  edges  are  slightly  waxy  ;  and  each 
fibre  touclies  six  others  (fig.  237,  5),  viz., 
two  on  each  side,  with  one  above,  and  an- 
other below  :  contiguous  fibres  are  there- 
fore dovetailed  together,  and  this  inter- 
locking is  best  seen  in  the  lens  of  the  cod- 
fish. 

The  ends  are  soft  and  not  well-defined, 
and  are  connected  with  the  partitions  on  the  opposite  surfaces  of  the  lens 
in  this  way  : — those  attached  at  the  union  of  two  septa  on  the  one  aspect, 
are  fixed  to  the  extremity  of  a  septum  on  the  other  aspect :  and  the  fibres 
passing  between  two  septa  are  nearer  to  the  pole  at  one  end,  and  farther 
from  it  at  the  other,  while  the  middle  ones  are  at  the  same  distance  from 
the  ends  of  the  septa  on  both  aspects. 

Changes  in  the  lens  with  age.  The  form  of  the  lens  is  nearly  spherical 
in  the  fcetus  ;  but  its  convexity  decreases  with  age,  particularly  on  the  an- 
terior aspect,  until  it  becomes  flattened  in  the  adult. 

In  the  foetus  it  is  soft,  is  reddish  in  color,  and  is  not  quite  transparent ; 
in  mature  age  it  is  firm  and  clear;  and  in  old  age  it  becomes  flatter  on  both 
surfaces,  denser,  and  of  a  yellowish  color. 


Views  of  the  Lens  Fibres,  after 
Henle. 
a.  Surface  fibres  with  their  nuclei,  in 
the  equatorial  region  of  the  lens. 
6.  Transverse  section  of  the   fibres  of 
the  surface  of  the  lens,  showing 
their  union  with  others. 


670  DISSECTION    OF    THE    EAR- 


CIIAPTEE  XL 

DISSECTION  OF  THE  EAR. 

The  organ  of  hearing  is  made  up  of  complex  parts,  which  are  lodged 
in,  and  attached  to  the  surface  of  the  temporal  bone. 

The  fundamental  structure,  as  in  the  eyeball,  is  an  expansion  of  a  spe- 
cial nerve  over  a  membrane  containing  fluid.  This  delicate  apparatus  is 
inclosed  in  bone  for  its  protection ;  and  it  is  surrounded  by  certain  acces- 
sory bodies  which  convey  to  it  the  vibrations  produced  by  the  sonorous 
undulations  of  the  air. 

The  auditory  apparatus  may  be  arranged  into  the  parts  outside,  and 
those  within  the  substance  of  the  temporal  bone. 

In  the  EXTERNAL  SET  wliich  may  be  flrst  examined,  are  included  the 
pinna  or  auricle,  and  the  auditory  canal:  the  former  has  been  noticed  at 
p.  45,  and  the  latter  is  described  below. 

Tlie  AUDITORY  CANAL  (fig.  238)  (meatu.s  auditorius  externus)  is  the 
passage  which  leads  from  the  pinna  to  the  cavity  (tympanum)  in  tlie  tem- 
poral bone,  and  transmits  inwards  sonorous  undulations  of  the  air. 

Dissection.  To  obtain  a  view  of  this  canal,  a  recent  temporal  bone  is 
to  be  taken,  to  which  the  cartilaginous  pinna  remains  attaclied.  After  the 
removal  of  the  soft  parts,  the  squamous  piece  of  the  bone  in  front  of  the 
Glaserian  fissure  is  to  be  sawn  oflT;  and  the  front  of  the  meatus,  except  a 
ring  internally  which  gives  support  to  the  thin  membrana  tympani,  is  to 
be  cut  away  with  a  bone  forceps. 

The  canal  (fig.  238)  is  about  one  inch  and  a  quarter  in  length,  and  is 
formed  partly  by  bone,  and  partly  by  cartilage.  It  is  directed  forwards 
somewhat  obliquely.  In  shape  it  is  rather  flattened  from  before  back- 
wards; and  it  is  narrowest  in  the  osseous  part.  The  outer  extremity  is 
continuous  with  a  hollow  (concha)  of  the  external  ear,  and  the  inner  is 
closed  by  the  membrana  tympani. 

The  cartilaginous  part  («)  is  largest.  It  is  about  half  an  inch  in 
length,  and  is  formed  chiefly  by  the  pinna  of  tlie  outer  ear  which  is  at- 
tached to  the  margin  of  the  meatus;  but  at  the  u[)per  and  posterior  aspect 
the  cartilage  is  deficient,  and  the  tube  is  closed  by  fibrous  tissue.  One  or 
two  fissures  (fissures  of  Santorini)  cross  the  piece  of  cartilage. 

The  osseous  part  (6)  is  about  three-quarters  of  an  inch  long  in  the  adult, 
and  is  constricted  sometimes  about  the  middle.  Its  outer  extremity  is 
dilated,  and  the  posterior  part  projects  farther  than  the  anterior;  the  greater 
portion  of  the  margin  is  rough,  and  gives  attachment  to  the  cartilage  of 
the  pinna.  The  inner  end  is  smaller,  and  is  marked  in  the  dry  bone  by  a 
groove  for  the  insertion  of  the  membrane  of  the  tympanum;  it  is  so  sloped 
that  the  anterior  v/all  juts  beyond  the  posterior  by  about  two  lines. 

In  the  fcEtus  the  osseous  part  of  the  meatus  is  absent.  After  birth  it 
grows  out  of  the  osseous  ring  (tympanic  bone)  which  su[)ports  the  mem- 
brana tympani. 

Lining  of  the  meatus.     A  prolongation  of  the   integument  lines   the 


BOUNDARIES    OF    TYMPANUM, 


671 


auditory  passage,  and  is  united  more  closely  to  the  osseous  than  the  carti- 
laginous portion;  it  is  continued  over  the  membrane  of  the  tympanum  in 
the  form  of  a  thin  pellicle.  At  the  entrance  of  the  meatus  are  a  lew  hairs. 
In  the  subcutaneous  tissue  of  the  cartilaginous  part  of  the  meatus  lie  some 
ceruminous  glands  of  a  yellow-brown  color,  resembling  in  form  and  ar- 
rangement the  sweat  glands  of  the  skin;  these  secrete  the  ear  wax,  and 

Fig.  238. 


Vrrtical  Section  of  thk  Meatus  Auditorius  axd  Tympanum  (Scarpa). 
a.  Cartilaginous  part  of  the  meatus.  d.  Cavity  of  the  tympanum. 

6.  Osseous  portion.  e.  Eustachian  tube, 

c.  Membrana  tympani. 


open  on  the  surface  by  separate  orifices:  they  are  absent  in  the  osseous 
part,  and  are  most  abundant  in  that  portion  of  the  tube  which  is  ibrmed 
by  fibrous  tissue. 

Vessels  and  nerves.  The  meatus  receives  its  arteries  from  the  posterior 
auricular,  the  internal  maxillary,  and  the  temporal  branch  of  the  external 
carotid.  Its  nerves  are  derived  from  the  auriculo-temporal  branch  of  the 
fifth  nerve,  and  enter  the  auditory  passage  between  the  bone  and  the  carti- 
lage (p.  96). 

Inner  parts  of  the  ear.  The  internal  constituents  of  the  organ  of 
hearing  are  inclosed  within  the  temporal  bone,  and  consist  of  two  large 
spaces — tympanum  and  labyrinth,  with  their  accessory  parts. 

The  tympanum,  or  drum  of  the  ear  (fig.  238,  c?),  is  a  hollow  interposed 
between  the  meatus  auditorius  and  the  labyrinth.  It  communicates  with 
the  pharynx  by  a  tube  (e)  (pAistachian),  through  which  the  air  has  ac- 
cess ;  and  it  is  traversed  by  a  chain  of  small  bones,  with  which  special 
muscles  and  ligaments  are  connected.  Minute  vessels  and  nerves  are 
contained  in  the  space. 

Dissection.  The  tympanic  cavity  should  be  examined  in  both  a  dried 
and  a  recent  bone. 

On  the  dry  temporal  bone,  after  removing  most  of  the  squamous  portion 


672  DISSECTION    OF    THE    EAR. 

by  means  of  a  vertical  cut  of  the  saw  through  the  root  of  the  zygoma  and 
the  Glaserian  fissure,  tlie  tympanum  will  be  brought  into  view  by  cutting 
away  with  the  bone  forceps  some  of  the  upper  surface  of  the  petrous  portion, 
and  tlie  anterior  part  of  the  meatus  auditorius. 

In  the  recent  bone  prepare  the  dissection  as  above,  but  without  doing 
injury  to  the  membrana  tympani,  the  chorda  tympani  nerve,  and  the  chain 
of  bones  with  its  muscles. 

Form.  The  cavity  of  the  tympanum  has  the  form  of  a  slice  of  a  small 
cork,  about  a  quarter  of  an  inch  thick,  the  outer  and  inner  boundaries 
being  flattened  and  the  circumference  circuUu*.  Its  size  is  greater  across 
the  space,  than  from  without  inwards  ;  in  the  former  direction  it  measures 
about  half  an  inch,  but  in  the  latter  not  more  than  a  quarter  of  an  inch. 

The  inner  boundary  (fig.  239)  is  of  greater  extent  than  the  outer,  and 
on  it  the  following  objects  are  to  be  noticed.  Occupying  nearly  the  whole 
surface  is  the  large  projection  of  tlie  promontory  {ci)  ;  tliis  is  pointed  pos- 
teriorly, and  is  marked  by  two  or  three  minute  grooves  {d)  which  lodge 
the  nerves  in  the  anastomosis  of  Jacobson.  Above  and  below  the  nar- 
rowed part  of  the  promontory  is  a  large  aperture  ;  both  lead  into  the 
labyrinth. 

The  upper  opening  (&),  semicircular  in  shape,  with  the  convexity  placed 
upwards,  is  \\&.meA  fenestra  ovalis :  into  it  the  inner  bone  (stapes)  of  the 
osseous  chain  is  fixed.  The  lower  aperture  (c) — -fenestra  rotunda,  is 
rather  triangular  in  shape,  and  leads  into  the  cochlea;  it  is  situate  within 
a  hollow,  which  is  somewhat  semi-elliptical  in  form.  In  the  recent  state 
it  is  closed  by  a  thin  membrane,  the  secondary  membrane  of  the  tym- 
panum. 

The  onter  boundary  of  the  cavity  is  formed  by  the  membrana  tympani 
(fig.  238,  c),  and  the  surrounding  bone.  Above  and  in  front  of  the  mem- 
brane, is  the  Glaserian  or  glenoid  fissure,  which  is  occupied  in  the  fresh 
condition  by  the  long  process  of  one  of  the  small  bones  (malleus)  ;  by  a 
small  muscle,  the  laxator  tympani ;  and  by  tympanic  vessels.  Crossing 
the  membrane  towards  the  upper  part  is  the  chorda  tympani  nerve,  which 
issues  through  the  Glaserian  fissure. 

The  circumference  of  the  tympanum  is  circular,  and  is  rough  and 
uneven  on  the  surface  here  and  there :  round  it  the  student  may  observe 
the  following  facts. 

The  roof  is  flattened,  and  consists  of  the  thin  osseous  plate  separating 
the  tympanic  cavity  from  the  cranium.  The  floor  is  narrower  than  the 
roof,  and  is  curved  over  the  subjacent  jugular  fossa  ;  it  has  more  or  less 
of  an  areolar  condition,  and  some  small  apertures  communicate  with  the 
fossa  beneath. 

At  the  posterior  part  of  the  circumference,  towards  the  roof,  is  one 
large  with  other  small  apertures,  leading  into  the  mastoid  cells  (fig.  230). 
Below  those  apertures,  but  near  the  inner  wall  and  on  a  level  with  the 
narrowed  part  of  the  promontory,  is  the  small  conical  hollow  projection 
(e)  of  thii  pyramid ;  this  is  perforated  by  an  aperture,  and  contains  the 
stapedius  muscle  ;  a  minute  canal  connects  its  cavity  with  the  aip^educt  of 
Fallopius  :  sometimes  a  small  round  spiculum  of  bone  attaches  the  pyramid 
to  the  promontory.  In  a  line  with  the  pyramid,  and  arching  upwards 
above  the  fenestra  ovalis,  is  a  bony  ridge  (/)  marking  the  situation  of  tlie 
aqueduct  of  Fallopius. 

The  front  of  the  tympanic  cavity  corresponds  with  the  carotid  artery, 
only  a  thin  piece  of  bone  intervening.     In  it  are  the  apertures  of  two 


SPECIAL    PARTS    IN    TYMPANUM, 


673 


canals  which  lie  on  the  outer  side  of  the  passage  for  the  vessel :  the  upper 
{h)  contains  the  tensor  tympani  muscle  ;  and  the  lower  (?)  is  the  Eusta- 
chian tube.  Between  the  two  canals  is  a  thin  osseous  lamina,  which  is 
hollowed  above  and  dilated  at  the  inner  end,  and  is  named  processus 
cochleariformis. 


Promontory. 
Fenestra  ovalis. 
Fenestra  rotunda. 
Nerve  grooves  on  the  promon- 
tory. 
e.  Pyramid. 
/.  Prominence    of    aqueduct    of 

Fallopius. 
g.  Openings  of  mastoid  cells. 
h.  Canal  of  tensor  tympani. 
t.  Osseous    part    of    Eustachian 

tube. 
k.  Internal  carotid  artery. 
1.  Facial  nerve. 


View  of  the  Inner  Wall  of  the  Tympanum  enlarged  (Bowman). 


Some  parts  that  have  been  referred  to  above,  viz.,  the  membrana  tym- 
pani, the  Eustachian  tube,  and  the  secondary  tympanic  membrane,  require 
separate  notice. 

The  memhrana  tympana  (fig.  240,  a)  is  a  thin  translucent  stratum  be- 
tween the  meatus  auditorius  and  the  cavity  of  the  tympanum.  It  measures 
one-third  of  an  inch  across,  is  oval  in  form,  and  is  attached  by  its  circum- 
ference to  a  groove  at  the  inner  end  of  the  auditory  passage ;  but  in  the 
foetus  it  is  fitted  into  a  separate  osseous  ring,  the  tympanic  bone.  The 
membrane  is  placed  very  obliquely  so  that  it  forms  with  the  floor  of  the 
meatus  an  angle  of  45  degrees,  and  the  outer  surface  is  directed  down- 
Avards.  Towards  the  auditory  canal  the  surface  is  concave  ;  but  in  the 
tympanum  it  is  convex,  and  attached  to  its  upper  half  is  the  handle  of 
the  malleus  {h) — one  of  the  ossicles. 

Structure.  The  membrane  is  formed  of  three  strata — external,  internal, 
and  middle.  The  outer  one  is  continuous  with  the  integuments  of  the 
meatus  auditorius ;  and  the  inner  is  derived  from  the  mucous  membrane 
of  the  tympanum.  The  middle  layer  is  formed  of  white  and  yellow  fibrous 
tissues,  and  is  fixed  to  the  groove  in  the  bone.  From  its  centre,  where  it 
is  connected  with  the  handle  of  the  malleus,  fibres  radiate  towards  the 
circumference ;  and  near  the  margin,  at  the  inner  surface,  lies  a  band  of 
stronger  circular  fibres  (fig.  240,  c),  which  bridges  across  the  notch  at 
the  upper  part  of  the  tympanic  bone. 

The  Eustachian  tube  (fig.  238,  e)  is  the  channel  through  which  the  tym- 
panic cavity  communicates  with  the  fauces.  It  is  about  an  inch  and  a  half 
in  length,  and  is  directed  downwards  and  inwards  to  the  pharynx.  Like 
the  meatus  auditorius,  it  is  partly  osseous  and  ))artly  cartilaginous  in 
texture. 

The  osseous  part  is  rather  more  than  half  an  inch  in  length,  and  is  nar- 
rowed at  the  middle.     Its  course  in  the  temporal  bone  is  along  the  angle 
43 


674 


DISSECTION    OF    THE    EAR 


Inner  View  of  the  Mem- 

BRANA  TYMPASI  IN  THE 
F(KTC8,  WITH  THE  MAL- 
LKCS  ATTACHED. 

a.  Membrane  or  drum  of 

the  tympanum. 
6.  Malleus. 

c.  Baud  of  circular  fibres 

at  the  circumference. 

d.  Inferior,  and  e,  superior 

tympanic  artery. 
/   Tympanic  bone. 


of  union  of  the  squamous  and  petrous  portions,  out- 
side the  passage  for  the  carotid  artery.  Externally 
it  ends  in  a  dilated  and  somewhat  oval  opening,  with 
an  irregular  margin,  which  gives  attachment  to  the 
cartilage. 

The  cartilaginous  part  of  the  tube  is  nearly  an 
inch  in  length,  and  extends  from  the  temporal  bone 
to  the  interior  of  the  pharynx  (p.  126). 

Through  this  tube  the  mucous  membrane  of  the 
drum  of  the  ear  is  continuous  with  that  of  the  pha- 
rynx ;  and  through  it  the  mucus  escapes. 

The  secondary  membrane  of  the  tympanum,  is 
placed  within  the  fenestra  rotunda,  and  is  rather 
concave  towards  the  tympanum,  but  convex  towards 
the  cochlear  passage,  which  it  closes. 

It  is  formed  of  three  strata,  like  the  membrane  on 
the  opposite  side  of  the  cavity,  viz.,  an  external  or 
mucous,  derived  from  the  lining  of  the  tympanum  ; 
an  internal  or  serous,  continuous  with  that  clothing 
the  cochlea ;  and  a  central  layer  of  fibrous  tissue. 

Ossicles  of  the  Tympanum  (fig.  242).  Three 
in  number,  they  are  placed  in  a  line  across  the  tym- 
panic cavity.  The  outer  one  is  named  malleus  from  its  resemblance  to  a 
mallet ;  the  next,  incus,  from  its  similitude  to  an  anvil ;  and  the  last, 
stapes,  from  its  likeness  to  a  stirrup.  For  their  examination  the  student 
should  be  provided  with  some  separate  ossicles. 

The  malleus  (fig.  241)  is  the  longest  bone,  and  is  twisted  and  bent.  It 
is  large  at  one  end  (a)  (head)  and  pmall  and  pointed  at  the  other  (c) 
(handle)  ;  and  it  has  two  processes  with  a  narrowed  part  or  neck.  The 
head  or  capitulum  (a)  is  free  in  the  cavity,  is  oval  in  shape,  and  is  smooth 
except  at  the  back,  where  there  is  a  depression  for  articulation  with  the 
next  bone.  The  neck  (b)  is  the  slightly  twisted  part  between  the  head 
and  the  processes.  The  handle  or  manubrium  (c)  decreases  in  size  towards 
the  tip,  and  is  flattened  from  beibre  backwards ;  but  at  the  extremity  it  is 
compressed  from  within  outwards  :  to  its  outer  margin  the  special  fibrous 
stratum  of  the  membrana  tympani  is  connected. 

The  processes  of  the  bone  are  two  in  number,  long  and  short.  The 
short  one  {c)  springs  from  the  root  of  the  handle  on  the  outer  side,  and 
touches  tlie  membrane  of  the  tympanum.  The  long  process — processus 
gracilis  (cf),  is  a  flattened  slender  piece  of  bone,  whicli  projects  from  the 
neck  of  the  malleus  at  the  anterior  aspect,  and  extends  into  the  Glaserian 
fissure  :  in  the  adult  this  process  is  joined  with  the  surrounding  bone,  and 
cannot  be  separated  from  it. 

The  incus  is  a  flattened  bone  (fig.  241),  and  possesses  a  body  and  two 
processes.  The  body  (b)  is  hollowed  at  the  upper  and  anterior  part  to 
articulate  with  the  malleus.  The  two  processes  (short  and  long)  extend 
from  the  side  opposite  to  the  articulation  : — The  shorter  process  (c)  is 
somewhat  conical,  and  is  received  into  the  large  aperture  of  the  mastoid 
cells :  the  long  process  (d)  decreases  towards  the  extremity,  where  it  curves, 
and  ends  in  a  rounded  point  (e),  the  orbicular  process. 

The  stapes  (fig.  241)  has  a  base  or  wider  part,  and  a  head,  with  two 
sid'.^s  or  crura,  like  a  stirrup.     The  base  (d)  is  formed  by  a  thin  osseous 


OSSICLES    AND    LIGAMENTS.  676 

plate,  which  is  convex  at  one  margin  and  almost  straight  at  the  other,  cor- 
responding with  the  shape  of  the  fenestra  ovalis  :  the  surface  turned  to  the 
vestibule  is  convex,  while  the  opposite  is  excavated.  The  head  (a)  is 
marked  by  a  superficial  depression  which  receives  the  orbicular  process  of 
the  incus;  and  below  it  is  a  constricted  part  (6),  the  neck  of  the  bone. 
The  crura  (c)  extend  from  the  neck  to  the  base,  and  are  grooved  on  the 
inner  surface :  the  anterior  crus  is  shorter  and  straighter  than  the  other. 


The  three  Ossicles  op  the  Tympanum:  the  central  bone  is  the  Malleus,  the  left-hand 
BONE  Incus,  and  the  right-hand  one  Stapes. 
Malleus  :  a.  head  ;  6,  neck  ;  c,  long  handle  ;  d,  long,  and  e,  short  process. 
Incus  :  a,  head  ;  6,  body  ;  c,  short  process  ;  d,  long  process  ;  e,  orbicular  process. 
Stapes:  a,  head  ;  6,  neck  ;  c,  crus  ;  d,  base. 

Position  of  the  ossicles  (fig.  242).  The  malleus  (cT)  is  placed  vertically 
in  the  tympanum,  with  the  head  upwards,  and  the  joint  surface  turned 
backwards  to  articulate  with  the  incus.  Its  handle  is  inserted  externally 
into  the  membrana  tympani  between  the  mucous  and  fibrous  layers ;  and 
its  long  process  is  directed  forwards  into  the  Glaserian  fissure. 

The  iiicus  (e)  is  also  upright,  so  that  the  long  process  is  vertical,  and 
the  short  one  horizontal.  Externally  it  is  united  with  the  malleus  ;  the 
short  process  is  received  into  the  large  aperture  of  the  mastoid  cells ;  and 
the  long  one  descends,  like  the  handle  of  the  malleus,  but  rather  posterior 
to  it  and  nearer  the  inner  wall  of  the  cavity,  to  join  inferiorly  with  the 
stapes. 

The  stirrup  bone  (/)  has  a  horizontal  position,  with  the  crura  directed 
forwards  and  backwards  :  its  base  is  fixed  over  the  fenestra  ovalis,  and  its 
head  is  united  with  the  long  process  of  the  incus. 

Ligaments  of  the  ossicles.  The  small  bones  of  the  tympanic  cavity  are 
united  into  one  chain  by  joints,  and  are  further  kept  in  position  by  liga- 
ments fixing  them  to  the  surrounding  wall. 

Joints  of  the  bones.  Where  the  ossicles  touch  they  are  connected  together 
by  articulations  corresponding  with  the  joints  of  larger  bones  ;  for  the  osse- 
ous surfaces  are  covered  with  cartilage,  are  surrounded  by  a  thin  capsular 
ligament  of  fibrous  tissue,  and  lubricated  by  a  synovial  sac.  One  articu- 
lation of  the  nature  above  described  exists  between  the  heads  of  the  mal- 
leus and  incus,  and  a  second  between  the  extremity  of  the  long  process  of 
the  incus  and  the  head  of  the  stapes. 

Union  of  the  hones  to  the  wall.  The  bones  are  kept  in  place  by  the 
reflection  of  the  mucous  membrane  over  them,  and  by  special  ligaments. 
From  the  head  of  the  malleus  a  short  suspensory  band  of  fibres  is  directed 
upwards  to  the  roof  of  the  tynpanum.  Another  ligamentous  band  {poste- 
rior) passes  backwards  from  the  incus,  near  the  end  of  its  short  process, 


676 


DISSECTION    OF    THE    EAR. 


Fig.  242. 


to  the  bone  supporting  it.  And  the  base  of  the  stapes  is  connected  to  the 
margin  of  the  fenestra  ovalis  by  fibres  constituting  an  orbicular  ligament. 
In  tlie  recent  bone  the  thin  mucous  membrane  closes  the  interval  be- 
tween the  crura  of  the  stapes,  and  is  attached  to  the  groove  on  the  inner 
aspect. 

Muscles  of  the  ossicles  (fig.  242).  Three  muscles  which  possess  trans- 
versely striated  fibres  are  connected  with  the  chain  of  bones  ;  two  of  tliese 
are  attached  to  the  malleus,  the  other  to  the  stapes. 

The  tensor  tympani  (fig.  242,  h)  (internal  muscle  of  the  malleus)  is  the 
largest  and  must  distinct  of  the  muscles  of  the  tympanum,  and  takes  the 
shape  of  its  containing  tube,  which  must  be  laid  open  to  see  it  com[)letely. 
The  muscle  arises  from  the  surface  of  its  bony  canal,  also  slightly  in  front 
from  the  cartilage  of  the  Eustachian  tube.  Posteriorly  it  ends  in  a  ten- 
don w^hich  is  reflected  over  the  end  of  the 
cochleariform  process,  and  is  inserted  in- 
to the  inner  border  of  the  handle  of  the 
malleus,  near  its  base. 

Action.  The  muscle  draws  inwards 
the  handle  of  the  malleus  towards  the  in- 
ner wall  of  the  tympanic  cavity,  and 
tightens  the  membrane  of  the  tympanum ; 
and  as  the  long  process  of  the  incus  is 
moved  inwards  with  the  malleus  the  base 
of  the  stapes  will  be  pressed  into  the 
fenestra  ovalis. 

Laxator  tympani  (fig.  242,  g)  (exter- 
nal muscle  of  the  malleus).  It  is  con- 
nected externally  with  the  spinous  process 
of  the  sphenoid  bone ;  and  passing  through 
the  Glaserian  fissure,  it  is  attached  to  the 
neck  of  the  malleus  above  the  processus 
gracilis. 

Action.  The  muscle  draws  inwards  and 
forwards  the  upper  part  of  the  malleus, 
and  tilts  outwards  the  handle,  so  as  to  re- 
lax the  membrana  tympani ;  and  on  the 
cessation  of  the  contraction  of  the  tensor, 
it  can  move  out  the  bony  chain. 

The  stapedius  (fig.  242,  «)  is  lodged 
in  the  canal  holowed  in  the  interior  of 
the  pyramid.  Arising  inside  the  tube, 
the  muscle  ends  in  a  small  tendon,  which 
issues  from  tlie  pyramid,  and  is  inserted 
into  the  neck  of  tlie  stapes  at  the  poste- 
rior part. 

Action.  By  directing  the  neck  of  the 
stapes  backwards  the  muscle  raises  the  fore  part  of  the  base  out  of  the 
fenestra  ovalis,  diminishing  the  pressure  on  the  fluid  in  the  vestibule  ;  and 
supposing  it  to  contract  simultaneously  with  tlie  tensor,  it  would  prevent 
the  sudden  jar  of  the  stapes  on  that  fluid. 

Mucous  membrane  of  the  tympanum.  The  mucous  lining  of  the  tym- 
panic cavity  adheres  closely  to  the  wall ;  it  is  continuous  with  that  of  the 


Plan  op  thb  Ossicles  in  Position  in 
THE   Tympanum    with   their    Mus- 

CLES. 

a.  Cavity  of  the  tympanum, 
ft.  Membrana  tympani. 

c.  Eustachian  tube. 

d.  Malleus. 

e.  Incus. 
/.  stapes. 

g.  Laxator  tympani  muscle. 
h.  Tensor  tympani. 
i.    Stapedius. 


VESSELS    AND    NERVES    OF    TYMPANUM.  677 

pharynx  through  the  Eustachian  tube,  and  is  prolonged  into  the  mastoid 
cells  through  the  apertures  leading  into  them. 

It  assists  to  form  part  of  the  membrana  tympani,  and  of  the  secondary 
membrane  in  the  fenestra  rotunda  ;  it  is  reflected  also  over  the  chain  of 
bones  and  the  muscles,  ligaments,  and  cliorda  tympani  nerve.  In  the 
tympanum  the  membrane  is  thin,  not  very  vascular,  and  secretes  a  watery 
fluid  ;  but  in  the  lower  part  of  the  Eustachian  tube  it  is  thick  and  more 
vascular,  is  provided  with  numerous  glands,  and  its  epithelium  is  lami- 
nated. 

Its  surface  is  covered  with  a  columnar  ciliated  epithelium^  but  on  the 
membrana  tympani  and  the  ossicula  it  is  laminar  and  unciliated. 

Bloodvessels.  The  arteries  of  the  tympanum  are  furnished  from 
the  following  branches  of  the  external  carotid,  viz.,  internal  maxillary, 
posterior  auricular,  ascending  pharyngeal ;  and  some  offsets  come  from  the 
internal  carotid  in  the  temporal  bone.  The  veins  join  the  middle  menin- 
geal and  paryngeal  branches. 

The  internal  maxillary  artery  supplies  the  tympanic  branch  (fig.  240, 
d)  (inferior,  p.  93),  which  enters  the  cavity  through  the  Glaserian  fissure, 
and  distributes  a  branch  to  the  membrane  of  tiie  tympanum. 

The  stylo-mastoid  branch  of  the  posterior  auricular  artery  (p.  86), 
entering  the  lower  end  of  the  aqueduct  of  Fallopius,  gives  twigs  to  the 
back  of  the  cavity,  and  the  mastoid  cells.  One  of  this  set,  superior  tym- 
panic (tig.  240,  e),  anastomoses  with  the  tympanic  branch  of  the  internal 
maxillary  artery,  and  forms  a  circle  around  the  membrana  tympani,  from 
which  offsets  are  directed  inwards. 

Other  branches  from  the  ascending  pharyngeal,  or  from  the  inferior 
palatine  artery,  enter  the  fore  part  of  tlie  space  by  the  Eustachian  tube. 

Nerves.  The  lining  membrane  of  the  tympanum  is  supplied  from  the 
plexus  (tympanic)  between  Jacobson's  and  the  sympathetic  nerve  :  but 
the  muscles  derive  their  nerves  from  other  sources.  Crossing  the  cavity 
is  the  chorda  tympani  branch  of  the  facial  nerve. 

Dissection  (fig.  243).  The  preparation  of  the  tympanic  plexus  will 
require  a  separate  fresh  temporal  bone,  which  has  been  softened  in  diluted 
hydrochloric  acid,  and  in  which  the  nerves  have  been  hardened  afterwards 
in  spirit. 

The  origin  of  Jacobson's  nerve  from  the  glosso-pharyngeal  is  first  to  be 
sought  close  to  the  skull ;  and  the  fine  auricular  branch  of  the  pneumo- 
gastric  may  be  looked  for  at  the  same  time  (p.  113).  Supposing  the  nerve 
to  be  found,  the  student  should  place  the  scalpel  on  the  outer  side  of  the 
Eustachian  tube,  and  carry  it  backwards  through  the  vaginal  and  styloid 
processes  of  the  temporal  bone,  so  as  to  take  away  the  outer  part  of  the 
tympanum,  but  without  opening  the  lower  end  of  the  aqueduct  of  Fal- 
lopius. 

After  the  tympanum  has  been  laid  open,  Jacobson's  nerve  is  to  be  fol- 
lowed in  its  canal ;  and  the  brandies  in  the  grooves  on  the  surface  of  the 
promontory  are  to  be  pursued :  one  of  these  arching  forwards  joins  in  the 
carotid  plexus  ;  and  two  others  directed  upwards,  unite  with  the  large 
superficial  petrosal,  and  the  facial  nerve. 

The  connections  of  the  chorda  tympani  nerve  can  be  seen  on  the  prepa- 
ration used  for  the  muscles. 

The  tympanic  branch  of  the  glosso-pharyngeal  nerve  (fig.  243,  ^),  nerve 
of  Jacobson  (p.  112),  enters  a  special  aperture  in   the  temporal   bone,  to 


678 


DISSECTION    OF    THE    EAR 


reach  the  inner  wall  of  the  tympanum.  In  this  cavity  the  nerve  supplies 
filaments  to  the  lining  membrane  and  the  fenestra  rotunda  ;  and  it  termi- 
nates in  the  three  undermentioned  branches,  which  are  contained  in 
grooves  on  the  promontory,  and  connect  this  nerve  with  others.^ 

Fig.  243. 


Jacobson's  Nerve  in  the  Tympanum  (Breschet). 


a.  Carotid  artery. 

6.  Tensor  tympaui  muscle. 

c.  Inferior  maxillary  trunk  of  the  fifth  nerve. 

d.  Otic  ganglion. 

Neirves  : 
1.  Petrous  ganglion  of   the  glosso-pharyn- 
geal. 


2.  Nerve  of  Jacobson. 

3.  Sympathetic  on  the  carotid. 

4.  Small  superficial  petrosal  nerve. 

5.  Offset  to  join  large  peti-osal  nerve. 

6.  Branch  to  Eustachian  tube. 

7.  Facial  nerve  ;  8,  chorda  tympani  branch. 
9.  Nerve  of  the  otic  ganglion  to  the  tensor 

muscle. 


Branches.  One  branch  is  arched  forwards  and  downwards,  and  enters 
the  carotid  canal  to  communicate  with  the  sympathetic  (^)  on  the  artery 
(p.  116). 

A  second  (^)  is  directed  upwards  to  join  the  large  superficial  petrosal 
nerve  in  the  hiatus  Fallopii. 

And  the  third  (*)  has  the  following  course  :  It  ascends  in  front  of  the 
fenestra  ovalis,  and  near  the  gangliform  enlargement  on  the  facial  nerve, 
to  which  it  is  connected  by  filaments  (fig.  8o).  Beyond  the  union  with 
the  facial,  the  nerve  is  named  s)7iall  superficial  petrosal,  and  is  continued 
forwards  through  the  substance  of  the  temporal  bone,  to  end  in  the  otic 
ganglion  (p.  144). 

Nerves  to  muscles.  The  tensor  tympani  muscle  is  supplied  by  a  branch 
from  the  otic  ganglion  (fig.  243,  ')  :  the  stapedius  receives  an  offset  from 
the  facial  trunk  ;  and  tlie  laxator  tympani  from  the  chorda  tympani  nerve  (?). 

•  Instead  of  viewing  these  filaments  as  ofTsets  of  the  nerve  of  Jacobson  they 
may  be  supposed  to  come  from  the  other  nerv(;s  :  according  to  tliis  view  tlie  tym- 
panic plexus  would  be  derived  from  several  sources. 


BOUNDARIES    OF    VESTIBULE. 


679 


The  chorda  tympani  (fig.  243,  ^)  is  a  branch  of  the  facial  nerve  (p.  144). 
Entering  the  cavity  behind,  it  crosses  the  membrana  tympani,  and  issues 
from  the  space  by  an  aperture  in,  or  internal  to  the  Glaserian  fissure ;  it 
joins  tlie  gustatory  nerve,  and  its  farther  course  to  the  tongue  is  described 
at  page  97. 

The  auricular  branch  of  the  vagus  nerve,  though  not  a  nerve  of  the 
tympanum,  is  an  offset  to  the  outer  ear,  and  may  be  now  traced  in  the 
softened  bone.  Arising  in  the  jugular  fossa  (p.  113),  the  nerve  enters  a 
special  canal,  and  crosses  through  the  substance  of  the  temporal  bone  to 
the  back  of  the  ear. 

The  Labyrinth.  The  inner  portion  of  the  organ  of  hearing  is  so 
named  from  its  complexness.  It  consists  of  three  spaces  surrounded  by 
dense  bone ;  and  of  sacs  containing  fluid  for  the  expansion  of  the  auditory 
nerve,  which  are  contained  within  the  former. 

The  OSSEOUS  labyrinth  includes  the  vestibule,  the  semicircular  canals, 
and  the  cochlea:  these  communicate  externally  with  the  tympanum,  and 
internally,  through  the  meatus  auditorius  internus,  with  the  cranial  cavity. 

The  VESTIBULE  (fig.  244),  or  the  central  cavity  of  the  osseous  labyrinth, 
is  placed  behind  the  cochlea,  but  in  front  of  the  semicircular  canals. 


Fijr.  244. 


View  of  the  Vestibcle  obtained  by  crTTixa  awat  the  outer  BoaxDART  in  a  Fcetds, 
enlarged  thre3  times. 
a.  Fovea  hemispherica.  e.  Upper  vertical  semicirjular  canal    partly 

h.  Crista  vestibuli.  laid  open. 

c.  Aperture  of  aqueduct  of  the  vestibule.  /.  Horizoatal  semicircular caavl,  partlyopeaed. 

d.  Common  opening  of  two  semicircular  canals,     g.  Opening  of  the  scala  vestibuli. 


Dissection.  This  space  may  be  seen  on  the  dry  bone  which  has  been 
used  for  the  preparation  of  the  tympanum.  The  bone  is  to  be  sawn 
through  vertically  close  to  the  inner  wall  of  the  tympanum,  so  as  to  lay 
bare  the  fenestra  ovalis  leading  into  the  vestibule.  By  enlarging  the 
fenestra  ovalis  a  very  little  in  a  direction  upwards  and  forwards,  the  ves- 
tibular space  will  appear ;  and  the  end  of  the  superior  semicircular  canal 
will  be  opened. 


680  DISSECTION    OF    THE    EAR. 

Other  views  of  the  cavity  may  be  obtained  by  sections  of  the  temporal 
bone  in  different  directions,  according  to  the  knowledge  and  skill  of  the 
dissector. 

The  vestibular  space  (rig.  244)  is  ovoidal  in  form,  and  the  extremities 
are  directed  forwards  and  backwards.  The  larger  end  is  turned  back,  and 
the  under  part  or  floor  is  more  narrowed  than  the  upper  part  or  roof.  It 
measures  about  ^th  of  an  inch  in  length,  but  it  is  narrower  from  without 
inwards.  The  following  objects  are  to  be  noted  on  the  boundaries  of  the 
space. 

In  front,  close  to  the  outer  wall,  is  a  large  aperture  (^g)  leading  into  the 
cochlea ;  and  behind  are  five  round  openings  of  the  three  semicircular 
canals  (c?,  e,/). 

The  outer  wall  corresponds  with  the  tympanum,  and  in  it  is  the  aper- 
ture of  the  fenestra  ovalis.  On  the  inner  wall,  nearer  the  front  than  the 
back  of  the  cavity,  is  a  vertical  ridge  or  crista  (b).  In  front  of  the  ridge 
is  situate  a  circular  depression,  fovea  hemlspherica  («),  which  is  pierced 
by  minute  apertures  for  nerves  and  vessels,  and  corresponds  with  the 
bottom  of  the  meatus  auditorius  internus.  Behind  the  crest  of  bone, 
near  the  common  opening  of  two  of  the  semicircular  canals,  is  the  small 
aperture  of  the  aqueduct  of  the  vestibule  (c),  which  ends  on  the  posterior 
surface  of  the  petrous  portion  of  the  temporal  bone. 

The  roof  is  occupied  by  a  slight  transversely  oval  depression,  fovea 
semi -elliptic  a  ;  this  is  separated  from  the  fovea  hemispherica  by  a  prolonga- 
tion of  the  crista  (6)  on  the  inner  wall  before  mentioned. 

The  SEMICIRCULAR  CANALS  (fig.  245)  are  three  osseous  tubes,  which 
are  situate  behind  the  vestibule,  and  are  named  from  their  form. 

Dissection,  These  small  canals  will  be  easily  brought  into  view  by  the 
removal  of  the  surrounding  bone  by  means  of  a  file  or  bone  forceps.  Two 
may  be  seen  opening  near  the  aperture  made  in  the  vestibule,  and  may 
be  followed  thence  ;  but  the  third  is  altogether  towards  the  posterior  aspect 
of  the  petrous  portion  of  the  temporal  bone. 

The  canals  are  unequal  in  length,  and  each  forms  more  than  half  an 
ellipse.  They  communicate  at  each  end  with  the  vestibule,  but  the  con- 
tiguous ends  of  two  are  blended  together  so  as  to  give  only  five  openings 
into  that  cavity.  Each  is  marked  by  one  dilated  extremity  which  is 
called  the  ampulla.  When  a  tube  is  cut  across  it  is  not  circular,  but  is 
compressed  laterally,  and  measures  about  ^^(jth  of  an  inch,  tliough  in  the 
ampulla  the  size  is  as  large  again. 

From  a  difference  in  the  direction  of  the  tubes,  they  have  been  named 
superior  vertical,  posterior  vertical,  and  horizontal. 

The  superior  vertical  canal  (a)  crosses  the  upper  border  of  the  petrous 
part  of  the  temporal  bone,  and  forms  a  projection  on  the  surface.  Its 
outer  end  is  marked  by  the  ampulla,  whilst  the  inner  is  joined  with  the 
following. 

The  posterior  vertical  tube  {b)  is  directed  backwards  from  its  junction 
with  the  preceding  towards  the  posterior  surface  of  the  temporal  bone;  the 
upper  end  is  united  with  the  superior  vertical  canal,  and  the  lower  end  is 
free  and  dilated. 

The  horizontal  canal  (c)  has  separate  apertures,  and  is  the  shortest  of 
the  three.  Deeper  in  position  than  the  superior  vertical,  it  lies  in  the  sub- 
stance of  the  bone  nearly  on  a  level  with  the  fenestra  ovalis ;  its  dilated 
end  is  at  the  outer  side  close  above  that  aperture. 


SEMICIRCULAR    CANALS 


681 


Lining  membrane  of  the  osseous  labyrinth.  A  thin  fibrous  periosteal 
membrane  lines  the  vestibule  and  the  semicircular  canals,  and  is  continuous 
with  the  fibrous  process  in  the  aqueduct  of  the  vestibule.  On  the  outer 
wall  of  the  cavity  it  stretches  over  the  fenestra  ovalis;  and  in  front  it  is 
prolonged  into  the  cochlea  through  the  aperture  of  the  scala  vestibuli  (fig. 
244,  g). 

Fig.  245. 


a.  Upper  vertical ;   h,   posterior  vertical ;    and  c, 
horizontal  canal. 

d.  Common  opeuing  of  the  two  vertical  canals. 

e.  Part  of  the  vestibular  cavity. 

/.  Opening  of  the  aqueduct  of  the  vestibule. 


Representation  of  the  Semicircular  Canals  Enlarged 
(from  a  model  in  University  College  Museum). 

The  outer  surface  of  the  membrane  is  adherent  to  the  bone;  but  the 
inner  is  covered  by  a  single  layer  of  flattened  epithelium.  It  is  supplied 
by  the  vestibular  vessels;  and  it  secretes  a  thin  serous  fluid,  liquor  Cotun- 
nii,  or  perilymph^  which  surrounds  the  membranous  labyrinth,  and  occu- 
pies for  a  short  distance  the  aqueduct :  this  fluid  also  fills  the  scalae  of  the 
cochlea. 

Cochlea.  This  part  of  the  osseous  labyrinth  has  a  position  anterior 
to  the  vestibule,  and  has  received  its  name  from  its  resemblance  to  a  spiral 
shell. 

Dissection.  To  obtain  a  view  of  the  cochlea  it  will  be  needful  to  cut 
or  file  away  the  bone  between  the  promontory  of  the  tympanum  and  the 
meatus  auditorius  internus,  on  the  preparation  before  used  for  displaying 
the  vestibule;  or  this  section  may  be  mjide  on  another  temporal  bone  in 
which  the  semicircular  canals  are  not  laid  bare.  For  the  same  dissection 
in  the  recent  state,  a  softened  bone  should  be  used. 

The  cochlea  (fig.  246)  is  conical  in  form,  and  is  placed  almost  horizon- 
tally in  front  of  the  vestibular  space.  The  base  of  this  body  is  turned  to 
the  meatus  auditorius  internus,  and  is  perforated  by  small  apertures  ;  whilst 
the  apex  is  directed  to  the  inner  wall  of  the  tympanum,  opposite  the  canal 
for  the  tensor  tympani  muscle.  Its  length  is  about  a  quarter  of  an  inch, 
and  its  width  at  the  base  is  about  the  same.  Resembling  a  spiral  shell  in 
construction,  the  cochlea  consists  of  a  tube  wound  round  a  central  part  or 
axis;  but  it  differs  from  the  shell  in  having  its  tube  subdivided  by  a  par- 
tition. 

The  axis  or  modiolus  (fig.  246,  «)  is  the  central  stem  which  supports 


682 


DISSECTION    OF    THE    EAR. 


the  windings  of  the  spiral  tube.  Conical  in  shape,  its  size  diminishes 
rapidly  towards  the  last  half  turn  of  the  tube,  but  it  enlarges  at  the  tip  of 
the  cochlea,  forming  a  second  small  cone  (b),  which  is  bent.  The  axis  is 
perforated  by  canals  as  far  as  the  contracted  part  in  the  last  half  turn,  and 
the  central  one  is  larger  than  the  others;  these  transmit  vessels  and 
nerves  in  the  fresh  state. 


Fiff.  246. 


s.7n. 


a.  Axis  with  its  canals. 

b.  Infundibulum  or  enlarged  upper 

end  of  the  axis. 

c.  Septum  of  the  cochlea. 

d.  Membrane  of  Corti. 

e.  Membrane  of  Reissner. 
/.  Hiatus  or  helicotrenia. 
8.  t.  Scala  tympani. 

s.  V.  Scala  vestibuli. 


Sectfon  through  the  Cochlea  (Breschet). 

The  spiral  tube  forms  two  turns  and  a  half  around  the  stem,  and  termi- 
nates above  in  a  closed  extremity  named  the  cupola.  When  measured 
along  the  outer  side,  it  is  about  one  inch  and  a  half  long.  Its  diameter  at 
the  beginning  is  about  one-tenth  of  an  inch,  but  it  diminishes  gradually  to 
half  tliat  size  towards  the  opposite  end. 

Of  the  coils  that  the  tube  makes,  the  first  is  much  the  largest;  this  pro- 
jects towards  the  tympanum,  and  gives  rise  to  the  eminence  of  the  pro- 
montory on  the  inner  wall  of  that  cavity.  Tiie  second  turn  is  included 
within  the  first  coil.  The  last  half  turn  bends  sharply  round,  and  presents 
a  free  margin  (6)  (the  edge  of  the  axis). 

In  the  recent  bone  the  tube  is  divided  into  two  main  passages  (scala?) 
by  the  septum  (fig.  246,  c).  In  the  dry  bone  a  remnant  of  this  partition 
is  seen  in  the  form  of  a  thin  plate  bone, — lamina  spiralis,  projecting  from 
the  axis ;  and  on  the  outer  wall  is  a  slight  groove,  opposite  the  ridge  of 
bone. 

Septum  of  the  spiral  tube  (fig.  247).  The  partition  in  the  recent  bone 
dividing  the  tube  of  the  cochlea  into  two  passages,  consists  of  an  osseous 
and  a  membranous  portion  : — 

The  osseous  part  (^),  formed  by  the  laminae  spiralis,  extends  about  half 
way  across  the  tube.  Inferiorly  it  begins  in  the  vestibule,  where  it  is  wide, 
and  is  attached  to  the  outer  wall  so  as  to  shut  out  the  fenestra  rotunda  from 
that  cavity  ;  and  diminishing  in  size  ends  above  in  a  })oint, — the  hamulus, 
opposite  the  last  half  turn  of  the  cochlea.  Between  the  hamulus  and  the 
axis  a  sj)ace,  which  is  converted  by  tlie  membranous  part  of  the  se|)tum 
into  a  foramen  (fig.  240,/)  (hiatus,  helicotrema),  and  allows  the  inter- 
communication of  tlie  two  chief  passages  of  the  cochlear  tube. 

The  lamina  spiralis  is  formed  by  two  plates  of  tlie  bone,  which  inclose 
canals  for  vessels  and  nerves,  and  are  separated  farthest  from  each  otlier  at 


COMPOSITION    OF    SEPTUM    COCHLEA. 


683 


le  axis.  The  surface  of  the  lamina  which  is  turned  to  the  lower  of  the 
"two  cochlear  passages  (st)  is  most  pierced  by  apertures.  The  opposite 
surface  is  covered  in  the  outer  fifth  of  its  extent  by  a  border  or  limhus  of 
fibrous  structure  («),  which  ends  in  wedge-shaped  teeth  near  the  margin 
of  the  bony  plate  {^denticulate  lamma,  Bowman). 

Fig.  247. 


A  Diagram  of  a  Section  of  the  Tube  of  the  Cochlea  Enlarged  (modified  from  Henle). 


SV.  Scala  vestibuli. 
ST.  Scala  tympani. 
CC.  Canal  of  the  cochlea. 

1.  Membrane  of  Reissner. 

2.  Cochlear  branch  of  the  auditory  nerve. 

3.  Lamina  spiralis  ossea. 

4.  Ligamentum  spirale. 
a.  Lamina  denticulata. 

b.  Sulcus  spiralis. 


c.  Tympanic  lip  of  the  sulcus  spiralis. 

d.  Inner  rods  of  Corti. 

e.  Outer  rods  of  Corti. 
/.  Lamina  reticularis. 
i.  Inner  hair  cells. 

mb.  Membranabasilaris. 
m  e.  Membrane  of  Corti. 

p.  Outer  hair  cells. 
s  m.  Central  space  between  the  rods. 


Between  the  teeth  and  the  underlying  bone  is  a  channel  (6),  lined  by 
flat  epithelium,  which  is  called  sulcus  spiralis :  its  edges  are  named  ves- 
tibular («)  and  tympanic  (c). 

The  membranous  part  of  the  septum  (membrana  basilaris,  fig.  247,  m  h) 
reaches  from  the  lower  edge  (c)  of  the  laminae  spiralis  to  the  groove  in  the 
outer  wall  of  the  cochlear  tube.  Its  width  varies  : — near  the  base  of  the 
cochlea  it  forms  half  of  the  partition  across  the  tube,  but  at  the  apex, 
where  the  bony  part  is  wanting,  it  constructs  the  septum  altogether. 

This  membrane  is  firm  and  stiflf",  and  possesses  fine  radiating  lines  which 
cause  it  to  split  in  shreds.  At  its  outer  attachment  there  is  a  fibrous  band 
(*)  (ligamentum  spirale,  Kolliker)  fixing  it  to  the  bone. 

ScalcB  of  the  cochlea  (fig.  246).  The  tube  of  the  cochlea  is  divided  by 
the  septum  into  two  primary  passages,  of  which  one  is  the  scala  tympani 
(st)  and  the  other  scala  vestibuli  (sv);  but  the  latter  is  rendered  smaller 
by  two  canals  being  cut  off  from  it  by  membranes. 

These  passages  are  placed  one  above  another,  the  scala  vestibuli  (sv) 
being  the  nearest  the  apex  of  the  cochlea.  Above  they  communicate 
through  the  aperture  named  helico-trema  (/).     lielow  they  end  differently, 


684  DISSECTION    OF    THE    EAR. 

as  the  names  express  : — the  scala  vestibuli  opens  into  the  front  of  the  ves- 
tibule (fig.  244,  g') ;  but  the  scala  tympani  is  shut  out  from  the  vestibular 
cavity  by  the  lamina  spiralis  of  the  septum  cochleie,  and  is  closed  below 
by  the  membrane  of  the  fenestra  rotunda,  though  in  the  dry  bone  it  opens 
into  the  tympanum. 

Each  has  certain  peculiarities.  The  vestibular  scala  extends  into  the 
apex  of  the  cochlea ;  whilst  the  tympanic  scala  is  largest  near  the  base. 
Connected  with  the  last  is  the  small  aqueduct  of  the  cochlea^  which  begins 
close  to  a  ridge  near  the  lower  end  of  the  scala,  and  opens  at  the  lower 
border  of  the -petrous  portion  of  the  temporal  bone. 

The  scalae  are  clothed  with  a  thin  fibrous  membrane,  continuous  with 
that  in  the  vestibule :  in  the  scala  tympani  it  helps  to  close  the  fenestra 
rotunda,  forming  the  inner  layer  of  the  secondary  membrane  of  the  tym- 
panum, and  joins  the  fibrous  process  in  the  aqueduct  of  the  cochlea.  The 
fluid  of  the  vestibular  space  fills  both  scalae. 

Smaller  partitions  of  the  cochlea  (fig.  247).  Two  thin  mem- 
branes are  prolonged  from  the  septum  to  the  outer  wall,  across  the  vestibu- 
lar scala.  One  is  called  membrane  of  Reissner,  and  the  other  membrane 
of  Corti. 

The  membrane  of  Reissner  (^),  which  is  easily  torn,  is  prolonged  ob- 
liquely from  the  upper  surface  of  the  septum  cochleae,  where  the  limbus 
ends,  to  the  outer  part  of  the  tube  of  the  cochlea,  so  as  to  cut  off  a  small 
channel, — the  canal  of  the  cochlea  (cc).  It  is  formed  by  a  very  thin  layer 
of  fine  connective  tissue  with  blood  capillaries,  and  is  covered  by  the  epi- 
thelial lining  of  the  two  spaces  between  which  it  intervenes. 

The  membrane  of  Corti  (mc)  (membrana  tectoria)  stretches  horizon- 
tally across  the  tube  of  the  cochlea  near,  and  parallel  to  the  membrana 
basilaris.  Internally  it  is  attached  to  the  limbus  of  the  septum  cochleae, 
and  externally  to  the  wall  of  the  cochlear  tube.  It  is  a  thin  elastic  trans- 
versely-fibred layer,  which  is  thicker  internally  than  externally.  Between 
it  and  the  membrana  basilaris  (mb)  is  a  narrow  channel  for  the  reception 
of  the  organ  of  Corti. 

Smaller  passages  of  the  cochlea  (fig.  247).  The  spaces  result- 
ing from  the  subdivision  of  the  scala  vestibuli  by  the  membranes  above 
noticed  are  two  in  number,  viz.,  canal  of  the  cochlea,  and  space  for  the 
organ  of  Corti. 

The  canal  or  duct  of  the  cochlea  (cc)  is  the  narrow  interval  towards 
the  outer  part  of  the  cochlear  tube,  between  the  membrane  of  Reissner  ('), 
and  the  membrane  of  Corti  (mc).  It  extends  from  apex  to  base  of  the 
cochlea  like  the  larger  scalae  ;  it  is  lined  by  epithelium,  and  contains  a 
fluid  (endolymph). 

Above  it  reaches  into  the  cupola  and  is  closed.  Below  it  is  joined  by 
a  very  small  tube  (fig.  248,  c)  (canalis  reuniens  Hensen),  with  the  saccule 
in  the  vestibule. 

Tiie  space  for  the  organ  of  Corti  is  a  narrow  interval  corresponding  in 
in  depth  with  the  sulcis  spiralis,  and  is  placed  between  the  membrane  of 
Corti  (mc)  and  the  membrana  basilaris  (mb).  It  contains  the  organ  of 
Corti  and  is  filled  with  fluid. 

The  organ  of  Corti  (fig.  247)  rests  on  the  membrana  basilaris  (mb), 
and  occupies  a  narrow  space  between  this  and  the  membrane  of  Corti ;  it 
consists  of  rods  and  cells  placed  vertically  on  each  side  of  a  median  space 
(sm). 

The  rods  are  firm  peculiar  bodies,  which  are  arranged  in  two  rows  (d 


THE    MEMBRANOUS    LABYRINTH.  685 

ind  e)  over  an  intervening  triangular  space  ;  they  slant  towards  each  other 
above,  and  are  separated  below  like  the  rafters  in  a  roof.  The  inner  row, 
the  more  numerous,  are  in  contact  with  each  other  on  the  sides,  and  the 
outer  set  touch  only  by  the  upper  end.  Where  they  touch  above  they  are 
flattened  and  directed  out,  the  inner  (d)  overlapping  the  outer  (e) ;  and 
where'  they  rest  on  the  membrana  basilaris  each  is  provided  with  a  nucleus- 
like body. 

The  cells,  somewhat  like  columnar  epithelium  (fig.  247),  are  nucleated, 
and  are  arranged  vertically  on  the  sides  of  the  rods  :  the  lower  end  is  fur- 
nished with  a  process  which  directed  to  the  membrana  basilaria,  and  the 
other  placed  upwards,  is  provided  with  stiff  filaments  or  hairs. 

The  inner  set  (i)  stand  in  a  single  line  between  the  sulcus  spiralis  and 
the  inner  row  of  rods.  The  other  set  (jo)  four  deep,  are  flattened  and 
riband-like,  and  bulged  below,  and  are  placed  outside  the  external  row 
of  rods ;  the  filaments  at  the  upper  end  project  through  apertures  in  the 
layer  (/)  above  them. 

Lamina  reticularis  (/)  (KoUiker).  A  very  thin  layer  of  flattened  par- 
ticles (phalanges)  is  continued  over  the  outer  half  of  the  organ  of  Corti  ; 
in  it  are  apertures,  through  which  pass  the  filaments  at  the  end  of  the 
cells.  And  around  the  upper  ends  of  the  inner  cells  is  a  similar  uniting 
material.     It  is  supposed  to  fix  and  keep  in  place  the  cells. 

An  epithelial  layer,  consisting  of  cubical  cells,  covers  the  floor  of  the 
space  outside  and  inside  the  organ  of  Corti. 

The  3IEMBRAN0US  LABYRINTH  (fig.  248)  is  Constituted  of  sacs,  contain- 
ing fluid,  in  which  the  auditory  nerve  is  expanded.  The  sacs  are  two  in 
number,  viz.,  utricle  and  saccule,  and  have  the  general  shape  of  the  sur- 
rounding bony  parts  ;  they  are  confined  to  the  vestibule  and  the  semicir- 
cular canals.     Surrounding  them  is  the  perilymphic  fluid. 

Dissection.  The  delicate  internal  sacs  of  the  ear,  with  their  nerves, 
cannot  be  dissected  except  on  a  temporal  bone  w^hich  has  been  softened  in 
acid,  and  afterwards  put  in  spirit.  The  previous  instructions  for  the  dis- 
section  of  the  osseous  labyrinth  will  guide  the  student  to  the  situation  of 
the  membranous  structures  within  it,  but  the  surrounding  softened  mate- 
rial must  be  removed  with  great  care. 

A  microscope  will  be  needed  for  the  complete  examination  of  the  sacs. 
For  the  display  of  the  bloodvessels  a  minute  injection  will  be  required. 

The  utricle  (fig.  248,  c?),  or  the  common  sinus,  is  the  larger  of  the  two 
sacs,  and  is  situate  at  the  posterior  and  upper  part  of  the  vestibule,  oppo- 
site the  fovea  semi-elliptica  in  the  roof.  It  is  transversely  oval  in  form, 
and  connected  with  it  posteriorly  are  three  looped  tubes,  which  are  pro- 
longed into  the  semicircular  canals. 

These  prolongations  (y)  are  smaller  than  the  osseous  tubes,  being  only 
one  third  of  their  diameter ;  and  the  interval  between  the  bone  and  the 
membrane  is  filled  by  fluid — the  perilymph.  In  form  they  resemble  the 
bony  cases,  for  they  are  marked  at  one  end  by  a  dilatation  (/)  corre- 
sponding with  the  ampulla  of  the  osseous  tube  ;  and  further,  two  are 
blended  at  one  end,  like  the  canals  they  occupy  :  they  communicate  with 
the  utricle  by  five  openings,  and  are  filled  with  the  fluid  of  that  sac.  At 
each  ampullary  enlargement  there  is  a  transverse  projection  into  the  inte- 
rior of  the  cavity,  and  at  that  spot  a  branch  of  the  auditory  nerve  enters 
the  wall. 

The  utricle  and  its  offsets  are  filled  with  a  clear  fluid,  like  water,  which 


686 


DISSECTION    OF    THE    EAR. 


is  named  endolymph  ;  and  in  the  wall  of  the  sac  is  a  small  calcareous  de- 
posit (otolith,  e)  opposite  the  entrance  of  the  nerve  into  it. 

The  saccule  (fig.  248,  a)  is  a  smaller  and  rounder  cyst  than  the  utricle, 
and  is  placed  in  front  of  it  in  the  hollow  of  the  fovea  hemispherica.  It  is 
separate  from  the  other ;  but  it  is  continuous,  below,  by  a  short  and  small 
duct  (c,  ductus  reuniens)  with  the  canal  of  the  cochlea. 

Like,  the  larger  sac  it  has  a  translucent  wall,  in  which  is  an  otolith  (6) 
opposite  the  entrance  of  the  nerve;  it  is  also  filled  by  endolymph,  which  is 
continued  into  the  canal  of  the  cochlea  through  the  ductus  reuniens. 

Fig.  248. 


Petrous  Bone  partly  removed  to  show  the  Membranous  Labyrinth  in  place  (Breschet). 
a.  Small  sac.  e.  Its  otolith. 

6.  Its  otolith.  /.  Ampiillary  enlargement  on  a  semi- 

c.  Ductus  reuniens.  circular  tube. 

d.  Large  sac,  or  utricle.  g.  Semicircular  tube. 


Strncture  of  the  sacs.  The  wall  of  the  sacs  of  the  membranous  labyrinth 
is  translucent  and  firm  ;  but  it  is  more  opaque  where  the  vessels  and 
nerves  enter  it.  Three  strata  enter  into  its  construction,  together  with 
bloodvessels  and  nerves. 

The  outer  fibrous  covering  is  loose  and  flocculent,  is  easily  detached, 
and  contains  irregular  pigment  cells  with  ramifying  bloodvessels.  The 
middle  stratum  (tunica  propria)  is  clear  and  tough,  like  the  hyaloid  mem- 
brane in  the  interior  of  the  eyeball :  its  inner  surface  is  irregular,  owing 
to  slight  eminences  ;  and  in  the  ampulla  of  the  semicircular  tube  this  layer 
forms  a  transverse  projection.  The  inner  one  is  formed  by  a  layer  of 
flattened  nucleated  cells,  which  are  continued  over  the  eminences  in  the 
interior.  In  the  region  of  the  nerve,  both  in  the  ampulla  of  tlie  semicir- 
cular canal  and  in  the  sacs,  the  epithelium  is  said  to  become  columnar, 
and  to  have  intermixed  spindle-shaped  nucleated  cells  (like  the  olfactorial), 
wiiich  possess  hair-like  processes  at  their  free  ends. 

The  small  calcareous  masses,  or  the  otoliths,  consist  of  minute,  elon- 
gated, six  or  eiglit-sided  particles  of  carbonate  of  lime,  which  are  pointed 
at  the  ends,  and  are  situate  in  the  inner  part  of  the  wall  of  the  utricle  and 


AUDITORY    BLOODVESSELS    AND    NERVES.  687 

jcule.  Within  the  enlargement  of  each  semicircular  tube  there  is  also 
a  calcareous  material. 

Bloodvessels.  The  membranes  of  the  labyrinthic  cavity  receive 
their  blood  from  an  artery  which  enters  the  internal  auditory  meatus  with 
tlie  nerve  ;  but  some  offsets  from  the  posterior  auricular  supply  their 
hinder  part. 

The  internal  auditory  artery  arises  from  the  basilar  trunk  within  the 
skull  (p.  175),  and  enters  the  internal  meatus  with  the  auditory  nerve. 
In  the  bottom  of  that  hollow  it  divides  into  two  branches — one  for  the 
vestibule,  the  other  for  the  cochlea. 

The  branch  of  the  vestibule^  after  piercing  the  wall  of  the  cavity,  sub- 
divides into  small  offsets,  which  supply  the  lining  membrane,  and  ramify 
over  the  sacs,  and  the  tubes  occupying  the  semicircular  canals.  The 
vessels  end  in  a  network  of  capillaries  on  the  exterior  of  the  special 
layer  of  the  sacs,  and  this  is  most  developed  about  the  termination  of  the 
nerves. 

The  branch  of  the  cochlea  subdivides  into  twigs  which  enter  the  canals 
in  the  modiolus.  Small  offsets  from  these  are  directed  outwards  through 
canals  in  the  lamina  spiralis,  and  communicate  together  in  loops  near  the 
margin  of  that  osseous  zone.  From  this  anastomosis  vessels  are  supplied 
to  the  basement  layer  and  the  membrane  lining  the  scalae  ;  but  the 
septum  cochleae  prevents  the  communication  of  the  vessels  of  the  two 
passages. 

A  longitudinal  vessel  is  placed  on  that  surface  of  the  membranous  part 
of  the  septum  cochlese  which  is  turned  to  the  scala  tympani,  and  is  oppo- 
site the  outer  rods  of  Corti ;  it  communicates  here  and  there  with  the 
arterial  loops  before  mentioned. 

The  vein.  One  branch  of  vein  is  derived  from  the  cochlea,  and 
another  from  the  membranous  labyrinth  :  the  two  are  united  near  the 
cochlea,  and  the  trunk  ends  in  the  superior  petrosal  sinus  in  the  base  of 
the  skull. 

Nerve  of  the  Labyrinth  (fig.  249).  Only  one  special  nerve,  audi- 
tory (p.  181),  is  distributed  to  the  labyrinth.  Entering  the  internal 
auditory  meatus,  the  nerve  divides  into  two  branches,  like  the  artery, 
viz.,  an  anterior  for  the  cochlea,  and  a  posterior  for  the  membranous 
labyrinth.  In  the  trunk  and  in  both  branches  nerve  cells  are  contained  : 
in  the  branch  to  the  labyrinth  they  form  a  swelling  (intumescentia  ganylio' 
for  mis  of  Scarpa). 

The  cochlear  branch  divides  at  the  base  of  the  modiolus  into  twigs, 
which  enter  it,  and  are  directed  outwards  with  the  vessels  into  the  canals 
in  the  lamina  spiralis  (fig.  247,  '*).  As  they  enter  the  lamina  they  form 
a  plexus  with  ganglion  cells,  and  are  continued  onwards  near  the  scala 
tympani,  being  still  plexiform,  as  far  as  the  edge  of  the  bone.  At  this 
spot  they  leave  the  bone,  and  are  arranged  in  conical  bundles,  which  pass 
through  apertures  at  the  junction  of  the  bone  with  the  lamina  basilaris  of 
the  septum  cochleae  :  consisting  now  of  axis  cylinders  they  are  directed 
towards  the  cells  of  the  organ  of  Corti,  but  their  ending  is  unknown. 

The  vestibular  branch  ends  in  three  nerves  for  the  membranous  laby- 
rinth ;  these  pierce  the  cribriform  plate  in  the  bottom  of  the  meatus,  and 
are  thus  distributed: — One  appertains  to  the  utricle, (<?),  and  to  the  en- 
largements on  the  tubes  contained  in  the  superior  vertical  and  horizontal 
semicircular  canals  (fig.  249)  ;  a  second  ends  in  the  saccule  (c/)  ;  and  the  third 


688 


DISSECTION    OF    THE    EAR. 


belongs  to  the  ampullary  swelling  (b)  on  the  tube  in  the  posterior  vertical 
semicircular  canal. 

On  the  sacs  the  nerve  divides,  and  its  filaments  separate,  some  fibrils 
passing  through  the  otolith  and  others  outside  it,  and  pierce  the  middle 
layer  of  the  wall.     Now  becoming  axis  cylinders  they  divide,  and  unite 

Fig.  249. 


DisTEiBiTTioif  OF  Nertes  TO  THE  Mkmbranous  LABYRINTH  (Breschet). 
a.  Nerve  to  the  saccule.  c.  Branch  of  nerve  entering  the  large  sac  or 

6.  Nerve  entering  the  ampullary  enlargement  utricle, 

on  a  semicircular  tube. 

in  a  plexus  beneath  the  epithelium,  and  are  thought  to  be  united  with  the 
deep  ends  of  the  spindle-shaped  cells  with  hair-like  processes. 

On  the  ampullar^  enlargement  of  the  semicircular  tubes  the  nerve 
enters  the  external  side,  where  it  forms  a  forked  eminence  (Steifensand), 
corresponding  with  the  projection  in  the  interior.  The  nerve  divides  at 
first  into  two  chief  pieces,  which  are  directed  to  the  sides;  and  it  is  doubtful 
whether  filaments  extend  into  the  tube  beyond  those  eminences.  Finally 
it  pierces  the  wall  of  the  tube,  and  forming  a  sub-epithelial  plexus  of 
nerve-fibres,  as  in  the  utricle,  is  supposed  to  be  connected  with  similar 
auditorial  cells. 


INDEX, 


The  letter  (o)  refers  to  the  origin,  (c)  to  the  course,  and  (d)  to  the  distribution 
of  a  nerve  or  vessel  which  is  described  in  different  pages. 


ABDOMEN,  430 
surface  of,  404 
Abdominal  aorta,  444,  489 
cavity,  430 
hernia,  420 
regions,  431 
ring,  external,  410 
internal,  417,  422 
Abducens  nerve,  (o)  180,  (d)  57,  (c)  32 
Abductor  minimi  digiti,  278 
pedis,  616 
pollicis  manus,  277 
pedis,  616 
Accessorius  muscle,  620 

ad  sacro-lumbalem,  362 
Accessory  nerve  of  the  obturator,  (o)  495, 
(d)  577 
pudic  artery,  399,  516 
spleens,  465 
Acini  of  the  liver,  structure,  469 
Acromial  artery,  inferior,  234 
cutaneous  nerves,  242 
thoracic  artery,  233 
Acromio-clavicular  articulation,  246 
Adductor  brevis,  577 
longus,  576 
magnus,  579,  599 
minimi  digiti,  278 
oculi,  57 

pollicis  manus,  278 
pedis,  621 
Air-cells  of  the  lung,  335 
Alar  ligaments  of  the  knee,  637 
Alveolar  plexus,  142 
Ampullfe,  membranous,  685 

of  the  semicircular  canals,  680 
Amygdaloid  lobe  of  cerebellum,  213 
Anastomotic  artery  of  brachial,  254 

femoral,  568 
Anconeus  muscle,  285 
Angular  artery,  40 

vein,  40 
Ankle-joint,  708 

Annular  ligament  of  ankle,  anterior,  628 
external,  628 
internal,  614 
of  wrist,  anterior,  282 
posterior,  282,  289 
protuberance,  188 
44 


Annulus  of  Vieussens,  316 
Anterior  elastic  layer  of  cornea,  658 

commissure,  207 

medullary  velum,  214 
Anti-helix,  46 
Anti-tragus,  46 

muscle,  46 
Anus,  386 
Aorta,  320  325 

abdominal,  441,  489 

thoracic,  3/6,  336 
Aortic  arch,  350 

opening,  487 

plexus,  443 

sinus,  327 
Aperture  of  the  aorta,  321 

of  the  cavse,  316 

of  Eustachian  tube.  127 

for  the  femoral  arterv,  579 

of  the  heart,  315,  320 
larynx,  128 
mouth,  128 
nares,  126 
oesophagus,  128 
pulmonary  artery,  318 
veins,  319 
thorax,  120 
Aponeurosis,  epicranial,  18 

of  external  oblique,  409 

over  femoral  artery,  568 

of  internal  oblique,  412 

lumbar,  357 

palmar,  274 

of  the  pharynx,  124 

plantar,  615 

of  the  soft  palate,  129 

temporal,  19 

of  the  transversalis  muscle,  414 

vertebral,  360 
Appendages  of  the  eye,  43 
Appendices  epiploicae,  434 
Appendix  auriculae,  315,  319 

caeci,  463 

vermiformis,  462 
Aqueduct  of  the  cochlea,  684 

of  Sylvius,  206 

of  the  vestibule,  680 
Aqueous  humor,    663 
Arachnoid  membrane  of  the  brain,  172 


690 


INDEX 


Arachnoid  membrane — 
of  the  cord,  375 
Arbor  vitae  cerebelli,  217 
Arch  of  aorta,  32l) 

crural  or  femoral,  559 
of  diaphragm,  486 
palmar,  deep,  280 

superficial,  273 
plantar,  623 
of  soft  palate,  128 
Arciform  fibres,  186 
Areola  of  the  mamma,  226 
Arm,  dissection  of,  248 

veins  of,  249 
Arter.  acromialis  inferior,  234 
anastomotica  brachialis,  254 

magna,  568 
angularis  faciei,  40 
aorta  abdominalis,  444,  489 

thoracica,  326,  336 
articulares  inferiores,  595 

superiores,  595 
articularis  azygos,  595 
articularis  posterior,  21,  86 
auditoria,  176,  687 
axillaris,  232 
basilaris,  175 
brachialis,  253 
brachio-cephalica,  327 
bronchiales,  336,  337 
buccalis,  94 
capsularis  inferior,  489 
media,  474,  489 
superior,  491 
carotis  communis  dextra,  81 
sinistra,  120,  328 
externa,  83 
interna,  33,  106,  176 
carpi  ulnaris  anterior,  269 
posterior,  269 
radialis  anterior,  266 
posterior,  289 
centralis  retinae,  56,  666 
cerebelli  inferior,  175 

inferior  anterior,  175 
superior,  175 
cerebri  anterior,  176 
media,  176 
posterior,  175 
cervicalis  ascendens,  78 

profunda,  78,  368 
choroidea  cerebri,  175,  176 
ciliares  anteriores,  56,  662 

posteriores,  56,  662 
circumflexa  anterior,  235,  244 
externa,  572 

ilii  interna,  420,  491,  590 
superficialis,  407,  554 
interna,  578,  590 
posterior,  235,  244 
coccygea,  588 
cochlearis,  687 
coeliaca,  446 
colica  dextra,  441 


Arter.  colica — 

media,  441 

sinistra,  442 
comes  nervi  ischiadic!,  588 

phrenici,  330 
communicans  cerebri  anterior,  176 
posterior,  176 

palmaris,  274 

plantaris,  623 
coronaria  dextra,  313 

labii  inferioris,  40 
superioris,  40 

sinistra,  314 

ventriculi,  447 
corporis  bulbosi,  399,  532 

cavernosi,  399,  534 
cremasterica,  418 
cryco-thyroidea,  85 
cystica,  448 
deferentialis,  515 
dentalis  anterior,  105 

inferior,  93,  97 

superior,  94,  105 
diaphragmatica,  490 
digitales  manus,  274 

pedis,  623 
dorsales  pollicis,  289 
dorsalis  carpi  radialis,  289 

carpi  ulnaris,  269 

indicis,  289 

linguae,  101 

pedis,  624,  631 

penis,  399,  408 

pollicis,  289 

scapulae,  235,  248 
epigastrica,  419,  491 

superficialis,  407,  554 
ethmoidals,  anterior,  57,  142 

posterior,  57,  142 
facialis,  40,  85 
femoralis,  564,  568 
frontalis,  20,  57 
gastricae,  447,  455 
gastro-epiploica  dextra,  447 

sinistra,  447 
glutea,  515,  586 
hemorrhoidalis  inferior,  390 

media,  515 

superior,  443,  516,  533 
helicinae,  531 
hepatiea,  447,  471 
hyoidea  lingual  is,  101 

thyroideae,  85 
hypogastrica,  513 
iliaca  communis,  490 

externa,  491 

interna,  513 
ileo-colica,  441 

lumbalis,  513 
incisoria,  90 
infra-orbitalis,  94,  104 

scapularis,  235,  241 
innominata,  327 
inten-ostales  anteriores,  239,  337 


INDEX 


691 


Lrter.  intercostales — 

rami  aiiteriores,  337,  419 
posteriores,  368,  379 
intercostalis  superior,  78,  337 
interossea,  269 

anterior,  271  * 

posterior,  288 
interossese  manus,  280,  289 

pedis,  632 
intestinales,  440 
intra-spinales,  385 
ischiadica,  516,  588 
labialis  inferior,  40 
lachrymalis,  45,  56 
laryngealis  inferior,  158 

superior,  85,  158 
lingualis,  85,  101 
lumbales,  498 

rami  anteriores,  498 
posteriores,  368 
magna  pollicis  manus,  280 

pedis,  624 
malleolares,  631 
mammaria,  externa,  234 

interna,  77,  239,  330,  419 
masseterica,  94 

maxillarus  interna,  89,  93,  142 
mediana,  271 
mediastinae,  239,  337 
miningea  media,  29,  93 

parva,  29,  93 
meningese  anteriores,  29 

posteriores,  30,  80,  174 
mesenterica  inferior,  441 

superior,  439 
metacarpa  radialis,  289 

ulnaris,  269 
matatarsea,  632 
muscnlo-phrenica,  239,  490 
mylo-hyoidea,  93 
nasalis,  57,  142 

lateralis,  40 

septi,  40 
nutritia  femoris,  578 

fibulse,  613 

humeri,  254 

tibic-e,  612 
obturatoria,  515,  580 
occipitalis,  21,  86,  368 
ODsophageales,  337,  447 
ophthalmica,  33,  56 
ovariana,  490,  516 
palatina  inferior,  86 

superior,  142 
palmaris  profunda,  274 
palpebrals  inferior,  45,  57 

superior,  45,  57 
pancreaticae,  447 
pancreatico-doudenalis,  440,  448 
perforantes  femorales,  578,  599 

mammarije  internse,  239 

manus,  280 

pedis,  623,  632 
pericardiacae,  337 


Arter. — 

perinjei  superficialis,  393 
peronea,  613 

anterior,  613 
petrosa,  29 

pharyngea  ascendens,  109 
phrenicse  inferiores,  490 

superiores,  330,  490 
plantaris  externa,  617,  623 

interna,  617 
poplitea,  594 
princeps  cervicalis,  360 

pollicis,  280 
profunda  cervicis,  71,  368 

femoris,  565,  578 

inferior,  254 

superior,  254,  258 
pterygoideae,  94 
pterygo-palatina,  142 
pudenda  externa,  554,  565 

interna,  390,  398,  408,  516 
pulmonalis,  318,  325,  335 

dextra,  325 

sinistra,  325 
pylorica  inferior,  448 

superior,  447 
radialis,  265,  280,  289 

indicis,  280 
ranina,  101 
receptaculi,  33 
recurrens  interossea  posterior,  288 

radialis,  262 

tibialis,  631 

ulnaris  anterior,  268 
posterior,  269 
renales,  476,  489 
sacro-media,  489,  517 
sacro-lateralis,  515 
scapularis  posterior,  78,  248,  359 
sciatica,  516,  588 
sigmoidea,  442 
spermatica,  484,  489 
spheno-palatina    142 
spinales  posteriores,  174,  380 
spinalis  anterior,  174,  379 
splenica,  447,  466 
sterno-mastoidea,  85 
stylo-mastoidea,  86 
subclavia  dextra,  75 

sinistra,  118,  328 
sublingualis,  101 
submentalis,  86 
subscapularis,  235 
superficialis  cervicalis,  359 

perinaei,  393 

volae,  266 
supra-orbitalis,  21,  56 

scapularis,  78,  247,  359 

spinalis,  248 

tarsea,  631 
temporales  profundae,  94 
temporalis,  86 

anterior,  21 

media,  87 


692 


INDEX 


Arter.  temporalis — 

posterior,  21 

superficialis,  20,  83 
thoracica  acroniialis,  234 

alaris,  234 

longa,  234 

suprema,  234 
thyroidea  ima,  121 

inferior,  78,  121 

superior,  85,  121 
tibialis  antica,  630 

postica,  612 
tonsillaris,  86 
transversalis  colli,  78,  363 

faciei,  41,  87 

perinaei,  393 

pontis,  175 

pubis,  419 
tjmpanica,  93 

inferior,  677 

superior,  677 
ulnaris,  267 
nrabilicalis,  513 
nterina,  516 
vaginalis,  516 
vertebralis,  77,  165,  174 
vesicalis  inferior,  515,  526 

superior,  515 
vestibuli,  687 
vidiana,  142 
Articular  popliteal  arteries,  595 

nerves,  596 
Articulation,  acromio-clavicular,  246 
astragalo-scaphoid,  645 
astragalus  to  os  calcis,  644 
atlo-axoidean,  165,  170 
of  bones  of  the  tympanum,  675 
calcaneo-cuboid,  646 

scaphoid,  645 
of  carpal  bones,  298 
carpo-metacarpal,  300 
of  cervical  vertebrse,  166 
chondro-costal,  346 

sternal,  345 
of  coccygeal  bones,  544 
coraco-clavicular,  246 
of  costal  cartilages,  346 
costo-clavicular,  171 

vertebral,  346 
crico-arytsenoid,  162 

thyroid,  161 
of  cuneiform  bones,  648 
cuneiform  to  cuboid,  648 

to  scaphoid,  648 
of  dorsal  vertebrse,  346 
femoro-tibial  or  knee,  634 
humero-cubital  or  elbow,  293 
ilio-femoral  or  hip,  600 
of  lower  jaw,  90 
of  lumbar  vertebrae,  346 
•of  the  metacarpal  bones,  299 
metacarpo-phalangeal,  301 
metatarsal,  649 
metatarso-phalangeal,  651 


Articulation — 

occipito-atloidean,  168 

axoidean,  168 
OS  calcis  to  cuboid,  646 

to  scaphoid,  645 
peroneo-tibial,  641 
phalangeal  of  fingers,  302 

of  toes,  651 
of  pubic  symphysis,  546 
radio-carpal  or  wrist,  296 
cubital  inferior,  297 
superior,  294 
sacro-coccygeal,  544 
iliac,  544 
vertebral,  544 
scaphoid  to  cuboid,  648 

to  cuneiform,  648 
scapulo-humeral,  290 
sterno-clavicular,  170 
sternum,  pieces  of,  346 
tarsal  transverse,  647 
tarso-metatarsal,  649 
temporo-maxillary,  90 
thyro-arytsenoid,  162 
of  the  thumb,  300 
tibio-tarsal  or  ankle,  642 
of  vertebrse,  346 
Arcus  externus  diaphragmatis,  487 

internus  diaphragmatis,  487 
Arytseno-epiglottidean  folds,  157 
Arytsenoid  cartilages,  160 
glands,  131 
muscle,  153 
Ascending  cervical  artery,  78 
vein,  77 
colon,  433 
pharyngeal  artery,  109 
vein,  110 
Attollens  aurem,  18 
Attrahens  aurem,  18 
Auditory  artery,  175,  687 
tube,  external,  670 
nerve  (o)  191,  (d)  687 
nucleus,  188 
Auricle  of  the  ear,  45 
Auricles  of  the  heart,  313 
left,  319 
right,  315 
structure  of,  322 
Auricular,  315,  319 

Auricular  artery,  posterior,  (d)  21,  (o)  86 
nerves,  anterior,  23 
great,  23,  GQ 
inferior,  96 
posterior,  23,  48 
vein,  21,  86 

nerve  of  vagus,  (o)  113,  (d)  679 
Auriculo-temporal  nerve.  23,  96 
ventricular  aperture,  left,  320 
right,  318 
rings,  321 
Auricularis  magnus  nerve,  23,  66 
Axilla,  228 

dissection  of,  228 


INDEX 


093 


Axillary  artery,  232 

glands,  230 

plexus,  235 

vein,  235 
Axis,  coGliac,  of  artery,  446,  485 

of  cochlea,  681 

thyroid,  of  artery,  78 
Azygos,  artery,  595 

veins,  (o)  498,  (d)  338,  495 

uvulae  muscle,  131 


BACK,  dissection  of,  353 
Base  of  brain,  190 
Base  of  the  skull,  arteries  of,  29,  33 
dissection  of,  26 
nerves  of,  30,  33 
Basilar  artery,  175 

membrane,  683 

sinus,  29 
Basilic  vein,  249 
Biceps  femoris  muscle,  597,  635 

flexor  cubiti,  252,  271,  291 
Bicuspid  teeth,  133 
Bile  ducts,  450,  457.  472 

structure,  461,  472 
Bi ventral  lobe,  213 
Bladder,  512,  524 

interior  of,  525 

connections  of,  506,  512 

ligaments  of,  503,  504 

structure  of,  524 
Bones  of  the  ear,  674 

ligaments  of,  675 

muscles  of,  676 
Brachial  ai)oneurosis,  251 

artery,  253 

plexus,  79,  235 

veins,  255 
Brachialis  anticus,  256,  271 
Brachio-cephalic  artery,  327 

vein,  left,  329 

right,  328 

Brain,  base  of,  190 

examination  of  interior,  199 

membranes  of,  24,  26,  172 

origin  of  nerves,  177 

preservation  of,  26 

removal  of,  25 

vessels  of,  173 
Breast,  226 

Broad  uterine  ligament,  510 
Bronchial  arteries,  (d)  336,  (o)  337 

glands,  340 

veins,  336,  337 
Bronchus,  left,  333 

right,  333 

structure  of,  333 
Brunner's  glands,  460 
Buttock,  dissection  of,  581 

muscles,  583 

vessels  and  nerves,  586,  588 
Buccal  artery,  94 

nerve,  95 


Buccinator  muscle,  39 
Bulb  of  the  urethra,  509 

artery  of,  399,  (d)  532 

nerve  of,  399 
Bulbi  vestibuli,  536 
Bulbous  part  of  the  urethra,  509,  527 
Bulbus  olfactorius,  179 


C TECUM  coli,  462 
connections  of,  433 
structure  of,  463 
Calamus  scriptorius,  217 
Calices  of  the  kidney,  477 
Calciform  papillae,  148 
Canal  of  cochlea,  684 
of  Petit,  668 
of  spinal  cord,  382 
of  the  tensor  tympani,  673 
Canine  teeth,  133 
Capsular  arteries,  inferior,  489 
middle,  479,  489 
superior,  490 
ligament  of  the  hip,  600 
knee,  634 
shoulder,  290 
thumb,  300 
Capsule  of  crystalline  lens,  668 
of  Glisson,  469 
suprarenal,  478 
Caput  coli,  462 

gallinaginis,  526 
Cardiac  nerve,  inferior,  (o)  117,  (d)  332 
middle,  (o)  117,  (d)  332 
of  pneumogastric,  (o)  114,  331, 

(d)  332 
superior,  (o)  117,  (d)  314,  333 
plexus,  314,  332 
veins,  314 
Carnse  columnae,  317,  320 
Carotid  artery,  external,  83 

internal,  (d)  33,  176,  (c)  106 
left  common,  120,  328 
right  common,  81 
plexus,  33 
Carpal  artery,  radial  anterior,  266 
posterior,  290 
ulnar  anterior,  268 
posterior,  269 
Carpo-metacarpal  articulations,  300 
Cartilage,  arytaenoid,  160 
cricoid,  159 
cuneiform,  160 
of  the  ear,  46 
thyroid,  159 

triangular  of  the  nose,  134 
Cartilages  of  the  eyelids,  44 
of  the  nose,  42 
of  Santoriui,  160 
of  trachea,  167 
Caruncula  lachrymalis,  45 
Carunculae  myrtiformes,  535 
Cauda  equina,  379 
Cava,  inferior,  317,  444,  492 


694 


INDEX. 


Cava — 

superior,  316 
Cavernous  body,  508,  530 

artery  of,  (o)  399,  (d)  530 
plexus,  33 
sinus,  28 
structure,  530 
Cavity  of  the  omentum,  437 
Central  artery  of  the  retina,  (o)  56,  (d) 
666 
ligament  of  cord,  376 
lobe  of  brain,  194 
pillar  of  cochlea,  681 
point  of  the  perineum,  394 
Central  ovale  cerebri,  199 
Cephalic  vein,  250 
Cerebellar  arteries,  inferior,  175 

superior,  175 
Cerebellum,  form  of,  211 
lobes  of,  213 
structure  of,  214 
Cerebral  artery,  anterior,  176 
middle,  176 
posterior,  175 
Cerebrum,  division  into  lobes,  193 
convolutions,  195 
form  of,  189 
interior,  199 
structure,  209 
Cervical  fascia,  63,  68 

ganglion,  inferior,  117 
middle,  117 
superior,  116 
glands,  81 
nerves,  anterior  branches,  79,  165 

posterior,  165 
plexus  of  nerves,  80 
deep  branches,  80 
superficial,  QQ,  68,  80 
Cervicalis  ascendens  artery,  78 
muscle,  363 
veins,  79 
profunda  artery,  (o)  78,  (d)  368 

veins,  77,  368 
superficialis  nerve,  6Q,  68 
Cervico-facial  nerve,  50 
Cervix  uteri,  537 

vesicae,  506 
Chamber  of  the  eye,  anterior,  663 

posterior,   663 
Check  ligaments,  168 
Cheeks,  132 

Chiasma  of  the  optic  nerves,  179 
Chondro-costal  articulations,  346 
glossus  muscle,  149 
sternal  articulations,  345 
Chorda  tympani  nerve,  (o)  144,  (d)  97, 

102 
Chords  tendineae,  318,  320 
vocales,  156 
Willisii,  32 
Choroid  artery  of  the  brain,  175 
coat  of  the  eye,  658 
plexuses  of  the  brain,  205,  218 


Choroid — 

veins  of  the  eye,  663 
brain,  206 
Cilia,  44 
Ciliary  arteries,  (o)  56,  (d)  662 

ligament,  661 

muscle,  660 

processes  of  the  choroid,  659 

of  the  suspensory  ligament,  668 

nerves  of  nasal,  (o)  54,  (d)  663 
of  lenticular  ganglion,  55,  663 
Circle  of  Willis,  176 
Circular  sinus,  29, 

Circumflex  artery,  anterior,  235,  ^44 
external,  572 
internal,  578,  590 
posterior,  235,  244 

iliac  artery,  deep,  420,  491 
superficial,  554,  565 

nerve,  (o)  236,  (d)  244 
Clavicular  cutaneous  nerves,  66,  80 
Clitoris,  534 
Coccygeal  artery,  588 

muscle,  501 

nerve,  519 
Cochlea,  681 

canal  of,  684 

nerve  of,  687 

vessels  of,  687 
Coeliac  artery,  446 

plexus,  451 
Colic  artery,  left,  442 

middle,  441 

right,  441 
Colon,  433,  461 

course  of,  433 

structure  of,  463 
Columnar  layer  of  retina,  664 
Columnse  carneae,  317,  320 
Columns  of  the  cord,  382 

vagina,  536 
Comes  nervi  ischiatici  artery,  588 

phrenici  artery,  330 
Commissure,  anterior,  207 

of  the  cerebellum,  213,  215 

of  the  cord,  382 

great,  200 

of  the  optic  nerves,  179 

posterior,  216 

soft,  206 
Commissural  fibres  of  the  medulla,  186 
Communicating  artery  of  anterior  cere- 
bral, 176 
of  posterior  cerebral,  176 
in  the  palm,  273 

peroneal  nerve,  606 
Complexus  muscle,  364 
Compressor  of  the  bulb,  395 

of  the  nose,  35 
Coniarum,  208 
Concha,  45 

Cones  of  the  retina,  664 
Congenital  hernia,  424 
Coni  vasoulosi,  482 


INDEX 


695 


Conical  papillae,  146 
Conjoined  tendon,  414 
Conjunctiva,  45 
Conoid  ligament,  246 
Constrictor  inferior,  124 

of  the  fauces,  130 

middle,  124 

superior,  124 
.    urethrje,  397,  403 
Conus  arteriosus,  317 
Convolutions  of  the  brain,  195,  198 

of  hemisphere,  195 

of  longitudinal  fissure,  197 
Coraco-brachialis  muscle,  252 

clavicular  articulation,  246 

humeral  ligament,  291 
Cordiform  tendon,  480 
Cords  of  the  abdominal  wall,  427 
Cornea,  657 

structure,  657 
Cornicula  laryngis,  160 
Cornua  of  gray  crescent,  382 

of  lateral  ventricle,  200 
Corona  glandis,  509 

radiata,  209 
Coronary  vessels  of  the  heart,  313 
of  the  lips,  40 

artery  of  the  stomach,  447 

ligament  of  the  liver,  438 

plexus  of  the  stomach,  451 

plexuses  of  the  heart,  314 

sinus,  314,  329 

vein  of  the  stomach,  448 
Corpora  albicantia,  192 

Arantii,  318,  321 

cavernosa,  508,  530 

geniculata,  207,  211 

Malpighiana,  466,  474 

mamillaria,  192 

olivaria,  183,  185 

pyramidalia  anteriora,  183,  185 
posteriora,  183,  184 

quadrigemina,  208 
Corpora  restiformia,  183,  184 
Corpus  callosum,  192,  199 

dentatum  cerebelli,  215 
medullae,  188 

fimbriatum  uteri,  541 

geniculatum  externum,  207 
internum,  207 

Highmori,  481 

luteum,  540 

olivare,  183,  184,  208 

spongiosum  urethrae,  509,  531 

striatum,  203,  211 

thyroideum,  120 
Corpuscles  of  Malpighi,  466,  475 
Corrugator  cutis  ani,  389 

supercilli  muscle,  37 
Cortex  of  the  tongue,  149 
Cortical  substance  of  the  kidney,  474 
Costo-clavicular  ligament,  171 

coracoid  membrane,  232 

transverse  li^raments,  345 


Cotunnius,  nerve  of,  140 
Cotyloid  ligament,  602 
Covered  band  of  Reil,  199 
Cowper's  glands,  398 
Cranial  aponeurosis,  18 

nerves,  30,  (o)  137 
Cremaster  muscle,  412 
Cremasteric  artery,  418,  420 

fascia,  413 
Cribriform  fascia,  555 
Crico-arytsenoid  articulation,  162 

muscle,  lateral,  153 
posterior,  152 

thyroid  articulation,  161 
membrane,  161 
muscle,  152 
Cricoid  cartilage,  159 
Crista  vestibuli,  680 
Crucial  ligaments,  637 
Crura  cerebelli,  215 

cerebri,  190,  211 

of  the  diaphragm,  486 

of  the  fornix,  203 
Crural  arch,  559 

deep,  419,  560 

canal,  560 

hernia,  429,  562 

nerve,  (o)  497,  (d)  572 

ring,  428,  561 

sheath,  428,  560 
Crypts  of  Lieberkiihn,  459 
Crystalline  capsule,  668 

lens,  668 

structure,  669 
Cuneiform  cartilages,  160 
Cupola  cochleae,  681 
Curve  of  the  urethra,  508 
Cutaneous  nerves  of  the  abdomen,  406 

of  the  arm,  249 

of  the  back,  354 

of  the  buttock,  581 

of  the  face,  48 

of  the  foot,  back,  626 
sole,  624 

of  the  forearm,  261 

of  the  hand,  back,  261 
palm,  272 

of  the  head,  21 

of  the  leg,  back,  606 
front,  626 

of  the  neck,  behind,  354 
fore  part,  68 

of  the  perin.-eum,  391,  393 

of  the  shoulder,  242 

of  the  thigh,  front,  556 

of  the  thorax,  225 
Cystic  arterv,  448 

duct,  473 

plexus  of  nerves,  452 


D 


ARTOID  tissue,  408 

Decussation  of  the  oblong  medulla, 
186 


696 


INDEX 


Deep  cervical  artery,  (o)  78,  (d)  368 
crural  arch,  449,  560 
transverse  muscle  of  perinseum,  395, 
400 
Deferential  artery,  523 
Deltoid  ligament,  643 

muscle,  242 
Dens  sapientisB,  133 
Dental  artery,  anterior,  105 
inferior,  93,  97 
superior,  94,  105 
nerve,  anterior,  105 
inferior,  96 
posterior,  104 
Dentate,  lamina,  204 

ligament,  376 
Denticulate  lamina,  683 
Depressor  anguli  oris,  39 
epiglottidis,  154 
labii  inferioris,  38 
alae  nasi,  36 
Descendens  noni  nerve,  83,  115 
Descending  colon,  434 
Diaphragm,  305,  484 
arteries  of,  490 
plexus  of,  451 
Digastric  muscle,  82 

nerve,  48 
Digital  arteries  of  plantar,  624 
of  radial,  280 
of  tibial,  anterior,  624 
of  ulnar,  274 
nerves  of  median,  275 
of  plantar,  617 
of  radial,  262 
of  ulnar,  274 
Dilator  of  the  nose,  35 

of  the  pupil,  661 
Discus  proligerus,  540 
Dissection  of  the  abdomen,  404 
of  the  abdominal  cavity,  430 
of  the  anterior  commissure,  207 
of  the  arm,  225,  248 
of  the  axilla,  227 
of  the  back,  253 
of  the  base  of  the  skull,  26 
of    the     brain,     membranes,     and 

nerves,  172 
of  the  buttock,  581 
of  the  cardiac  plexus,  331 
of  the  carotid  artery,  internal,  106 
of  the  carotid  plexus,  33 
of  the  cerebellum,  211 
of  tlie  cerebrum,  189 
of  the  corpus  callosum,  192,  199 
of  the  corpus  striatum,  203,  211 
of  the  cms  cerebri,  191 
of  the  external  ear,  45,  670 
of  the  internal  ear,  671 
of  the  eighth  nerve,  110 
of  the  eye,  655 

lids,  43 
of  the  face,  34 
of  fascia  lumborum,  357 


Dissection — 

of  femoral  hernia,  427,  559 

of  the  fifth  ventricle  of  the  brain, 

202 
of  the  foot,  back,  626 

sole,  614 
of  the  forearm,  260 
back,  282 
front,  260 
of  the  fourth  ventricle,  215 
of  the  glosso-pharyngeal  nerve,  110 
of  the  hand,  back,  261 

palm,  272 
of  the  head,  external  parts,  17 

internal  parts,  24 
of  the  heart,  311 
of  the  hypogastric  plexus,  444 
of  the  inferior  maxillary  nerve,  94 
of  inguinal  hernia,  420 
of  the  internal  maxillary  artery,  93 
of  Jacobson's  nerve,  112,  677 
of  the  labyrinth,  679 
of  the  larynx,  151 
cartilages,  158 
muscles,  151 
nerves,  157 
of  the  lateral  ventricles,  200 
of  the  left  side  of  the  neck,  118 
of  the  leg,  back,  605 

front,  626 
of  the  ligaments  of  atlas  and  axis,  167 
atlas  and  occiput,  168 
axis  and  occiput,  168 
clavicle  and  scapula,  246 
hip  joint,  600 
jaw,  91 

lower  limb,  634 
pelvis,  543 
ribs,  344 
shoulder,  290 
upper  limb,  290 
the  vertebrae,  347 
of  the  lower  limb,  634 
of  Meckel's  ganglion,  138 
of  tlie  medulla  oblongata,  182 
of  the  neck,  61 

anterior  triangle,  69 
left  side,  118 
posterior  triangle,  63 
of  the  ninth  nerve,  115 
of  the  nose,  1 33 
of  the  ophthalmic  of  the  fifth  nerve, 

31,  51 
of  the  orbit,  50 
of  the  otic  ganglion,  144 
of  the  pelvis,  female,  509 
side  view,  511 
male,  499 

side  view,  500 
of  the  perinseum,  female,  401 

male,  386 
of  the  pharynx,  122 
of  the  pneumo-gastric  nerve,  110, 
330,  453 


INDEX. 


697 


Dissection — 

of  the  pons,  188 

of  tlie  popliteal  space,  593 

of  the  portio  dura  nerve,  47,  143 

of  the  prevertebral  muscles,  163 

of  the  pterygoid  region,  88 

of  the  sacral  plexus,  518 

of  the  saphenous  opening,  559 

of  tlie  semilunar  ganglia,  451 

of  the  shoulder,  241 

of  the  soft  palate,  128 

of  the  solar  plexus,  451 

of  the  spinal  cord,  374 

accessory  nerve,  110 
of  the  subclavian  artery,  73 
of  the  submaxillary  region,  97 
of   the   superior   maxillary   nerve, 

103 
of  the  testis,  479 
of  the  thigh,  back,  592,  597 

front,  552 
of  the  third  ventricle,  206 
of  the  thorax,  305 
of  the  tongue,  146 
of  the  triangular  space  of  the  thigh, 

560 
of  the  tympanum,  671 

vessels  and  nerves,  677 
of  the  upper  limb,  224 
of    the    vena    cava    inferior,    444, 

492 
of  the  vidian  nerve,  141 
Dorsal  artery  of  the  foot,  624,  631 
of  the  penis,  399,  (d)  408 
of  the  tongue,  101 
of  the  scapula,    (o)   235,    (d), 
248 
nerves,  anterior  branches,  239,  343, 
378 
posterior  branches,  367,  378 
cutaneous  of  the  hand,  262 
of    the    penis,     (o)     399,     (d) 
408 
Ductus  ad  nasum,  61 
arteriosus,  325 
communis    choledochus,    450,   457, 

461 
cysticus,  473 
ejaculatorius,  523 
hepaticus,  450,  472 
lymphaticus,  79,  340 
pancreaticus,  465 
reuniens,  686 
Ductus  Riviniani,  103 
Stenonis,  41 

thoracicus,  118,  339,  494 
venosus,  469 
Whartonii,  98,  103 
Duodenum,  connections,  445 

peritoneum  of,  438 
Dura  mater,  24,  26 
of  the  cord,  374 
nerves  of,  30,  377 
vessels  of,  29,  377 


EAR,  external,  45,  670  • 
internal,  671 
Eighth  nerve,  32,  (o)  181 
Ejaculator  urinae,  394 
Elastic  layers  of  cornea,  658 
Elbow  joint,  293 
Eminentia  collateralis,  202 

teres,  217 
Encephalon,  173 
Endocardium,  324 
Endolymph,  686 
Ependyma  ventriculorum,  200 
Epididymis,  483 
Epigastric  artery,  419,  491 

superficial,  407,  565 
region  of  the  abdomen,  431 
veins,  429 
Epiglottidean  glands,  157 
Epiglottis,  160 
Erector  clitoridis,  408 
penis,  394 
spinse,  362 
Ethmoidal  arteries,  56 
Eustachian    tube,    cartilaginous    part, 
126 
osseous  part,  674 
valve,  317 
Extensor  carpi  radialis  brevis,  284 
longus,  284 
carpi  ulnaris,  285 
digiti  minimi,  285 
digitorum  brevis,  632 
communis,  285 
longus  pedis,  629 
indicis,  288 
ossis  metacarpi,  287 
proprius  pollicis,  629 
primi  internodii  policis,  287 
secundi  internodii  policis,  287 
External  cutaneous  nerves  of  arm,  250, 
262 
of  thigh,  (o)  497,  (d)  556 
saphenous  nerve,  596,  606,  627 
vein,  606,  626 
Eyeball,  665 
brows,  43 
lashes,  43 
lids,  43 

muscles  of,  44 
nerves  of,  45 
structure,  43 
vessels,  45 


FACE,  dissection  of,  34 
Facial  artery,  (d)  40,  (o)  85 
nerve,  (d)  46,  (c)  645,  (o)  180 
Falciform  ligament  of  the  liver,  439 

border  of  saphenous  opening,  559 
Fallopian  tube,  511,  540 
Falx  cerebelli,  27 

cerebri,  25 
Fascia,  axillary,  225 
brachial,  250 


698 


INDEX. 


Fascia — 

cervical  deep,  63,  68 

costo-coracoid,  232 

cremasteric,  412 

cribriform,  555 

of  the  forearm,  262 

iliac,  428,  494 

intermuscular  of  the  humerus,  258 
of  the  thigh,  572 

lata,  557,  593 

of  the  leg,  606,  627 

lumborum,  357 

obturator,  500 

palmar,  272 

pelvic,  500 

perinaeal,  deep,  396 
superficial,  393 

plantar,  deep,  615 

propria,  562 

recto-vesical,  502 

spermatic,  423 

temporal,  19 

transversalis,  417,  428 
Fasciculus  teres,  277 
Femoral  arterv,  554,  568 

hernia,  427,  562 

ligament,  559 

vein,  565,  568 
Femoro-tibial  articulation,  634 
Fenestra  ovalis,  672 

rotunda,  672 
Fibres  of  the  cerebrum,  209 

of  the  cerebellum,  215 

of  Muller,  665 
Fibro-cartilage.     See  Interarticular. 
of  heart,  322 
of  tongue,  148 
Fibrous  coat  of  eye,  655 
Fifth  nerve,  31,  180 

ventricle  of  brain,  202 
Filiform  papillse,  146 
Fillet  of  the  corpus  callosum,  200 

of  the  olivary  body,  186,  188,  208 
Filum  terminale,  372 
Fimbriae  of  the  Fallopian  tube,  541 
First  nerve,  (o)  134,  (c)  30,  (d)  137 
Fissure,  longitudinal,  193 

parieto-occipital,  193,  198 

of  Rolando,  193 

of  Sylvius,  193 

transverse  of  brain,  204 
Fissures  of  Santorini,  47 

of  the  cord,  381 

of  the  cerebrum,  193 
Flexor  accessorius  muscle,  620 

brevis  minimi  digiti,  278 
pedis,  623 

carpi  radialis,  264,  282 
ulnaris,  265 

digitorum  brevis  pedis,  616 
longus  pedis,  610,  620 
profundus,  270,  276 
sublimis,  266,  276 

pollicis  longus,  270,  277 


Flexor  pollicis  longus — 

pedis,  610,  620 
brevis,  278 
pedis,  621 
Flocculus  cerebelli,  214 
Follicles,  Meibomian,  44 

ceruminous,  740 

solitary,  459,  464 
Foot,  dorsum,  626 

sole,  614 
Foramen  of  Monro,  203 

ovale,  317 

for  vena  cava,  487 

of  Winslow,  437 
Foramina  Thebesii,  316 
Forearm,  dissection  of,  260 

cutaneous  nerves,  261 
veins,  262 
Fornix,  202 
Fossa,  ischio-rectal,  387 

navicular  of  the  urethra,  528 

of  the  pudendum,  534 

ovalis,  316 
Fossae  of  abdominal  wall,  427 
Fourth  nerve,  (o)  180,  (c)  31,  (d)  51 

ventricle,  217 
Fovea  centralis,  664 

hemispherica,  680 

semi-elliptica,  680 
Fovese  of  fourth  ventricle,  217 
Fraenulum  labii,  534 
Fraenum  linguae,  146 

prseputii,  509 
Frontal  artery,  21,  57 

nerve,  51 

lobe,  193 

vein,  21 
Fungiform  papillae,  146 
Funiculus  gracilis,  184 

lateralis,  183 


GALACTOPHORUS  ducts,  221 
Galen,  veins  of,  206 
Gall  bladder,  472 

structure,  472 
Ganglia,  cervical,  inferior,  117,  122 
middle,  117,  122 
superior,  116,  122 
lumbar,  497 
sacral,  519 
semilunar,  451 
of  spinal  nerves,  378 
thoracic,  339 
Ganglion  of  the  vagus,  112 
Gasserian,  31 
impar,  519 
jugular,  111 
lenticular,  55 
Meckel's,  139 
ophthalmic,  55 
otic,  144 
petrosal,  111 
spheno-palatine,  139 


INDEX 


699 


Ganglion — 

submaxillary,  101 

thyroid,  117 
Gastric  arteries,  447 

vein,  449 
Gastro-colic  omentum,  437 
Gastro-epiploic  arteries,  447,  448 
vein,  449 

hepatic  omentum,  437 
Gastrocnemius  muscle,  608 
Gemellus  inferior  muscle,  589 

superior  muscle,  589 
Geniculate  bodies,  207,  211 
Genio-hyo-glossus,  101,  149 

hyoid  muscle,  100 
Genital  organs,  507,  533 
Genito-crural  nerve,  (o)  497,  (d)  413,  556 
Gimbernat's  ligament,  411,  560 
Gland,  lachrymal,  51 

parotid,  48 

prostate,  507,  521 

sublingual,  103 

submaxillary,  97 
Glands,  arytsenoid,  131 

axillary,  230 

Bartlioline's,  537 

bronchial,  340 

Brunner's,  460 

cardiac,  339 

ceruminous,  671 

cervical,  66,  61 

concatenate,  67 

Cowper's,  398,  508 

Haver's,  603 

inguinal,  407,  554 

intercostal,  340 

intestinal,  443 

labial,  133 

laryngeal,  157 

lingiial,  150 

lumbar,  495 

mammary,  226 

mediastinal,  339 

Meibomian,  44 

mesenteric,  441 

molar,  42 

oesophageal,  339 

of  Pacchloni,  24 

pelvis,  522 

Peyer's,  459 

popliteal,  597 

solitary,  459,  464 

sternal,  339 

tracheal,  339 
Glans  of  the  clitoris,  534 

of  the  penis,  509 
Glaserian-fissure,  672 
Glenoid  ligament,  209 
Glisson's  capsule,  469 
Globus  major  epididymis,  483 

minor  epididymis,  483 
Glomerulus,  475 

Glosso-pharyngeal  nerve,   (o)   111,    (d) 
151,  181 


Glosso-pharyngeal — 
nucleus,  188 
Glottis,  155 

Gluteal  artery,  (o)  515,  (d)  586 
nerve,  superior,  496,  586 
nerves,  inferior,  588 
Gluteus  maximus  muscle,  583 
medius  muscle,  585 
minimus  muscle,  586 
Graafian  vesicles,  540 
Gracilis  muscle,  574 
Granular  layer  of  retina,  666 
Gray  commissure  of  the  cord,  382 
crescent  of  the  cord,  382 
substance  of  the   corpus  striatum, 
203 
of  the  medulla  oblongata,  186, 

217 
of  the  third  ventricle,  206 
tubercle  of  Rolando,  187 
Great  omentum,  437 
Gustatory  nerve,  97,  (d)  101,  151 
Gyrus  fornicatus,  197 


H HEMORRHOIDAL  artery,  inferior,  390 
middle,  515 
superior,  (o)  443,  516,  (d)  533 

nerve,  inferior,  443 

plexus,  520 

veins,  517 
Ham,  592 

Hamulus  laminse  spiralis,  682 
Hand,  dissection  of,  272 
Head,  dissection  of,  17 
Heart,  312 

constituents,  312 

dissection  of,  315 

position,  312 

structure  of,  312 
Helicine  arteries,  531 
Helicis  major  muscle,  46 

minor  muscle,  46 
Helicotrema,  682 
Helix,  46 
Hepatic  artery,  447,  (d)  471 

cells,  459 

ducts,  450,  (o)  472 

plexus,  451 

veins,  471,  492 
Hernia,  crural  or  femoral,  429,  562 

inguinal,  external,  421 
internal,  424 

umbilical,  426 
Hiatus  cochleje,  682 
Hip  joint,  600 
Hippocampus  major,  204 

minor,  204 
Hollow  before  elbow,  263 
Humero-cubital  articulation,  293 
Hunter's  canal,  568 
Hyaloid  membrane,  667 
Hymen,  535 
Ilyo-glossus  muscle,  99,  148 


700 


INDEX. 


Hyo-glossal  membrane,  148 

Hyoid  bone,  159 

Hypochondriac  region  of  abdomen,  431 

Hypogastric  artery,  513 
plexus  of  nerves,  444 
region  of  the  abdomen,  431 

Hypoglossal  nerve,  (o)  182,  (c)  115,  (d) 
83,  102 
nucleus,  187 


TLEO-CiECAL  valve,  462 
1      Ileo-colic  artery,  441 

valve,  462 
Ileum  intestine,  connections  of,  433 

structure  of,  456 
Iliac  artery,  common,  490 
external,  491 
internal,  513 
fascia,  495 

region  of  the  abdomen,  431 
vein,  common,  491 
external,  491 
internal,  513 
Iliacus  muscle,  493,  580 
Ilio-costalis,  362 

femoral  articulation,  600 
hypogastric  nerve,  (o)  416,  492,  582 
inguinal  nerve,  (o)  497,  (d)  416,  556 
lumbar  artery,  514 
Incisor  branch  of  nerve,  96 

teeth,  133 
Incus,  674 

Indicator  muscle,  288 
Infantile  hernia,  424 
Inferior  cornu  of  the  lateral   ventricle, 
200 
maxillary  nerve,  (o)  32,  (d)  94 
Infra-costal  muscles,  342 
orbital  artery,  94,  105 
nerves,  49,  104 
vein,  105 
scapular  artery,  235,  242 
trochlear  nerve,  54 
Infra-spinatus  muscle,  244 
Infundibulum  of  the  brain,  192 
Inguinal  canal,  421 
glands,  407,  554 
hernia,  external,  421 

internal,  424 
region  of  the  abdomen,  431 
Innominate  artery,  327 

veins,  328 
Inter-articular  cartilage  of  the  jaw,  91 
of  the  hip,  602 
of  the  knee,  638 
of  the  ribs,  344 
of  the  scapula,  246 
sacro-iliac,  544 
sterno-clavicular,  170 
of  the  symphysis  pul>is,  547 
of  the  vertebrae,  347 
of  tlio  wrist,  296 
Interclavicular  ligament,  170 


Jnteroolumnar  fascia,  410 

fibres,  410 
Intercostal  arteries,  anterior  branches, 
240,  337,  419 
posterior  branches,  368,  384 
artery,  superior,   (o)  78,  (d)  338 
muscle,  external,  237,  342 

internal,  238,  342  ' 
nerves,  237,  343,  416 

cutaneous,  anterior,  226 
lateral,  226 
veins,  superior,  338 
Intercosto-humeral  nerve,   (o)  226,  (d) 

256,  343 
Intermediate  tract,  383 
Intermuscular  septa  of  the  arm,  258 
of  the  foot,  615 
of  the  thigh,  572 
Internal  cutaneous   nerve  of  arm,  236, 
250,  256 
of  thigh,  (o)  573,  (d)  556 
saphenous  vein,  557,  626 
nerve,  596,  606,  627 
Interosseous  arteries  of  the  foot,  631 
of  the  hand,  280,  289 
artery,  anterior,  244,  271 

posterior,  288 
ligament  of  the  arm,  295 

of  the  leg,  642 
muscles  of  the  foot,  624 

of  the  hand,  281 
nerve,  anterior,  271 
posterior,  289 
Interspinal  muscles,  370 
Intertransverse  muscles,  165,  370 
Intervertebral  ganglia,  378 

substance,  347 
Intestinal  arteries,  440 
canal  divisions,  433 
structure,  456,  463 
Intestine,  large,  433,  461 

small,  433,  456 
Intra-spinal  arteries,  384 

veins,  385 
Iris,  661 

nerves  of,  662 

structure  of,  661 

vessels  of,  662 

Ischio-rectal  fossa,  388 

Island  of  Reil,  194 

Isthmus  faucium,  128 

of  the  thyroid  body,  120 
of  the  uterus,  538 
Iter  a  tertio  ad   quartum  ventriculum, 
206 
ad  infundibulum,  206 


JACOB'S  membrane,  664 
structure,  664 
Jacobson's  nerve,  (o)  112,  (d)  678 
Jejunum,  connections  of,  433 

structure,  456 
Joint,  ankle,  642 


INDEX 


01 


Joint — 

elbow,  293 

great  toe,  649 

hip,  600 

knee,  634 

lower  jaw,  90 

shoulder,  290 

thumb,  300 

wrist,  296 
Jugular  ganglion,  111 

vein,  anterior,  71 
external,  42,  62 
internal,  82,  109 


KIDNEY,  473 
connections  of,  435 
structure,  475 
vessels  of,  476 
Knee  of  the  corpus  callosum,  192 
joint,  634 


LABIA  pudendi  externa,  534 
interna,  535 
Labial  glands,  133 

artery,  inferior,  40 

nerve,  96 
Labyrinth,  679 

lining  of,  681 

membranous,  685 

osseous,  679 
Lachrymal  artery,  45,  56 

canals,  60 

duct,  61 

gland,  51 

nerve,  52 

point,  43,  60 

sac,  61 
Lactiferous  ducts,  227 
Lacunse  of  the  urethra,  528 
Lamina  cinerea,  192 

dentata,  204 

reticularis,  685 

spiralis  cochlese,  683 
Laminae  of  cerebellum,  213 

of  the  lens,  669 
Large  intestine,  connections,  433 

structure  and  form  of,  461 
Laryngeal  arteries,  158 

nerve,  external,  113 

inferior,     (o)     114,    331,    (d) 

158 
superior,  (o)  113,  (d)  158 

pouch,  156 
Larynx,  151 

aperture  of,  128,  155 

cartilages  of,  159 

interior  of,  154 

ligaments,  160 

muscles,  151 

nerves,  158 

ventricle,  156 

vessels,  158 


Lateral    column   of    the   medulla,   183, 
185 
of  the  cord,  382 
Lateral  sinus,  28 

ventricles,  200 
Latissimus  dorsi,  236,  356 
Laxator  tympani,  676 
Leg,  dissection  of  the  back,  605 

front,  626 
Lens  of  the  eye,  668 

structure  of,  669 
Lenticular  ganglion,  55 
Levator  anguli  oris,  38 
scapulae,  358 
ani,  390,  501 
glandulae  thyroidese,  120 
labii  superioris,  38 

alaeque  nasi,  35 
inferioris,  38 
palati,  129 

palpebrae  superioris,  53 
Levatores  costarum,  373 
Lieberkiihn's  crypts,  459 
Ligament  of  the  lung,  307 
Ligaments  of  the  bladder,  503,  504 
of  the  larynx,  261 
of  the  ovary,  512 
of  the  pinna,  47 
of  the  uterus,  510 
Ligament,  acromio-clavicular,  246 
alar  of  the  knee,  637 
annular,  anterior  of  the  ankle,  628 
external  of  the  ankle,  628 
internal  of  the  ankle,  614 
anterior  of  the  wrist,  282 
posterior  of  the  wrist,  282,  289 
anterior,  special,  of  ankle,  643 
of  elbow  joint,  283 
of  knee  joint,  636 
of  wrist  joint,  296 
of  carpus,  298 
astragalo-scaphoid,  645 
alto-axoid,  anterior,  167 
posterior,  167 
transverse,  169 
.    calcaneo-astragaloid,  644 
cuboid,  646 
scaphoid,  645 
capsular  of  the  hip,  600 
of  the  knee,  634 
of  the  shoulder,  290 
of  the  thumb,  300 
carpal,  dorsal,  297 

palmar,  297 
carpo-metacarpal,  300 
chondro-sternal,  345 
common,  anterior,  of  vertebrae,  346 
common,  posterior,  347 
conoid,  246 
coraco-acromial,  246 
clavicular,  245 
humeral,  291 
costo-clavicular,  171 
coracoid,  232 


702 


INDEX. 


Ligament — 

costo-transverse,  anterior,  345 
middle,  345 
posterior,  345 

vertebral,  344 

xiphoid,  346 
cotyloid,  602 
crico-thyroid,  161 
crucial,  637 
deltoid,  643 

dorsal  of  the  carpus,  298 
of  Gimbernat,  416,  StJO 
glenoid,  290 
ilio-femoral,  600 

lumbar,  546 
interarticular,  of  the  clavicle,  171 

of  the  hip,  602 

of  the  jaw,  91 

of  the  knee,  638 

of  the  pubes,  546 

of  the  ribs,  344 

of  the  wrist,  296 
interclavicular,  170 
interosseous   of  astragalus   and  os 
calcis,  637 

of  carpus,  298 

of  cuneiform  bones,  648 

of  metacarpal  bones,  299 

of  metatarsal  bones,  649 

of  radius  and  ulna,  294 

of  the  scaphoid  and  cuboid,  648 

of  the  tibia  and  fibula,  642 
Interosseous,  inferior,  of  the   tibia 

and  fibula,  642 
interspinal,  350 
intertransverse,  350 
intervertebral,  347 
lateral,  external  of  the  ankle,  643 

internal,  643 

external  of  the  carpus,  298 

internal,  298 

external  of  the  elbow,  293 

internal,  293 

phalangeal  of  the  foot,  651 
of  the  hand,  308 

external  of  the  jaw,  90 

internal,  91 

external  of  the  knee,  634 

internal,  634 

external  of  the  wrist,  296 

internal,  296 
long  plantar,  647 
metacarpal,  dorsal,  299 

palmar,  299 
metatarsal,  dorsal,  649 

plantar,  649 
mucous,  637 
obturator,  546 
occipito-atloid,  anterior,  168 

posterior,  168 
occipito-axoid,  1(58 
odontoid,  169 

orbicular  of  the  radius,  294 
of  the  patella,  636 


Ligament — 

palmar  of  carpus,  298 
peroneo-tibial,  641 
of  Poupart,  411,  559 
posterior  of  ankle,  643 

of  carpus,  298 

of  elbow,  293 

of  knee,  636 

of  scapula,  247 

of  wrist,  296 
proper  of  the  scapula,  246 
pubic  anterior,  546 

superior,  547 
round  of  the  hip,  602 
round  of  the  radius  and  ulna,  295 
sacro-coccygeal,  anterior,  544 

posterior,  544 
sacro-iliac,  anterior,  544 

posterior,  544 
sacro-sciatic,  large,  545,  592 

small,  545,  592 
sacro-vertebral,  544 
of  the  scapula,  anterior,  247 

posterior,  247 
sterno-clavicular,  170 
stylo-hyoid,  106 

maxillary,  91 
subpubic,  547 
supraspinous,  350 
suspensory  of  penis,  408 
tarso-metatarsal,  dorsal,  650 

lateral,  650, 

plantar,  650 
thyro-arytaenoid,  162 

epiglottidean,  162 

hyoid,  161 
tibio-tarsal,  643 
transverse  of  the  atlas,  170 

of  the  fingers,  273 
transverse  of  the  hip,  602 

of  the  knee,  639 

of  metacarpus,  280 

of  metatarsus,  624 

of  the  toes,  615 
trapezoid,  246 
triangular  of  the  abdomen,  411 

of  the  urethra,  396 
of  Winslow,  or  posterior,  636 
Ligamentum  arcuatum,  486 
denticulatum,  376 
du-ctus  arteriosi,  325 
latum  pulmonis,  307 
longum  plantae,  647 
mucosum,  637 
nuchse,  356 
patellae,  636 
spirale,  683 
subflavum,  34 
teres,  602 
Limb,  upper,  224 

lower,  552 
Limbus  cochleae,  683 

luteus,  664 
Limiting  membrane  of  retina,  666 


INDEX 


703 


Linea  alba,  410 

semilunaris,  416 
Liiieae  trans versae,  415 
Lingual  artery,  85,  101 
glands,  150 
nerve,  97,  101,  150 
vein,  101 
Lingualis  muscles,  149 
Lips,  133 

Liquor  Cotunnii,  681 
Lithotomy,  parts  cut,  399 
Liver,  466 

connections  of,  435 
ligaments,  438 
structure,  469 
vessels,  471 
Lobes  of  the  cerebellum,  213 

of  the  cerebrum,  193 
Lobules  of  the  testis,  482 

of  the  liver,  469 
Lobulus  auris,  46 
oaudatus,  467 
quadratus,  467 
Spigelii,  467 
Locus  niger,  191 

perforatus  anticus,  192 
posticus,  191 
Longissimus  dorsi,  363 
Longitudinal  fibres  of  the  brain,  210 
fissure  of  the  liver,  468 
sinus,  inferior,  27 
superior,  25 
Longus  colli  muscle,  163 
Lumbar  aponeurosis,  357 
arteries,  498 

anterior  branches,  498 
posterior  branches,  368 
ganglia,  497 
glands,  495 
nerves,  anterior  branches,  495 

posterior  branches,  368,  384 
plexus,  496 

region  of  the  abdomen,  431 
veins,  492,  498 
Lumbo-sacral  nerve,  495 
Lumbricales  of  the  foot,  620 

of  the  hand,  277 
Lungs,  333 

connections,  308 
physical  characters,  334 
structure,  334 
vessels  and  nerves,  335 
Lymphatic  duct,  119,  340 

right,  79,  340 
Lymphatics  of  the  arm,  250 
of  the  axilla,  230 
of  the  groin,  407,  554 
of  the  lungs,  336 
of  the  mesentery,  441 
of  the  neck,  67 
of  the  pelvis,  520 
of  the  popliteal  space,  597 
of  the  thorax,  339 
Lyra,  203 


MALLEOLAR  arteries,  637 
Malleus,  674 
muscles  of,  676 
Malpighian  corpuscles  of  spleen,  466 

of  kidney,  475 
Mamillse  of  the  kidney,  474 
Mamma,  226 

structure  of,  227 
Mammary  artery,  internal,  (o)  77,  (c) 
239,  330,  419 
gland,  226 
Masseter  muscle,  87 
Masseteric  artery,  94 

nerve,  95 
Mastoid  cells,  672 
Maxillary  artery,  internal,  93,  142 
nerve,  inferior,  (o)  32,  (d)  94 

superior,  32,  104 
vein,  internal,  94 
Meatus  auditorius  externus,  670 
nerves  of,   671 
vessels  of,  671 
urinarius,  527 
Meatuses  of  the  nose,  134 
Meckel's  ganglion,  139 
Median  basilic  vein,  249 
cephalic  vein,  249 
nerve,  (o)  236,  (c)  255,  (d)  269,  274 
vein,  249,  261 
Mediastinal  arteries,  239,  337 
Mediastinum  of  thorax,  307 
Mediastinum  of  testis,  481 
Medulla  oblongata,  182 

gray  matter  of,  186,  317 
Medulla  spinalis,  380 
Medullary  substance  of  the  kidney,  474 
velum,  anterior,  215 
posterior,  215 
Meibomian  follicles,  44 
Membrana  basilaris,  683 
granulosa,  540 
pigmenti,  666 
pupillaris,  661 
reticularis,  685 
sacciformis,  297 
tympani,  673 
Membrane  of  Corti,  684 
of  Demours,  657 
hyaloid,  667 
Jacob's,  664 
of  the  labyrinth,  681 
of  Reissner,  684 
Membranes  of  the  brain,  24,  172 

of  spinal  cord,  374 
Membranous  labyrinth,  685 
part  of  the  cochlea,  683 
of  the  urethra,  527 
Meningeal  artery,  anterior,  29 
middle,  29,  93 
posterior,  29,  86,  174 
small,  29,  93 
nerves,  30 
Mesenteric  artery,  inferior,  441 
superior,  439 


704 


INDEX. 


Mesenteric — 
glands,  441 
plexus  inferior,  443 

superior,  443 
vein,  inferior,  443 
superior,  441 
Mesentery,  438 
Meso-cjecuin,  438 
colon   left,  438 
right,  438 
transverse,  438 
rectum,  438,  503 
Metacarpal  arteries,  269,  289 
Metatarsal  artery,  632 
Mitral  valve,  320 
Modiolus  of  the  cochlea,  682 
Molar  teeth,  133 

glands,  42 
Mons  Veneris,  534 
Motor  oculi  nerve,  (o)  180,  (c)  30,  (d) 

54,  57 
Mouth,  cavity  of,  132 
Mucous  ligament,  637 
Multifidus  spinse  muscle,  370 
Muscularis  mucosae,  457 
Musculi  papillares,  318,  320 

pectinati,  316,  319 
Musculo-phrenic  artery,  239,  490 

cutaneous  nerve,  (o)  633,  (d)  626 
of  the  arm,  (o)  234,  (c)  256,  (d) 
259 
spiral  nerve,  236,  259 
Muse,  abductor  digiti  minimi,  278 
pedis,  616 
indicia,  280 
pollicis,  277 
pedis,  616 
accessorius  pedis,  620 

ad  sacro-lumbalem,  362 
adductor  brevis,  577 
digiti  minimi,  279 
longus,  576 
magnus,  579,  599 
policis  manus,  278 
pedis,  621 
anconeus,  285 
anti-tragicus,  46 
arytsenoideus,  153 
attollens  aurem,  18 
attrahens  aurem,  18 
azygos  uvulae,  131 
biceps  femoris,  597,  635 

flexor,  cubiti,  252,  271,  291 
brachialis  anticus,  256,  271 
buccinator,  39 
cervicalis  ascendens,  363 
chondro-glossus,  148 
ciliaris,  660 

circumflexus  palati,  129 
coccygeus,  501 
complexus,  364 
compressor  naris,  35 
constrictor  inferior,  124 


Muse,  constrictor — 

medius,  124       * 
superior,  124 
urethrje,  397,  403 
coraco-brachialis,  252 
corrugator  cutis  ani,  389 

supercilii,  37 
cremastericus,  412 
crico-arytaenoideus  lateralis,  153 
posticus,  152 
thyroideus,  152 
deltoides,  242 
depressor  anguli  oris,  39 
epiglottidis,  154 
labii  inferioris,  38 
alse  nasi,  36 
diaphragm  a,  484,  343 
digastricus,  82 
dilatator  naris,  35 

pupillae,  661 
ejaculator  urinae,  394 
erector  clitoridis,'403 
penis,  394 
spinas,  362 
extensor  carpi  radialis  brevior,  284 
longior,  284 
ulnaris,  285 
digiti  minimi,  285 
digitorum  brevis  pedis,  632 
communis,  285 
longus  pedis,  629 
indicis,  288 

ossis  metacarpi  pollicis,  287 
pollicis  proprius,  629 
primi  internodii  pollicis,  287 
secundi  internodii  pollicis,  287 
flexor  accessorius,  620 

brevis  digiti  minimi,  278 

pedis,  620 
carpi  radialis,  264,  282 

ulnaris,  265 
digitorum  brevis  pedis,  616 
longus  pedis,  610,  619 
profundus,  270,  276 
sublimis,  266,  276 
pollicis  longus,  270,  277 
pedis,  610,  620 
pollicis  brevis,  278 
pedis,  621 
gastrocnemius,  608 
gemellus  inferior,  589 

superior,  589 
genio-hyo-glossus,  100,  149 

hyoideus,  100 
glosso-pharyngeus,  149 
gluteus  maximus,  583 
medius,  585 
minimus,  586 
gracilis,  574 
helicis  major,  46 

minor,  46 
hyo-glossus,  99,  182 
iliacus,  493,  580 
ilio-costalis,  362 


INDEX 


705 


Muse. — 

indicator,  288 
infra-costalis,  342 
infra-spinatus,  244 
intercostales  externi,  237,  342 

interni,  238,  342 
interossei  maims  dorsales,  281 
palmares,  281 

pedis  dorsales,  625 
plantares,  624 
interspinal es,  370 
intertransversales,  165,  370 
kerato-cricoideus,  153 
latissimus  dorsi,  236,  356 
laxator  tympani,  676 
levator  anguli  oris,  38 
scapulae,  358 

ani,  390,  501 

glandulse  thyroidese,  120 

labii  superioris,  38 
alse  nasi,  36 
inferioris,  38 

palati,  129 

palpebrse,  53 

uvulae,  181 
levatores  costarum,  373 
linguales,  149 
longissimus  dorsi,  363 
longus  colli,  163 
lumbricales  manus,  277 

pedis,  620 
mallei  externus,  676 

internus,  676 
massetericus,  87 
multifidus  spinse,  371 
mylo-hyoideus,  98 
obliquus  abdominis  externus,  409 
internus,  411 

capitis  inferior,  369 
superior,  369 

oculi  inferior,  59 
superior,  53 
obturator  externus,  580,591 

internus,  543,  590 
occipito-frontalis,  18 
omo-hyoideus,  72,  359 
opponens  digiti  minimi,  279 

pollicis,  278 
orbicularis  oris,  37 

palpebrarum,  36 
orbitalis,  60 
palato-glossus,  130,  148 

pliaryngeus,  130 
palmaris  brevis,  272 

longus,  265 
pectineus,  576 
pectoralis  major,  230,  231 

minor,  231 
peroneus  brevis,  633 

longus,  625,  633 

tertius,  629 
plantaris,  609 
platysma  myoides,  62,  67 
popliteus,  610,  635 

45 


Muse. — 

pronator  quadratus,  271 

radii  teres,  264 
psoas  magnus,  492,  580 

parvus,  493 
pterygoideus  externus,  89 

internus,  90 
pyramidalis  abdominis,  416 

nasi,  34 
pyriformis,  542,  587 
quadratus  femoris,  590 

lumborum,  494 
rectus  abdominis,  415 

capitis  anticus  major,  164 
minor,  165 
lateralis,  115 
posticus  major,  369 
minor,  369 

femoris,  570,  587 

oculi  externus,  57 
inferior,  57 
internus,  57 
superior,  53 
retrahens  aurem,  18 
rliomboideus  major,  358 

minor,  358 
risorius  Santorini,  39 
rotatores  dorsi,  369 
sacro-lumbalis,  362 
salpingo-pharyngeus,  126 
sartorius,  566 
scalenus  anticus,  75 

medius,  75 

posticus,  75 
semi-spinalis  colli,  370 

dorsi,  370 
semi-membranosus,  598,  636 
semi-tendinosus,  597 
serratus  magnus,  236 

posticus  inferior,  360 
superior,  360 
soleus,  608 

sphincter  ani  externus,  389 
internus,  389 

pupillse,  661 

vaginae,  402 
spinalis  dorsi,  362 
splenius  capitis,  361 

colli,  361 
stapedius,  676 
sterno-cleido-mastoideus,  71 

hyoideus,  72 

thyroideus,  73 
stylo-glossus,  100,  148 

hyoideus,  83 

pliaryngeus,  106 
subaneoneus,  259 
subclavius,  232 
subcrureus,  572 
subscapularis,  241 
supinator  radii  brevis,  288 

longus,  284 
supraspinatus,  247 
temporalis,  20,  88 


706 


INDEX 


Masc. — 

tensor  palati,  129 

tarsi,  59 

tympani,  676 

vaginae  femoris,  570 
teres  major,  245 

minor,  245 
thyro-arjtaenoideiis,  153 

hyoideus,  73 
tibialis  anticus,  628 

posticus,  612,  625 
trachelo-mastoideus,  363 
tragicus,  46 
trans versalis  abdominis,  413 

colli,  363 
transversus  auris,  47 

linguae,  149 

pedis,  621 

perinaei,  395,  403 
alter,  395 

profundus,  398,  403 
trapezius,  354 
triangularis  sterni,  238 
triceps  extensor  cruris,  570 

cubiti,  258 
vastus  externus,  571 

internus,  571 
zygomaticus  major,  39 

minor,  39 
Mylo-hyoid  artery,  93 
muscle,  98 
nerve,  96 


VfARES,  42,  126 

ll      Nasal  artery,  internal,  57,  142 

artery,  lateral,  40 

cartilages,  42 

duct,  61 

fossae,  134 

nerve,  (d)  54,  (c)  141,  (o)  57 
Naso-palatine  nerve,  140 

artery,  142 
Neck,  anterior  triangle  of,  69 

posterior,  63 

dissection  of,  61 
Nerve  of  Jacobson,  112,  678 

Wrisberg,  (o)  236,  (d)  251,  256 
Nerve  to  the  inferior  gemellus  and  quad- 
ratus,  589 

latissimus,  236 

levator  anguli  scapulae,  80 

obturator  internus,  518,  590 

pectineus,  573 

pterygoid,  internal,  145 

pyriformis,  518 

rhomboid  muscle,  80,  359 

scaleni,  80 

serratus  muscle,  (o)  79,  (d)  236 

subclavius,  80 

superior  gemellus,  589 

tensor  palati,  145 
tympani,  145 
vaginae  femoris,  574 


Nerve — 

teres  major,  236 
minor,  245 
vastus  externus,  573 
internus,  573 
Nervous  tunic  of  eyeball,  663 
Nerv.  abducens,  (o)  180,  (c)  32,  (d)  57 
accessorius  obturatorius,  497,  577 

spinalis,  114,  181,  356 
acromiales,  cutanei,  80,  242 
articulares  poplitei,  596 
articularis     poplitei     obturatorius, 

577,  596 
auditorius,  181,  680 
auriculares  anteriores,  23 
auricularis  magnus,  23,  i)6 

pneumogastricus,  (o)  113,  (d) 

679 
inferior,  96 
posterior,  23,  48 
auriculo-temporalis,  23,  90 
buccales,  50,  95 
buccinatorius,  95 

cardiacus  inferior,  (o)  117,  122,  (d) 
332 
medius,  (o)  117,  122,  (d)  332 
pneumogastrici,  114,  331,    (d) 

332 
superior,  (o)  11  ,  122,  (d)  314, 
333 
cervicales  nervi  facialis,  68 
rami  anteriores,  79,  165 
posteriores,  165,  365 
cervicalis  superficialis,  66,  68 
cervico-facialis,  50 
chorda  tympani,  97,  144 
ciliares  ganglii  ophthalmici,  55,  663 
ciliaris  nasalis,  54,  (d)  663 
circumflexus,  236,  244 
claviculares  cutanei,  66 
coccygealis,  373,  518 
cochlearis,  687 
communicans  fibularis,  606 
corporis  bulbosi,  399 
cruralis,  (o)  497,  (d)  572 
cutanei  abdominis,  anteriores,  407 

laterales,  406 
cutaneus   externus   brachialis,   (o) 
235,  (c)  256,  (d)  262 
lumbalis,  (o)  497,  (d)  556 
musculo-spiralis,  250,  259, 
262 
internus  brachialis,  major,  236, 
256,  261 
minor,  236,  251,  256 
femoris,  (d)  556,  (o)  573 
musculo-spiralis,  250,  259 
medius   femoris,    (o)    573,   (d) 

556 
musculo-cutaneus,  250 
palmaris,  269,  272 
plantaris,  613 
radialis,  262 
dorsalis  mantis,  269 


INDEX 


TOT 


Nerv. — 

dentales  posteriores,  104 
dental  is,  anterior,  104 

inferior,  96 
descendens  noni,  83,  115 
diaphragmaticus,  (o)  80,  (d)  330 
digastricus  48 
digitales  median!,  275 

plantares,  619 

radiales,  262 

ulnares,  274 
dorsales,  rami  anteriores,  239,  343, 
378 
posteriores,  367,  378 
dorsalis  penis,  399,  408 

ulnaris,  262,  269 
facialis,  47,  143 
frontalis,  52 
genito-cruralis,  497,  556 

ramus  femoralis,  556 
genitalis,  418 
glosso-pharyngeus.  111,  151,  181 
glutei  infer  lores,  588 
gluteus  superior,  496,  586 
gustatorius,  97,  101,  151 
haraorrlioidales  superiores,  443 
hseraorrhoidalis  inferior,  390 
hypoglossus,  83,  102,  115,  151 
ilio-liypogastricus,  416,  496,  582 

inguinalis,  416,  497,  55^ 
incisorius,  96 
infra-maxillares  faoiales,  50,  68 

orbitales  nervi  facialis,  49 

orbitalis,  60,  104 

trochlearis,  54 
intercostales,  239,  416 
intercosto-cutanei    anteriores,   226, 
406 

laterales,  206,  406 

humeralis,  254,  226,  251 
interosseus  anticus,  271 

posticus,  289 
labialis,  96 
lachrymalis,  52 
laryngeus  externus,  114 

inferior,  (o)  331,  (d)  114,  158 

superior,  (o)  113,  (d)  158 
lumbales,  rami  anteriores,  495 
posteriores,  369,  384 
lumbo-sacralis,  496 
malares  nervi  facialis,  48 
massetericus,  95 
maxillaris  inferior,  (o)  32,  (d)  94 

superior,  31,  104 
medianus,  236,  255,  269,  274 
meningei,  30 
nioUes,  116 
motor  oculi,  (o)  180,  (c)  32,  (d)  54, 

57 
musculo-cutaneus  brachii,  236,  256, 
262 

cruris,  633,  (d)  626 
musculo-spiralis,  (o)  236,  (d)  259 
mjlo-hyoideus,  9Q 


Nerv. — 

nasalis,  (o)  51,  (d)  54,  57,  141 
naso-platinus,  141 
obturatorius,  (o)  497,  (d)  577 

articularis,  577,  596 
occipitalis,  major,  366 

minor,  (d)  24,  (o)  66 
cesopliageales,  331 
olfactorius,  (c)  30,  (d)  136,  (o)  178 
ophthalmicus,  32,  51 
opticus,  57,  137,  179,  207 
orbitalis,  (d)  60,  (o)  104 
palatinus  magnus,  140 

medius,  141 

minor,  141 
palpebrales,  45,  104 
pulmaris  cutaneus,  272 

ulnaris  profundus,  280 

superficialis,  274 
patellaris,  557,  573 
perforans  Casserii,  (o)  236,  (c)  256, 

(d)  262 
perinseales  superficiales,  391,  394 
peronealis,  596 

petrosus  superficialis  externus,  33 
magnus,  33,  141 
parvus,  33,  678 
pharyngei,  112,  117 
pharyngeus,  113 
phrenicus,  80,  330 
plantaris  externus,  619 
profundus,  624 

internus,  624 
pneumo-gastricus,    112,    181,    330, 

452 
popliteus  externus,  596 

internus,  596 
portio  dura,  47,  142,  180 

mollis,  (o)  181,  (d)  687 
pterygoidei,  95 

pterygoideus  internus,  95,  145 
pudendus  inferior,  (o)  589,  (d)  394, 
407 

internus,  (o)  518,  (d)  391,  399, 
408 
pulmonares  anteriores,  331 

posteriores,  331 
radialis,  263,  270 
recurrens,  114,  331,  (d)  158 

articularis,  633 
sacrales,  rami  anteriores,  518 
posteriores,  372,  581 
saphenus  externus,  606,  (d)  627 

internus,  (o)  573,  (d)  557,  573, 
627 
sciaticus  magnus,  519,  589.  599 

parvus,  519,  582,  584,  599 
spermatici,  443 
spheno-palatini,  104 
sj^lanchnicus  major,  (o)  342,  452 

minor,  (o)  342,  (d)  452 

minimus,  (o)  342,  (d)  452 
splenici,  451 
stylo-hyoideus,  48 


708 


INDEX 


Nerv. — 

suboccipital  is,  ramus  anterior,  115 

posterior,  368 
subscapulares,  236 
superficialis  cordis  dexter,  (o)  117 
(d)  332 
sinister,  (o)  122,  (d)  314 
supraraaxillares  nervi  facialis,  48 
orbitalis,  22,  51 
scapularis,  80,  248,  359 
trochlearis,  23,  52 
sympatheticus  abdominis,  443,  450, 
497 
cervicis,  115 
pelvis,  519 
thoracis,  331,  341 
temporales  nervi  facialis,  48 
profundi,  95 

superficiales,   (d)    23,    (o)  48 
teraporo-facialis,  48 

malaris,  60,  104 
thoracici,  anteriores,  236 

laterales,  226 
thoracicus  posterior,  80,  236 
tibialis  anticus,  627,  (d)  632 

posticus,  613 
trigeminus,  31,  180 
trochlearis,  31,  51,  180 
tympanicus,  (o)  112,  (d)  678 
ulnaris,  255,  269,  274 
uterini,  520 
vaginales,  520 
vestibularis,  687 
vidianus,  141 
Ninth  nerve,  (o)    182,  (c)  115,  (d)  83, 

102 
Nipple  of  the  breast,  226 
Nodule,  212 
Nose,  cartilages,  42 
cavity  of,  133 
meatuses  of,  134 
nerves  and  vessels  of,  139,  141 
Nuclei  of  medulla  oblongata,  187 
Nucleus  caudatus,  203 

lenticularis,  203 
Nutritious  artery  of  fibula,  613 
of  femur,  578 
of  humerus,  254 
of  tibia,  612 
Nymphse,  534 


OBLIQUUS  abdominis  externus,  409 
internus,  411 
capitis  inferior  muscle,  369 

superior  muscle,  369 
oculi  inferior,  59 
superior,  53 
Obturator  artery,  (o)  515,  (d)  580 
fascia,  500 
ligament,  546 
membrane,  54b 
muscle,  external,  580,  591 
internal,  543,  590 


Obturator  nerve,  (o)  497,  (d)  577 
Occipital   artery,  (o)    86,  (c)    368,    (d) 
21 

lobe,  194 

vein,  21,  86 

sinus,  27 
Occipito-atloid  articulation,  168 

ligaments,  168 
Occipito-axoid  ligaments,  169 

frontalis  muscle,  18 
Odontoid  ligaments,  169 
(Esophagus,  connections  of,  121,  339 

structure,  131,  339 
(Esophageal  arteries,  337,  447 

nerves,  331 

opening  of  diaphragm,  487 
Olfactory  bulb,  179 

cells,  137 

nerve,  (o)  178,  (d)  138 

region,  137 
Olivary  body,  183,  185 

commissure,  186 

fasciculus,  186,  189,  208 
Omentum,  great,  437 

small,  437 

splenic,  437 
Omo-hyoid  muscle,  72 
Ophthalmic  artery,  33,  56 

ganglion,  55 

nerve,  (o)  31,  (c)  32,  (d)  51 

vein,  57 
Opponens  pollicis  muscle,  278 
Optic  commissure,  179 

nerve,    (o)    179,  207,    (c)    57,    (d) 
664 

thalamus,  207,  211 

tract,  179 
Ora  serrata,  663 

Orbicular  ligament  of  the  radius,  294 
Orbicularis  oris,  37 

palpebrarum,  36 
Orbit,  50 

muscles  of,  53,  57 

nerves,  51 

periosteum  of,  50 

vessels,  56 
Orbital  branch  of  nerve,  (d)  60,  (o) 

104 
Organ  of  Corti,  684 

of  Giraldes,  483 
Orifice  of  the  urethra,  535 

of  the  uterus,  535 

of  the  vagina,  535 
Os  hyoides,  159 
Ossicles  of  the  tympanum,  674 
Os  tincse,  537 
Os  uteri  externum,  537 
Otic  ganglion,  144 
Otoliths,  686 
Outlet  of  the  pelvis,  386 
Ovaries,  512,  539 

appendage  to,  540 

arteries  of,  490,  516 
Ovicapsule,  540 


INDEX 


709 


Ovisacs,  540 
Ovum,  539 


PALATE  (soft),  128 
Palatine,  arteries,  superior,  143 
artery,  inferior,  86 
nerve,  external,  141 
large,  140 
small,  141 
Palato-glossus,  130,  148 
Palato-pharyngeus,  130 
Palm  of  the  liand,  272 

cutaneous  nerves  of,  272 
Palmar  arch,  deep,  280 
superficial,  273 
nerve  of  the  ulnar,  deep,  280 

superficial,  274 
cutaneous  nerves,  272 
fascia,  272 
Palmaris  brevis  muscle,  272 

longus  muscle,  265 
Palpebrse,  43 
Palpebral  arteries,  45,  57 
ligament,  44 
nerves,  45 
veins,  45 
Pancreas,  464 

connections,  446 
structure  of,  464 
Pancreatic  arteries,  447 
duct,  457,  465 
veins,  448 
Pancreatico-duodenal     arteries,    440, 

448 
Papilla  lachrjmalis,  45 
PapilLie  of  the  tongue,  146 
Parietal  lobe,  194 
Parovarium,  540 
Parotid  gland,  41 

arteries,  86 
Patellar  nerve,  573 

plexus,  557 
Pectineus  muscle,  576 
Pectoralis  major  muscle,  230,  231 

minor  muscle,  231 
Peduncle   of  the    cerebellum,    inferior, 
215 
middle,  215 
superior,  215 
of  the  cerebrum,  190,  211 
of  the  pineal  body,  208 
Peduncular  fibres,  207 
Pelvis,  female,  dissection  of,  509 
male,  499 

dissection  of,  499 
Pelvic  cavity,  499 
fascia,  500 
plexus,  519 
Penis,  508 

integument  of,  407 
structure  of,  529 
vessels  of,  532 
Peptic  glands,  455 


Perforating  arteries  of  the  femoral,  578, 
599 
of  internal  mammary,  239 
of  the  palm,  280 
of  the  sole,  623,  632 
Perforans   Casserii   nerve,  (o)    236,  (c) 

256,  (d)  262 
Pericardium,  310 

vessels  of,  311,  337 
Perilymph,  681 
Perinseum,  female,  400 

male,  386 
Perinaeal  artery,  superficial,  393 
fascia,  deep,  396 

superficial,  392 
nerves,  superficial,  391,  393,  399 
Periosteum  of  the  orbit,  50 
Peritoneal  prolongation  on  the  cord,  417 
Peritoneum,  435 

of  female  pelvis,  510 
of  male  pelvis,  504 
Peroneal  artery,  613 
anterior,  613 
nerve,  596 
Peroneus  brevis  muscle,  633 
longus  muscle,  625,  633 
tertius  muscle,  629 
Peroneo-tibial  articulations,  641 
Pes  hippocampi,  204 
Petrosal  ganglion.  111 
sinus,  inferior,  29 

superior,  29 
nerve,  large,  33,  141 
small,  33,  678 
external,  33 
Peyer's  glands,  459 
Pharynx,  124 
interior,  126 
muscles  of,  124 
openings  of,  126 
Pharyngeal  ascending  artery,  109 
nerve,  113 
vein,  112 
Pharyngeo-glossal  muscle,  149 
Phrenic  artery,  330,  490 

nerve,  80,  330 
Pia  mater  of  the  brain,  173 

of  the  cord,  376 
Pigmentary  layer  of  retina,  666 
Pigment  cells  of  choroid,  660 

iris,  662 
Pillars  of  the  abdominal  ring,  410 
of  the  fornix,  208 
of  the  iris,    658 
of  the  soft  palate,  128 
Pineal  body,  208 
Pinna,  or  auricle  of  the  ear,  45 
Pituitary  body,  192 
Plantar  aponeurosis,  615 
arch  of  tlie  artery,  623 
arteries,  617,  623 
ligament,  long,  647 
nerve,  external,  619,  624 
internal,  619 


45' 


710 


INDEX. 


Plantaris  muscle,  609 
Platysma  myoides  muscle,  62,  67 
Pleura,  307 
Plexus,  aortic,  443 

brachial,  79,  235 

cardiac,  superficial,  314 
deep,  332 

carotid,  33 

cavernous,  33 

cervical,  80 

posterior,  367 

clioroides  cerebri,  205 
cerebelli,  218 

coeliac,  451 

coronary,  anterior,  314 
posterior,  314 

coronary  of  the  stomach,  451 

diaphragmatic,  451 

gul«,  331 

hepatic,  451 

haemorrhoidal,  520 

hypogastric,  444 

lumbar,  496 

mesenteric,  inferior,  443 

mesenteric,  superior,  443 

oesophagean,  331 

ovarian,  520 

patellar,  557 

pelvic,  519 

pharyngeal,  113 

prostatic,  520 

pterygoid  of  veins,  94 

pulmonary  anterior,  331 
posterior,  331 

renal,  451 

supra,  451 

sacral,  518 

solar,  451 

spermatic  of  nerves,  443 
of  veins,  492 

splenic,  451 

tympanic,  678 

uterine,  520 

vaginal,  520 

vesical,  520 

vertebral,  117,  166 
Plica  semilunaris,  45 
Pneumogastric  nerve,  (o)  181,  (d)  112, 

181,  330,  452 
Pons  Tarini,  191 

Varolii,  188 

structure  of,  184 
Popliteal  artery,  594 

glands,  597 

nerve,  external,  596 
internal,  596 

space,  593 

vein,  596 
Popliteus  muscle,  610,  635 
Portal  veins,  448 
Portio  dura,  (c)  144,  (d)  47,  (o)  180 

mollis,  (o)  181,  (d)  687 
Porus  opticus,  664 
Posterior  commissure,  207 


Posterior — 

elastic  layer  of  cornea,  658 

ligament  of  knee,  636 

medullary  vellum,  214 

pyramid,  184,  186 

triangle  of  the  neck,  63 

vesicular  column,  383 
Poupart's  ligament,  411,  559 
Pouch,  laryngeal,  155 

of  the  auricula,  316,  319 
Prepuce,  583 
Princeps  cervicalis  artery,  368 

pollicis  artery,  280 
of  the  foot,  624 
Processus  cochleariformis,  673 

vermiformis,  212,  216 
Profunda  artery,  inferior,  254 

of  the  neck,  (o)  78,  (d)  368 

of  the  thigh,  565,  578 

superior,  (o)  254,  (d)  258 
Promontory,  672 
Pronator  quadratus  miiscle,  271 

radii  teres  muscle,  264 
Prostate  gland,  571 

connections,  507 

structure,  521 
Prostatic  part  of  the  urethra,  526 

sinuses,  527 
Psoas  magnus  muscle,  492,  580 
Psoas  parvus  muscle,  493 
Pterygoid  arteries,  95 

nerve,  external,  95 
internal,  95,  145 

plexus  of  veins,  94 
Pterygoideus  externus  muscle,  89 

internus  muscle,  90 
Pterygo-maxillary  ligament,  124 
region,  87 

palatine  artery,  142 
Pubic  region  of  the  abdomen,  431 

symphisis,  546 
Pudendal  inferior  nerve,  (o)  589,  (d)  394 
Pudic  arteries,  external,  554,  565 

artery,  internal,  (d)  390,  (c)  398, 
408,  (o)  516 

nerve,  internal,   (o)  408,  (d)  390, 
398 
Pulmonary  artery,  (d)  318,  325,  335 

nerves,  331 

veins,  319,  329,  336 
Puncta  lachrymalia,  43,  60 
Pupil,  muscles  of,  661 
Pylorus,  453 
Pyloric  arteries,  447 
Pyramid,  anterior,  183,  185 

decussation  of,  186 

of  the  cerebellum,  213 

of  the  thyroid  body,  120 

of  tlie  tympanum,  672 

posterior,  184,  186 
Pyramidal  fibres  of  the  medulla,  185 

masses  of  kidney,  474 
Pyramidalis  abdominis  muscle,  416 

nasi  muscle,  34 


INDEX 


711 


Pyramids  of  Malpighi,  474 
Pyriformis  muscle,  542,  587 


QUADRATUS  femoris  muscle,  590 
lumborum  muscle,  494 


RADIAL  artery,  265,  (d)  280,  289 
nerve,  262,  270 

veins,  266 

cutaneous,  261 
Radialis  indicis  artery,  272 
Radio-carpal  articulation,  296 
Radio-ulnar  articulations,  294,  297 
Ranine  artery,  101 

vein,  101 
RapliS  of  tlie  corpus  callosum,  200 

of  the  medulla,  186 

of  the  perinseum,  386 
Receptaculum  chyli,  495 
Recto-vesical  fascia,  5,02 

pouch,  504 
Rectus  abdominis  muscle,  415 

capitis  anticus  major,  164 
minor,  165 
posticus  major,  369 

minor,  369 
lateralis,  115 

femoris,  570,  587 
Rectus  oculi  externus,  57 

inferior,  57 

internus,  57 

superior,  53 
Rectum,  connections  of,  in  the  female, 
510 

connections  of,  in  the  male,  504 

structure,  532 
Recurrent  interosseous  artery,  288 

radial,  266 

tibial,  631 

ulnar,  anterior,  268 
posterior,  268 
Recurrent  nerve  of  pneumogastric,  (o) 
114,  331,  (d)  158 

nerve  of  the  tibial,  631 
Renal  artery,  (d)  476,  (o)  489 

plexus,  451 

vein,  (o)  476,  (c)  492 
Restiform  body,  184,  186 
Rete  testis,  482 
Retina,  663 

structure,  664 
Retrahens  aurem,  18 
Rhomboideus  major  muscle,  358 

minor,  358 
Rima  of  the  glottis,  155 
Ring,  abdominal,  external,  410 

internal,  417,  421 
Risorius  Santorini  muscle,  39 
Rods  of  retina,  665 
Root  of  the  lung,  309,  310 
Roots  of  the  nerves,  307,  383 
Rotatores  dorsi,  371 


Round  ligament  of  the  hip  joint,  602 
of  the  liver,  468 
of  the  uterus,  418,  512,  539 


SACCULE  of  the  ear,  686 
Sacculus  laryngis,  155 
vestibuli,  685 
Sacral  artery,  lateral,  515 
middle,  489,  517 
ganglia,  519 
nerves,  anterior  branches,  518 

posterior   branches,    372,    581, 
584 
plexus,  518 
Sacro-coccygeal  articulation,  544 
iliac,  544 
vertebral,  544 
lumbalis  muscle,  362 
sciatic  ligament,  large,  545,  592 
small,  545,  592 
Salpingo-pharyngeus  muscle,  126 
Salvatella  vein,  361 
Saphenous  vein,  external,  606,  626 

internal,  555,  573,  606,  (o)  626 
opening,  559 

nerve,  external,  606,  (d)  627 
internal,  (o)  573,  (d)  557, 
573,  627 
Sartorius  muscle,  566 
Scala  tympani,  684 

vestibuli,  684 
Scalenus  anticus  muscle,  75 
medius,  75 
posticus,  75 
Scapular  artery,  posterior,  78,  248,  359 
ligaments,  247 
muscles,  240,  244 
Scapulo-clavicular  articulation,  246 

humeral,  290 
Scarpa's  triangle,  563 
Schneiderian  membrane,  135 
Sciatic  artery,  (o)  516,  (d)  588 
nerve,  large,  519,  589,  599 
small,  519,  582,  588,  599 
Sclerotic  coat  of  the  eye,  655 

structure,  656 
Scrotum,  408 

Second  nerve,  (o)  179,  (c)  57,  (d)  664 
Secondary  membrane  of  the  tympanum, 

672,  673 
Segments  of  the  cord,  382 
Semicircular  canals,  680 
Semilunar  cartilages,  638 
ganglia,  451 
valves  of  aorta,  321 

of  pulmonary  artery,  318 
Semi-bulbs  of  vagina,  527 
Semi -membranes  us  muscle,  598,  636 
Seminal  ducts,  523 
Seminiferal  tubes,  481 
Semi-spinalis  colli  muscle,  370 

dorsi  muscle,  370 
Semi-tendinosus  muscle,  597 


712 


INDEX 


Septum  auricularum,  322 

cochleae,  682 

crurale,  428,  561 

intermuscular,  of  the  arm,  258 
of  the  thigh,  572 

lucidum,  202 

nasi,  134 

pectiniforme,  530 

scroti,  408 

of  the  tongue,  147 

ventriculorum,  324 
Serratus  magnus  muscle,  236 

posticus  inferior,  360 
superior,  360 
Seventh  nerve,  (o)  180,  (c)  142,  (d)  47 
Sheath  of  the  fingers,  273 

of  the  rectus,  415 

of  the  toes,  616 
Shoulder  joint,  290 
Sigmoid  artery,  442 

flexure  of  the  colon,  434 

valves,  318,  321 
Sinus,  basilar,  29 

of  the  bulb,  527 

cavernous,  28 

circular,  of  Ridley,  29 

coronary,  314 

lateral,  28 

longitudinal,  inferior,  27 
superior,  25 

occipital,  27 

petrosal,  inferior,  29 
superior,  29 

pocularis,  526 

prostaticus,  527 

straight  of  the  skull,  27 

torcular,  27 

transverse,  29 

of  Valsalva,  321 
Sixth  nerve,  (o)  180,  (c)  32,  (d)  57 
Small  intestine,  429,  456 

omentum,  438 
Socia  parotidis,  41 
Soft  commissure,  206 
Soft  palate,  128 

muscles  of,  128 
Solar  plexus,  451 
Sole  of  the  foot,  dissection  of,  614 
Soleus  muscle,  608 
Solitary  glands,  459,  464 
Spermatic  artery,  (o)  489,  (d)  484 

cord,  418 

fascia,  423 

plexus,  443 

veins  (o)  484,  (c)  492 
Spheno-palatine  artery,  142 
ganglion,  139 
nerves,  104 
Sphincter  ani  externus,  389 
internus,  389 

of  the  pupil,  661 

vaginae,  402 

vesicae,  525 
Spigelian  lobe,  467 


Spinal  accessory  nerve,  (o)  181,  (d)  114 
nucleus,  187 

arteries,  174,  379 

cord,  380 

membranes  of,  374 
structure,  382 

nerves,  377 

filaments  of  origin,  383 
roots  of,  377 

veins,  385 
Spinalis  dorsi  muscle,  362 
Spiral  tube  of  the  cochlea,  682 
Splanchnic  nerve,  large,  342,  (d)  452 
small,  342,  (d)  452 
smallest,  342,  (d)  452 
Spleen,  465 

connections,  435 

structure,  465 
Splenic  artery,  447,  466 

omentum,  447 

plexus  of  nerves,  451 

vein,  448 
Splenius  capitis  muscle,  361 

colli,  361 
Spongy  bones,  134 

part  of  the  urethra,  527 
Stapedius  muscle,  676 
Stapes  bone,  675 
Stellate  ligament,  344 
Stenson's  duct,  41 
Sterno-clavicular  articulation,  170 

cleido-mastoid  muscle,  71 

hyoid  muscle,  73 

thyroid,  73 
Stomach,  form  and  divisions,  453 

connections  of,  431 

structure  of,  453 
Straight  sinus,  27 
Striate  body,  203,  211 
Stylo-hyoid  ligament,  106 
muscle,  83 
nerve,  48 

glossus  muscle,  99,  148 

mastoid  artery,  94 

maxillary  ligament,  91 

pharyngeus  muscle,  106 
Subanconeus  muscle,  259 
Subarachnoid  space,  376 
of  the  cord,  376 
Subclavian  artery,  left,  118,  (o)  328 
right,  75 

vein,  79 
Subclavius  muscle,  232 
Subcrureus,  572 

Subcutaneous  malar  nerve,  60,  104 
Sublingual  artery,  101 

gland,  103 
Submaxillary  ganglion,  101 

gland,  97 

region,  97 
Submental  artery,  86 
Suboccipital  nerve,  anterior  branch,  115 

posterior  branch,  367 
Subpeduncular  lobe,  214 


INDEX 


713 


Subperitoneal  fat,  417,  561 
Subpubic  ligament,  547 
Subscapular  artery,  235 

nerves,  236 
Subscapularis  muscle,  241 
Substantia  gelatinosa,  383 

perforata  antica,  192 
Sulci  of  brain,  193,  213 
Sulcus,  longitudinal,  of  the  liver,  467 
spiralis,  683 
transverse,  467 
Superficial  fascia  of  tlie  abdomen,  405 
of  the  perinseum,  392 
of  the  thigh,  553,  554 
Superficialis  cervicalis  artery,  359 

volse  artery,  266 
Supinator  radii  brevis,  288 

longus,  284 
Supra-orbital  artery,  21,  56 
nerve,  22,  52 
renal  capsule,  478 

plexus,  451 
scapular  artery,  78,  247,  359 

nerve,  80,  248,  359 
spinal  artery,  248 
spinatus  muscle,  247 
trochlear  nerve,  23,  52 
Suspensory  ligament  of  the  lens,  667 
of  the  liver,  439 
of  the  penis,  408 
Sympathetic  nerve  in  the  abdomen,  443, 
452 
in  the  head,  33 
in  the  loins,  497 
in  the  neck,  115 
in  the  pelvis,  519 
in  the  thorax,  341 
Symphysis  pubis,  446 
Synovial  gland  of  Havers,  603 


TAENIA  hippocampi,  204 
semicircularis,  204 
Tarsal  artery,  631 
articulation,  647 
cartilages,  44 
Tarso-metatarsal  articulations,  649 
Taste  buds,  147 
Teeth,  132 
Tegmentum,  191 
Temporal  aponeurosis,  19 
artery,  86 
deep,  94 
middle,  87 
superficial,  21 
fascia,  19 
muscle,  20,  88 
nerves,  deep,  95 

superficial,  23,  48 
vein,  21,  88 
Temporo-fascial  nerve,  48 
malar  nerve,  60 

maxillary  articulation,  90 
sphenoidal  lobe,  194 


Tendo  Achillis,  609 

palpebrarum,  40 
Tendon  of  triceps  extensor,  566 
Tensor  palati  muscle,  129 

tarsi,  59 

tympani,  676 

vaginjB  femoris,  570 
Tentorium  cerebelli,  27 
Teres  major  muscle,  245 

minor,  245 
Testes,  479 

Thalamus  opticus,  207,  211 
Thebesian  foramina,  316 

valve,  317 
Thigh,  dissection  of,  back,  592,  597 

front,  552 
Third  nerve,  (o)  180,  (d)  54,  57,  (c)  30 

ventricle,  206 
Thoracic  duct,  118,  339,  494 

ganglia,  339 
Thoracic-acromial  artery,  234 

alar,  234 

humeral,  234 

long,  234 

superior,  234 
Thorax,  boundaries  of,  305 

parietes  of,  342,  237 
Thymus  body,  308 
Thyro-arytsenoid  articulation,  162 
ligaments,  156 

arytsenoideus  muscle,  153 

epiglottidean  ligament,  162 

hyoid  membrane,  161 
muscle,  73 
Thyroid  artery,  inferior,  78,  121 
superior,  85,  121 

axis  of  artery,  78 

body,  120 

cartilage,  159 

plexus  of  veins,  121 

vein,  inferior,  78,  121 
middle,  82 
superior,  85 
Tibial  artery,  anterior,  630 
posterior,  612 

nerve,  anterior.  683,  (d)  627 
posterior,  613 

veins,  anterior,  632 
posterior,  613 
Tibialis  anticus  muscle,  628 

posticus,  611,  625 
Tibio-tarsal  articulation,  643 
Tongue,  146 

muscles  of,  148 

nerves  of,  151 

vessels  of,  101 
Tonsil,  131 
Tonsilitic  artery,  86 
Torcular  Herophili,  27 
Trachea,  connections  of,  121,  333 

structure  of,  162 
Trachelo-mastoid  muscle,  363 
Tractus  intermedio-lateralis,  383 
Tragus,  46 


lU 


INDEX. 


Tragus — 

muscle,  46 
Transverse  colon,  434 

fissure  of  the  cerebrum,  204 

of  the  liver,  468 
ligament  of  the  acetabulum,  602 
of  the  atlas,  169 
of  the  fingers,  273 
of  the  knee,  639 
of  the  metacarpus,  280 
of  the  metatarsus,  624 
of  the  toes,  615 
perinaeal  artery,  393 
sinus,  29 

tarsal  articulation,  647 
Transversalis  abdominis  muscle,  413 
cervicalis  artery,  (o)  78,  (d)  359 
colli  muscle,  363 
faciei  artery,  (o)  87,  (d)  41 
fascia,  417,  428 
Transversus  auriculae  muscle,  47 
linguae,  150 
pedis,  621 
perinsei,  395,  403 
deep,  397,  403 
Trapezius  muscle,  354 
Trapezoid  ligament,  246 
Triangle  of  the  neck,  anterior,  69 

posterior,  69 
Triangular  cartilage  of  the  nose,  134 
fibro-cartilage  of  wrist,  297 
ligament  of  groin,  411 

of  the  urethra,  396 
space  of  the  thigh,  562 
surface  of  the  bladder,  525 
Triangularis  sterni  muscle,  238 
Triceps  extensor  cruris,  570 

cubiti,  258 
Tricuspid  valve,  318 
Trigeminal  nerve,  (o)  180,  (c)  31 
Trigonum  vesicae,  525 
Trochlea,  53 
Trochlear  nerve,  infra,  54 

supra,  23,  52 
Tube  of  the  cochlea,  681 
Tuber  cinereum,  206 
Tubercle  of  Rolando,  187 
Tubules  of  the  stomach,  454 
of  small  intestine,  459 
of  large  intestine,  463 
Tubuli  seminiferi,  481 

uriniferi,  474 
Tunica  albuginea  testis,  481 
Ruyschiana,  660 
vaginalis,  480 
oculi,  655 
vasculosa  testis,  481 
Turbinate  bones,  134 
Twelfth  intercostal  nerve,  416,  498,  581 
Tympanic  artery,  93 
Tympanum,  674 
arteries  of,  674 
lining  membrane,  677 
nerves  of,  677 


ULNAR  artery,  267,  273 
nerve,  (o)  236,  (c)  255,  (d)  269,  274 
veins,  268 

cutaneous  anterior,  261 
posterior,  261 
Umbilical  hernia,  426 

region  of  the  abdomen,  431 
vein,  469 
Umbilicus,  404 
Ureter,  477,  510,  526 
Urethra,  female,  541 

connections,  512 
orifice  of,  535 
structure,  542 
male,  interior,  526 

connections,  507,  526 
structure,  527 
Uterine  arteries,  511',  539 
plexus  of  nerves,  520 
veins  and  sinuses,  517 
Uterus,  537 

interior  of,  538 
ligaments  of,  510 
connections  of,  511 
structure  of,  538 
Utricle  of  the  ear,  685 
Uvea  iridis,  661 
Uvula  cerebelli,  212 
palati,  128 
vesicae,  574 


VAGINA,  connections,  512,  535 
structure  and  form,  536 
Vaginal  arteries,  516,  537 

plexus,  520 

veins,  517 
Vagus  nerve,  112,  181,  330,  452 

nucleus,  187 
Vallecula,  212 
Valve,  Eustachian,  317 

of  caecum,  462 

mitral,  320 

semilunar,  318,  321 

of  Thebesius,  317 

tricuspid,  318 

of  Vieussens,  215 
Valvulae  conniventes,  457 
Vas  deferens,  418,  483,  523 

aberrans,  483 
Vasa  aberrantia,  250 

brevia,  447 

efferentia  testis,  482 

rete  testis,  482 

vorticosa,  660 
Vascular  coat  of  eye,  658 
Vastus  extern  us  muscle,  571 

internus  muscle,  571 
Vein,  alveolar,  142 

angular,  21 

ascending  cervical,  78 
lumbar,  498 
pharyngeal,  110 

auditory,  687 


INDEX 


715 


Vein- 


auricular,  posterior,  21 

axillary,  235 

azygos,  large,  338,  495 

small,  338,  494 

superior,  left,  338 
basilic,  249 
brachial,  255 
bracliio-ceplialic,  left,  329 

right,  328 
bronchial,  left,  336,  337 

right,  336,  337 
cardiac,  anterior,  314 

great,  314 

small,  314 
cava,  inferior,  329,  444,  492 

superior,  328 
cephalic,  250 
cerebellar,  177 
cerebral,  177 
choroid,  206 
ciliary,  anterior,  662 

posterior,  663 
circumflex  iliac,  420,  491 
coronary  of  the  heart,  314 

of  the  stomach,  448 
of  the  corpus  cavernosum,  531 

striatum,  206 
deep  cervical,  77,  368 
diaphragmatic,  inferior,  492 
dorsal,  of  the  penis,  517 
dorsi-spinal,  369 
emissary,  21 
emulgent,  476,  492 
epigastric,  deep,  420,  491 

superficial,  407,  554 
facial,  40,  b6 
femoral,  565,  568 
frontal,  21 
of  Galen,  208 
gastro-epiploi'c,  left,  449 
hemorrhoidal,  517,  533 
hepatic,  471,  492 
iliac,  common,  491 

external,  491 

internal,  517 
infraorbital,  40,  105 
innominate,  328 
intercostal,  338 

posterior  branch,  368,  385 

superior,  left,  338 
right,  338 
intraspinal,  385 
interlobular,  471 
intralobular,  471 
jugular,  anterior,  71 
external,  42,  62 

internal,  left,  118 
right,  82,  109 
laryngeal,  158 
lingual,  101 
longitudinal,  of  the  spine,  anterior, 

385 
lumbar,  369,  498 


Vein — 

mammary,  internal,  238,  329 
median,  of  the  arm,  249,  261 

basilic,  249 

cephalic,  249 

maxillary,  internal,  94,  329 
anterior,  internal,  40,  142 
mesenteric,  inferior,  443 

superior,  441 
occipital,  21,  80,  369 
ophthalmic,  57 
ovarian,  492 
palpebral,  inferior,  40 
pancreatic,  448 
perineal,  superficial,  393 
pharyngeal,  110 
phrenic,  inferior,  492 
popliteal,  596 
portal,  448,  471 

posterior,  spinal,  plexus  of,  385 
profunda  of  the  thigh,  579 
pterygoid  plexus,  94 
pudic  external,  555 

internal,  (o)  399,  (c)  532 
pulmonary,  319,  329 
radial  cutaneous,  261 
ranine,  101 
renal,  476,  492 
sacral,  lateral,  517 

middle,  517 
saphenous,  external,  606,  (o)  626 

internal,  555,  (o)  626 
spermatic,  484,  492 
spinal,  380 
splenic,  448 
subclavian,  79 
sublobular,  471 
supra-orbital,  21 

renal,  479,  492 

scapular,  78,  248,  359 
temporal,  21,  87 

superficial,  21 
thyroid,  inferior,  78,  121,  329 

middle,  82 

superior,  85 
tibial  anterior,  632 

posterior,  613 
transverse  cervical,  78,  359 
ulnar,  267 

cutaneous,  anterior,  261 
posterior,  261 
umbilical,  469 
uterine,  517 
vaginal,  517 
vertebral,  77,  166 
vesical,  517 
of  the  vertebrae,  385 
Velum  interpositum,  205 
pendulum  palati,  128 
Vena  cava,  inferior,  444,  492 

superior,  328 
port*,  449,  (d)  471 
:  Ven.ie  cavje  hepaticse,  471 
I  Venous  arch  of  the  foot,  626 


716 


INDEX 


Venous  arch — 

of  the  hand,  261 
Ventricles  of  the  brain,  200 
fifth,  202 
fourth,  217 
lateral,  200 
third,  206 
of  the  heart,  313 
left,  320 
right,  317 
structure  of,  321 
of  the  larynx,  156 
Vermiform  appendix,  433,  462 

processes,  212,  216 
Vertebral  artery,  (o)  77,  (c)  165,  (d)  174 
plexus,  117,  166 
vein,  77,  (o)  166 
Veru  montanum,  526 
Vessels  of  the  brain,  174 

of  the  dura  mater,  29,  376 
Vesica  urinaria,  524 
Vesical  artery,  inferior,  515 
superior,  515 
plexus  of  nerves,  520 
veins,  517 
Vesicula  prostatica,  526 
Vesicular  column  of  cord,  383 
Vesiculse  seminales,  connections,  507 
structure,  522 


Vestibule  of  the  ear,  679 
artery  of,  687 
nerve  of,  687 

of  the  vulva,  535 
Vestigial  fold  of  pericardium,  311 
Vidian  artery,  142 

nerve,  141 
Villi,  intestinal,  458 
Vitreous  body,  666 

fluid,  667 
Vocal  cords,  156 
Vulva,  533 


WHARTON'S  duct,  98,  103 
White    commissure   of    the   cord^ 
382 
Winslow's  foramen,  437 
Wrisberg's  nerve,  236,  251,  256 
Wrist-joint,  296 


ELLOW  spot  of  eyeball,  664,  666 


ZONULE  of  Zinn,  667 
Zygomaticus  major  muscle,  39 
minor  muscle,  39 


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Edited  BY  I.  MINIS  HAYS,  M.D., 

is  published  Quarterly,  on  the  first  of  January,  April,  July,  and  October.  Each  num- 
ber contains  nearly  three  hundred  large  octavo  pages,appropriately  illustrated  wher- 
ever necessary.  It  has  now  been  issued  regularly  for  over  fifty  years,  during  the 
whole  of  which  time  it  has  been  under  the  control  of  the  presentseuior  editor.  Through- 
out this  long  period,  it  has  maintained  its  position  in  the  highest  rank  of  medical  peri- 
odicals both  at  home  and  abroad,  and  has  received  the  cordial  support  of  the  entire 
profession  in  this  country.  Among  its  Collaborators  will  be  found  a  large  number  of 
the  most  distinguished  names  of  the  profession  in  every  section  of  the  United  States, 
rendering  its  original  department  a  truly  national  exponent  of  American  medicine.* 

Following  this  is  the  "'Rkview  Department,"  containing  extended  and  impartial 
reviews  of  important  new  works,  together  with  numerous  elaborate  "Analytical  and 
Bibliographical  Notices"  giving  a  complete  survey  of  medical  literature. 

This  is  followed  by  the  "Quarterly  Summary  of  Improvements  and  Discoveries 
in  the  Medical  Sciences,"  classified  and  arranged  under  different  heads,  presenting 
a  very  complete  digest  of  medical  progress  abroad  as  well  as  at  home. 

Thus,  during  the  year  1878,  the  "Journal"  furnished  to  its  subscribers  77  Original 
(Communications,  183  Reviews  and  Bibliographical  Notices,  and  ^55  articles  in  the 
Quarterly  Summaries,  making  a  total  of  Four  Hundred  and  Sixty-five  arti(-les 
illustrated  with  48  maps  and  wood  engravings,  emanating  from  the  best  professional 
minds  in  America  and  Europe. 

'i'hat  the  efforts  thus  made  to  maintain  the  high  reputation  of  the  "Journal"  are 
successful,  is  shown  by  the  position  accorded  to  it  in  both  America  and  Europe  as  a 
leading  organ  of  medical  progress: — 

This  16  uuivevHally  acknowledged  as  the  leading  Oar  venerable  contemporary  has  our  best  wishes, 
American  Journal,  and  has  been  conducted  by  Dr.  j  and  we  can  only  express  the  hope  that  it  may  con- 
Hays  alone  until  1869,  when  his  sou  was  associated  tinue  its  work  with  as  much  vigor  and  excellence  for 
wich  him.  We  quite  agree  with  the  critic,  that  this  the  next  fifty  years  as  it  has  exhibited  iu  the  past, 
journal  is  second  to  uoue  in  the  language,  and  cheer-  j  — London  Lancet,  Nov.  24,  1877, 
fully  accord  to  it  the  first  place,  for  nowhere  shall !  „.  •,    j   ,   ,  •     nr  j-     ,        ^  t.,      -it 

we  find  more  able  and  more  impartial  criticism,  and  The  Philadelphia  Medical  and  Physical  Journal 
nowhere  such  a  repertory  of  able  original  articles,  issued  its  first  number  in  1820,  and,  after  a  brilliant 
Indeed,  now  that  the  "B'riiish  and  Foreign  Medico-  career,  was  succeeded  in  1827  by  the  American 
Chirurgical  Review"  has  terminated  its  career,  the  :  Journal  of  the  Medical  Sciences,  a  periodical  of 
American  Journal  stands  without  a  rival.— Zoredon  world-wide  reputation;  the  ablest  and  one  of  the 
Med.  Times  and  Gazette,  Nov.  24,  1877.  oldest  periodicals  in  the  world— a  journal  which  has 

„,     ,  ,.     ,  J  ,        .,  ..       X      Ti        an  unsullied  record. — Gross's  History  of  American 

The  best  medical  jourual  on  the  continent  — Bos-    ^^d   Literature   1876 
ton  Med  and  Surg.  Journal,  h.-^v\\n,\%lQ.  i      m,  •    •    .,  j'      ,  •  ■.    ,  ,.  . 

,    .  .  ,,         ,  ,,,.,,,,.       I      Ihis  IS  the  medical  journal  of  our  country  to  whicn 

It  18  universally  acknowledged  to  be  the  leading   ^1,^  American  physician  abroad  will  point  witli  tht 


American  medical  journal,  and,  in  our  opinion. 


greatest  satisfaction,  as  reflecting  the  state  of  medical 


second  to  none  in  ttie  language— fio*f on  Med.  and  culture  in  his  country.     For  a  great  many  years  it 

tiarg.  Journal^  Oct.  IS//.  ^i'd.^  been  the  medium  through  which  our  ablest  writ- 

The  present  number  of  the  American  Journal  is  an  ers  have  made  known  their  discoveries  and  observa- 

exceedingly  good  one,  and  gives  every  promise  of  tions — Address  of  L.  P.  Yandell,  M.D., before  Inter- 

maintaining  the  well  earned  reputation  iif  the  review,  national  Med.  Congress,  Sept.  1876. 

And  that  it  was  specifically  included  in  the  award  of  a  medal  of  merit  to  the  Publisher 
in  the  Vienna  Exhibition  in  1873. 

'l"he  subscription  price  of  the  "American  Journal  of  the  Medical  Sciences"  has 
never  been  raised  during  its  long  career.  It  is  still  Five  Dollars  per  annum  ;  and 
when  paid  for  in  advance,  the  subscriber  receives  in  addition  the  "Medical  News  and 
Library,"  making  in  all  about  1.500  large  octavo  pages  per  annum,  free  of  postage. 

THE  MEDICAL  NEWS  AND  LIBRARY 

is  a  monthly  periodical  of  Thirty-two  large  octavo  pages,  making  384  pages_  per 
annum.  Its  "Library  DkpartmexXt"  is  devoted  to  publishing  standard  works  on  the 
various  branches  of  medical  science,  paged  separately,  so  that  they  can  be  detached 
for  i)inding,  when  complete.  In  this  manner  subscribers  have  received,  without  ex- 
pense, such  works  as  "Watson's  Practice,"  "West  on  Children,"  "Malgaignk's 
Surgery,"  "Stokes  on  Fever,"  Gosselin's  "Clinical  Lectures  on  Surgery,"  and 
many  other  volumes  of  the  highest  reputation  and  usefulness.  With  July,  1878,  was 
commenced  the  publication  of  "Lectures  on  Diseases  of  the  Nervous  System,"  by 
J.  M.  Charcot,  Professor  in  the  Faculty  of  Medicine  of  Paris,  translated  from  the 
French  by  (jFiorge  Sigerson,   M.D.,  Lecturer  on  Biology,  etc.,  Catholic  Univ.  of 

*  Coramiinlcatious  are  invited  from  gentlemen  in  all  parts  of  the  country.    Elaborate  articles  inserted 
by  the  Editor  are  paid  for  by  the  Publisher. 


Henry  C.  Lea's  Publications— (^wi.  Journ.  Med.  Sciences).         3 

Ireland  [see  p.  17),  which  will  be  continued  to  completion  during  1879.  New  sub- 
scribers, commencing  with  Junuary,  1879,  can  procure  the  previous  portion  by  a 
remittance  of  50  cents,  if  promptly  made. 

The  "  Nkws  Dkpartmknt"  of  the  "Mkdical  News  and  Library"  presents  the 
current  information  of  the  month,  with  Clinical  Ijectures  and  Hospital  Gleanings. 
A  new  and  attractive  feature  of  this  will  be  found  in  an  elaborate  series  of  Original 
American  Clinical  Lectures,  specially  contributed  to  the  News  by  gentlemen  of 
the  highest  reputation  in  the  profession  throughout  tho  United  States.  During  1878 
there  have  appeared  Lectures  by 

S.  D.  Gross,  M.D.,  Prof,  of  Surgery,  Jefferson  Med.  Coll.,  Philada. 

T.  Gaillard  Thomas,  M.D.,  Prof.  Obstetrics,  &c..  Coll.  Phys.  and  Surg.,  N.  Y. 

William  Pepper,  M.D.,  Prof.  Clin.  Medicine,  Univ.  of  Penna. 

Lewis  A.  Sayre.M.D.,  Prof.  Orthopaedic  Surg.,  Bellevue  Hosp. Med.  Coll.,  N.Y. 

Egberts  Bartiiolow,  M.D.,  Prof.  Theory  and  Practice  of  Med.,  Med.  Coll.  of  Ohio. 

T.  G.  Richardson,  M.D.,  Prof.  Genl.  and  Clin.  Surg.,  Univ.  of  La.,  New  Orleans. 

S.  W.  Gross,  M.D.,  Surg,  to  Philada.  Hospital. 

F.  Peyre  Porcher,  M.D.,Prof.  of  Mat.  Med.  and  Clin.  Medicine,  Med.  CoU.of  S.  C. 

William  Goodell,  M.D.,  Prof.  Clin.  Gynaecology,  Univ.  of  Penna. 

N.  S.  Davis,  M.D.,  Prof.  Prin.  and  Pra'c.  of  Med.,  Chicago  Med.  Coll. 

W.  H.  Van  Buren,  M.D.,  Prof.  Surgery,  Bellevue  Hosp.  Med.  Coll.,  N.Y. 
To  be  followed  by  others  of  similar  value  from 

Austin  Flint,  M.D.,  Prof.  Prin.  and  Prac.  of  Med.,  Bellevue  Hosp.  Med.  Coll.,  N.Y. 

FoRDYCE  Barker.  M.D.,  Prof.  Clin.  Midwifery ,&c.,  Bellevue  Hosp.  Med.  Coll.,  N.Y. 

L.  A,  DuHRiNG,  M.D.,  Clin.  Prof,  of  Diseases  of  the  Skin,  Univ.  of  Penna. 

Theophilus  Parvin,  M.D.,  Prof.  Obstetrics,  &c.,  Coll.  Phys.  and  Surg., Indianapolis. 

J.  P.  White,  M.D.,  Prof,  of  Obstetrics,  &c.,  Univ.  of  Buffalo. 

John  Ashhurst,  Jr.,  M.D.,  Prof,  of  Clin.  Surg.,  Univ.  of  Penna. 

D.  Warren  Brickell,  M.D.,  Prof.  Obstetrics,  &c..  Charity  Hosp.  Med.  Coll.,  N.  0. 

J.  Lewis  Smith,  M.D.,  Clin.  Lee.  on  Dis.  of  Chil.,  Bellevue  Hosp.  Med.  Coll.,  N.  Y. 

William  F.  Nqrris,  M.D.,  Clin.  Prof,  of  Diseases  of  the  Eye,  Univ.  of  Penna. 

P.  S.  Conner,  M.D.,  Prof.,  of  Anat.  and  Clin.  Surgery,  Med.  Coll.  of  Ohio,  Cin. 

S.  Weir  Mitchell,  M.D.,  Phys.  to  the  Infirmary  for  Nervous  Diseases,  Philada. 

J.  M.  DaCosta,  M.D.,  Prof.  Prin.  and  Prac.  of  Med.,  Jeff.  Med.  Coll.,  Philada. 

Thomas  G.  Morton,  M.D.,  Surgeon  to  Penna.  Hospital,  Philada. 

F.  J.  Bumstead,  M.D.,  late  Prof,  of  Venereal  Dis.,  Coll.  Phys.  and  Surg.,  N.Y. 

J.  H.  Hutchinson,  M.D.,  Physician  to  Penna.  Hospital. 

Christopher  Johnson,  M.D.,  Prof,  of  Surgery,  Univ.  of  Md.,  Baltimore. 

William  Thomson,  M.D.,  Lecturer  on  Ophthalmology,  Jeff.  Med.  Coll.,  Philada. 

With  contributors  such  as  these,  representing  every  portion  of  the  United  States, 
the  publisher  feels  safe  in  promising  to  the  subscriber  a  series  of  practical  lectures 
unsurpassed  in  variety,  interest,  and  value. 

As  stated  above,  the  subscription  price  of  the  "  Medical  News  and  Library"  is 
One  Dollar  per  annum  in  advance;  and  it  is  furnished  without  charge  to  all  advance- 
paying  subscribers  to  the  "American  Journal  of  the  Medical  Sciences." 

III. 

THE  MONTHLY  ABSTRACT  OF  MEDICAL  SCIENCE 

is  issued  on  the  first  of  every  month,  each  number  containing  forty-eight  large  octavo 
pages,  thus  furnishing  in  the  course  of  the  year  about  six  hundred  pages.  The  aim 
of  the  •'  Abstract"  is  to  present — without  duplicating  the  matter  in  the  "Journal" 
and  "  News" — a  careful  condensation  of  all  that  is  new  and  important  in  the  medical 
journalism  of  the  world,  and  all  the  prominent  professional  periodicals  of  both  hemi- 
spheres are  at  the  disposal  of  the  Editors.  'I'o  show  the  manner  in  which  this  plan 
has  been  carried  out  it  is  sufficient  to  state  that  during  the  year  1878  it  contained — 

30  Articles  on  Anfitoniy  and  I'hysiologij. 

/><»  **  •'    Mati'vla  Medica  and  Therapeutics, 

'^30         «  «    AK'diiine. 

15  L  '*  "     Surf/eri/. 

79.        <•  «*     3li(iitu/'rrfj  and  Gf/na^coloyif, 

I'J  '*  "    JSli'dical  fTtiri.sprudeuce  uiid  Toxicology — 

making  in  all  .558  articles  in  a  single  year. 

The  subscription  to  the  "  Monthly  Abstract,"  free  of  postage,  is  Two  Dollars 
AND^  Half  a  year,  in  advance. 

As  stated  above,  however,  it  will  be  supplied  in  conjunction  with  the  "American 
Journal  of  the  Medical  Sciences"  and  the  "Medical  News  and  Library,"  making 
in  all  about  Twenty-one  Hundred  pages  per  annum,  the  whole /ree  of  postage,  for 
Six  Dollars  a  year,  in  advance. 

In  this  effort  to  bring  so  large  an  amount  of  practical  information  within  the  reach 
of  every  member  of  the  profession,  the  publisher  confiJently  anticipates  the  friendly 


4  Henry  C.  Lea's  Publications — {Dictionaries). 

aid  of  all  who  are  interested  in  the  dissemination  of  sound  medical  literature.  He 
trusts,  especially,  that  the  subscribers  to  the  "Amkrican  Medical  Journal"  will  call 
the  attention  of  their  acquaintances  to  the  advantages  thus  ottered,  and  that  he  will 
be  sustained  in  the  endeavor  to  permanently  establish  medical  periodical  literature 
on  a  footinir  of  cheapness  never  heretofore  attempted. 

PREMIUM  rOR  OBTAINING  NEW  SUBSCEIBERS  TO  THE  "JOURNAL." 

Any  (rentleman  who  will  remit  the  amount  for  two  subscriptions  for  1879,  one  of 
which  must  be  for  a  neiu  t^uhscnher,  will  receive  as  a  premium,  free  by  mail,  a  copy  of 
"  Holden's  Landmarks,  Medical  and  Suhgical"  (for  advertisement  of  which  see  p. 
6),  or  of  Fothehgill's  "  Antagonism  of  Medicines"  (see  p.  If.),  or  of  "  Browne  on 
THE  Use  of  the  Ophthalmoscope"  (seep.  20),  or  of  "  Ffjnt's Essays  on  Conservative 
Medicine"  (see  p.  I.t),  or  of  "Sturges's  Clinical  Medicine"  (see  p.  14),  or  of  the 
new  edition  of  "Swayne's  Obstetric  Aphorisms"  (see  p.  21),  or  of  "Tanner's 
Clinical  Manual"  (see  p.  5),  or  of  "Chambers's  Restorative  Medicine"  (see  p. 
18),  or  of  "West  on  Nervous  Disorders  of  Children  '  (see  p.  20;. 

*^*  Gentlemen  desiring  to  avail  themselves  of  the  advantages  thus  offered  will  do 
well  to  forward  their  subscriptions  at  an  early  day,  in  order  to  insure  the  receipt  of 
complete  sets  for  the  year  1879. 

t^  The  safest  mode  of  remittance  is  by  bank  check  or  postal  money  order,  drawn 
to  the  order  of  the  undersigned.  Where  these  are  not  accessible,  remittances  for  the 
"Journal"  may  be  made  at  the  risk  of  the  publisher,  by  forwarding  in  registered 
letters.     Address, 

HENRY  C.  LEA,  Nos.  706  and  708  Sansom  St.,  Philadelphia,  Pa. 


jyUNOLISON  {ROBLEY),  M.D., 

'^'^  Late  Professor  of  Institutes  of  Medicine  in  Jefferson  Medical  College,  Philadelphia. 

MEDICAL  LEXICON;   A  Dictionary  op  Medical  Science:   Cor- 

tfiining  a  concise  eKpltination  of  the  various  Subjects  and  Terms  of  Anatomy,  Physiology, 
Pathology,  Hygiene,  Therapeutics.  Pharmacology,  Pharmacy,  Surgery,  Obstetrics,  Medicnl 
Jurisprudence,  and  Dentistry.     Notices  of  Climate  and  of  Mineral  Waters  ;  Formulae  fur 
Officinal,  Empirical,  and  Dietetic  Preparations;  with  the  Accentuation  and  Etymology  of 
the  Terms,  and  the  French  and  other  Synonymes  ;  so  as  to  constitute  a  French  as  well  as 
English  Medical  Lexicon.     A  New  Edition.     Thoroughly  Revised,  and  very  greatly  Mod- 
ified and  Augmented.     By  Richard  J.  I>unglison,  M.D.     In  one  very  large  and  hand- 
some  royaloctavo  volume  of  over  1100  pages.     Cloth,  $6  50;  leather,  raised  bands,  $7  50. 
(J?/5<  Issued.) 
The  object  of  the  author  from  the  outset  has  not  been  to  make  the  work  a  mere  lexicon  or 
dictionary  of  terms,  but  to  afford,  under  each,  a  condensed  view  of  its  various  medical  relations, 
and  thus  to  render  the  work  an  epitome  of  the  existing  condition  of  medical  science.    Starting 
with  this  view,  the  immense  demand  which  has  existed  forthe  work  has  enabled  him,  in  repeated 
revisions,  to  augment  its  completeness  and  usefulness,  until  at  length  it  has  attained  the  position 
of  a  recognised  and  standard  authority  wherever  the  language  is  spoken. 

Special  pains  have  been  taken  in  the  preparation  of  the  present  edition  to  maintain  this  en  • 
viable  reputation.  During  the  ten  years  which  have  elapsed  since  the  last  revision,  the  additions 
to  the  nomenclature  of  the  medical  sciences  have  been  greater  than  perhaps  in  any  similar  period 
of  the  pait,  and  up  to  the  time  of  his  death  the  author  labored  assiduously  to  incorporate  every- 
thing requiring  the  attention  of  the  student  or  practi^Joner.  Since  then,  the  editor  has  been 
equally  industrious,  so  that  the  additions  to  the  vocabulary  are  more  numerous  than  in  any  pre- 
vious revision.  Especial  attention  has  been  bestowed  on  the  accentuation,  which  will  be  found 
marked  on  every  word.  The  typographical  arrangement  has  been  much  improved,  rendering 
reference  much  more  easy,  and  evary  care  has  been  taken  with  the  mechanical  execution.  The 
work  has  been  printed  on  new  type,  small  but  exceedingly  clear,  with  an  enlarged  page,  so  that 
the  additions  have  been  incorporated  with  an  increase  of  but  little  over  a  hundred  pages,  and 
the  volume  now  contains  the  matter  of  at  least  four  ordinary  octavos. 

^^ience  so  extensive,  and  with  such  collaterals  as  medi- 
;ine,  it  is  as  much  a  necessity  also  to  the  practising 
ohynician.  To  meet  the  wants  of  students  and  most 
physiitians,  the  dictionary   must  be  condensed  while 


A  book  well  known  to  our  readers,  and  of  which 
every  American  ought  to  he  proud.  When  the  learned 
author  of  the  work  paused  away,  probably  all  of  us 
feared  lest  the  book  should  not  maintain  its  place 
in  the  advancing  science  whoRo  terms  it  defines.  For- 
tunately, Dr.  llichard  J.  Dun|ili3on,  having  assisted  liis 
father  in  the  revision  of  several  editions  of  the  work, 
and  having  been,  therefore,  trained  in  the  methods  and 
imbued  with  the  spirit  of  the  book,  has  been  able  to 
edit  it,  not  in  the  patchwork  manner  so  dear  to  the 
heart  of  book  editors,  so  repulsive  to  the  taste  of  intel- 
ligent book  readers,  but  to  edit  it  as  a  work  of  the  kind 
should  be  edited — to  carry  it  on  steadily,  without  jar 
or  interruption,  along  the  grooves  of  thought  it  has 
travelled  during  its  lifetime.  To  show  the  magnitude 
of  the  task  which  Dr.  Dunglison  has  assumed  and  car- 
ried through,  it  is  only  nec<;ssary  to  state  that  more 
than  six  thousand  new  subjects  have  been  added  in  the 
present  edition.— P^iZa.  Med.  Times,  Jan.  3,  1874. 

About  the  first  book  purchased  by  the  medical  stu- 
dent is  the  Medical  Dictionary.  The  lexicon  explana- 
tory of  technical  term?"  is  simply  a  iitie  qua  non.  In  a  ' 


comprehensive,  and  practical  while  perspicacious.  Jt 
'vas  becaupe  Dunglison's  met  these  indications  that  it 
became  at  once  the  dictionary  of  general  use  wherever 
medicine  was  studied  in  the  Knglish  language.  In  no 
formerrevision  have  the  alterations  and  additions  been 
■(o  great.  More  than  six  thousand  new  subjects  and  terms 
liave  been  added.  The  chief  terms  have  been  set  in  black 
letter,  while  the  derivatives  follow  in  small  caps;  an 
arrangement  which  greatly  facilitates  reference.  We 
may  safely  confirm  the  hope  ventured  by  the  editor 
"  that  the  work,  which  possesses  for  him  a  filial  as  well 
as  an  individual  interest,  will  be  found  worthy  a  con- 
tinuance of  the  position  so  long  accorded  to  it  as  a 
standard  authoritv."— Cincinnrtrt  Clinic,  Jan.  10, 1874. 
It  has  the  rare  merit  that  it  certainly  has  no  rival 
In  the  English  language  for  accHracy  and  extent  of 
refereuces. — London  Medical  Oatette. 


Henry  C.  Lea's  Publications — {Manuals), 


A  CENTURY  OF  AMERICAN  MEDICINE,  1776-1876.  By  Doctors  E.  H. 
-^  Clarke,  H.  J.  Bigelow,  S.  D.  Gross,  T.  G.  Thomas,  and  J.  S.  Billings.  In  one  very  hand- 
some 12mo.  volume  of  about  350  pages  :  cloth,  $2  25.      {Just  Ready.) 

This  work  appeared  in  the  pages  of  the  American  Journal  of  the  Medical  Sciencesduring  the 
year  1876.  As  a  detailed  account  of  the  development  of  medical  science  in  America,  by  gentle- 
men of  the  highest  authority  in  their  respective  departments,  the  profession  will  no  doubt  wel- 
come  it  in  a  form  adapted  for  preservation  and  reference. 


E 


OBLYN  {RICHARD  D.),  M.D. 

A  DICTIONARY  OF  THE  TERMS  USED  IN  MEDICINE  AND 

THE  COLLATERAL  SCIENCES.     Revised,  with  numerous  additions,  by  Isaac  Hays, 
M.  D.,  Editor  of  the  "  American  Journal  of  the  Medical  Sciences."     In  or^  large  royal 
12mo.  volume  of  over  600  double-columned  pages;  cloth,  $1  50  ;  leather,  $z  00 
It  is  the  best  book  of  defluitions  we  have,  aud  ought  always  to  be  upou  the  student's  i&h\Q.— Southern 
Med.  and  Surg.  Journal.  

T>OD  WELL  [G.  F),  F.R.A.S..  ^r. 

A  DICTIONARY  OF  SCIENCE:  Comprising  Astronomy,  Chem- 
istry, Dynamics,  Electricity,  Heat,  Hydrodynamics,  Hydrostatics,  Light,  Magnetism, 
Mechanics,  Meteorology,  Pneumatics,  Sound,  and  Statics.  Preceded  by  an  Essay  on  the 
History  of  the  Physical  Sciences.  In  one  handsome  octavo  volume  of  694  pages,  and 
many  illustrations  :  cloth,  $5. 

l^EILL  {JOHN),  M.D.,  and    J^MITH  {FRANCIS  G.),  M.D., 

"^  Prof,  of  the  Institutesvf  Medicine  in  the  Univ.  of  Penna. 

AN    ANALYTICAL    COMPENDIUM    OF    THE    VARIOUS 

BRANCHES  OF  MEDICAL  SCIENCE;  for  the  Use  and  Examination  of  Students.  A 
new  edition,  revised  and  improved.  In  one  very  large  and  handsomely  printed  royal  12mo  . 
volume,  of  about  one  thousand  pages,  with  374  wood-cuts,  cloth,  $4  ;  strongly  bound  in 
leather,  with  raised  bands,  $4  75. 


H 


ARTSHORNE  {HENRY),  M.  D., 

Professor  of  Hygiene  in  the  University  of  Pennsylvania. 

A    CONSPECTUS    OF    THE    MEDICAL    SCIENCES;    containing 

Handbooks  on  Anatomy,  Physiology,  Chemistry,  Materia  Medica,  Practical  Medicine, 
Surgery,  and  Obstetrics.  Second  Edition,  thoroughly  revised  and  improved.  In  one  large 
royal  12mo.  volume  of  more  than  1000  closely  printed  pages,  with  477  illustrations  on 
wood.     Cloth,  $4  25  ;  leather,  $5  00.     {Lately  Issued.) 

dents,  btit  to  many  others  whomay  desire  torefresh 
their  memories  with  the  smallest  possible  expendi- 
ture of  time. — N.  Y.  Med.  Journal,  Sept.  1874. 

The  student  will  find  this  the  most  convenient  and 
useful  book  of  the  kind  on  which  he  can  lay  his 
hand. — Pacific  Med.  and  Surg.  Journ.,  Aug.  1S74. 
This  is  the  best  book  of  its  kind  that  we  have  ever 
examined.  It  is  an  honest,  accurate,  aud  concise 
compend  of  medical  sciences,  as  fairly  as  possible 
representing  their  present  condition.  The  changes 
and  the  additions  have  been  so  judicious  and  tho- 
rough as  to  render  it,  so  far  as  it  goes,  entirely  trust- 
worthy. If  students  mast  have  a  conspectus,  they 
will  be  wise  to  procure  that  of  Dr.  Hartshorne. — 
Detroit  Rev.  of  Med   and  Pharm.,  Aug.  1874. 


We  can  say  with  the  strictest  truth  that  it  is  the 
best  work  of  the  kind  with  which  wc  artacqnainted. 
It  embodies  ina  condensed  form  ii.il  recent  coutiibu- 
tions  to  practical  medicine,  ana  is  therefore  useful 
to  every  busy  practitioner  throughout  our  country, 
besides  being  admirably  adapted  to  the  use  of  stu- 
dents of  medicine.  The  book  is  faithfully  and  ably 
executed. — Charleston  Med.  Journ.,  April,  1875. 

The  work  is  intended  as  an  aid  to  the  medical 
student,  and  as  such  appears  to  admirably  fulfil  its 
object  by  itsexcellent  arrangement,  the  full  compi- 
lationof  facts,  the  perspicuity  and  terseness  of  lan- 
guage, and  the  clear  and  instructive  illustrations 
in  some  parts  of  the  work — American  Journ.  of 
Pharmacy,  Philadelphia,  July,  1874. 

The  volume  will  be  found  useful,  not  only  to  stu- 


TUDLOW  {J.L.),  M.D. 
A   MANUAL   OF  EXAMINATIONS  upon  Anatomy,  Physiology, 

Surgery,  Practice  of  Medicine,  Obstetrics,  Materia  Medica,  Chemistry,  Pharmacy,  and 
Therapeutics.  To  which  is  added  a  Medical  Formulary.  Third  edition,  thoroughly  revised 
and  greatly  extended  and  enlarged.  With  370  illustrations.  In  one  handsome  royal 
12mo.  volume  of  816  large  pages,  cloth,  $3  25  ;  leather,  $3  75.  ' 
The  arrangement  of  this  volume  in  the  form  of  question  and  answer  renders  it  especially  suit- 
able for  the  office  examination  of  students,  and  for  those  preparing  for  graduation. 

/TANNER  {THOMAS  HAWKES),  M.D.,  §-c. 

^  A  MANUAL  OF  CLINICAL  MEDICINE  AND  PHYSICAL  DIAG- 

NOSIS.     Third  American  from  the  Second  London  Edition.    Revised  and  Enlarged  by 
Tilbury  Fox,  M.  D.,  Physician  to  the  Skin  Department  in  University  College  Hospital, 
Ac.   In  one  neat  volumesmall  12mo.,  of  about  375  pages,  cloth,  $150. 
*^*  On  page  4,  it  will  be  seen  that  this  work  is  offered  as  a  premium  for  procuring  neW 
subscribers  to  the  "Amekican  Journal  op  the  Medical  Sciences." 


Henry  C.  Lea's  Publications — (Anatomy). 


QRAY  {HENRY),  F.R.S., 

Lecturer  on  Anatomy  at  St.  George's  Hospital,  London. 

ANATOMY,  DESCRIPTIVE    AND  SURGICAL.     The  Drawings  by 

H.  V.  Carter,  M.D.,  and  Dr.  Westmacott.    The  Dissecbionsjointly  by  the  Author  and 
Dr.  Carter.     With  an   Introduction   on    General   Anatomy  and  Development  by  T. 
lIoLMBS,  M.A.,  Surgeon  to  St.  George's  Hospital.     A  new  American,  from  the  eighth 
enlargec  and  improved  London  edition.     To  which  is  added  *'  Landmarks,  Medical,  and 
Surgical,"  by  Luther  Holden,  F.R  C.S.,  author  of  "  Human  Osteology,"  '*  A  Manual 
of  Dissections,"   etc.     In  one  magnificent  imperial  octavo  volume  of  983  pages,  with 
522  large  and  elaborate  engravings  on  wood.     Cloth,  $6;  leather,  raised  bands,  $7. 
{^Just  Ready.) 
The  author  has  endeavored  inthisworkto  cover  a  more  extendedrange  of  subjects  than  iscue- 
tomary  in  tWe  ordinary  text-books,  by  giving  not  only  the  details  necessary  for  the  student,  but 
also  the  application  of  those  details  in  the  practice  of  medicine  and  surgery,  thusrendering  it  both 
a  guide  for  the  learner,  and  an  admirable  work  of  reference  for  the  active  practitioner.  The  en- 
gravings form  a  special  feature  in  the  work,  many  of  them  being  the  size  of  nature,  nearly  all 
original,  and  having  the  names  of  the  various  parts  printed  on  the  body  of  the  cut,  in  place  of 
figures  of  reference,  with  descriptions  at  the  foot.  They  thus  form  a  complete  and  splendid  series, 
which  will  greatly  assist  the  student  in  obtaining  a  clear  idea  of  Anatomy,  and  will  also  serve  to 
refresh  the  memory  of  those  who  m^ay  find  in  the  exigencies  of  practicethenecessity  of  recalling 
the  details  of  the  dissecting  room  ;  while  combining,  as  it  does,  a  complete  Atlas  of  Anatomy,  with 
a  thorough  treatise  on  systematic,  descriptive,  and  applied  Anatomy,  the  work  will  be  found  of 
essential  use  to  all  physicians  who  receive  students  in  their  offices,  relieving  both  preceptor  and 
pupil  of  much  labor  in  laying  the  groundwork  of  a  thorough  medical  education. 

Since  the  appearance  of  the  last  American  Edition,  the  work  has  received  three  revisions  at  the 
hands  of  its  accomplished  editor,  Mr.  Holmes,  who  has  sedulously  introduced  whatever  has  seemed 
requisite  to  maintain  its  reputation  as  a  complete  and  authority  iive  standard  text-book  and  work 
of  reference.  Still  further  to  increase  its  usefulness,  there  has  been  appended  to  it  the  recent 
work  by  the  distinguished  anatomist,  Mr.  Luther  Holden — "Landmarks,  Medical  and  Surgical" 
— which  gives  in  a  clear,  condensed,  and  systematic  way,  all  the  information  by  which  the  prac- 
titioner can  determine  from  the  external  surfiice  of  the  body  the  position  of  internal  parts.  Thus 
complete,  the  work,  it  is  believed,  will  furnish  all  the  assistance  that  can  be  rendered  by  type  and 
illustration  in  anatomical  study.  No  pains  have  been  spared  in  the  typographical  execution  of 
the  volume,  which  will  be  found  in  all  respects  superior  to  former  issues.  Notwithstanding  the 
increase  of  size,  amounting  to  over  100  pages  and  57  illustrations,  it  will  be  kept,  as  heretofore, 
at  a  price  rendering  it  one  of  the  cheapest  works  ever  offered  to  the  American  profession. 


The  recent  work  of  Mr.  Holden,  which  was  no- 
ticed hy  us  ou  p.  53  of  this  volume,  has  been  added 
as  an  appendix,  so  that,  altogether,  this  is  the  mott 
practical  and  complete  anatomical  treatise  available 
to  American  students  and  phynicians.  The  former 
finds  in  it  the  necessary  guide  in  making  dissec- 
tions ;  a  very  comprehensive  chapter  on  mittute 
matom-v;  and  about  all  that  can  he  taught  him  on 


to  consult  his  books  oa  anatomy.  The  work  is 
simply  indispensable,  especially  this  present  Amer- 
ican edition.-— Fa.  Med.  Monthly,  Sept.  187?. 

The  addition  of  the  receut  work  of  Mr.  Holden, 
as  an  appendix,  renders  this  the  most  practical  and 
complete  treatise  available  to  American  students, 
who  find  in  it  a  comprehensive  chapter  on  minute 


jreneraiVnd  special  anatomy;  while  the  latter,  in     anatomy,  about  all  that  can  be  taught  on  general 
*t8  treatment  of  each  region  from  a  surgieal  point  of    an^i  special  anatomy,  while  its  treatment  of  each 


view,  and  in  the  valuable  edition  of  Blr  Holden 
will  find  all  that  will  be  essential  to  him  in  his 
practice —i\^ew  Remedies,  Aug.  1878. 

This  work  is  as  near  perfection  as  one  could  pos- 
sibly or  reasonably  expect  any  book  intended  as  a 
text-book  or  a  genera)  reference  book  on  anatomy 
to  be.  The  American  publisher  deserves  the  thanks 
of  the  profession  for  appending  the  recent  work  of 
Mr.  Holden,  ^*  Landmarks,  Medical  and  Surgical,''^ 
which  has  already  been  commended  as  a  separate 
book.  The  latter  work— treating  of  topographical 
anatomy— Jias  become  an  essential  to  the  library  of 
every  intelligent  practitioner.  We  know  of  no 
book  tliat  can  take  its  place,  written  as  it  is  by  a 
most  distinguished  anatomist.  It  would  be  simply 
a  waste  of  words  to  say  anything  further  in  praise 
of  Gray's  Anatomy,  the  text-book  in  almost  every 
medical  college  in  this  country,  and  the  daily  refer- 
ence book  of  every  practitioner  who  has  occasion 


egion,  from  a  surgical  point  of  view,  in  the  valu- 
able section  by  Mr.  Holden, is  all  that  will  be  essen- 
tial to  them  in  practice.— 0/ito  Mtdical  Recorder, 
Aug.  1878. 

It  is  diflicult  to  speak  in  moderate  terms  of  this 
new  edition  of  "Gray."  It  seems  to  be  as  nearly 
perfect  as  it  is  possible  to  make  a  book  devoted  to 
any  branch  of  medical  science.  The  labors  of  the 
eminent  men  who  have  successively  revised  the 
eight  editions  through  which  it  has  passed,  would 
seem  to  leave  nothing  for  future  editors  to  do.  The 
addition  of  Holden's  "  Landmarks"  will  make  it  as 
indi8pen.sable  to  tl;e  practitioner  of  medicine  and 
surgery  as  it  has  been  heretofore  to  th»  student.  As 
regards  completeness,  ease  of  reference,  utility, 
beauty,  and  cheapness,  it  has  no  rival.  No  stu- 
dent should  enter  a  medical  school  without  it  ;  no 
physician  can  afford  to  have  it  absent  from  his 
library.- S^  Louis  Clin.  Record,  Sept.  1878. 


Also  for  sai/e  separate — 
TTOLDEN  {LUTHER),  F.R.C.S., 

J- J-  Surgeon  to  St.  Bartholomew' s  and  the  Foundling  Hospitals. 

LANDMARKS,  MEDICAL  AND  SURGICAL.   From  the  2d  London 

Ed.   In  one  handsome  volume,  royal  12mo.,  of  128  pages  :  cloth,  88  cents.    {Now  Ready.) 
TJEATH  {CHRISTOPHER),  F.R.G.S., 

-■3[  Teacher  of  Operative  Surgery  in  University  College,  London. 

PRACTICAL  ANATOMY:   A  Manual  of  Dissections.     From  the 

Second  revised  and  improved  London  edition.  Edited,  with  additions,  by  W.  W.  Keen, 
M.  D.,  Lecturer  on  Pathological  Anatomy  in  the  Jefferson  Medical  College,  Philadelphia. 

In  one  handsome  royal  12mo. volume  of  578  pages,  with  247  illustrations.  Cloth,  $3  60  ; 

leather,  $4  00. 


Henry  C.  Lea's  Publications — {Anatomy). 


A  LLEN  {HARRISON),  M.D. 

-^J-  Pro/esior  of  Thy aio logy  in  the  Univ.  of  Pa. 

A  SYSTEM  OF  HUMAN  ANATOMY:  INCLUDING  ITS  MEDICAL 

and  Surgical  Relations.  For  the  Use  of  Practitioners  and  Students  of  Medicine.   With  an 
Introductory  Chapter  on  Histology.  By  E.  0.  Shakespeahe,  M  D.,  Ophthalmologist  to  the 
Phila.  IIosp.    In  one  large  and  handsome  quarto  volume,  with  several  hundred  original 
illustrations  on  lithographic  plates,  and  numerous  wood-cuts  in  the  text.      (Preparing.) 
In  this  elaborate  work,  which  has  been  in  active  preparation  for  several  years,  the  author  has 
sought  to  give,  not  only  the  details  of  descriptive  anatomy  in  a  clear  and  condensed  form,  but  also 
the  practical  applications  of  the  science  to  medicine  and  surgery.  The  work  thus  has  claims  upon 
the  attention  of  the  general  practitioner,  as  well  as  of  the  student,  enabling  him  not  only  to  re- 
fresh his  recollections  of  the  dissecting  room,  but  also  to  recognize  the  significance  of  all  varia- 
tions from  normal  conditions.     The  marked  utility  of  the  object  thus  sought  by  the  author  is 
self-evident,  and  his  long  experience  and  assiduous  devotion  to  its  thorough  development  are  a 
sufficient  guarantee  of  the  manner  in  which  his  aims  have  been  carried  out.  No  pains  have  been 
sp.ared  with  the  illustrations.   Those  of  normal  anatomy  are  from  original  dissecti^Jns,  drawn  on 
stone  by  Mr.  Hermann  Faber,  with  the  name  of  every  part  clearly  engraved  upon  the  figure, 
after  the  manner  of  "Holden"  and  "Gray,"  and  in  every  typographical  detail  it  will  be  the 
effort  of  the  publisher  to  render  the  volume  worthy  of  the  very  distinguished  position  which  is 
anticipated  for  it. 

-UiLLIS  [GEORGE  FINER), 

-*-^  Emeritus  PrifKSHor  of  Anatomy  in  University  College,  London. 

DEMONSTRATIONS  OF  ANATOMY;  Being  a  Guide  to  the  Know- 

ledge  of  the  Human  Body  by  Dissection.  By  George  Viner  Ellis,  Emeritus  Professor 
of   Anatomy  in    University  College,    London.     From  the  Eighth  and  Revised  London 
Edition.     In  one  very  handsome  octavo  volume  of  oyer  700  pages,  with  256  illustrations. 
Cloth,  S4. 25  ;  leather,  $5.25.      {Jvst  Ready.) 
This  work  has  long  been  known  in  England  as  the  leading  authority  on  practical  anatomy, 
and  the  favorite  guide  in  the  dissecting-room,  as  is  attested  by  the  numerous  editions  through 
which  it  has  passed.     In  the  last  revision,  which  has  just  appeared  in  London,  the  accomplished 
author  has  sought  to  bring  it  on  a  level  with  the  most  recent  advances  of  science  by  making  the 
necessary  changes  in  his  account  of  the  microscopic  structure  of  the  different  organs,  as  devel- 
oped by  the  latest  researches  in  textural  anatomy. 
Ellife's  Demoastrations  is  the  favorite  text-book  ]  its  leadership  over  the  English  manuals  upon  dis- 


of  the   English    Btudent   of   anatomy.     In  passing 

thi-oufi;h  eight  editions  it  has  been  bO  revised  and 

adapted  to  the  needs  of  the  student  ibat  it  would 

seem  that  it  had  almost  reached  perfection  in  Ibirs 

special  line.     The  descriptions  are  clear  and   the  ,  -  .    ,  .  .    •,     , 

methods  of  pursuing  anatomical  inve.'.tigations  are  |  tain  y  saying  a  very  great  deal.     As  a  text-book  to 


secting. — Phila,  Med.  Timts,  May  24,  1879. 

As  a  dissector,  or  a  work  to  have  in  hand  and 
studied  while  one  is  engaged  in  dissecting,  we  re 
gard  it  as  tlie  very  best  work  extant,  which  is  cer- 


be  studied  in  the  dissecling-room,  it  is  superior  to 
any  of  the  works  upon  anatomy.— Ci7iet'?ina<i  Med. 
News,  May  21,  1879. 


given  with  such  detail  that  the  book  is  honestly 
entitled  to  its  name. — St.  Louis  Clinical  Record, 
June,  1879.  | 

The  success  of  this  old  manual  seems  to  be  as  well  I  We  most  unreservedly  recommend  it  to  every 
deserved  in  the  present  as  in  the  past  volumes,  practitioner  of  medicine  who  can  possibly  get  it. — 
The  book  seems  destined  to  maintain  yet  for  years  >  Va.  Me'1.  Monthly,  June,  1879. 


w 


ILSON  [ERASMUS),  F.R.S. 

A  SYSTEM  OF  HUMAN  ANATOMY,  General  and  SpeciaL  Edited 

by  W.  H.  GoBRECtiT,  M.D  ,  Professor  of  General  and  Surgical  Anatomy  in  the  Medical  Col- 
lege of  Ohio.  Illustrated  with  three  hundred  and  ninety-seven  engravings  on  wood.  In 
one  large  and  handsome  octavo  volume,  of  over  600  large  pages  ;  cloth,  $4  ;  leather,  $5. 


^MITH  [HENRY H.),  M.D.,         and  JJORNER  [  WILLIAM  E.),  M.D., 

Prof  .of  Surgery  in  the  Univ.  of  Penna.,  Ac.  Late  Prof .  of  Anatomy  in  the  Univ.ofPenna. 

AN    ANATOMICAL   ATLAS,   Illustrative   of  the  Structure  of  the 

Human  Body.  In  one  volume,  large  imperial  octavo,  cloth,  with  about  six  hundred  and 
fifty  beautiful  figures.     $4  50. 


s 


CHAFER  [ED  WARD  ALBERT),  M.D., 

Assistant  Professor  of  Physiology  in  University  ColUge,  London. 

A  COURSE  OF  PRACTICAL  HISTOLOGY:  Being  an  Introduction  to 

the  Use  of  the  Microscope.     In  one  handsome  royal  12mo.  volume  of  304  pages,  with 
numerous  illustrations:  cloth,  $2  00.     {Just  Issued.) 


HORNER'S  SPECIAL  ANATOMY  AND  HISTOL- 
OGY. Eighth  edition,  extensively  revised  and 
modified.  In  2  vols.  8vo.,  of  over  1000  pages, 
with  320  wood-cuts  :  cloth,  *6  00. 

SHARPEY  AND  QUAIN'S  HUMAN  ANATOMY. 
Revised,  by  Joseph  Leidt,  M.D.,Prof  of  Anat. 
in  Univ.  of  Penn.     In  two  octavo  vols,  of  about 

'   1300  pages,  with  511  iUustrations     Cloth,  |6  00. 


BELLAMYS  STUDENT'S  GUIDE  TO  SURGICAL 
ANATOMY:  A  Text  book  for  Students  preparing 
for  their  Pass  Examiration.  With  engiavinffs  on 
wood.  In  one  handsome  royal  12mo.  volume. 
Cloth,  $2  2.1. 

CLELAND'S  DIRECTORY  FOR  THE  DISSECTION 
OF  THE  HUMAN  BODY.  In  one  small  volume, 
ruyal  12mo.  of  182  pages :  cloth,  *1  25. 


8 


Henry  C.  Lea's  Publications — (Physiology). 


ffARPENTER  (  WILLIAM  B.),  M.  D.,  F.  R.  S.,  F.G.S.,  F.L.S., 

Registrar  to  University  of  London,  etc. 

PRINCIPLES  OF  HUMAN  PHYSIOLOGY;  Edited  by  Henry  Power, 

M.B.  Lond.,  F.R.C.S..  Examiner  in  Natural  Sciences,  University  of  Oxford.  Anew 
American  from  the  Eighth  Revised  and  Enlarged  English  Edition,  with  Noteg  and  Addi- 
tions, by  Francis  G.  Smith,  M.D.,  Professor  of  thelnstitutescf  Medicine  in  the  Univer- 
sity of  Pennsylvania,  etc.  In  one  very  large  and  handsome  octavo  volume,  of  1088  pages, 
with  twoplatesand873engravingson  wood;  cloth, $6  50;  leather,  $6  50.    {Jnst  Issued.) 

Thegreatwork,  the  crowning  labor  of  the  distinguished  author,  and  through  which  so  many 
generations  of  students  have  acquired  their  knowledge  of  Physiology, has  been  almost  meta- 
morphosed in  the  effort  to  ac'apt  it  thoroughly  to  the  requirements  of  modern  science.  Since 
the  appearance  of  the  last  American  edition,  it  has  had  several  revision.s  at  the  experienced 
hand  of  Mr.  Power,  who  has  modified  and  enlarged  it  so  as  to  introduce  all  that  is  important 
in  the  investigations  and  discoveries  of  England,  France,  and  Germany,  resulting  in  an  enlarge- 
ment of  about  one-fourth  in  the  text.  The  series  of  illustrations  has  undergone  a  like  revision, 
a  large  proportion  of  the  former  ones  having  been  rejected,  and  the  total  number  increased 
to  nearly  four  hundred.  The  thorough  revision  which  the  work  has  so  recently  received  in 
England,  has  rendered  unnecessary  any  elaborate  additions  in  this  country,  but  the  American 
Editor,  Professor  Smith,  has  introduced  such  matters  as  his  long  experience  has  shown  him  to 
be  requisite  for  the  student.  Every  care  has  been  taken  with  the  typographical  execution,  and 
the  work  i?  presented,  with  its  thousand  closely,  but  clearly  printed  pages,  as  emphatically  the 
text-book  for  the  student  and  practitioner  of  medicine — the  one  in  which,  as  heretofore,  especial 
care  is  directed  to  show  the  applications  of  physiology  in  the  various  practical  branches  of 
medical  science.  Notwithstanding  its  very  great  enlargement,  the  price  has  not  been  in- 
creased, rendering  this  one  of  the  cheapest  works  now  before  the  profession. 


We  have  been  agreeably  surprised  to  find  the  vol- 
anie  60  complete  in  regard  to  the  structure  and  func- 
tions of  tbe  nervous  system  in  all  its  relations,  a 
subject  that,  in  many  respects,  is  one  of  the  most  diffi- 
cult of  all,  in  tbe  whole  range  of  physiology,  upon 
which  to  produce  a  full  and  «ati8factory  treati.se  of 
the  class  to  which  the  one  before  us  belongs.  The 
additions  by  the  American  editor  give  to  the  work  as 
it  is  a  considerable  value  beyond  that  of  the  last 
English  edition.  In  conclusion,  we  can  give  our  cor- 
dial recommendation  to  the  work  as  it  now  appears. 
The  editors  have,  with  their  additions  to  the  only 
work  on  physiology  in  our  language  that,  in  the  full- 
est sen^e  of  the  word,  is  the  production  of  a  philoso- 
pher as  well  as  a  physiologist,  brought  it  up  as  fully 
as  could  be  expected,  if  not  desired,  to  the  standard 
of  our  knowledge  of  its  subject  at  the  present  day. 
It  will  deservedly  maintain  the  place  it  has  always 
had  iu  the  favor  of  ihe  medical  profession. — Journ. 
of  Nervous  and  Mental  Dumse,  April,  1877. 

"Good  wine  needs  no  bush"  says  the  proverb,  and 
an  old  and  faithful  servant  like  the  "  big"  Carpenter,  as 
carefully  brought  down  as  this  edition  has  been  by  Mr. 
Henry  Power,  needs  little  or  no  commendation  by  us. 
Such  enormous  advances  have  i-ecent'y  been  made  iu 
our  physiological  knowledge,  that  what  was  perfectly 
new  a  year  or  two  ago.  looks  now  as  if  it  had  been  a 
THceived  and  established  fact  for  years.  In  this  ency- 
clopaedic way  it  is  unrivalled.  Here,  as  it  seems  to 
us,  is  the  great  value  of  the  book:  one  is  safe  in  sending 
a  student  to  it  for  information  on  almost  any  given 


subject,  perfectly  certain  of  the  fulness  of  information 
it  will  convey,  and  well  satisfied  of  the  accuracy  with 
which  it  will  there  be  found  stated. — London  Med. 
Times  and  Gazette,  Feb.  17,  1877. 

Thus  fully  are  treated  the  structure  and  functions  ol 
all  the  important  organs  of  the  body,  while  there  are 
chapters  on  sleep  and  somnambulism ;  chapterson  eth 
nology,  a  full  section  on  general  ion.  and  abundant  re- 
ferences to  the  curiosities  of  physiology,  as  the  evolu 
tion  of  light,  heat,  electricity,  etc.  In  short,  this  new 
edition  of  Carpenter  is,  as  we  have  said  at  the  start, 
a  very  encyclopedia  of  modern  physiology. — The  Glin- 
tc,  Feb. 24, 1877. 

The  merits  of"  Carpenter'sPhysiology"  are  so  widely 
known  and  appreciated  that  we  need  only  allude  briefly 
to  the  fact  that  in  the  latest  edi(  ion  will  be  found  a  com- 
prehensive embodiment  of  the  results  of  recent  physio 
los^icfil  investigation.  Care  has  been  taken  to  preserve 
the  practical  character  of  the  original  work.  In  fact 
the  entire  work  has  been  brought  up  to  date,  and  bears 
evidence  of  the  amount  of  labor  that  has  been  bestowed 
upon  it  by  its  distinguished  editor,  Mr.  Henry  Power. 
The  American  editor  has  made  the  latest  additions,  in 
order  fully  to  cover  the  time  that  has  elapsed  since  the 
last  English  edition. — N.  Y.  Med.  Journal, ia^n,  1877. 

A  more  thorough  work  on  physiology  could  not  be 
found.  In  this  all  the  facts  discovered  by  the  late  re- 
searches are  noticed,  and  neither  student  nor  practi- 
tioner should  be  without  this  exhaustiTe  treatise  on  &u 
important  elementary  branch  of  medicine. — Atlanta 
Med.  and  Surg.  Journal,  Dec.  1876. 


JZIRKES  [WILLIAM  SENHOUSE),  M.D. 

A  MANUAL  OF  PHYSIOLOGY.     Edited  by  W.  Morrant  Baker, 

M.D.,  F.R.C.S.  A  new  American  from  the  eighth  and  improved  London  edition.  With 
about  two  hundred  and  fifty  illustrations.  In  one  large  and  handsome  royal  12mo.  vol- 
ume.    Cloth,  $3  25;  leather,  $3  75.     {Lately  Issued.) 

On  the  whole,  there  is  very  little  in  the  book  |  physiology  which  we  have  in  our  language. — N.Y. 
whicheitherthestudent  or  practitioner  will  not  find  i  Med    Record,  April  15,  1873. 

of  i>taciical  value  and  consistent  with  our  present  I      -,..■,  ,e         .^.      t  ■    ,  4.,t4v 

knowledge  of  this  rapidly  changing  science;  and  we  ^  ^°  !'«  enlarged  orm  It  is,  in  our  opinion,  etlll  the 
have  no  h^'eeitation  in  expre-i^g  our  opinion  that  ^%' ^;«,f  ;^°  PVCr^I'n^^'o  7.7^^  '''  thestudent. 
this  eighth  edition  is  one  of  the  best  handbooks  on  I  -PMa.  Med.  Times,  Aug.  .SO,  1873. 


HARTSHOKNE'S  nANI>BOOK  OF  ANATOMY  AND 
PHYSIOLOGY.  Second  edition,  revised.  In  one 
roval  12mo.  vol.,  with  220  woodcuts  ;  cloth, 
♦i:.>. 

LEMMANN'S  MANUAL  OF  CHEMICAL  PHYSIOL- 
0  JY.     Traaslated  from  the  German,  with  Notes 


and  Additions,  by  J  CnnsTOW  Morris  M.D.  With 
illustrations  on  wood.  In  one  octavo  volume  of 
3.36  pages.  Cloih,  $2  2.-5. 
LEHMANN'S  PHYSIOLOGICAL  CHEMISTRY  Com- 
plete in  two  large  octavo  volumes  of  1200  pages, 
with  200  illustrati)n8;  cloth,  ^3. 


Henry  C.  Lea's  Publications — (Physiology). 


nALTON  (/.  C),  M.D., 

•^  Professor  of  Physiology  in  the.  College  of  Physicians  and  Surgeons,  New  Torlt,  Ac. 

A  TREATISE  ON  HUMAN  PHYSIOLOGY.    Designed  for  the  use 

of  Studentsand  Practitioners  of  Medicine.   Sixth  edition,  thoroughly  revised  and  enlarged, 
■with  three  hundred  and  sixteen  illustrations  on  wood.    In  one  very  beautiful  octavo  vol- 
ume, of  over  800  pages.     Cloth,  $5  50  ;  leather,  $6  50.     iJust  Issued.) 
During  the  past  few  years  several  new  works  on  phy-i      This  popular  text-book  on  physiology  comes  to  us  in 
Biology,  aiid  new  editions  of  old  works,  liave  appeared     ' 


competing  for  the  favor  of  the  medical  student,  but 
none  will  rival  this  new  edition  of  Dalton.  As  now  en- 
larged, it  will  be  found  also  to  be,  in  general,  a  satisfac- 
tory work  of  reference  for  the  practitioner. — Chicago 
Med.  Journ.  and  Examiner,  Jan.  1 876. 

Prof.  Dalton  has  discussed  conflicting  theories  and 
conclusions  regarding  phy.siological  (juestions  with  a 
fairness,  a  fulness,  and  a  conciseness  which  lend  fresh- 
ness and  vigor  to  the  entire  book.  But  bis  discussions 
have  been  so  guarded  by  a  refusal  of  admission  to  those 
speculative  and  theoretical  explanations,  which  at  best 
exist  in  the  minds  of  observers  themselves  as  only  pro- 
babilities, that  none  of  his  readers  need  be  led  into 
gr,ave  errors  while  makiug  them  a  study. — The  Medical 
Record,  Feb.  19, 1876. 

The  revision  of  this  great  work  haSjbrought  it  forward 
with  the  physiological  advances  of  the  day,  and  renders 
it,  as  it  has  ever  heen,  the  finest  work  for  students  ex- 
tant.— 2\"ashviUe  Journ.  of  Med.  and  Surg.,  Jan.  1876. 

For  clearness  and  perspicuity,  Daltoii's  Physiology 
commended  itself  to  the  student  years  ago,  and  was  a 
pleasant  relief  from  the  verbose  productions  which  it 
supplanted.  Physiology  has,  however,  made  many  ad- 
vances since  then— and  while  the  style  has  been  pre- 
served intact,  the  work  in  the  present  edition  has  been 
brought  up  fully  abreast  of  the  times.  The'new  chemical 
notation  and  nomenclature  have  also  been  introduced 
into  the  present  edition.  Notwithstanding  the  multi- 
plicity of  text-books  on  physiology,  this  will  lose  none 
of  its  old  time  popularity.  The  mechanical  execution 
of  the  work  is  all  that  could  be  desired. — Peninsular 
Journal  of  Medicine,  Dec.  1875. 


ts  sixth  edition  with  the  addition  of  about  fifty  per  cent, 
of  new  matter,  chiefly  in  the  departments  of  patho- 
logical chemistry  and  the  nervous  system,  where  the 
principal  advances  have  been  realized.  With  so  tho- 
rough revision  and  additions,  that  keep  the  work  well 
up  to  the  times,  its  continued  popularity  may  be  confi- 
dently predicted,  notwithstanding  the  competition  it 
may  encounter  .  The  publisher's  work  is  admirably 
done. — St.  Louis  Med.  and  Surg.  Journ,  Dec.  1875. 

We  heartily  welcome  this,  the  sixth  edition  of  this 
admirable  text  book,  than  which  thereare  noneof  equal 
brevity  more  valuable.  It  iscordially  recommended  by 
the  Professor  of  Physiology  in  theUniversity  of  Louisi- 
ana, as  by  all  competent  teachers  in  the  United  States, 
and  wherever  the  Knglish  language  is  read,  this  book 
has  been  appreciai.ed.  The  present  edition,  with  its  316 
admirably  executed  illustrations,  has  been  carefully 
revised  and  very  much  enlarged,  although  its  bulk  does 
not  seem  perceptibly  increased. — New  Orleans  Medical 
and  Surgical  Journal,  March,  1876. 

The  present  edition  is  very  much  superior  to  every 
other,  not  only  in  that  it  brings  the  subject  up  to  the 
times,  but  that  i*^.  do<«s  so  more  fully  and  satisfactorily 
than  any  previous  edition.  Take  it  altogether  it  remains 
inourhumbleopinion,thebest  text  book  on  physiology 
in  any  land  orlant;uage. — The  Clinic.  Nov.  6,  1875. 

As  a  whole,  we  cordially  recommend  the  work  as  a 
text-book  for  the  student,  and  as  one  of  the  best. — 
The  Journal  of  Nervous  and  Mental  Disease,  Jan.  1876. 

Still  holds  its  position  as  a  masterpiece  of  lucid  writ- 
in?,  and  is,  we  believe,  on  the  whole,  the  best  book  to 
place  in  the  hands  of  the  student. —  London  Students' 
Journal. 


fjLASSEN  {ALEXANDER), 

^^  Professor  in  the  Royal  Polytechnic  School,  Aixla-Chapdle. 

ELEMENTARY    QUANTITATIVE    ANALYSIS.     Translated  with 

notes    and  additions  by  Edgar   F.   Smith,   Ph.D.,  Assistant  Prof,   of  Chemistry  in  the 
Towne  Scientific  School,  Univ.  of  Penna.     In  one  handsome  royal  12mo.  volume,  of  324 
pages,  with  illustrations;  cloth,  $2  00.     {Just  Ready.) 
It  is  probably  the  bast  manual  of  an  elementary  |  advancing  to  the  analysis  of  minerals  and  such  pro- 
nature  extant,  insomuch  as  its  methods  are  the  best.  I  ducts  as  are  met  with  in  applied  chemistry.     It  is 
It   teaches  by  examples,   commencing   with   single  j  an  indi.spen«able  book  for  students  in  chemistry. — 
determinations,  followed  by  separations,  and  then  i  Boston  Journ.  of  Chemistry,  Oct.  1878. 

rfALLOWAY  [ROBERT),  F.C.S., 

^-^  Prof  of  Applied  Chemtttry  in  the  Royal  College  of  Science  for  Ireland,  etc. 

A  MANUAL  OF  QUALITATH^E  ANALYSIS.  From  the  Fifth  Lon- 
don Edition.  In  one  neat  royal  12mo.  volume,  with  illustrations  ;  cloth,  $2  75.  {Lately 
Issued.) 

jyo  WMAN  [JOHN  E.) ,  M.D. 

INTRODUCTION  TO  PRACTICAL  CHEMISTRY,  INCLUDING 

ANALYSIS.  Sixth  American,  from  the  sixth  and  revised  London  edition.  With  numer- 
*          ous  illustrations.     In  one  neat  v61.,  royal  12mo.,  cloth,  $2  25. 
J^Y  THE  SAME  AUTHOR.  

PRACTICAL  HANDBOOK  OF  MRDICAL  CHEMISTRY.    New 

edition.     In  one  neat  volume,  royal  12rao.     {Preparing.) 


E 


W 


EMSEiV{IRA),  M.D.,  Ph.D., 

Professor  of  Chemistry  in  the  Johns  Hopkins  University,  Baltimore. 

PRINCIPLES  OF  THEORETICAL  CIIH]MISTllY,  with  special  reference 

to  the  Constitution  of  Chemical  Compounds.  In  one  handsome  royal  12mo.  vol.  of  over 
232  pages:  cloth,  $1  50.     {Just  Issued.) 

'OHLER  AND  FITTIG. 

OUTLINES  OF  ORGANIC  CHEMISTRY.  Translated  with  Ad- 
ditions from  the  Eighth  German  Ed.  By  Ira.  Rrmskn,  M.D.,  Ph.D.,  Prof,  of  Chem- 
andPhysics  in  Williams  College,  Mass.  In  one  volume,  royal  12mo.of  550  pp.,  cloth,  $3, 


10 


Henry  C.  Lea's  Publications — {Chemistry] 


JPOWNES  [GEORGE),  Ph.D. 

A  MANUAL  OF  ELEMENTARY  CHEMISTRY;  Theoretical  and 

Practical.   Revised  and  corrected  by  Uknrv  Watts,  B.A.,  F.R.S.,  author  of  "A  Diction- 
ary of  Chemistry,"  etc.    With  a  colored  plate,  and  one  hundred  and  seventy-seven  illus- 
trations.   A  new  American,  from  thi  twelfth  and  enlarged  London  edition.     Edited  by 
Robert  Bridges,  M.D.       In   one  large  royal  12mo.  volume,  of  over  1000  pages  j 
cloth,  $2  75  ;  leather,  $3  25.     {Just  Ready.) 
Two  careful  revisions  by  Mr.  Watts,  since  the  appearance  of  the  last  American  edition  of 
"Fownes,"  have  so  enlarged  the  work  that  in  England  it  has  been  divided  into  two  volumes.   In 
reprinting  it,  by  the  use  of  a  small  and  exceedingly  clear  type,  cast  for  the  purpose,  it  has  been 
found  possible  to  comprise  the  whole,  without  omission,  in  one  volume,  not  unhandy  for  study  and 
reference.   The  enlargement  of  the  work  has  induced  the  American  Editor  to  confine  his  additions 
to  the  narrowest  compass,  and  he  has  accordingly  inserted  only  such  discoveries  as  have  been  an- 
nounced since  the  very  recent  appearance  of  the  work  in  England,  and  has  added  the  standards 
in  popular  use  to  the  Decimal  and  Centigrade  systems  employed  in  the  original. 

Among  the  additions  to  this  edition  will  be  found  a  very  handsome  colored  plate,  representing 
a  number  of  spectra  in  the  spectroscope.  Every  care  has  been  taken  in  the  typographical  execu- 
tion to  render  the  volume  worthy  in  every  respect  of  its  high  reputation  and  extended  use,  and 
though  it  has  been  enlarged  by  more  than  one  hundred  and  fifty  pages,  its  very  moderate  price 
will  still  maintain  it  as  one  of  the  cheapest  volumes  accessible  to  the  chemical  student. 


This  work,  inorganic  and  organic,  i.s  complete  in 
one  convenient  volume.  In  its  earliest  editions  it 
was  fully  up  to  the  latest  advancements  and  theo- 
ries of  that  time.  In  its  present  form,  it  presents, 
in  a  remarkably  convenient  and  satisfactory  man- 
ner, the  principles  and  leading  facts  of  the  chemistry 
of  to-day.  Concerning  the  manner  in  which  the 
various  subjects  are  treated,  much  deserves  to  be 
said,  and  mostly,  too,  in  praise  of  the  book.  A  re- 
view of  such  a  work  as  Fownes's  Chemistry  within 
the  limits  of  a  book-notice  for  a  medical  weekly  is 
simply  out  of  the  question. — Cincinnati  Lanctt  and 
QHnic,  Dec.  14, 1878. 

When  we  state  that,  in  our  opinion,  the  present 
edition  sustains  in  every  respect  the  high  reputation 
which  its  predecessors  have  acquired  and  eujoyed, 
we  express  therewith  our  full  belief  in  its  intrinsic 
value  as  a  text-book  and  work  of  reference. — Am. 
Journ.  of  Pharm.,  Aug.  1878. 

The  conscientious  care  which  has  been  bestowed 
upon  it  by  the  American  and  English  editors  renders 
it  still,  perhaps,  the  bes^t  book  for  the  student  and  the 
practitioner  who  would  keep  alive  the  acquisitions 
of  his  student  days.    It  has,  indeed,  reached  a  some- 


what formidable  magnitude  with  its  more  than  a 
thousand  pages,  but  with  less  than  this  no  fair  repre- 
sentation of  chemistry  as  it  now  is  can  be  given.  The 
type  is  small  but  very  clear,  and  the  sections  are  very 
lucidly  arranged  to  facilitate  study  and  reference.— 
Med.  and  Surg.  Reporter,  Aug   3,  1878. 

The  work  is  too  well  known  to  American  students 
to  need  any  extended  notice;  sallice  it  to  say  that 
the  revi.-ion  by  the  English  editor  has  been  faithfully 
done,  and  that  Professor  Bridges  has  added  some 
fresh  and  valuable  matter,  especially  in  the  inor- 
ganic chemistry.  The  book  has  always  been  a  fa- 
vorite in  this  country,  and  in  its  new  shape  bids 
fair  to  retain  all  its  former  prtsiig'e. — Boston  Jour, 
of  Chemistry ,  Aug.  1878. 

It  will  be  entirely  unnecessary  for  us  to  make  any 
remarks  relating  to  the  general  character  of  Fownes' 
Manual.  For  over  twenty  years  it  has  held  the  fore- 
most place  as  a  text-book,  and  the  elaborate  and 
thorough  revisions  which  have  been  made  from  time 
to  time  leavelittlechauce  for  any  wide  awake  rival  to 
step  before  ii.— Canadian  Pharm.  Jour.,  Aug.  187S. 

As  a  manual  of  chemistry  it  is  without  a  superior 
in  the  language.— ilfd.  Med.  Jour.,  Aug.  1878. 


ATTFIELD  {JOHN),  Ph.D., 
Professor  of  Practical  Chemistry  to  the  Pharmaceutical  Society  of  Great  Britain,  Sec. 

CHEMISTRY,  GENERAL,  MEDICAL,  AND  PHARMACEUTICAL; 

including  the  Chemistry  of  the  U.  S.  Pharmacopoeia.  A  Manual  of  the  General  Principles 
of  the  Science,  and  their  Application  to  Medicine  and  Pharmacy.  Eighth  edition  revised 
by  the  author.  In  one  handsome  royal  12mo.  volume  of  700  pages,  with  illustrations. 
Cloth,  $2  50  ;  leather,  $3  00.  {Jjist  Ready.) 
We  have  repeatedly  expressed  our  favorable  f  of  chemistry  in  all  the  medical  colleges  in  the 
opinion  of  this  work,  and  on  the  appearance  of  a  i  United  States.  The  present  edition  contains  such 
new  edition  of  it,  little  remains  for  us  to  say,  ex-  |  alterations  and  additions  as  seemed  necessary  for 


cept  that  we  expect  this  eighth  edition  to  be  as 
indispensable  to  us  as  the  seventh  and  previous 
editions  have  been.  While  the  general  plan  and 
arrangement  have  been  adhered  to,  new  matter 
has  been  added  covering  the  observations  made 
since  the  former  edition  The  present  differs  from 
the  preceding  one  chiefly  in  these  alterations  and 
in  about  ten  pages  of  useful  tables  added  in  the 
appendix  —Am.  Jour,  of  Pharmacy,  May,  18'9. 

A  standard  work  like  Attfield's  Chemistry  need 
only  be  mentioned  by  its  name,  without  further 
comments  The  present  edition  cantains  such  al 
terations  and  additions  as  seemed  necessary  for 
the  demonstration  of  the  latest  developments  of 
chemical  principles,  and  the  latest  applications  of 
chemistry  to  pharmacy.  The  author  has  bestowed 
ardnois  labor  on  the  revision,  and  the  ex'ent  of 
the  information  thus  introduced  may  be  estimated 
from  the  fact  that  the  index  <*outains  three  hun- 
dred new  references  relating  to  additional  mate- 
rial.—i>)'Mgrgriirf^'  Circular  and  Chemical  Gazntte, 
May,  1879. 

This  very  popular  and  meritorious  work  has 
now  reached  its  eighth  edition,  which  fact  speaks 
in  the  highest  terms  in  commendation  of  its  excel 
lence.     It  has  now  become  the  principal  text-book 


the  demonstration  of  the  latest  developments  of 
chemical  principles,  and  the  latesc  applications  of 
chemistry  to  pharmacy.  It  is  scarcely  neccsary 
for  us  to  say  that  it  exhibits  chemistry  in  its  pre- 
sent advanced  si»,ie.— Cincinnati  Medical  Ntws, 
April,  1^79. 

The  popularity  which  this  work  has  enjoyed  is 
owing  to  the  original  and  clear  disposition  of  the 
facts  of  the  science,  the  accuracy  of  the  details,  and 
the  omission  of  much  which  freights  many  treatises 
heavily  without  bringing  corresponding  instruction 
to  the  reader.  Dr.  Attfield  writes  for  students,  and 
primarily  for  medical  students;  he  always  has  an 
eye  to  the  pharmacopoeia  and  its  officinal  prepara- 
tions; and  he  is  continually  putting  the  matter  in 
the  text  so  that  it  responds  to  the  questions  with 
which  each  section  is  provided.  Thus  the  student 
learns  easily,  and  can  always  refresh  and  test  his 
knowledge.— 3f«;rf  andSurff.  Reporter,  Apriil9,'79. 

We  noticed  only  about  two  years  and  a  half  ago 
the  publication  of  the  preceding  edition,  and  re- 
marked upon  the  exceptionally  valuable  character 
of  the  work.  The  work  now  iaclndes  the  whole  of 
the  chemistry  of  the  pharmacopoeia  of  the  United 
States,  Great  Britain,  and  India.— i^Teto  Remedies, 
May,  1879. 


Henry  C.  Lea's  Publications — {Chemistry). 


11 


F 


^ARQUHARSON  {ROBERT),  M.D., 

Lecturer  on  Materia  Medica  at  St.  Mary'' s  Hospital  Medical  School. 

GUIDE  TO  THERAPEUTICS  AND  MATERIA  MEDICA.  Se- 
cond American  edition,  revised  by  the  Author.  Enlarged  and  adapted  to  the  U.  S. 
Pharmacopoeia.  By  Franic.  WoODBunv,  M.D.  In  one  neat  rojal  12mo.  volume  of  498 
pages  :  cloth,  $2.25.      (Just  Ready.) 

This  work  contaiDS  in  moderate  compass  such 
■well-digested  facts  concerniug  the  physiologiPal 
and  therapeutical  action  of  rencedies  as  are  reason- 
ably established  up  to  the  present  time.  By  a  con- 
venient arrangement  the  correspondiEg  effects  of 
each  article  in  health  and  disease  are  presented  in 
parallel  columns,  not  only  rendering  reference 
easier,  but  also  impressing  the  facts  more  strongly 
upon  the  mind  of  the  reader.  The  hook  has  been 
adapted  to  the  wants  of  the  American  student,  and 
copious  notes  have  been  introduced,  embodying  the 
latest  revision  of  tie  Pharmacopoeia,  together  with 
the  antidotes  to  the  more  prominent  poisons,  and 
such  of  the  newer  remedial  agents  as  seemed  neces- 


The  appearance  of  a  new  edition  of  this  conve- 
nient and  handy  book  in  less  than  two  years  may 
certainly  be  taken  as  an  indication  of  its  useful 
ness.  Its  convenient  arrangement,  and  its  terse- 
nefis,  and,  at  the  same  time,  completeness  of  the 
information  given,  make  it  a  handy  book  of  refer 
e ace. —.4m.  Journ.  of  Pharmacy,  June 


1S79. 


The  early  appearance  of  a  second  eiition  of  Dr. 
Farquharson's  work  bears  sufficient  testimony  to 
the  appreciation  of  it  by  American  readers.  The 
plan  is  such  as  to  bring  the  character  and  action  of 
drugs  to  the  eye  and  mind  with  clearness  The 
care  with  which  both  author  and  editor  have  done 


their  work  is  conspicuous  on  every  page. —ifed.ancij  gary  co  the  completeness  of  the  work.     Tables  of 
Surg.  Reporter,  May  31,  1S79.  weights  and  measures,  and  a  good  alphabetical  in- 

The  second  edition,  enlarged  and  revised,  is  a  !  ^^^>  end  the  ^olnm^.-Drnggists'  Circular  and 
happy  medium   between  the   first  edition, 


which  !  Ohemical  Gazette,  June,  1S79. 


was  rather  too  brief  on  some  important  matters, 
and  the  larga  octavos  of  Wood  and  Birtbolow.  It 
is  brought  up  to  the  most  recent  researches,  one 
note  referring  to  an  article  published  in  April  of 
this  year.  The  favorable  reception  accorded  it, 
shown  by  this  reissue  in  two  years,  was  one  well 
iQetUQdi.—Louismlle  Med.  Neios,  June  7,  1S79. 


It  is  a  pleasure  to  think  that  the  rapidity  with 
which  a  second  edition  is  demanded  may  be  taken 
as  an  indication  that  the  sense  of  appreciation  of  the 
value  of  reliable  information  regarding  the  use  of 
remedies  i-  not  entirely  overwhelmed  in  the  cultiva- 
tion of  pathological  studies,  characteristic  of  the  pre- 
sent day.  This  work  certainly  merits  the  success  it 
has  so  quickly  achieved.— .ft^eio  Remedies,  July,  '79. 


B 


LOXAM  iC.L.), 

Profes-ior  of  Chemistry  in  King^s  College,  London. 

CHEMISTRY,  INORGANIC  AND  ORGANIC.    From  the  Second  Lon- 
don Edition.     In  one  very  handsome  octavo  volume,  of  700  pages,  with  about  300  illus- 


Cloth,  $4  00;  leather,  $5  00 
work  a  eompleteand  most  excel- 


trations, 

We  have  in  th 
lent  text-book  for  the  use  of  schools,  and  can  heart- 
ily recommend  it  as  such. — Boston  Med.  and  Surg. 
Journ.,  May  28,  1S74. 

The  above  is  the  title  of  a  work  which  we  can  most 
conscientiously  recommend  to  students  of  chemis- 
try. It  is  as  easy  as  a  work  on  chemi.-try  could  be 
made,  at  thesame  time  that  it  preseutsa  full  account 
of  thatscience  as  it  now  stands.  We  have  spoken 
of  the  work  as  admirably  adapted  to  the  wants  of 
students;  it  is  quite  as  well  suited  to  the  require- 
ments of  practitioners  who  wish  to  review  their 
chemistry,  or  have  occasion  to  refresh  their  memo- 
ries on  any  point  relating  to  it.  In  a  word,  it  is  a 
book  to  be  read  by  all  who  wish  to  know  what  is 
thpchemistry  of  the  present  day. — American  Prae 
titioner,  Nov.  1873. 


{^Lately  Issued.) 

It  would  be  difficult  for  a  practical  chemist  and 
teacher  to  find  any  material  fault  with  this  most  ad- 
mirable treatise.  The  author  has  given  us  almost  a 
cj  clopffidia  within  the  limits  of  a  convenient  volume, 
and  has  done  so  without  penning  the  useless  para- 
graphs too  commonly  making  up  a  great  part  of  the 
bulk  of  many  cumbrous  works.  The  progressive 
scientist  is  not  disappointed  when  he  looks  for  the 
record  of  new  and  valuable  processes  acd  discover- 
ies, while  the  cautious  conservative  does  not  find  its 
pages  monopolized  by  uncertain  theories  and  specu- 
lations. A  peculiar  point  of  excellence  is  the  crys- 
tallized form  of  expression  in  which  great  truths  are 
expressed  in  very  short  paragraphs.  One  is  surprised 
at  the  brief  space  allotted  to  an  important  topic,  and 
yet,  after  reading  it,  he  feels  that  little,  if  any  more 
should  have  been  said.  Altogether,  it  is  seldom  yoi 
see  a  text-book  so  nearly  faultless.  —  Cincinnati 
Lancet,  Nov.  1S73. 


rfLOWES  (FRANK),  D.Sc.  London. 

^^  Senior  Science- Master  otthe  HigkSchool,  Xewcastle-under Lyme,  etc. 

AN  ELEMENTARY  TREATISE  ON  PRACTICAL  CHEMISTRY 

AND  QUALITATIVE  INORGANIC  ANALYSIS.  Specially  adapted  for  Use  in  the 
Laboratories  of  Schools  and  Colleges  and  by  Beginners.  From  the  Second  and  Revised 
English  Edition,  with  about  fifty  illustrations  on  wood.  In  one  very  handsome  royal 
12mo.  volume  of  372  pages  :  cloth,  $2  50.      {Now  Ready.) 

It  is  short,  concise,  and  eminently  practical.  We 
therefore  heartily  commend  it  to  students,  and  e^^pe- 
cially  to  those  who  are  obliged  to  dispense  with  a 
master.  Of  course,  a  teacher  is  in  every  way  desi- 
rable, but  a  good  degree  of  technical  skill  and  prac- 
tical knowledge  can  be  attained  with  no  other 
instructor  than  the  very  valuable  handbook  now 
under  consideration. — St.  Louis  Clin.  Record,  Oct. 
1877. 


The  work  is  so  written  and  arranged  that  it  can  be 
comprehended  by  the  student  without  a  teacher,  and 
the  descriptions  and  directions  forthe  various  work 


are  so  simple,  and  yet  concise,  as  to  be  interesting 
and  intellig'ble.  The  work  is  unincumbered  with 
theoretical  deductions,  dealing  wholly  with  the 
practical  matter,  which  it  is  the  aim  of  this  compre- 
hensive textbook  to  impart.  The  accuracy  of  the 
analytical  methods  are  vouched  for  from  the  fact 
that  they  have  all  been  worked  through  by  the 
author  and  the  members  of  his  class,  from  the 
printed  text.  We  can  heartily  recommend  the  work 
to  the  student  of  chemistry  as  being  a  reliable  acd 
comprehensive  one. — Druggists'  Advertiser,  Oct. 
15,  1877. 


KNAPP'S  TECHNOLOGY;  or  Chemistry  Applied  to 
.the  Arts,  and  to  Manufactures.  With  American 
additions  by  Prof.  Walter  R.  Johx.son.    In  two 


very  handsome  octavo  volumes,  with  500  wood 
engravings,  cloth,  $6  00. 


12      Henry  C.  Lea's  Publications — {Mat..  3Ied.  and  Therapeutics). 


pARRISH  {EDWARD), 

Late  Professor  of  Materia  Medica  in  the  Philadelphia  College  of  Pharmacy. 

A  TREATISE  ON  PHARMACY.    Designed  as  a  Text-Book  for  the 

Student,  and  as  a  Guide  for  the  Physician  and  Pharmaceutist.    With  many  Formulae  and 

Prescriptions.     Fourth  Edition,  thoroughly  revised,  by  Thomas  S.  Wiegand.     In  one 

handsome  octavo  volume  of  977  pages,  with  280  illustrations ;  cloth.  $6  50  ;  leather,  $6  50. 

{Lately  Issjied.) 

Of  Dr.  Parrish's  great  work  on  pharmacy  it  only  l  the  work,  not  only  to  pharmacist?,  but  also  to  the 

remains  to  be  said  that  the  editor  has  accomplished    multitude  of  medical  practitioners  who  are  obliged 

his  work  so  well  as  to  maintain,  in  this  fourth  edi- ;  to  compound  their  own  medicines.    It  will  ever  hold 

tion,  the  high  standard  of  excellence  which  it  bad    an  honored  place  on  our  own  bookshelves. — Dublin 

attained  in  previous  editions,  under  the  editorship  of,  Med.  Press  and  Circular,  Aug.  12,  1874. 

Its  accomplished  author.    This  has  not  been  accom 


plished  without  much  labor, and  many  additionsand 
Improvements,  involving  changes  in  the  ariange- 
mentof  the  several  parts  of  the  work,  and  the  addi- 
tion of  much  new  matter.  With  the  modifications 
thus  effected  it  constitutes, as  now  presented,  a  co 


We  expressed  our  opinion  of  a  former  edition  in 
terms  of  unqualified  praise,  and  we  are  in  no  mood 
to  detract  from  that  opinion  in  reference  to  the  pre- 
sent edition,  the  preparation  of  which  has  fallen  into 
competent  hands.  It  is  a  book  with  which  no  pharma- 


pendium  of  the  science  and  art  indispensable  to  the    ^'^^^*°  dispense,  and  from  which  no  physician  can 

-  '  fail  to  derive  much  information  of  value  to  him  in 

practice.— Pa ci/?c  Med.  and  Surg .  Journ. ,  June, '74. 


pharmacist,  and  of  the  utmost  value  to  every 
practitioner  of  medicine  desirous  of  familiarizing 
himself  with  the  pharmaceutical  preparation  of  the 
articles  which  he  prescribes  for  his  patients. — Chi- 
cago Med.  Journ.,  July,  1S74. 

The  work  is  eminently  practical,  and  has  the  rare 


Perhaps  one,  if  not  the  most  important  book  upon 
pharmacy  which  has  appeared  in  the  English  lan- 
guage has  emanated  from  the  transatlantic  press. 
"Parrish's  Pharmacy"  is  a  well-known  work  on  this 


merit  of  being  readable  and  interesting,  while  itpre-  j  side  of  the  water,  and  the  factshowsns  that  a  really 


srves  astrictly  scientificcharacter.  The  whole  work 
reflects  the  greatest  credit  on  author,  editor,  and  pub- 
lisher. Itwillconveysomeideaof  the  liberality  which 
has  been  bestowed  upon  itsproduction  when  we  men- 
tion that  thereare  no  less  than  280 carefully  executed 
illustrations.  In  conclusion,  we  heartily  recommend 


useful  work  never  becomes  merely  local  in  its  fame. 
Thanks  to  the  judicious  editing  of  Mr.  Wiegand,  the 
posthumous  edition  of  "  Parrish"  has  been  saved  to 
the  public  with  all  the  mature  experience  of  its  au- 
thor, and  perhaps  none  the  worse  for  a  dash  of  new 
blood.— io7id.  Pharm.  Journal,  Oct.  17,  1874. 


S 


TJLLE  [ALFRED),  M.  D., 

Professor  of  Theory  and  Practice  of  Medicine  in  the  University  of  Penna. 

THERAPEUTICS  AND  MATERIA  MEDICA ;  a  Systematic  Treatise 

on  the  Action  and  Uses  of  Medicinal  Agents,  including  their  Description  and  History. 

Fourth  edition,  revised  and  enlarged.  In  two  large  and  handsome  8vo.  vols,  of  about  2000 

pages.     Cloth,  $10;  leather,  $12.     (Lately  Issued.) 

of  the  present  edition,  a  whole  cyclopaedia  of  thera- 
peutics.—O/ucap'o  Medical  Journal,  Feb.  1875. 

The  rapid  exhaustion  of  three  editions  and  the  uni- 
versal favor  with  which  the  work  has  been  received 
by  the  medical  profession,  are  sufficient  proof  of  its 
excellence  as  a  repertory  of  practical  and  useful  In- 
formation for  the  physician.  The  edition  before  us 
fully  sustain.^  this  verdict,  as  the  work  has  been  care- 
fully revised  and  in  some  portions  rewritten,  bring- 
ing it  up  to  the  present  time  by  the  admission  of 
chloral  and  crotonchloral,  nitrite  of  ainyl,  bichlo- 
ride of  methylene,  methylic  ether,  lithium  com- 
pounds, gelseminnm,  and  other  remedies.— .4m. 
Journ.  of  Pharmacy,  Feb.  1875. 

We  can  hardly  admit  that  it  has  a  rival  in  the 
multitude  of  its  citations  and  the  fulness  of  its  re- 
search into  clinical  histories,  and  we  must  assign  it 
a  place  in  the  physician's  library;  not,  indeed,  as 
fully  representing  the  present  state  of  knowledge  in 
pharmacodynamics,  but  as  by  far  the  most  complete 
treatise  upon  the  clinical  and  practical  side  of  the 
question. — Boston  Med.  and.  Surg.  Journal,  Nov.  5, 
1874. 


It  is  unnecessary  to  do  much  more  than  to  an- 
nounce the  appearance  of  the  fourth  edition  of  this 
well  known  and  excellent  work. — Brit,  and  For. 
Med.-Chir.  Review,  Oct.  1875. 

For  all  who  desire  a  complete  work  on  therapeutics 
and  materia  medica  for  reference,  in  casesiuvolving 
medico-legal  questions,  as  well  as  for  information 
concerning  remedial  agents,  Dr.  Still^'s  is  ^^par  ex- 
cellence'^ the  work.  The  work  being  out  of  print,  by 
the  exhaustion  of  former  editions,  the  author  has  laid 
the  profession  under  renewed  obligations,  by  the 
careful  revision,  importantadditions,  and  timely  re 
issuing  a  work  not  exactly  supplemented  by  any 
other  in  the  English  language,  if  in  any  language. 
The  mechanical  execution  handsomely  sustains  the 
well-known  skill  and  good  taste  of  the  publisher. — 
St.  Louis  Med.  and  Surg.  Journal,  Dec.  1874. 

From  the  publication  of  the  first  edition  "Still^'s 
Therapeutics"  has  been  one  of  the  classics;  its  ab- 
sence from  our  libraries  would  create  a  vacuum 
which  could  be  filled  by  no  other  work  in  the  lan- 
guage, and  its  presence  supplies,  in  the  two  volumes 


QRIFFITH  [ROBERT  E.),  M.D. 

A  UNIVERSAL  FORMULARY,  Containing  the  Methods  of  Prepar- 

ing  and  Administering  OfBcinal  and  other  Medicines.  The  whole  adapted  to  Physiciar-s  and 
Pharmaceutists.  Third  edition,  thoroughly  revised,  with  numerous  additions,  bj  John  M. 
Maisch,  Professor  ofMateria  Medica  in  the  Philadelphia  College  of  Pharmacy.  In  one  large 
and  handsome  octavo  volume  of  about  800  pp.,  cl.,  $4  50  ;  leather,  $5  50.  (Lately  Issued.) 
To  the  druggist  a  good  formulary  is  simply  indis- 
pensable, and  perhaps  no  formulary  has  been  more 


msively  used  than  the  well-known  work  before 
us.  Many  physicians  have  to  officiate,  also,  as  drug- 
gist.?. This  is  true  especially  of  the  country  physi- 
cian, and  a  work  which  shall  teach  hira  the  means 
by  which  to  administer  or  combine  his  remedies  in 
the  most  efficacious  and  pleasant  manner,  will  al- 
ways hold  its  place  upon  his  shelf.  A  formulary  of 
this  kind  is  of  benefit  also  to  the  city  physician  in 
largest  practice,— Omcfnnofi  Qlinic,  Feb.  21,  1874. 


A  more  complete  formulary  than  it  is  in  its  pres- 
ent form  the  pharmacist  or  physician  could  hardly 
desire.  To  the  first  some  such  work  is  indispensa- 
ble, and  it  is  hardly  les.^i  essential  to  the  practitioner 
who  compounds  his  own  medicines.  Much  of  what 
is  contained  in  the  introduction  ought  to  be  com- 
mitted to  memory  by  every  student  of  medicine. 
As  a  help  to  physicians  it  will  be  found  invaluable, 
and  doubtle.ss  will  make  its  way  into  libraries  not 
already  supplied  with  a  standard  work  of  the  kind. 
—  The  American  Practitioner ,LoviisviUe,  July, '74. 


Henry  C.  Lea's  Publications— (Jia^.  MeA,  and  Therapeutics.)      13 


^TILLE 


,E  (ALFRED),  M.D,LL.D.,  and  JlfAISCH  {JOHN  M.),  Ph.D., 

*^        Prof  of  Theory  and  Practice,  of  Medicine  -^^        Prof,  of  Mat.  Med.  and  Bot.  in  Phila. 

and  of  Clinical  Med.  in  Univ.  of  Pa.  Coll.  Pharmacy,  Secy,  to  the  American 

Pharmaceutical  Axsociation. 

THE   NATIONAL  DISPENSATORY:  Containinp:  the  Natural  History, 

Chemistry,  Pharmacy,  Actions  and  Uses  of  Medicines,  including  those  recognized  in 
the  Pharmacopoeias  of  the  United  States  and  Great  Britain.  In  one  very  handsome 
octavo  volume  of  1628  paces,  virith  over  200  illustrations.  Extra  cloth,  $6  76  ;  leather, 
raised  bands,  $7  50.     {Notv  Ready) 

EXTRACT  FROM  THE  PREFACE. 
"  In  the  rapid  progress  of  modern  research,  few  subjects  have  of  late  years  received  greater  acces- 
sions of  facts  than  the  group  of  sciences  connected  with  materia  mediea  and  therapeutics.  The 
new  resources  thus  placed  at  the  cotutnand  of  the  pharmaceutist  and  physician  have  seemed  to  the 
authors  to  justify  an  attempt  to  make,  from  the  advanced  stand-poini  of  the  present  day,  a  concise 
but  complete  statement  of  all  that  is  of  practical  importance  to  both  professions — a  digest  in  which 
that  which  is  old  and  that  which  is  new  shall  be  so  brought  t'^gether  as  to  give  to  the  reader,  within 
the  most  moderate  practicable  compass,  all  the  details  in  pharmacology,  pharmacy,  and  thera- 
peutics, which  he  is  likely  to  need  in  his  daily  avocations.  In  the  almost  intinite  accumulation  of 
material,  this  has  required  a  careful  and  conscientious  sifting  to  discard  that  which  is  obsolete, 
untrustworthy,  or  comparatively  trivial,  without  impairing  the  practical  completeness  of  the 
work.  Th.it  they  have  wholly  accomplished  their  object  the  authors  do  not  venture  to  claim  ;  but 
they  can  say  that  years  of  constant  labor  have  been  devoted  to  the  task  of  producing  a  work  to 
which  the  inquirer  may  refer  with  the  certainty  of  finding  everything  which  experience  has  stored 
up  as  worthy  of  confidence  in  the  subjects  embraced  within  its  scope." 

We  intend  to  draw  the  attention  of  our  brother  l  the  preface,  and  now  that  it  has  been  published  and 
pharmacists  to  this  publication,  wliich  cannot  fail  j  opens  to  us  its  vast  stores  of  information,  we  may 
to  exercise  a  widespread  and  m  ij  ked influence  upon  add  that  it  was  almost  a  necess^itv  ;  and  this  we  say 
the  discharge  of  tbe  duties  of  their  vocation.  '1  be  i  without  meaning  to  impugn  the  great  excellence  of 
material  embodied  in  the  work  is  truly  immense,  the  works  of  similar  character  ti  hich  have  precfded 
as  shown  alone  by  the  almost  countless  number  if  |  it.  All  of  the  descriptions,  whether  medical,  botun- 
fiubjects  treated.  We  congratulate  the  authors  upon  j  ical,  or  pharmaceutical,  are  clear,  in  good  English, 
their  success  in  having  brought  to  a  close  a  work  i  and  unencumbered  with  obsolete  and  unintelligible 
which  must  inevitably  take  its  placeas  one  of  the    terms.      Those   portions   which   have    reference  to 


most  important  con  ributious  to  medical  and  phar- 
maceutical literature.  —  ^m.  Journ.  o/  Pharm, 
May,  1879. 

The  association  of  such  distinguished  authors  as 
Professors  Still6  and  Maisch  in  tbe  composition  of  a 
work  of  this  character  has  excited  the  strongest  in- 
terest and  the  highest  expectati.  ns  in  the  mind  of 
every  physician  and  pharmacist  in  the  country. 
For  once  we  can  truly  say  that  the  promise  of  ex- 
cellence hai  been  fufllled  to  the  letter,  and  the  Na- 
tional  Di.'-pensatory  has  come  almost  perfect  from 


therapeutics  form  a  convenient  treatise  on  that  sub- 
ject, and  are  made  the  more  valuable  and  available 
by  a  complete  therapeutical  index.  The  purely 
pharmacal  part  is  as  perfect  as  it  is  possible  to  make 
it,  and  less  could  not  have  been  expected  when  we 
consider  Prof.  Maisch's  great  qualifications  for  work 
of  that  kind.— iV.  0  Med.  Journ.,  March,  1S79. 

The  therapeutic  part  is  as  rich  as  would  he  ex- 
pected of  the  author  of  the  most  comprehensive  work 
on  the  subject  in  our  language.  The  physiological 
effects  of  drugs  receive  due  attention,  and  their  iu- 


the  hands  of  its  makers.  The  entire  work  is  a  most  j  fiuence  over  disease  is  stated  succinctly.  For  the 
excellent  one  and  cannot  fail  to  satisfy  the  pur-  j  ta.^k  of  wiaaowing  the  immense  accumulation  of 
chaser.  We  can  couj-cientious  y  recommend  it  f)  |  periodical  literature,  the  experience  and  matured 
every  student  and  practitioner  of  medicine  and  j  judgment  of  Prof.  Stille  were  emiuen'ly  fitted.  No 
pharmacy.— ,S^  Louis  Clinical  Record,  Apr  1879.  i  pharmacist  or  doctor  will  repent  the  purchase  of  a 
This  magnificent  work  has  at  last  arrived,  and  !  Jook  which  is  at  once  a  trea'.ury  of  facts  and  the 
we  are  at  floss  for  words  to  express  our  apprecia-    fe^^  ^^^Jr^ri'i^g       ^  -Louz.vtlle  Med. 

tionand  togi^e  our  readers  au  idea  of  it     The  sub-    '^*^'^'  ^^^arcn  zj,  i6/9. 

jeBt-matter  is  brought  to  date,  showiug  that  it  has  The  pharmaceutical  world  has  for  a  long  time 
been  the  unceasing  aim  of  the  authors  to  supply  a  j  been  ou  the  quivive,  in  expectation  of  the  forthcom- 
much  needed  book,  one  that  will  contain  all  the  im-  |  ,„,  Dispensatory  by  Profs.  Stillo  and  Maisch,  who 
portaat  facts,  and  not  dwell  upon  points  that  are  of  i  have  acquired  fuch  a  reputation  in  their  re>peclive 
comparatively  little  interest  to  any  but  a  specially  Departments  that  nothing  but  a  satisfactory  work 
interested  student  While  this  work,  ou  account  of  |  could  be  expected  ;  this  expectation  has  been  quite 
its  conciseness,  is  adapted  to  the  pharmacal  student,  |  realized.  We  have  examined  the  work  with  some 
it  is  equally  adapted  to  the  medica|  student  and  j  care,  and  are  very  much  plea.^ed  that  we  can  pro- 
practitioner  by  its  well  arranged  therapeutical  in-  nounce  it  to  be  reliable,  comprehensive,  and  includ- 
dex  containingabont  37,o0  references,  while  the  ma- I  ing  the  latest  re)'earche8  available  to  its  authors, 
teria  mediea  index  embraces  about  10  400.  The  This  is  more  particularly  true  as  regards  the  portion 
physician  sees  at  a  glance  all  medicines  tha^.  are  j  devoted  to  pharmaceutical  subjects.  We  are  fully 
used  for  any  certain  class  of  disease.— GAicapoP/iar- !  jQstifled  in  stating  that  it  is,  taken  altogether. 


macist  and  Chemiat,  April,  1S79. 

The  present  Dispensatory  is  arranged  in  alpha- 
betical order  from  the  commencement,  the  recent 
hdvaaces  in  chemistry  are  mentioned,  and  an  effort 


of  the  most  important  and  creditable  publications 
which  have  of  late  been  issued  by  the  American 
press.  It  will  be  an  indispensable  reference  book 
both  for  the   pharmacist  and  the  physician.— ^Veio 


made  to  include  the  late  novelties  in  the  review  of  j  Remedies,  April,  1879. 
the  resources  of  the  physician.  This  is  carried  out  |  ^  careful  examination  of  the  work  calls  forth  un- 
with  that  sound  conservative  judgment  which  cha-  |  qualified  praise  for  its  excellent  arran«ement,  full 
racterizes  all  Prof.  StiUe  a  wori.  The  chemical  i  yet  concise  information,  its  careful  adherence  to  the 
and  pharmaceutical  sections  have,  we  may  suppose,  .  ^^st  authority  on  each  particular  topic,  as  well  as 
received  the  especial  care  of  Prof.  Maisch;  and  as  t^e  entire  ehmiuation  of  all  unnecessary  and  obso- 
he  is  facile  jirincps  in  that  branch,  nothing  can  be  !  lete  data  and  particulars.  The  arrangement  of  all 
said  of  them  except  in  praise.— ^eci.  and  Sttrg.  Re-  \  topics  is  purely  alphabetical,  and  with  surprising 
porter  April  o,  1879,  fidelity  to  the  wants  both  of  th^^physiciau  and  phar- 

It  has  been  prepared  by  two  gentlemen  whose  j  maceutist.  New  remedies  which  have  come  Into 
learning  fully  qualified  them  for  the  difllcult  task,  i  recent  use  are  here  found  noticed,  with  .'•uch  facts 
and  whose  eminence  entitles  them  to  be  heard  with  i  as  have  been  collated  from  careful  investigation. — 
the  respect  and  attention  due  to  authority.  The  ;  Druggists'  Circular  and  Chemical  Gazette,  March, 
•'raisou  d'etre"  of  the  book  is  modestly  stated  in  \  1S79. 


14  Henry  C.  Lea's  Publications— (Pa/7?oZof;^,  ^c). 

nORNIL  (F.),  AND  TfANVIER  (L.), 

Prof,  in  the  Faculty  of  Med  ,  Paris.  "^  *'         Prof  in  the  College  of  France. 

MANUAL  OF  PATHOLOGICAL  HISTOLOGY.     Translated,  with 

Notes  and  Additions,  by  E.  0.  Siiakespeahe,  M.D.,  Pathologist  and  Ophthalmic  Surgeon 
to  Philada.  Hospital,  Lecturer  on  Refrflclion  and  Operative  Ophthalmic  Surgery  in  Univ. 
of  Penna.,  and  by  Hebtrv  C.  Simrs.  M  D.,  Demonstratrr  of  Pathological   Histology  in 
the  Univ.  of  Pa.         In  one  very  handsome  octavo  volume  of  about  600  pages,  with  over 
300  illustrations.     (iSkurtly.) 
So  much  has  been  done  of  late  years  in  the  elucidation  of  pathology  by  means  of  the  micro- 
scope, and  this  subject  now  occupies  so  prominenta  position  as  one  of  the  most  important  branches 
of  medical  science,  that  the  American  profession  cannot  fail  to  welcome  atranslation  of  the  pre- 
sent work,  wnich,  through  its  own   merits  and  through  the  well-known  reputation  of  its  distin- 
guished authors,  is  regarded  in  Europe  as  the  standard  text-book  and  work  of  reference  in  its 
department.   Such  investigations  and  discoveries  as  have  been  made  since  its  appearance  will  be 
introduced  by  the  translator,  and  the  work  is  confidently  expected  to  assume  in  this  country  the 
same  position  which  has  been  so  universally  accorded  to  it  abroad. 


PENWJCK  {SAMUEL),  M.D., 

-*■  Assistant  Physician  to  the  London  Hospitals 

THE  STUDENT'S  GUIDE  TO  MEDICAL  DIAGNOSIS.     From  the 

Third  Revised  and  Enlarged  English  Edition.     With   eighty-four  illustrations  on  wood. 

In  one  very  handsome  volume,  royal  12mo.,  cloth,  $2  25.  {Jtist  Issued.) 
Of  the  mpny  guid'^-books  on  medical  dlHgnobis,  are  few  books  of  this  sizeon  practical  medicine  that 
claimed  to  be  written  for  the  special  in.struction  of  j  contain  bo  much  and  convey  it  so  well  as  che  volume 
students,  this  Is  the  best.  Theauthor  is  evidently  a  |  before  us.  It  is  a  book  we  can  sincerely  recommend 
well-read  and  accomplished  physiciau.and  he  knows  |  to  the  student  for  direct  instruction,  and  to  thejprac- 
how  to  teach  practical  medicine.  The  charm  of  sim-  I  titioner  as  a  ready  and  useful  aid  to  his  meraorj.— 
plicity  is  not  thelea»=t  int<>restiagfeatnreiu  the  man-  Am.  Journ.  of  Syphilography,  Jan.  1874. 
ner  in  which  Dr.  Fen  wick  convey. •>  instruction.  The  re  ' 


G 


KEEN  {T.  HENRY), M.D., 

Lecturer  on  Pathology  and  Morbid  Anatomy  at  Charing-Crofis  Hospital  Medical  School,  etc. 

PATHOLOGY  AND  MORBID  ANATOMY.    Third  American,  from 

the  Fourth  and  Enlarged  and  Revised  English  Edition.     In  one  very  handsome  octavo 
volume  of  332  pages,  with  132  illustrations;   cloth,  $2  25.     (Just  Ready.) 

ciently  immerous,  and  usually  well  made.  In  the 
present  edition,  such  new  matter  has  been  added  as 
was  necessary  to  embrace  the  later  results  in  patho- 
logical research.  No  doubt  it  will  continue  to  enjoy 
the  favor  it  has  received  at  the  hands  of  the  profes- 
sion.— Med  and  Surg.  Reporter,  Feb.  1,  1S79. 

For  practical,  ordinary  daily  use,  this  is  undoubt- 
edly the  best  treatise  that  is  offered  to  students  of 


This  is  unquestionably  one  of  the  best  manuals  on 
the  subject  of  pathology  and  morbid  anatomy  that 
can  be  placed  in  the  student's  hands,  and  we  are 
glad  to  see  it  kept  up  to  the  times  by  new  editioos. 
Each  edition  is  carefully  revised  by  the  author,  with 
the  view  of  makiug  it  include  the  most  recent  ad- 
vances in  pathology,  and  of  omitting  whatever  may 
have  become  obsolete. — X.  Y.  Med.  Jour.,  Feb.  1879. 


The  treatise  of  Dr.  Green  is  compact,  clearly  ex-    pathology  and  morbid  anatomy. — Cincinnati  Lan 
pressf  d,  up  to  the  times,  and  popular  as  a  text-book,  {  cet  and  Clinic,  Feb.  8,  1S79. 
both  in  England  and  America.    The  cuts  are  suffi-  1 


JD 


AVIS  {NATHAN  S.), 

Prof,  of  Principles  and  Practice  of  Medicine,  etc.,  in  Chicago  Med.  College. 

CLINICAL  LECTURES  OX  VARIOUS  IMPORTANT  DISEASES; 

being  a  collection  of  the  Clinical  Lectures  delivered  in  the  Medical  Wards  of  Mercy  Hos- 
pital, Chicago.  Edited  by  Frank  H.  Davls,  M.D.  Second  edition,  enlarged.  In  one 
handsome  roy^l  12mo.  volume.     Cloth,  $1  75.     {Lately  Issued.) 


WHAT  TO  OBSERVE  AT  THE  BEDSIDE  axd  AFTER 
Death  in  Medical  Casks.  From  the  second  Lon- 
don edition.     1  vol  royal  12mo.,  cloth.    $100. 

CHRISTISON'SDISPENSATORT.  With  copious  ad- 
ditions, and  '2i;3  large  wood  engravings.  By  R. 
KoLKSFiRLD  GRIFFITH,  M.D.  One  vol.  Svo.,  pp. 
1000,  cloth.    $4  00. 

CARPENTER'S  PRIZE  ESSAY  ON  THE  USE  OF 
Alcoholic  Liquors  in  Health  and  Disease.  New 
edition,  with  a  Preface  by  D.  F.  Condie,  M.D.,  and 
explanationsof  scientiflcwords.  In  oneneatl2mo. 
volume,  pp.  178,  cloth.    60  cents. 

O  LUGE'S  ATLAS  OF  PATHOLOGICAL  HISTOLOGY 
Translated,  with  Notes  and  Additions,  by  Joseph 
Leidt,  M.  D.  In  one  volume,  very  large  imperial 
quarto,  with  320  copper-plate  figures,  plain  and 
colored,  cloth.     |l?00. 

LA  ROCHE  ON  YELLOW  FEVER, considered  in  its 
Historical,  Pathological.  Etiological,  and  Thera 
peutical  Relations.  In  two  large  and  handsome 
octavo  volumes  of  nearly  loOO  pp  ,  cloth.    $7  00. 

HOLLAND'S  MEDICAL  NOTES  AND  REFLEC- 
TI0N8.    1  vol.  8vo.,  pp.  500,  cloth.    $3  60. 


BARLOW'S  MANUAL  OF  THE  PRACTICE  OP 
MEDICINE.  With  Additions  by  D.  F.  Condif, 
M   D.     1  vol.  8vo.,  pp.  600,  cloth.    $2  50. 

TODD'SCLINICAL  LECTURES  ON  CERTAIN  ACUTB 
Diseases.  In  one  neat  octavo  volume,  of  320  pp  , 
cloth.    $2  60. 

STURGES'S  INTRODUCTION  TO  THE  STUDY  OF 
CLINICAL  MEDICINE.  Being  a  Guide  to  the  In- 
vestigation of  Disease.  In  one  handsome  12rao. 
volume,  cloth,  $1  2.3.    {Lately  Issxied.) 

STOKES'  LECTURES  ON  FEVER.  Edited  by  John 
William  Moork,  M.D. ,  Assistant  Physician  to  the 
Cork  Street  Fever  Hospital.  In  one  neat  Svo. 
volume,  cloth,  .$2  00.     {Juat  Issued.) 

THE  CYCL0P.T5DIA  OF  PRACTICAL  MEDICINE: 
comprising  Treatises  on  the  Nature  and  Treatment 
of  Diseases,  Materia  Medica  and  Therapeutics,  Dis- 
eases of  Women  and  Children,  .Medical  Jurispru- 
dence, etc.  etc.  By  Do'NOL.moN,  Fokbks,  Twkedie, 
and  CoNOLLV.  In'  four  large  super-royal  octavo 
volumes,  of  8'2.54  double-columned  p;ige.«,  strongly 
and  handsomely  bound  in  leather,  $15;  cloth,  $11. 


Henry  C.  Lea's  Publications — {Practice  of  Medicine),  15 


fpLINT  (AUSTIN),  M.D., 

-^  Professor  of  the  Priyiciples  and  Practice  of  Medicine  in  Sellevue  Med.  College,  N.  Y. 

A   TREATISE    ON   THE    PRINCIPLES  AND    PRACTICE    OF 

MEDICINE  ;  designed  for  the  use  of  Students  and  Practitioners  of  Medicine.     Fourth 
edition,  revised  and  enlarged.     In  one  large  and  closely  printed  octavo  volume  of  about 
1100  pp.;  cloth,  $6  00  J  or  strongly  bound  in  leather,  with  raised  bands,  $7  00.     (l.ate/y 
Issued. ) 
By  common  consentof  the  English  and  American  medical  press,  this  work  has  been  assigned 
to  the  highest  position  as  a  complete  and  compendious  text-book  on  the  most  advanced  condi- 
tion of  medical  science.     At  the  very  moderate  price  at  which  it  is  offered  it  will  be  found  one 
of  the  cheapest  volumes  now  before  the  profession. 

This  excellent  treatise  on  medicine  lias  acquired  His  own  clinical  studips  and  the  latest  contribu- 
foritselfin  the  United  States  a  reputation  similar  to  tions  tomf^dical  literature  both  in  this  country  and 
thateuioyed  in  England  by  the  admirable  lectures  in  Europe,  have  received  careful  attention,  to  that 
of  Sir  Thomas  Watson.  We  have  referred  to  many  |  some  portions  have  been  entirely  rewritten,  and 
of  the  most  important  chapters,  and  find  the  re^i-  j  about  seventy  pages  of  new  matter  have  been  ad- 
sion  spoken  of  in  the  preface  is  a  genuine  one,  and  ,  ded. — Chicago  Mtd  Jour.,  June,  1873. 
thattheauthorhasvery  fairly  brought  u^^^^^^^^^  |  ^         surpassed  as  a  text-book  for  stu- 

to  thelevel  oftheknowledgeof  thepresent  daj.  The  of  ready  reference  for  practition- 

workhasthispatrecommendation  thatU  s^^^^  The  force  of  its  logic,  its  simple  and  practical 

volume,andthereforewillnotDesoternfyiugtothe    teachings,  have  left  it  without  a  rival  in  the  field 

N.  Y.—Med.  Record,  Sept.  1.5,  1874. 


student  as  the  bulky  volumes  which  several  of  our 
En:?lish  text-books  of  medicine  have  developed  in  to. 
—British  and  Foreign  Med.-Chir.  Rev.,  Jan.  187^. 
It  is  of  course  unnecessary  tointroduce  or  eulogize 
this  now  standard  treatit^e.  The  present  edition 
has  been  enlarged  and  revised  to  bring  it  up  to  the 
author's  present  level  of  experience  and  reading. 


It  is  given  to  very  few  men  to  tread  in  the  steps  Of 
Austin   Flint,   whose  single  volume  on    medicine 
though  here  and  there  defective,  is  a  masterpiece  oj- 
lucid  condensation  and  of  general  grasp  of  an  enor. 
mously  wide  subject. — Lond.  Practitiojier.Dec.'lS^ 


-nY  THE  SAME  AUTHOH. 

CLINICAL  MEDICINE;    a  Systematic   Treatise  on    the  Diagnosis 

and  Treatment  of  Diseases.  Designed  for  Students  and  Practitioners  of  Medicine.  In 
one  large  and  handsome  octavo  volume  of  about  900  pages,  {hi  Press.) 
It  has  been  the  object  of  the  author  in  this  volume  to  present  the  scierce  and  art  of  medicine 
in  their  most  practical  aspect,  adapted  to  the  necessities  of  the  student  and  physician  in  the 
daily  routine  of  duties  at  the  bedside.  By  avoiding  the  discussion  of  questions  relating  to 
pathology  and  etiology,  space  is  gained  for  the  thorough  consideration  of  diagnosis  and  treat- 
ment, embracing  many  points  which  escape  attention  in  the  ordinary  text- books.  In  the  arrange- 
ment of  the  work,  diseases  are  classed  according  to  the  system  of  organs  primarily  affected  :  and 
affections  closely  related  are  grouped  together  so  as  to  elucidate  their  differentiation,  and  the 
appropriate  treatment  is  pointed  out  for  each.  The  preparation  of  the  work  has  occupied  the 
author  for  several  years,  and  is  presented  as  embodying  the  results  of  prolonged  observation  and 
experience  under  opportunities  more  extensive  than  often  fall  to  the  lot  of  the  physician. 


JDY  THE  SAME  AUTHOR. 

ESSAYS    ON    CONSERVATIVE   MEDICINE    AND    KINDRED 

TOPICS.     In  one  very  handsome  royal  12rao.  volume.     Cloth,  $1  38.     {Just  Issued.) 
fJARTSHOENE  [HENRY],  M.D., 

■»-*•  Professor  of  Hygiene  in  the  University  of  Pennsylvania. 

ESSENTIALS  OF  THE  PRINCIPLES  AND  PRACTICE  OF  MEDI- 
CINE.  A  handy-book  forStudents  and  Practitioners.    Fourth  edition,  revised  and  im- 
proved.   With  about  one  hundred  illustrations.    In  one  handsome  royal  ]2mo.  volume, 
of  about  550  pages,  cloth,  $2  63  ;  half  bound,  $2  88,     {Lately  Issued.) 
As  ahandbook,  which  clearly  sets  forth  theBssEN-  i  book,  it  cannot  be  improved  upon. — Chicago  Med. 
TI.4I.S  of  the  PRINCIPLES  ANi)  PRACTICE  OP  MEDICINE,     Examiner,  Nov.  15,  1874 

we  do  not  know  of  its  equal.- Fa.  Med.  Monthly.     \      Without  doubt  the  best  book  of  thekind  published 
As  a  brief,  condensed, .but  comprehensive  hand-  j  in  the  English  language. — St.  Louis  Med.  and  Surg. 

•  i  Journ  ,  Nov.  187-1. 


W: 


ATSON  [THOMAS],  M.D.,  ^c. 

LECTURES    ON    THE     PRINCIPLES    AND    PRACTICE    OF 

PHYSIC.    Delivered  at  King's  College,  London.     A  new  American,  from  the  Fifth  re- 
vised and  enlarged  English  edition.   Edited,  with  additions,  and  several  hundred  illustra- 
tions, by  Henry  Hartshorke,  M.D.,  Professor  of  Hygiene  in  the   University  of  Penn- 
sylvania.    In  two  large  and  handsome  8vo.  vols.    Cloth,  $9  00  ;  leather,  $11  00.     {Lately 
Published.) 
It  Is  a  subject  for  congratulation  and  for  thank- ,  cate  and  important  pathologicaland  practical  ques- 
ful  lessthat  Sir  Thomas  Watson,  during  a  period  of  |  tious,  the  results  of  his  clear  insight  and  his  calm 
comparative  leisure,  after  a  long,  laborious,  and  !  judgment  are  now  recorded  for  the  benefit  of  nutn- 
most  tioaorableprofessional  career,  while  retaining  \  kind,  in  language  which,  for  precision,  vigor,  and 
full  possession  of  his  high  mental  faculties,  should    classical  elegance,  has  rarely  been   equalled,  and 
have  employed  the  opportunity  to  submit  his  Lee-    never  surpassed      The  revision  has  evidently  been 
tures  to  a  more  thorough  revisionthan  was  possible    most  carefully  done,  and  the  results  appear  in  al- 
during  the  earlier  and   busier  period  of  his  life.  !  most  every  page. — Brit.  Med.  Journ.,  Oct.  14,  1S71. 
Carefully  passing  in  review  some  of  the  most  intri-  ; 


16 


Henry  C.  Lea's  Publications — {Practice  of  Medicine). 


IDRJSTO  WE  {JOHN  SVER),  M.D.,  F.R.C.F., 

J^  Phynician  and  Joint  Lecturer  on  Medicine.,  St.  Thomases  Hospital. 

A  MANUAL  OX  THE  PRACTICE  OF  MEDICINE.    Edited,  with 

Additions,  by  James  II.  IIuichinson,  M.D.,  Physician  to  the  Penna.  Hospital.     In  one 
handsome  octavo  volume  of  over  1100  pages  :  cloth,  $5  50;  leather,  $6  50.    {Just  Issued.) 


increHsed  by   the  judicious   noles  of  the  Editor. — 
Oincinnnti  Clinic,  Jan.  7,  1677. 

Auyone  who  want.s  a  good,  clear,  condensed  work 
upon  PfHCtice,  quite  up  with  the  most  recent  viewsin 
pathology,  will  tind  this  a  most  valuable  work.  The 
additions  made  by  Dr.  Hutchinson  are  appro))ilate 


This  portly  volume  is  a  model  of  condensation. 
In  a  style  at  once  clear,  interesting, and  concise,  Dr. 
Bristowe  passes  in  review  every  conceivable  subject 
connected  with  the  practice  of  medicine.  Those 
practitioners  who  purchase  few  books  will  find  this 

a  moft  opportune  publication,  because  fco  many  top-    _     

ics  not  usually  embraced  in  a  work  on  practice  are  I  and  useful,  andso  well  done  that  wewish  there  were 
adequately  handled.     The  book  is  athoroughly  good  i  more  of  them.— ^m,  Fractilioner,  Feb.  1877. 
one,  and  its  usefulness  to  American  readers  has  been  i 

T^OODBURY  {FRANK),  M.D., 

Phyffician  to  the  German  Hospital,  Philadelphia,  late  Chief  Assist,  to  Med.  Clinic,  Jeff.  College 
Hospital,  etc. 

A    HANDBOOK   OF    THE   PRINCIPLES   AND    PRACTICE    OF 

Medicine  ;   for  the  use  of  Students  and  Practitioners.     Based  upon  Husband's  Handbook 
of  Practice.     In  one  neat  volume,  royal  12mo.      (Li  Press.) 


flADERSHON  [S.  0.).  M.D. 

J- J-  Senior  Physician  to  and  late  Lecturer  on  the  Principtes  and  Practice  of  Medicine  at  Guy's 

Hospital,  etc. 

ON  THE  DISEASES  OF  THE  ABDOMEN,  COMPRISING  THOSE 

of  the  Stomach,  and  other  parts  of  the  Alimentary  Canal,  (Esophagus,  Caecum,  Intes- 
tines, and  Peritoneum.     Second  American,  from  the  third  enlarged  and  revised  Eng- 
lish edition.     With  illustrations.     In  one  handsome  octavo  volume  of  over  600  pages. 
Cloth,  $3  50.      {Noiv  Heady.) 
This  work  has  remained   s^me  time  out  of  print,   owing  to  the  careful  and  conscientious 
revision  which  it  has  enjoyed  at  the  hands  of  the   author,  and  which   hns  nearly  doubled  its 
size  since  the  appearance  of  the  first  edition.    Yet  there  is  no  work  accessible   to  the  profession 
to  take  its  place,  as  a  careful,  practical  guide  on  a  class  of  disea.se3,  which  form  so  large  and 
important  a  portion  of  the  duties  of  the   physician,  and  for  which   the  author's  position  has 
given  him  almost  unequalled  opportunities  for  observation  and  experience. 

We  can  do  very  little  to  add  to  the  favorable  re 
ception  which  has  already  been  given  by  the  medl 
cal  press  of  the  world  to  this  well  known  treatise 


We  commend  to  all  practitioners  a  careful  perusal 
of  Dr.  Hibershon's  work.  More  especially,  wedraw 
atteniion  to  the  number  of  intestinal  diseases  re- 
corded in  its  pages,  cases  of  extreme  interest  clini- 
cally and  pathologically.  This  careful  record  shows 
that  the  work  is  no  compilation,  but  a  careful  exposi- 
tion of  the  author's  personal  experience. — Canadian 
Med.  and  Surg.  Journ.,  May,  1879. 

As  a  work  of  reference,  as  well  as  daily  study,  no 
work  yet  emanating  from  the  med"cal  press  is 
worthy  of  more  cireful  consideration  by  the  general 
practitioner  than  the  above.  With  the  careful  re- 
vision given  this  edition.  Dr.  Habershon's  work 
will  sti  1  remain  at  tlie  head  of  the  list,  and  con 
tinue  to  be  regarded  as  one  of  the  best  treatises  on 
abdominal  diseasas  extant  — South.  Practitioner, 
June,  1879. 

There  have  been  many  laborers  in  this  depart- 
ment of  special  pathology,  and  among  them  no  one 
has  dane  better  service  than  Dr.  Habershon.  The 
first  -ditions  were  exhausted  long  since,  and  the 
author  has  revised  the  one  now  under  consideration 


with  great  care  and  thoroughness.  The  chapters  on 
constipation  and  intestinal  obstruction  are  of  high 
value,  and  are  worth  many  times  the  cost  of  the 
book,  wiiich,  altogether,  is  a  most  excellent  one. — 
St.  Louis  Vlin.  Record,  June,  1879. 

This  valuable  treatise  on  diseases  of  the  stomach 
and  al)dou.en  has  been  out  of  print  for  several  years, 
and  is  therefore  not  so  well  known  to  the  profession 
as  it  deserves  to  be.  It  will  be  found  a  cyclopjedia 
of  information,  systematically  arranged,  on  all  dis- 
eases of  the  alimentary  tract,  from  the  mouth  to  the 
rectum  A  fair  proportion  of  each  chapter  is  devot- 
ed to  symptoms,  pathology,  and  therapeutics.  The 
present  edition  is  fuller  than  former  ones  in  many 
particulars,  a»d  has  been  thoroughly  revi.sed  and 
amended  by  the  author.  Several  new  chapters  have 
been  added,  bringing  the  work  fully  up  to  the  times, 
and  making  it  a  volume  of  interest  to  the  practitioner 
in  every  field  of  medicine  and  surgery.  Perverted 
nutrition  is  in  some  form  associated  with  all  diseases 
we  have  to  combat,  and  we  need  all  the  light  that 
can  be  obtained  on  a  subject  so  broad  and  general. 
Dr  Habershon's  work  is  one  that  every  practiii  ner 
should  read  and  study  for  himself.— iV.  Y.  Mtd. 
Journ.,  April,  1879. 


J^OTHERGILL  (J  MILNER),  M.D.  Edm.,  M.R.G.P.  Land., 

-*-  Asst.  Phys.  to  the  West  Lond   Hosp.  :  Asst.  Phys.  to  the  City  of  Lond.  Hosp.,etc. 

THE  PRACTITIONER'S  HANDBOOK  OF  TREATMENT;  Or,  the 

Principles  of  Therapeutics.     In  one  very  neat  octavo  volume  of  about  560  pages  :  cloth, 

$4  00.  {Now  Ready.) 
Our  friends  will  find  this  a  very  readable  book:  and  ,  he  knew  bow  suggestive  and  helpful  it  would  be  to 
that  it  sheds  light  upon  every  theme  it  touches, causing  i  him.— .S^  Louis  Mtd.  and  Surg.  Journ  ,  April,  1877. 
the  practitioner  to  feel  more  certain  of  his  diagnosis  in  I  \Ve  heartily  commend  his  book  to  themedical  student 
difficult  cases.  We  confidently  commend  the  work  to  ««  an  honest  and  intelligent  guide  through  the  mazes  of 
our  readers  as  one  worthy  of  careful  perusal.  It  lights  therapeutics,  and  assure  the  practitioner  who  has  grown 
the  way  over  ot>scure  and  difficult  passes  in  medical  Nrray  in  the  harness  that  he  will  derive  pleasure  and  in- 
practice.  The  chapter  on  the  circulation  of  the  blood  struction  from  its  perusal  Valuable  sugge.-^tions  and 
is  the  most  exhaustive  and  instructive  to  be  found.  It  material  for  thought  abound  throughout.-  BoslonMed. 
is  a  book  every  practitioner  needs,  and  would  have,  If  i  ^„^^  ^;.„^^  Journal,  Mar.  8,  1877. 

■DY  THE  SAME  AUTHOR. 

THE  ANTAGONISM  OF  THERAPEUTIC  AGENTS,  AND  AVHAT 

IT  TEACHES.    Beinj;  the  Fothergillian  Prize  Essay  for  IS78.    In  one  neat  volume,  royal 
12mo.  of  106  p.iges;  cloth,  $1  00.      {Just  Ready.) 


Henry  C.  Lea's  Publications — (^Diseases  of  the  Skin^  &c.),         lY 
pEVNOLDS  {J.  RfTSSELL),  M.D., 

-*■  •^         Prof,  of  the  Principles  and  Practice  of  Medicine  in  Univ.  College,  London. 

A  SYS  TEM  GF  MRDTOINE.  with  Notes  and  Additions  by  Hkny  IIabts- 
HORNK,  M  D.,  late  Professor  of  Hygiene  in  the  University  of  Pennfi.  In  three  large  and 
h.indsoine  octavo  volumes,  containing  about  3000  closely  printed  double  columned  pages, 
with  numerous  illustrations,     {hi  Press  ) 

Reynolds's  System  of  Medicine,  recently  completed,  has  acquired,  since  the  first  appearance 
of  the  first  volume,  the  well-deserved  reputation  of  being  the  work  in  which  modern  British 
medicine  is  presented  in  its  fullest  and  most  practical  form.  This  could  scarce  be  otherwise  in 
view  of  the  fact  that  it  is  the  result  of  the  collaboration  of  the  leading  minds  of  the  profession, 
each  subject  being  treated  by  some  gentleman  who  is  regarded  as  its  highest  authority — as  for 
instance.  Diseases  of  the  Bladder  by  Sir  Henrv  Thompson,  Malpositions  of  the  Uterus  by 
Graily  Hewitt,  Insanity  by  Henry  Maudsley,  Consumption  by  J.  Hughes  Bennet,  Dis- 
eases of  the  Spine  by  Charles  Bland  Radcliffe,  Pericarditis  by  Francis  Sibson,  Alcoholism 
by  Francis  E.  Anstie,  Renal  Affections  by  William  Roberts,  Asthma  by  Hyde  Salter, 
Cerebral  Affections  by  tf  Charlton  Bastian,  Gout  and  Rheumatism  by  Alfred  Baring  Gak- 
ROD,  Constitutional  Syphilis  by  Jonathan  Hutchinson,  Diseases  of  the  Stomach  by  Wilson 
i-ox,  Dise.ises  of  the  Skin  by  Balmanno  Squire,  Affections  of  the  Larynx  by  Morell  Mac- 
>  ENZiE,  Diseases  of  the  Rectum  by  Blizard  Curling,  Diabetes  by  Lauder  Brunton,  Intes- 
tinal Liseases  by  John  Syer  Buistowr,  Catalepsy  and  Somnambulism  by  Thomas  King  Cham- 
bers, Apoplexy  by  J.  Hughlings  Jackson,  Angina  Pectoris  by  Professor  Gairdner,  Emphy- 
sema of  the  Lungs  by  Sir  William  Jenner,  etc.  etc.  All  the  leading  schools  in  Great  Britain 
have  contributed  their  best  men  in  generous  rivalry,  to  build  up  this  monument  of  medical  sci- 
ence. St.  Bartholomew's,  Guy's,  St  Thomns's,  University  College,  St  Mary's  in  London,  while 
the  Edinburgh,  Glasgow,  and  Manchester  schools  are  equally  well  represented,  the  Army  Medical 
School  at  Netley,  the  military  and  naval  services,  and  the  public  health  boards.  That  a  work 
conceived  in  such  a,spirit,  and  carried  out  under  such  auspices  should  prove  an  indispensable 
treasury  of  facts  and  experience,  suited  to  the  daily  wants  of  the  practitioner,  was  inevitable,  and 
the  success  which  it  has  enjoyed  in  England,  and  the  reputation  which  it  has  acquired  on  this 
side  of  the  Atlantic,  hnve  sealed  it  with  the  approbation  of  the  two  pre-eminently  practical  nations. 

Its  large  size  and  high  price  having  kept  it  beyond  the  reach  of  many  practitioners  in  this 
country  who  desire  to  possess  it,  a  demand  has  arisen  for  an  edition  at  a  price  which  shall  ren- 
der it  iicce.«sible  to  all.  To  meet  this  demand  the  pre-eent  edition  has  been  undertaken.  The 
five  volumes  and  five  thousar  d  pages  of  the  original  will,  by  the  use  of  a  smaller  type  and  double 
columns,  be  compressed  into  three  volumes  of  about  three  thousand  pages,  clearly  and  hand- 
somely printed,  and  offered  at  a  price  which  will  render  it  one  of  the  cheapest  works  ever  pre- 
sented to  the  American  profession. 

But  not  only  will  the  American  edition  be  more  convenient  and  lower  priced  than  the  English  ; 
it  will  also  be  better  and  more  complete.  Some  years  having  elapsed  since  the  appearance  of  a 
portion  of  the  work,  additions  will  be  required  to  bring  up  the  subjects  to  the  existing  condition 
of  sciei\ce.  Some  diseases,  al?!0,  which  are  comparatively  unimportant  in  England,  require  more 
elaborate  treatment  to  adapt  the  articles  devoted  to  them  to  the  wants  of  the  American  physi- 
cian ;  and  there  are  points  on  which  the  received  practice  in  this  country  differs  from  that 
adopted  nbroad.  The  supplying  of  these  deficiencies  has  been  undertaken  by  Henry  Harts - 
HORNE,  M.D.,  late  Professor  of  Hygiene  in  the  University  of  Pennsylvnnia,  who  will  endeavor 
to  render  the  Avork  fully  up  to  the  day,  and  as  useful  to  the  American  physician  as  it  has  proved 
to  be  to  his  English  brethren.  The  number  of  illustrations  will  also  be  largely  increased,  and 
no  effort  will  be  spared  to  render  the  typographical  execution  unexceptionable  in  every  respect. 
The  preparation  of  the  work  is  now  proceeding  as  rapidly  as  is  compatible  with  its  careful  exe- 
cution, and  its  appearance  may  be  expected  at  an  early  day. 

J^OX  [TILBURY),  M.D.,  F.R.C.P.,and  T.  C.  FOX,  B.A.,  M.R.G.S., 

Physician  to  the  Department  for  Skin  Diseases,  University  College  Uospitol. 
EPITOME  OF  SKIN   DISEASES.      WITH    FORMULAE.      For  Stu- 
dents and  Practitioners.    Second  edition,  thoroughly  revised  and  greatly  enlarged.  In 
one  very  handsome  12mo.  volume  of  216  pages.     Cloth,  $1  38.     {Just  Ready.) 
The  names  of  the  authors  are  quite  sufficient  to  i  exceeds  in  size,  and  Furpdsses  in  use,  its  predeces- 
comrnsnd    ttiis   book,  Dr    Tilbury  Fox   being  well  \  sor.     The  work  is  certainly  a  valuable  addition  to 
known   as  occnpying  a  place  in  the  front  rank  of  j  the '•  handy  volume"  department  of  medical  litera- 
dermatologists  of  the  A&y.— Canadian  .Journal  of    ture. — The  Med.  BuHeixn,  May,  ls7b 
Med.  Soi  ,  May,  l!'78.  p,^,,  gtudents  a  better  book  was  uwver  devised. — 

The  present  edition  of  the  Epitome  considerably  I  Cincinnati  Lancet  and  Ciinic,  May,  lb79. 

ILSON  ( ERASM US),  F. R. S. 

THE  STUDENT'S  BOOK  OF  CUTANEOUS  MEDICINE  aiidDis- 

BASES  OF  THE  SKIN.    In  one  very  handsome  royal  12mo.  volume.   $3  50. 
ILLIER  [THOMAS),  M.D., 

Physician  to  the  Skin  Department  of  University  College  Hospital,  etc. 

HAND-BOOK  OF  SKIN  DISEASES,  for  Students  and  Practitioners. 

Second  Am.  Ed.     In  one  royal  12mo.  vol.  of  358  pp.    With  Illustrationf      Cloth, $2  25. 

It  is  a  concise,  plain,  practical  treatise  on   the  I  dents   ard    practitioners.  —  Chicago   Medical  Ex- 

var  ous  diseases   of   the  skin  ;  just   such    a  work,     aminer,   Maj    1863. 

indeed,  as  was  much  needed,  both  by  medical  stu- 


W' 


H 


18 


Henry  C.  Lea's  Publications — {Practice  of  Medicine). 


PINLAYSON  {JAMES),  M.D., 

Physician  and  Lecturer  on  Clinical  Medinne  in  th'.  Glasgow  Western  Infirmary,  etc. 

CLINICAL    DIAGNOSIS;    A    Handbook    for    StucUnits   and    Prac- 

titioners  of  Medicine.  In  one  handsome  12mo.  volume,  of  546  pages,  Avith  85  illustra- 
tions. Cloth,  $2  63.  {Just  Ready.) 
The  concurrence  of  gentlemen  specially  familiar  with  the  several  subjects  being  requisite  to 
the  satisfactory  development  of  a  plan  so  extensive,  Dr.  Finlayson  hns  secured  the  co-operation 
of  Prof.  Gairdner,  who  has  contributed  the  chapter  on  the  Physiognomy  of  Disease  ;  Prof.  Wm. 
Stephenson  that  on  Disorders  of  the  Female  Organs;  Dr.  Alex.  Robertson  that  on  Insanity; 
Prof.  Samson  Gemmell  those  on  the  Sphygmograph  and  Physical  Diagnosis;  and  Dr.  Joseph 
Coates  those  on  the  Fauces,  Larynx,  and  Nares,  and  on  the  method  of  -peviorxaxwy;,  post-mortem 
examinations.  Other  chapters  have  enjoyed  the  advantage  of  revision  by  gentlemen  specially 
versed  in  their  several  subjects;  and  the  volume  is  presented  as  thoroughly  on  a  level  with 
the  most  advanced  condition  of  knowledge  in  a  department  which  has  made  such  rapid  strides 
of  advancement  within  the  last  few  years. 


The  book  is  aa  excellent  one,  clear,  coacisc,  conve- 
nieut,  practical.  It  is  replete  with  the  very  kuow- 
ledge  the  student  needs  when  he  quits  the  lecture- 
room  and  the  laboratory  for  the  ward  and  sick-room, 
aud  does  not  lack  in  iuformation  that  will  meet  the 
wants  of  experienced  and  older  men.— Phila.  Med. 
Times,  Jan.  4,  1S79. 

The  aim  of  the  author  is  to  teach  a  student  and 
practitioner  how  to  examine  a  case  so  as  to  use  "all 
his  knowledi/e'"  in  arriving  at  a  diaguosT.s.  All  the 
various  symptoms  of  the  several  systems  are  grouped 
together  in  sucii  a  manner  as  to  mtke  their  relations 
to  a  final  diagnosis  clear  and  easy  of  apprehension. 
This  work  has  been  done  by  men  of  large  experience 
and  trained  observation,  who  have  been  long  recog- 
nized as  authorities  upon  the  subj.  ess  which  they 
treat.  There  i.s  a  profusion  of  illustrations  to  illus- 
trate subjects  under  discussion.  The  application  of 
electricity,  and  instruments  of  precision  in  diagnosis, 
is  fully  di.--cussed.  This  book  i.s  all  good.  We  com- 
mend it  to  all  students  aud  practitioners  of  medicine 
as  a  work  worthy  of  a  place  in  their  libraries. — Ohio 
Med.  Recorder,  Dec.  1878. 


This  is  one  of  the  really  useful  book.s.  It  is  attrac- 
tive from  preface  to  the  final  page,  and  ought  to  l)e 
given  a  place  ou  every  otTico  table,  because  it  contains 
in  a  condensed  form  all  that  is  valuable  in  semeiology 
and  diagnostics  to  be  found  in  bulkier  volumes,  and 
because  in  its  arrangement  aud  complete  index,  it  is 
unusually  convenient  for  quick  reference  in  any 
emergency  ttiat  may  come  upon  the  busy  practitioner. 
—N.  0.  Med.  Journ.,  Jan.  1879. 

This  is  a  most  important  work  for  students,  and 
one  that  is  dtstined  to  become  rapidly  popular.  It 
is  composed  of  contributions  from  various  eminent 
sources  bearing  upon  this  subject.  The  real  secret 
of  succes.sful  practice  i.s  the  accurate  diagnosis  of 
disease.  This  manual  teaches  the  student  to  arrange 
his  investigation  in  such  sy.stera  as  to  enable  him, 
with  practice,  to  acquire  this  very  desirable  faculty. 
The  division  of  the  subject,  as  in  this  work,  among 
the  highest  authorities  living,  is  a  good  idea,  and 
gives  us  in  one  compact  form  a  series  of  monographs 
written  by  masters. — Nashville  Journal  of  Med. 
and  Surg.,  Jan.  1879. 


JJ^AMILTON  {ALLAN  MrLANE),  M.D., 

Attending  Physician  at  the  Hospital  for  Epileptics  and.  Paralytica,  BlacliwelVs  Island,  N.  Y., 
and  at  the  Out- Patients''  Department  of  the  New  York  Ho.i2nial. 

NERVOUS  DISEASES;  THEIR  DESCRIPTION  AND  TREATMENT. 

In  one  handsome  octavo  volume  of  512  pages,  with  53  illus.;  cloth,  $3  50.     {Just  Ready.) 

connected  with  the  nervous  system.  We  have  no 
he.sitatiou  in  saying  that  reliance  may  be  placed  on 
Dr.  Hamilton's  conscientious  performance  of  his  sel!- 
assigued  task,  on  his  soundness  of  judgment,  and 
freedom  from  empiricism. — Edinburgh  Med.  Journ., 
Oct.  1S78. 


This  is  unquestionably  the  best  and  mofet  com 
plete  text-book  of  nervous  diseases  that  has  yet  ap- 
peared, and  were  interuaiioaal  jealousy  in  scientific 
afi'airs  at  all  possible,  we  might  be  excused  f  >v  a 
feeling  of  chagrin  that  it  should  be  of  American 
parentage.  This  work,  however,  has  been  performed 
in  New  York   and  has  been  .so  well  performed  that  |      f,.„„  ^  pj,,gf„^  examination   of  the  whole 

no   room   is  ^left  for   auytl>mg  but  ^corameudation.  |  ^ork.wecar  justly  .say  that  the  author  has  not  only 
"' '        '""  "'   '■-     •"     clearly  and  fully  treated  of  diagnosis  and  treatment, 


With  great  skill.  Dr.  Hamilton  ha-*  presented  'o  h 
readers  a  succinct  and  lucid  survey  of  all  that  is 
known  of  the  pathology  of  the  nervous  sy.stem, 
viewed  in  the  light  of  the  most  recent  re-searche*. 
From  the  preliminary  description  of  the  methods  of 
examination  and  study,  and  of  the  instruments  of 
precision  employed  in  the  investigation  of  nervou^^ 
diseases,  up  till  the  final  collection  of  foruiulie,  tiie 
book  is  eminently  practical.  —  Brain,  London,  Oct. 
1S78. 

The  author  tells  us  in  his  preface  that  it  has  been 
his  object  to  produce  a  concise,  practical  book,  and 
we  think  he  has  been  successful,  considering  the  ex- 
tent of  the  subject  which  he  has  umlertakeu.  In 
fact,  it  is  more  extensive  than  :iie  title  properly  or 
accurately  indicates,  embracing- be.sides  wh>it  are 
u.sually  regarded  as  nervous  diseases — inflammatory 
aff"ections,  both  acute  and  chronic,  hemorrhages  and 
tumors  of  the  cerebrum  and  cerebellum,  medulla 
oblongata,  spinal  cord  and  nerves,  with  thrombosis 
and  embolism  of  the  arteries,  sinuses,  and  veins. 
The  reader  may  therefore  expect  information,  more 
or  less  full  and  satisfactory,  ou  almost  every  point 


but.  uulikH  most  works  of  this  class,  it  is  very  com- 
prehensive in  regard  to  etiology,  and  exposes  the 
pathology  of  nervous  diseases  in  the  light  of  the  very 
late-t  experiments  and  discoveries.  The  drawings 
are  excellent  and  well  selected.  After  this  careful 
revision,  we  can  heartily  recommend  this  work  to 
stu'^ents  and  general  practitioners  in  particular  as 
being  a  full  expo-ition  of  diseases  of  the  nervous  sy.-- 
tem,  their  pathology  and  treatment,  to  date.— iV.  Y. 
Med.    Record,  Aug.  3,  1878. 

As  stated  in  the  preface,  the  author's  object  lias 
been  to  write  a  concise  and  practical  book,  for 
which  there  is  certainly  a  place,  and  we  think  he 
has  succeeded  admirably  in  fulfilling  his  object. 
The  u.^ual  plan  is  adopted  in  the  classification  of 
the  different  disease^,  the  book  not  being  greatly 
unlike  Hammond's  in  this  respect,  although  it  is 
very  noticeable  throughout  that  the  author's  opin- 
ions vary  widely  from  those  of  l)r  Hammond. — Am. 
Sup  p.  O^atd.  Journ.  Great  Britain  and  Ireland, 
July,  1S7S. 


QHARCOT  {J.  M.), 

Professorto  the  Facility  of  Med.  Paris,  Phya.  to  La  Sa/p^tri^re,  etc. 

LECTURES  ON  DISEASES  OF  THE  NERVOUS  SYSTEM.    Trans- 

lated  from  the  Second  Edition  by  Gkoroe  SroKRSON,  M.D.,  M.Ch.,  Lecturer  on  Biology, 
etc.,  Cath.  Univ.  of  Ireland.  With  illustrations  {Puhli.^hing  iti  the  Medical  News  and 
Library,  commencing  with  the  July  No.  1878      See  page  2  ) 


Henry  C.  Lea's  Publications — (Diseases  of  the  Chesty  dec),       19 
'DRO  WN  [LENNOX),  F.R.G.S.  Ed., 

Senior  Surgeon  tothe  Central  London  Throat  and  Ear  HoftpHal,  etc., 

THE  THROAT   AND  ITS  D1SP]ASES.     With  one  luinclrccl  Typical 

Illustrations  in  colors,  and  fifty  wood  engravings,  designed  and  executed  by  the  author. 
In  one  very  hanil^ome  imperial  octavo  volume  of  351pages  ;  cloth,  $5  00.   {Now  Ready  ) 


The  author's  rare  artistic  skill  has  been  utilized 
in  the  iirocluction  of  one  liinidred  beautiful  illuslra- 
lions  ill  colors,  the  very  best  of  the  kind  we  have 
se«n,aud  which  have  been  distributed  in  ten  plales. 
Fifty  woud  engravings,  designed  and  executed  by 
the  autuor,  appear  la  the  body  of  the  work — these 


are  unusually  accurate.  In  conclusion,  we  recom- 
mend this  beautiful  volume  as  an  acceptable  addi- 
tion to  the  library  of  those  engaged  in  the  treatment 
of  diseases  of  the  throat. — N.  Y.  Med.  Record,  Nov. 

9,  1S7S. 


CfEILER  {CARL),  M.D., 

^  Lechirer  an  Laryngo.scupy  at  the  Univ.  of  Penna  ,   Chief  of  the  Throat  Dispensary  at  the 

Univ.  Hospital,  Phila.,  etc. 

HANDBOOK  OF  DIAGNOSIS  AND  TREATiMENT  OF  DISEASES  OF 

THE    THROAT   AND   NASAL   CAVITIES.      In  one  handsome  royal  12mo.  volume, 
of  156  pages,  with  35  illustrations;  cloth,  $1.      {Just  Ready.) 


pLINT  {AUSTIN),  M.D., 

Professor  of  the  Principles  and  Practice  of  Medicine  in  Bellevue  Hospital  Med.  College,  N.  Y. 

PHTHISIS:  ITS  MORBID  ANATOMY,  ETIOLOGY,  SYMPTOM- 
ATIC EVENTS  AND   COMPLICATIONS,  FATALITY  AND  PROGNOSIS,  TREAT- 
MENT, AND  PHYSICAL  DIAGNOSIS  ;  in  a  series  of  Clinical  Studies.     By  Austin 
Flint,  M.D.  ,  Prof,  of  the  Principles  and  Practice  of  Medicine  in  Bellevue  HcspitafMed. 
College,  New  York.     In  one  handsome  octavo  volume  :  $3  50.      {Lately  Issued.) 
This  book  contains  an  analysis,  in  the  authoi-'s  lucid  I  mend  the  book  to  the  perusal  of  all  interested  in  the 
piyle,  of  the  notes  which  he  has  made  in  several  bun-     study  of  iliis  disease. — Boston  Med.  and  Surg.  Journal, 
dred  cases  in  hospital  and  private  practice.    We  com-  |  Feb.  10,  1876. 


DY  THE  SAME   AUTHOR. 

A  MANUAL  OF  PERCUSSION  AND  AUSCULTATION;   of  the 

Physical  Diagno.sis  of  Diseases  of  the  Lungs  and  Heart,  and  of  Thoracic  Aneurism.    In 
one  handsome  royal  12mo.  volume:  cloth,  $1  75.     {Just  Issued.) 


JDF  THE  SAME  AUTHOR. 

A  PRACTICAL  TREATISE  ON  THE  DIAGNOSIS,  PATHOLOGY, 

AND  TREATMENT  OF  DISEASES  OF  THE   HEART.     Second  revised  and  enlarged 

edition.     In  one  octavo  volume  of  550  pages,  with  a  plate,  cloth,  $4. 

Dr.  Flint  chose  a  difficult  subject  for  his  researches,  ;  aud  clearest  practical  treatise  on  those  subjects,  and 

and  has  shown  remarkable  powers  of  observation  \  ihould  be  in  the  hands  of  all  practitioners  aud  stu- 

aud  reflection,  as  well  as  greatindustry,  in  his  treat-  j  ients.  It  is  a  credit  to  American  medical  literature. 

ment  of  it.   His  book  must  be  considered  the  fullest  |  —Amer.  Jotirn.  of  the  Med.  Sciences,  July,  1860. 

JJY  the  SAME  AUTHOR. 

A  PRACTICAL  TREATISE  ON  THE  PHYSICAL  EXPLORA- 
TION OF  THE  CHEST  AND  THE  DIAGNOSIS  OF  DISEASES  AFFECTING  THE 
RESPIRATORY  ORGANS.  Second  and  revised  edition.  In  one  handsome  octavo  volume 
of  595  pages,  cloth^$4  50. 

WILLIAMS'S   PULMONARY 


CONSUMPTION;  its 
Nature,  Varieties,  and  Treatment.  With  an  An- 
alysis of  One  Thousand  Cases  to  exemplify  its 
duration.  In  one  neat  octavo  volume  of  about 
.SoO  pages;  cloth,  $2  50. 
SLADE  ON  DIPHTHERIA;  Its  Nature  and  Treat- 
ment, with  an  account  of  the  History  of  its  Pre- 
valence in  various  Countries.  Second  and  revised 
edition.  In  one  neat  roval  12mo.  volume,  cloth, 
$1  2.5. 

WALSHE  ON  THE  DISEASES  OF  THE  HEART  AND 
GREAT  VESSELS.  Third  American  Edition.  In 
1  vol.  Svo.,  420  pp.,  cloth,  $3  GO. 

LECTURES  ON  THE  DISEASES  OF  THE  STOMACH. 
With  an  Introduction  on  its  .'Vaatomy  and  Physio- 
logy. By  Wii.MAM  Brinton,  M.D.,  F.R.S  From 
the  second  and  enlarged  Londonedition.  With  il- 
lustrations on  wood.  In  one  handsome  octavo 
volume  of  about  300  pages:  cloth,  $."3  26. 

LA  ROCHE  ON  PNEUMONIA.  1  vol.  8vo.,  cloth, 
of  .500  pages.    Price,  $3  00. 

LINCOLN'S  ELECTRO-THERAPEUTICS;  a  Concise 
Manual  of  Medical  Electricity.  In  one  very  neat 
royal  12rao.  volume,  cloth,  with  illustrations, 
$1    50. 

CLINICAL  OBSERVATIONS  ON  FUNCTIONAL 
NERVOUS  DISORDERS.  By  C.  Handfield  JoNEd, 
M.D.,  Physiciau  to  St.  Mary's  Hospital,  &c.  Sec 
end  American  Edition.  In  one  handsome  octavo 
volumeof  318  pages.cloth,  $3  25. 


FULLER  ON  DISEASES  OF  THE  LUNGS  AND  AIR- 
PASSAGES.  Their  Pathology,  Physical  Diagnosis, 
Symptoms,  and  Treatment.  From  the  second  and 
revised  English  edition.  In  one  handsome  ocatvo 
volume  of  about  500  pages  :  cloth,  $3  50. 

CHAMBERS'S  MANUAL  OF  DIET  AND  REGIMEN 
IN  HEALTH  AND  SICKNESS.  la  one  handsome 
octavo  volume.     Cloth,  ^2  75. 

CHAMBERS'S  RESTORATIVE  MEDICINE.  An  Har- 
veiau  Annual  Oration.  With  Two  Sequels.  In 
one  very  handsome  vol.  small  12mo.,  cloth,  $1  00. 

PAVY'S  TREATISE  ON  THE  FUNCTION  OF  DI- 
GESTION ;  its  Disorders  and  their  Treatment. 
From  the  second  London  edition.  In  one  hand- 
some volume,  small  octavo,  cloth,  ^2.  00. 

PAVY'S  TREATISE  ON  FOOD  AND  DIETETICS. 
Physiologically  and  Therapeutically  Considered. 
In  one  handsome  octavo  volume  of  nearly  600 
pages,  cloth,  if;!  75. 

S^IITH  ON  CONSUMPTION  ;  ITS  EARLY  AND  RE- 
MEDIABLE STAGES.    1  vol.  Svo. ,  pp.  2/54.   $2  2.'^. 

BASHAM  ON  RENAL  DISEASES:  a  Clinical  Guide 
to  their  Diagnoais  and  Treatment.  With  Illustra- 
tions   la  one  12mo.  vol.  of  304  pages,  cloth,  *2  00. 

LECTURES  ON  THE  STUDY  OF  FEVER.  By  A. 
HuDSox,  M.D.,  M.R.I. A.,  Physician  to  the  Meath 
Hospital.     In  one  vol.  Svo.,  cloth,  *2  50. 

A  TREATISE  ON  FEVER.  By  Robkrt  D.  Lyonp, 
K  C  C.  In  one  octavo  volume  of  3b2  pages,  cloth, 
*2  25. 


20  Henry  C.  Lea's  Publications — ( Venereal  Diseases^  &c.), 

DUMSTEAD  {FREEMAN  J.),  M.D., 

■*-'        ProfesHor  of  Venereal  Diseases  at  the  Col.  of  Phys.  and  Surg.,  New  York,  Ac. 

THE  PATHOLOGY  AND  TREATMENT  OF  VENEREAL  DIS- 
EASES. Including  the  results  of  recent  investigations  upon  the  subject.  Fourth  edition, 
revised  and  enlarged.  In  one  large  and  handsome  octavo  volume  ol  over  700  pages. 
(Pre2)aring.) 

flULLERIER  [A.],  and        J^UMSTEAD  [FREEMAN  J.), 

^        Surgeon  to  the  Ubpitaldu  Midi.  J~^       ProfsMsor  of  Venereal  Dismses  in  the  College  of 

Physioians  and  Surgeons.  N.  ¥. 

AN  ATLAS  OF  VENEREAL  DISEASES.  Translated  and  Edited  by 

Frkeman  J.  BuMSTBAD.  In  one  large  imperial  4to.  volume  of  328  pages,  double-columns, 
with  26  plates,  containing  about  160  figures,  beautifully  colored,  many  of  them  the  size  of 
life;  strongly  bound  in  cloth,  $17  00  ;  also,  in  five  parte,  stout  wrappers,  at  $3  per  part. 
Anticipating  a  very  large  sale  for  this  work,  it  is  offered  at  the  very  low  price  of  Thrkk  Dol- 
lars a  Part,  thus  placing  it  within  the  reach  of  all  who  are  interested  in  this  department  of 
practice.     Gentlemen  desiring  early  impressions  of  the  plates  would  do  well  to  order  it  without 
delay.     A  specimen  of  the  plates  and  text  sent  free  by  mail,  on  receipt  of  26  cents. 

of  illustrations  of  the  venereal  diseases.     There  is, 
however,  an  additional  interest  and  value  pohBesprd 


We  wish  for  once  that  our  province  was  not  re- 
strict d  to  methods  of  treatment,  that  we  might  say 
eomebing  of  the  exquisite  colojed  plates  in  this 
volume.  -London  Practitioner,  May,  1869. 

Other  writers  besides  M.  CuUerier  have  given  use 
good  g.ccount  of  the  disease."  of  which  he  treats,  bui 
no  one  has  furnished  us  with  such  a  complete  seriei 


by  the  volume  before  oi-;  for  it  is  an  Ajnericau  reprint 
and  translation  of  M  Cullerier's  work,  with  inc  • 
dental  remarks  by  one  of  the  most  eminent  Ameri- 
can syphilographers,  Mr.  Bumstead. — BritandFot . 
Medico-Chir.  Review,  July,  1869. 


'EE  {HENRY), 

■'        Prof,  of  Surgery  at  the  Royal  College  of  Surgeons  of  England,  etc. 

LECTURES  ON  SYPHILIS  AND  ON  SOME  FORMS  OF  LOCAL 

DISEASE  AFFECTING  PRINCIPALLY  THE  OBGANS  OF  GENERATION.    In  one 
handsome  octavo  volume:  cloth;  $2  25.     {Lately  Ptihlished.) 


TJILL  {BERKELEY), 

-^-*-  Surgeon  to  the  Lock  Hospital,  London. 

ON  SYPHILIS  AND  LOCAL  CONTAGIOUS  DISORDERS.     In 

one  handsome  octavo  volume  ;  cloth,  $3  25. 


^EST  ( CHARLES),  M.D., 

Physician  to  the  Hospital  for  Sick  Children,  London,  &c. 

LECTURES  ON  THE  DISEASES  OF  INFANCY  AND   CHILD- 

HOOD.  Fifth  American  from  the  sixth  revised  and  enlarged  English  edition.     In  one  large 
and  handsome  octavo  volume  of  678  pages.    Cloth,  $4  50  ;  leather,  $5  50.  {Lately  Issued  ) 

The  continued  demand  for  this  work  on  both  sides  of  the  Atlantic,  and  its  translation  into 
German,  French,  Italian,  Danish,  Dutch,  and  Russian,  show  that  it  fills  satisfactorily  a  want 
extennvely  felt  by  the  profession.  There  is  probably  no  man  living  who  can  speak  with  the 
authority  derived  from  a  more  extended  experience  than  Dr.  We8t,#nd  his  work  now  presents 
the  re.sults  of  nearly  2000  recorded  cases,  and  600  post-mortem  examinations  selected  from 
among  nearly  40,000  jases  which  have  passed  under  his  care.  In  the  prepar.ition  of  the  pre- 
sent edition  he  has  omitted  much  that  appeared  of  minor  importance,  in  order  to  find  room  for 
the  introduction  of  additional  aaatter,  and  the  volume,  while  thoroughly  revised,  is  therefore 
not  increased   materially  in  size. 

Jf  all  the  English  writers  on  the  diseases  of  chil-  j  highest  living  authorities  in  the  difficult  department 
dr^a,  there  is.  no  one  so  entirely  satisfactory  to  us  |  of  medical  science  Jn  which  he    is   most  widely 
as  Dr.  West.    For  years  we  have  held  his  opinion  I  known.-  Boston  Med.  and  Surg.  Journal. 
as  JQdicial,  and  have  regarded  him  as  one  of  the  | 


JDY  THE  SAME  AUTHOR.    (Lately  Issued.) 

ON  SOME  DISORDERS  OF  THE  NERVOUS  SYSTEM  IN  CHILD- 

HOOD;  being  the  Lumleian  Lectures  delivered   at  the  Royal  College  of  Physicians  of 
London,  in  March,  1871.     In  one  volume   small  12mo.,  cloth,  $1  00. 


^F  THE  SA^fE  AUTHOR. 

LECTURES  ON  THE  DISEASES  OF  WOMEN.     Third  American, 

from  the  Third  London  edition.     In  one  neat  octavo  volume  of  about  650  pages,  clotl, 
$3  75;  leather,  $4  75. 

CONDTE'S  PRACTICAL  TREATISE  ON  THE  DIS-  '  SMITH'S  PRACTICAL  TRE.\TISE  ON  THE  WAST- 


EASES  OF  CHILDREN.  Sixth  edition,  revised 
and  augmented.  In  one  large  octavo  volume  of 
nearly  8*^0  cio.sely-printed  pages,  cloth,  $5  2.0  ; 
leather,  $^  2o. 


IN«  DISEASES  OF  INFANCY  AND  CHILDHOOD. 
Second  American,  from  the  second  revised  and 
enlaigf^d  Englirili  edition.  In  one  bandiiiome  octa- 
vo volume,  cloth   $2  50. 


Henry  C.  Lea's  Fubltcations — (Diseases  of  Child^-en). 


21 


(^MITH{J.  LEWIS),  M.D., 

Clinical  Professor  of  Diseases  of  Children  in  the  Bellevue  Hospital  Med.  College,  N  T. 

A  COMPLETE  PRACTICAL  TREATISE  ON  THE  DISEASES  OF 

CHILDREN.  Fourth  Edition,  revised  and  enlarged.  In  one  handsome  octavo  volume 
of  about  750  pages,  with  illustrations.  Cloth,  $4  .^0  ;  leather,  $5  50,  (]^ow  Reridy.) 
The  very  marked  favor  with  which  this  work  has  been  received  wherever  the  English  lan- 
guage is  spoken,  has  stimulated  the  author,  in  the  preparation  of  the  Fourth  Edition,  to  spare 
no  pains  in  the  endeavor  to  render  it  worthy  in  every  respect  of  a  continuance  of  professional 
confidence.  Many  portions  of  the  volume  have  been  rewritten,  and  much  new  matter  intro- 
duced, but  by  an  earnest  effort  at  condensation,  the  size  of  the  work  has  not  been  materially 
ncreased. 


In  the  period  which  has  elapsed  since  the  third 
edition  of  the  work,  so  extensive  have  been  the  ad- 
vances that  whole  chapters  required  to  be  rewritten, 
and  hardly  a  page  could  pass  without  some  material 
correction  or  addition.  This  labor  has  occupied  the 
writer  closely,  and  he  has  performed  it  conscien- 
tiously, so  that  the  book  may  he  considered  a  faith- 
ful portraiture  of  an  exceptionally  wide  clinical 
experience  in  infantile  diseases,  corrected  by  a  care- 
ful study  of  the  recent  literature  of  the  subject.— 
Med.  and  Surg.  Reporter,  April  5,  1879. 

It  is  scarcely  necessary  for  us  to  say  the  work  be" 
fore  us  is  a  standard  work  upon  diseases  of  children, 
and  that  no  work  has  a  higher  standing  than  it  upon 
those  atfections.  In  consequence  of  its  thorough  re- 
vision, the  work  has  been  made  of  more  value  than 
ever,  and  may  be  regarded  as  fully  abreast  of  the 
times.  We  cordially  commend  it  to  stnd'^nts  and 
physicians.  There  is  no  better  work  in  the  language 
on  diseases  of  children.— Ci7icmna«  Med.  News, 
March,  1879. 

Ihe  author  has  evidently  determined  that  It  shall 
not  lose  ground  in  the  esteem  of  the  profession  for 
want  of  the  latest  knowledge  on  that  important 
department  of  medicine.  He  has  accirdingly  in- 
corporated in  the  present  edition  the  useful  and 
practical  remits  of  the  latest  study  and  experience, 
brth  American  and  foreign,  especially  those  beaiirg 
on  therapeutics.  Altogether  the  book  has  been 
greatly  improved,  while  it  has  not  been  greatly 
increased  in  size.  —  H'ew  York  Mtdlcal  Journal, 
June,  1879. 


This  excellent  work  is  so  well  known  that  an 
ftx'ended  notice  at  this  time  would  be  supertlnous. 
The  author  h^s  taVen  advantage  of  the  demand  for 
another  new  erit  on  to  revise  in  a  most  carelul 
manner  the  entire  book  ;  and  the  numerons  correc- 
tions and  additions  evince  a  determination  on  his 
part  to  keep  fully  abreast  with  the  rapid  progress 
that  Is  being  made  in  the  knowledge  and  treatment 
of  children's  diseases.  By  the  adoption  of  a  srme- 
what  closer  type,  an  increase  in  size  of  only  thirty 
pages  has  been  necestitated  by  the  new  subject 
matter  introduced.— jBos^oh  Med.  and  Surg.  Jour., 
May  29.  1879. 

Probably  no  other  work  ever  published  in  this 
country  upon  a  medical  subject  has  reached  such  a 
heighth  of  populirity  as  has  this  well-known  trea- 
tise. As  a  text  and  reference-book  it  is  preemi- 
nently  the  authority  upon  diseases  of  children.  It 
stands  deservedly  higher  in  the  estimation  of  the 
profession  than  any  other  work  upon  the  same  ^wh- 
jeci.— Nashville  Journ.  of  Med.  and  Surg.,  May, 
1879. 

The  author  of  this  work  has  acquired  an  immense 
experience  as  physician  to  three  of  the  large  char- 
ities of  New  York  in  which  children  are  treated. 
These  asylums  afford  unsurpassed  opportunities  for 
observing  the  effects  of  different  pluns  of  treatment, 
and  the  results  as  embodied  in  this  volume  may  be 
accepted  with  faith,  and  should  be  in  the  possession 
of  all  practitioners  now,  in  vipw  of  the  approacbing 
season  when  the  diseases  of  children  always  increase. 
—Nat.  Med.  Review,  April,  1879. 


S 


WAYNE  {JOSEPH  GRIFFITHS),  M.D., 

Physician-Accoucheur  to  the  British  General  Hospital,  Ac. 

OBSTETRIC  APHORISMS  FOR  THE  USE  OF  STUDENTS  COM- 
MENCING MIDWIFERY  PRACTICE      Second  American,  from  the  Fifth  and  Revised 
London  Edition,  with  Additions  by  E.  R.  Hutchins,  M.D.  With  Illustrations.   In  one 
neat  12mo.  volume.     Cloth,  $1  25.     {Lately  Issued.) 
***  See  p.  4  of  this  Catalogue  for  the  terms  on  which  this  work  is  offered  as  a  premium  to 
subscribers  to  the  "  American  Journal  of  the  Medical  Sciences." 


CHURCHILL  ON  THE  PUERPERAL  FEVER  AND 
OTHER  DISEASES  PECULIAR  TO  WOMEN.  1vol. 
Svo. ,  pp.  -l.^O,  cloth  .     $2  50. 

DEWEEh'R  TREATISE  ON  THE  DISEASES  OF  FE- 
MALES. With  illustrations.  Eleventh  Edition, 
with  the  Author's  lastimprovementsand  correc- 
tions. In  one  octavo  volume  of  536  pages,  with 
plates,  cloth.    $3  00. 


MEIGS  ON  THE  NATURE,  SIGNS.  AND  TREAT- 
MENT OF  CHILDBED  FEVER.    1  vol.  Svo.,  pp. 

.365.  cloth.     $2  CO. 

ASHWELL'b  PRACTICAL  TREATISE  ON  THE  DIS- 
EASES PECULIAR  TO  WOMEN.  Third  American, 
from  the  Third  and  revised  London  edition.  1  vol. 
Svo. ,  pp.  528,  cloth.    $3  50. 


J^ODQE  [HUGH  L.),  M.D., 

Emeritus  Professor  of  Obstetrics,  Ac,  in  the  University  of  Pennsylvania. 

ON  DISEASES  PECULIAR  TO  WOMEN  ;  including  Displacements 

of  the  Uterus.     With  original  illustrations.    Second  edition,  revised  and  enlarged.     In 

one  beautifully  printed  octavo  volume  of  531  pages,  cloth,  $4  50. 

Professor  Hodge's  work  is  truly  an  original  one  I  contribution  tothe  study  ofwomen'ediseases.itiprf 

from  beginning  to  end,  consequently  no  one  can  pe-    great  value,  and  is  abundantly  able  to  stand  on  its 

raseits  pageewithout  learning  something  new.  Af-a  I  own  merits. — N.  Y.  Medical  Record,  Sept.  15,  ICfci. 

HURCHILL  (FLEETWOOD),  M.D.,  M.R.I.A. 
ON  THE  THEORY  AND  PRACTICE  OF  MIDWIFERY.    A  new 

American  from  the  fourth  revised  and  enlarged  London  edition.  With  notes  and  additior  s 
by  D.  Francis  Condib,  M.D.,  authoY  of  a  "  Practical  Treatise  on  the  Diseases  of  Chil- 
dren," Ac.  With  one  hundred  and  ninety  four  illustrations.  In  one  very  handsome  octavo 
volume  of  nearly  700  large  pages.     Cloth,  $4  00  ;  leather,  $5  00. 


O' 


MONTGOMERY'S  EXPOSITION  OF  THE  SIGNS  RiOBY'b  SYSTEM  OF  MIDWIFERY.  \Vith  notes 
4.ND  SYMPTOMS  OF  PREGNANCY.  With  two  and  Additional  illastrations.  Second  American 
exquisitecoloredplates.  and  numeronswood  cuts  I  "^ition.  One  ▼olume  octavo,  cloth,  422  pages, 
In  1  vol.8vo.,ofnearly600pp.,clotb,$3  76.  I      $2  50. 


22 


Henry  C.  Lea's  Publications — (Diseases  of  Women). 


fTHOMAS  {T.GAILLARD),M.D., 

*•  Proftsfior  of  Obstetrics,  Ac,  in  the  College,  of  Physicians  and  Surgeons,  N.  T.,  Ac 

A  PRACTICAL  TREATISE  ON  THE  DISEASES  OF  WOMEN.  Fourth 

edition,  enlarged  and  thoroughly  revised.  In  one  large  and  handsome  octavo  volume  of 
800  pages,  with  191  illustrations.     Cloth,  $5  00;  leather,  $6  00.     (Just  Issued.) 
The  author  has  taken  advantage  of  the  opportunity  afforded  by  the  call  for  another  edition  of 
this  work  to  render  it  worthy  a  continuance  of  the  very  remarkable  favor  with  which  it  has  been 
received.  Every  portion  has  been  subjected  to  a  conscientious  revision,  and  no  labor  has  been 
spared  to  make  it  a  complete  treatise  on  the  most  advanced  condition  of  its  important  subject. 
A  work  which   has  reached  a  fourth   edition,  and    isclassical  without beingpedauticfiill  in  ihedetails 
thut.  too.  in  tlie  short  space  of  five  years,  has  achieved    of   anatoiny    and    pathology,    without  ponderous 
a  reputation  which  placef?  it  almost  beyond  the  rench  :  translation  of  pagesof  German  literature,  describes 
of  criticism,  and  the  favorable  opinions  which  we  have  i  distinctly  the  details  and  difficulties  of  each  opera- 
tion, without  wearying  and  useless  minutise,  and  is 


a  r..'ady  expressed  of  the  former  editions  seem  to  re- 
quire that  we  should  do  little  more  than  announce 
this  new  issue.    We  cannot  refrain  from  sayinp;  that, 
as  a  practical  work,  this  is  second  to  none  in  the  Eng-  j 
lish,  or.  indeed,  in  any  other  lanfjuage.    The  arrange- 1 
ment  of  the  contents,  the  admirably  clear  manner  in  | 
which    the    subject   of  the  ditferential   diagnosis  of 
several  of  the  diseases  is  handled,  leave  nothing  to  be  ' 
desired  by  the  practitioner  who  wants  a  thoroughly 
clinical  work,  one  to  which  he  can  refer  iu  difficult 
cases  of  doubtful  diagnosis  with  the  certainty  of  gain- 
ing light  and  instruction.  Dr.  Thomas  is  a  man  with  a 
very  clear  liend  and  decided  views,  and  there  seems  to 
be  nothing  which  he  so  much  dislikes  as  hazy  notions  1 
of  diagnosis  and  blind  routine  and  unreasonable  thera-  \ 
peutics.    The  student  who  will  thoroughly  study  this! 
b  )ok  and  test  its  principles  by  clinical  observation,  will  ' 
certainly  not  be  guilty  of  these  faults.— ZowdonZarace^  I 
Feb.  1.3,  187.5.  '  ! 

Reluctantly  we  are  obliged  to  close  this  unsatis-  [ 
factory  notice  of  so  excellent  a  work,  and  in  conclu- 
sion would  remark  that,  as  a  teacher  ofgyna;cology. 


in  all  respects  a  work  worthy  of  confidence,  justify- 
ing the  high  regard  in  which  its  distinguished  au- 
thor is  held  by  the  profession.— .4m.  Supplement, 
Ohstet.  Journ.,  Oct.  1874. 

Professor  Thomas  fairly  took  the  Profession  of  the 
United  States  by  storm  when  his  book  first  made  its 
appearance  early  in  1S6S.  Its  reception  was  simply 
enthusiastic,  notwithstanding  a  few  adverse  criti- 
cisms from  our  transatlantic  brethren,  the  first  large 
edition  was  rapidly  exhausted,  and  in  six  months  a 
second  one  was  issued,  and  in  two  years  athird  one 
was  announced  and  published,  and  we  are  now  pro- 
raised  the  fourth.  The  popularity  of  this  work  was 
not  ephemeral,  and  itssuccess  was  unprecedented  in 
the  annalsof  American  medical  literature.  Six  years 
is  a  long  period  in  medical  scientific  research,  but 
Thomas's  work  on  "  Diseases  of  Women"  is  still  the 
leading  native  production  of  the  United  States.  The 
order, .'the  matter,  the  absence  of  theoretical  disput  a- 
tiveness,  the  fairness  ofstatement,  and  the  elegance 


both  <\\A'irt\r-A„^  r.iin;«ai   P,.^«-  T^i^^wo^iT"         ^  ■  "i"    [  of  diction,  preserved  throughout  the  entire  range  of 

author  he  certainly  has  met  with  unusual  and  mer-  1  overestimate  bis  powers  when  he  conceived  the  idea 
ited  sacc^HB.-Am  Journ.  of  Obstetrics,  Nov    1874   i  ^^'^  «^?'^"ted  the  work  of  producing  a  new  treatise 
■'•        '^^  ^°'*- I  upon  diseases  of  women.— Prof.  Pallen,  in  ioMj*. 
L  ills  volume  of  Prof.  Thomas  in  its  revised  form    viUe  Med.  Journal,  Sept.  1874. 


J?ARNES  (ROBERT),  M.D.,  F.R.G.P., 

•*-^  Ob.stetric  Physician  to  St.  Thomas's  Hospital,  Ac. 

A  CLINICAL  EXPOSITION  OF  THE  MEDICAL  AND  SURGI- 
CAL diseases  OF  WOMEN.  Second  American,  from  the  Second  Enlarged  and  Revised 
English  Edition.  In  one  handsome  octavo  volume,  of  784  pages,  with  181  illustrations. 
Cloth,  f  4  50  ;  leather,  $5  50.     {Just  Ready.) 

The  call  for  a  new  edition  of  Dr.  Barnes's  work  on  the  Diseases  of  Females  has  encouraged 
the  author  to  make  it  even  more  worthy  of  the  favor  of  the  profession  than  before.  By  a  renr- 
rangement  and  ciireful  pruning  space  has  bpen  found  for  a  new  chapter  on  the  Gyngecologieal 
Relations  of  the  Bladder  and  Bowel  Disorders,  without  increasing  the  size  of  the  book,  while 
many  new  illustrations  have  been  introduced  where  experience  has  shown  them  to  be  needed.  It 
is  therefore  hoped  that  the  volume  will  be  found  to  reflect  thoroughly  and  accurately  the  present 
condition  of  gynecological  science. 

Dr  Barnes  stands  at  the  head  of  his  profession  in  the  work  is  a  valuable  one,  and  should  be  largely 
he^old^coiintry,  and  it  requires  but  scant  scrutiny    consulted  by  the  profession.— /Iw.  Svpp.  Obstetrical 

Journ.  Gt.  B7'itain  and  Ireland,  Ocl.lS7S. 


of  his  hook  to  show  that  it  has  been  sketched  by  a 
m  ister.  It  is  plain,  practical  common  sense  ;  shows 
very  deep  research  without  being  pedanitic;  is  emi- 
nently calculated  to  inspire  enthusiasm  without  in- 
culcating rahhness;  points  out  the  dangers  to  be 
avoided  as  well  as  the  success  to  be  achieved  in  the 
various  operations  connected  with  th's  branch  of 
medicine;  and  will  do  much  to  smooth  the  rugged 
path  of  the  young  gynecologist  and  relieve  the  per-  j 
plexity  of  the  man  of  mature  veavs.  —  Canadian  \ 
Journ.  of  Med.  Science,  Nov.  1878. 

We  pity  the  doctor  who,  having  any   consider-    

able  practice  in  diseases  of  women,  has  no  copy  of  have  been  made  since  the  appearance  of  tlieVirst  edi 
'  Barnes  '  for  daily  consultation  and  instruction.  It  tion.  The  American  references  are,  for  an  English 
is  at  once  a  book  of  great  learning,  research,  and  work,  especially  full  and  appreciative,  and  we  can 
individual  experience,  and  at  the  same  time  emi-  I  cordially  recommend  the  volume  to  American  read- 
nently  practical.  That  it  has  been  appreciated  by  '  ern.— Journ.  of  Nervous  and  Mental  Disease,  Oct, 
the   profession,  both   in   Great   Britain   and  in  this  '  1878. 

This  second  edition  of  Dr.  Barnes's  great  work 
comes  to  us  containing  many  additions  and  improve- 
ments which  bring  it  up  to  date  iu  every  feature. 
The  excellences  of  the  work  are  too  well  known  to 
require  onumeration,  and  we  hazard  the  prophecy 
that  they  will  for  many  years  maintain  its  high  po- 


No  other  gynajcological  work  holds  a  higher  posi- 
tion,  having  become  an  authority,  everywhere  in 
diseases  of  women.  The  work  has  been  brought 
fully  abreast  of  present  knowledge.  Every  practi- 
tioner of  medicine  should  have  it  upon  the  shelves 
of  his  library,  and  the  student  will  find  it  a  superior 
text-hook.— Cincinnati  Med.  News,  Oct.  1S7S. 

This  second  revised  edition,  of  course,  deserves  all 
the  commendation  given  to  its  predecessor,  with  the 
additional  one  that  it  appears  to  include  all  or  nearly 
all  the  additions  to  our  knowledge  of  its  subject  that 


country,  is  shown  by  the  second  edition  following 
so   soon  upon  the  first.— ^m.  Practitioner,   Nov. 

1S7S.  ' 

Dr.  Barnes's  work  is  one  of  a  practical  character, 
largely  illustrated  from  cases  in  his  own  experience, 
bat  by  no  means  confined  to  such,  as  will  be  learned 


from  the  fact  that  he  quotes  from  no  lef^s  than  628  sition  as  a  standard  text-book  an<l  guide  book  for 
medical  authors  in  numerous  countries.  Coming  students  and  practitioners. —  iV.  0.  Med.  Journ., 
from  such  an  author,  it  is  not  necessary  to  say  that    Oct.  1378. 


Henry  C.  Lea's  Publicatioxs — (Diseases  of  Women). 


23 


PMMET  [THOMAS  ADDIS),  M.D. 

•*^  burgeon  to  the  Woman's  Hoftpital,  New  York,  etc. 

THE  PRINCIPLES  AND  PRACTICE  OF  GYNAECOLOGY,  for  the 

use  of  Students  and  Practitioners  of  Medicine.  In  one  large  and  very  handsome  octavo 
volume  of  850  pages,  with  130  illustrations.  Cluth,  $5;  leather,  $6.  {Just  Ready.) 
Dr  Emmet  is  so  widely  known  as  among  the  most  eminent  of  those  who  have  made  gynse- 
cology  a  peculiarly  American  science  that  the  profession  cannot  fail  to  welcome  a  work  in  which 
he  has  condensed  the  results  of  his  long  and  extensive  experience.  He  has  sought  to  consider 
the  whole  subject  of  the  diseases  peculiar  to  females  in  a  manner  which  will  adapt  the  volume, 
not  only  to  the  wants  of  the  student  as  a  text-book,  but  to  those  of  the  practitioner  as  an  aid  in 
the  emergencies  of  daily  practice.  A  special  feature  of  the  work  will  be  found  in  the  numerous 
condensed  tables,  which  convey  at  a  glance,  and  within  the  narrowest  compass,  the  conclusions 
to  be  drawn  from  the  many  thousand  cases 'which  have  passed  under  the  care  of  the  author. 
With  trifling  exceptions,  the  illustrations  are  all  original,  and  the  volume  will  be  found  in  every 
point  of  typographical  execution  worthy  of  the  distinguished  position  which  is  confidently  anti- 
cipated for  it. 


It  may  be  said  that  he  has  had  opportunities  for 
observation  and  experience,  for  unfettered  and  un- 
restrained experimentation,  and  for  testing  the 
value  of  the  original  and  dazzling  operations  first 
proposed  and  performed  by  his  illustrious  predpces- 
sors  before  referred  to,  and  for  devising  new  opera- 
tions and  discovering  pathological  causes  never 
before  suspected  or  described,  which  uo  man  in  the 
profession  has  ever  before  secured.  We  also  think 
that  the  reader,  of  this  work  will  agree  with  us, 
after  its  careful  perusal,  that  he  has  a  rare  capacity 
for  discriminating  analy>is,  and  generally  for  phi- 
losophical deduction  and  the  equally  important 
quality  of  patient,  honest,  coniinued  work.  For  the 
work  a.s  a  whole,  we  have  only  praise.  It  deserves 
and  will  receive  the  careful  study  of  all  who  det^ire 
to  keep  on  a  level  with  the  prognss  of  Gynecology. 
It  embodies  a  larg.n- amount  of  carefully  analyzed 
personal  experience  in  a  unique  field  for  observa- 
tion than  any  volume  on  Diseases  of  Women  which 
has  yet  been  published.  Its  great  merit  cou.'-ists  in 
this— coining  as  it  does  from  a  thoroughly  honest, 
competent,  and  able  specialist,  who  became  a  spe- 
cialist only  after  an  (xcellent  training  and  experi- 
ence as  a  general  hospital  physician  and  surgeon. 
The  book  is  not  one  to  be  hastily  glanced  over,  but 
will  secure  the  critical  stu-ly  of  Gynajcologists.  Not 
only  its  style,  which  is  individual  and  somewhat 
peculiar,  but  the  new  facts  which  it  brings  out,  its 
original  suggestions,  its  numerous  and  important 
statistical  tables,  and,  in  some  instances,  its  unex- 
pected deductions,  will  compel  attention,  and  will 
form  the  basis  for  a  great  deal  of  Gy aiccological 
study  and  literature  in  the  future.  All  who  make 
themselves  familiar  with  the  contents  of  this  vol- 
ume, will  feel  assured  that  Dr.  Emmet  has  well 
earned  and  well  deserved  the  reputation  which  he 
has  already  won,  a,s  one  of  tte  great  Gynajcologists 
of  the  pres9nt  age. — Tke  Am.  Journ.  of  Obstetrics, 
April,  1S79, 

We  have  examined  this  book  with  something  more 
than  ordinary  care,  and  now  lay  it  aside  captivated 


by  our  impressions  of  it.  From  first  to  last,  each 
page  grows  in  interest,  and  one  is  struck  with  the 
practical  tone  of  all  that  is  said.  It  is  indeed  the 
gyna3cological  work  for  the  practitioner.  Its  equal 
is  not  yet  published,  or  at  least  we  have  not  seen  it. 
We  cannot  send  this  notice  forward  without  reiter- 
atirg  that,  in  our  estimation,  Emmet's  Principles 
and  Practice  of  Gynajcology  is  undoubtedly  thebest 
book  for  the  student,  as  well  as  the  general  practi- 
tioner, which  is  at  present  published.— Fa.  Med. 
Monthly,  May,  1879. 

The  advent  of  this  important  work  has  for  some 
time  been  anxiously  expected  hy  all  who  are  inter- 
ested in  the  subject  of  gynecology,  both  here  and 
abroad.  The  clinics  held  at  the  Woman's  Hospital, 
and  the  minor  writings  referred  to  have  acquired 
for  Dr.  Emmet  a  reputation  for  skill  as  an  operator, 
and  experience  in  the  special  branch  to  which  he 
has  exclusively  confined  his  attention,  which  is 
probably  unrivalled  by  any  one  on  this  continent. 
The  anticipations  which  have  been  awakened  re- 
garding the  character  of  this  extended  treatise,  are 
not  likely  to  be  disappointed,  if  one  may  judge  from 
the  very  cursory  review  we  have  made  of  its  con- 
tents.— New  Remedies,  May,  1S79. 

Few  have  had  the  rare  opportunities  of  Dr.  Em- 
met, and  none  have  better  improved  that  which  was 
at  their  disposal.  Sure  are  we  that  any  practi- 
tioner of  medicine,  specialist,  or  otherwisf ,  who  will 
read  carefully  this  volume,  will  find  that  he  pos- 
sesses a  clearer  insight  into  a  thousand  problems 
that  have  hitherto  perplexed  him.  It  is  one  of  the 
best  original  works  on  the  diseases  of  women  pub- 
lished in  this  or  any  other  land.  We  heartily  com- 
mend it  to  the  careful  study  of  every  medical  man. 
—Detroit  Lancet,  May,  1S79. 

We  are  satisfied  that  whoever  reads  the  book  care- 
fully will  agree  with  us  that  it  is  the  best  work  on 
gynaecology  that  has  ever  been  written.  This  is 
high  prai^e,  but  we  have  no  hesitation  iu  giving  it. 
—St.  Louis  Can.  Record,  May,  1£79. 


riHADWICK  [JAMES  E.),  A.M.,  M.D. 

A  MANUAL  OF  THE   DISEASES  PECULIAR  TO  WOMEN.    In  one 

neat  volume,  royal  12mo  ,  with  illustrations.  (Preparing.) 
America  has  contributed  so  largely  to  the  advances  which  have  made  the  treatment  of  Dis- 
eases of  Women  a  distinctive  department  of  medical  science,  that  the  student  Avill  naturally 
turn  to  American  Books  for  the  latest  and  most  trustworthy  instruction  on  the  subject  in  its 
most  modern  aspect.  Yet  there  has  thus  far  been  no  attempt  in  this  country  to  produce  a  handy 
manual,  presenting  in  a  condensed  and  convenient  form  the  information  requisite  for  the  learner 
or  for  the  general  practitioner.  This  want  it  has  been  the  effort  of  Dr.  Chadwick  to  supply,  and 
the  special  attention  which  he  has  devoted  to  the  subject  is  a  guarantee  of  the  value  of  his  labors. 
A  distinguishing  feature  of  the  work  will  be  a  number  of  diagrammatic  illustrations,  facilitating 
greatly  the  comprehension  of  the  text. 


TUI^CKEL  [F.), 

'  '  Professor  and  Director  of  the  Gyncecologieal  Clinic  in  the  University  of  Rostoclt. 

A  COMPLETE  TREATISE  ON  THE  PATHOLOGY  AND  TREAT- 
MENT OF  CHILDBED,  for  Students  and  Practitioners.  Translated,  with  the  consent 
of  the  author,  from  the  Second  German  Edition,  by  Jaxfes  Rk.\d  Cii.vdwick,  M.D.  In 
one  octavo  volume.     Cloth,  $4  00,     {Lately  Issued.) 


24  Henry  C.  Lea's  Publications— (il/ic72i;i/(?7'f/). 

JpLAYFAIR  (  W.  S.),  M.D.,  F.R.C.P., 

Professor  of  Obstetric  Medicine  in  King's  College,  etc.  etc. 

A  TREATISE  ON  THE  SCIENCE  AND  PRACTICE  OF  MIDWIFERY. 

Second  American,  from  the  Second  and  Revised  English  Edition.     Edited,  with  Addi- 
tions, by  RoBKUT  P.  Harhis,  M.D.     In  one  handsome  octavo  volume  of  G39  pages,  with 
182  illustrations.     Cloth,  §4  00  ;   Leather,  $5.00.      {Just  Ready  ) 
In  reprinting  this  work  from  the  second  London  edition,  the  position  which  it  has  assumed 
in  this  country  as  an  authoritative  text-book  seemed  to  call  for  such  additions  as  would  render 
it  more  completely  suited  to  the  wants  of  the  American  student.     A  careful  scrutiny  on  the  part 
of  the  editor  has  .«hown  that  but  little  was  required  for  this  purpose  ;  the  work,  though  condensed, 
being  very  complete  and  accurate.     With  the  exception  of  numerous  short  foot-notes,  therefore, 
his  additions  have  been  confined  to  points  in  which  the  experience  and  practice  of  American 
obstetricians  differ  from  those  of  England,  and  to  one  or  two  matters  of  recent  interest.     These 
are  chiefly  the  Cassarean  Section  ;  the  varieties  of  forceps,  and  their  use  in  the  dorsal  decubitus; 
dystocia  from  tetanoid  uterine  constriction;   and  the  intra-venous  injection  of  milk,  as  a  substi- 
tute for  the  transfusion  of  blood. 


The  position  which  this  work  has  «o  quickly  taken 
ia  this  country  as  an  aathoriiative  text-book  renders 
any  exteudeJ  con-idtration  of  it.-*  {Ian  and  scope 
unnecessary.  Its  merits,  which  are  many,  have  al- 
ready found  their  way  to  the  appreciation  of  students 
and  practitioners  alike  in  the  leug'h  and  breadth  of 
the  land.— .(4m.  fiupj).  Obdet.  Juurn.  of  Qt.  Britain 
and  Ireland,  Oct.lSTS. 

This  excellent  text-book  has  been  submitted  to  a 
thorough  and  careful  revision,  and  will  be  found 
fully  up  to  the  times  in  every  department.  The 
notes  by  the  American  editor  enhance  the  value  of 
the  work  for  the  Americitn  student.  Those  on  the 
use  of  forceps  are  particuUrly  gjod,  and  constitute 
by  themselves  a  valuable  chapter. — N.  Y.  Med. 
Journ  ,  Nov.  1S78. 

The  bast  work  on  the  subject  ever  published  in  the 
English  language  It  is  written  in  a  clear,  pleasant 
style,  without  that  verbosity  which  characterizes 
some  modern  and  highly  pretentiou.s  works.  The  au- 
thor is  quite  up  with  the  times,  both  in  practice  and 


theory.  It  is  the  best  text-book  we  have  for  students, 
a  nd  sufficiently  full  of  detail  to  supply  all  the  wants 
of  the  practitioner.  We  would  gladly  see  it  in  the 
hands  of  all  who  practise  midwifery.  — Canadian 
Journ.  of  Med.  Set,  Nov.  1S7S. 

Probably  this  is  the  very  best  and  most  useful 
manual  of  midwifery  now  available  to  the  profes- 
sion. Itis  written  in  lucid,  scholarly  English,  which 
some  of  our  els-Atlantic  writers  would  do  well  to 
imitate.  There  has  been  no  attempt  to  swell  the 
magnitude  of  the  work  by  fine  writing,  or  by  lengthy 
discussions  ofobs^cure  points  of  which  no  trustworthy 
solution  has  yet  been  reached  ;  on  the  contrary,  the 
tendency  is  throughout  obviously  towards  simplic- 
ity. The  chapter  upon  the  Mechanism  of  Labor 
(which  ouglit  to  he  the  crowning  chapter  in  a  trea- 
tise on  obstetrics)  is  remarkably  clear  and  good,  and 
is  divested  of  those  features  which  in  almost  every 
other  work  we  know  lets  only  darkness  instead  of 
light  in  upon  the  subject. — N.  C.  Med.  Journ.,  Oct. 
1878. 


T 


J^AElVES  (FANCOUKT),  M.D., 

-»-'  Physician  to  the  General  Lying-in  Hospital,  London. 

A  MANUAL  OF  MIDWIFERY  FOR  MIDWIVES.     With  numerous 

illustrations.     In  one  neat  royal  12mo.  volume,     {ht  Press.) 
JTANNER  {THOMAS  H.),  M.D. 

ON  THE  SIGNS  AND  DISEASES  OF  PREGNANCY.    First  American 

from  the  Second  and  Enlarged  English  Edition.     With  four  colored  plates  and  illustra- 
tions on  wood.     In  one  handsome  octavo  volume  of  about  500  pages,  cloth,  $4  25. 

HE  OBSTETRICAL  JOURNAL.     [Free  of  postage  for  1819.) 

THE  OBSTETRICAL  JOURNAL  of  Great  Britain  and  Ireland; 

-Including  Midwifery,  and  the  Diseases  os*  Women  and  Infants.  With  an  American 
Supplement,   edited  by  J.  V.  Ingham,   M.D.     A  monthly  of   about  96  octavo  pages, 
very  handsomely  printed.  Subscription,  Five  Dollars  per  annum.    Single  Numbers,  50 
cents  each. 
Commencing  with  April,  1873,  the  ObstetricalJournal  consists  of  Original  Papersby  Brit- 
ish  and   Foreign    Contributors  ;  Transactions   of  the   Obstetrical   Societies   in  England  and 
abroad.    Reports  of  Hospital   Practice;   Reviews  and    Bibliographical   Notices;   Articles  and 
Notes,   Edito.'ial,   Historical,  Forensic,  and  Miscellaneous;   Selections  from  Journtils;   Cor- 
respondence, Ac     Collecting  together  the  vast  amount  of  material  daily  accumulating  in  this 
important  and  rapidly  improving  department  of  medical  science,  the   value  of  the   infor- 
mation which  it  presents  to  the  subscriber  may  be  estimated  from  the  character  of  the  gen- 
tlemen who  have  already  promised  their  support,  including  such  names  as  those  of  Drs.  At- 

THILL,   AVKLING,   RoBERT  B  AUNES,  J.  HeNRY   BeNNET,  NATII  AN   BoZEMAN,   ThOM  AS  Ch  AM  BERS, 

Fleetwood  Churchill.  Charles  Clay,  John  Clav,  Matthews  Duncan,  Arthur  Farre, 
Robert  Greendalgh,  Graily  Hewitt,  Braxton  Hicks,  Alfred  Meadows,  W.  Leisu- 
MAN,  Alex.  Simpson,  Hevwood  Smith,  Tyler  Smith,  Edward  J.  Tilt,  Lawson  Tait, 
Spencer  Wells,  Ac.  Ac.  ;  in  short,  the  representative  men  of  British  Obstetrics  and  Gynes- 
cology. 

In  order  to  render  the  Obstetrical  Journal  fully  adequate  to  the  wants  of  the  Ameri- 
can profession,  each  number  contains  a  Supplement  devoted  to  the  advances  made  in  Obstet- 
rics and  Gynaecology  on  this  side  of  the  Atlantic.  This  portion  of  the  Journal  is  under 
the  editorial  charge  of  Dr  J.  V.  Ingham,  to  whom  editorial  communications,  exchanges, 
books    for    re/iew,  Ac,  may  be  addressed,  to  the  care  of  the  publisher. 

♦<f*  Complete  sets  from  the  beginning  can  no  longer  be  furnished,  but  subscriptions  can 
eomnence  with  January,  1879,  or  Vol.  Vll.,  No.  1,  April,  1879. 


Henry  C.  Lea's  Publications — {Midwifery^  Surgery). 


25 


^  FASHMAN  {WILLIAM),  M.D., 

Regius  Professor  of  Mtdwifury  in  the.  University  of  Glasgow,  Ac. 

A  SYSTEM  OF  MIDWIFERY,  INCLUDING  THE  DISEASES  OF 

PREGNANCY  AND  THE  PtiERPERAL  STATE.  Third  American  edition,  with  addi- 
tions by  John  S.  Parry,  M.D.,  Obstetrician  to  the  Philadelphia  Hospital,  Ac.  In  one 
large  and  very  handsome  octavo  volume,  with  about  two  hundred  illustrations.   {Shortly.) 

^ARRY  [JOHN  S.),  M.D., 

Obstetrician  to  the  Philadelphia  Hospital,  Vice-Prest.  of  the  Ohstet.  Stciety  of  Philadelphia. 

EXTRA-UTERINE    PREGNANCY:    ITS  CLINICAL  HISTORY, 

DIAGNOSIS,    PROGNOSIS,  AND    TREATMENT,     In  one  handsome  octavo  volume. 
Cloth,  $2  60.     {Lately  Isstted.) 


R 


ODGE  [HUGH  L.),  M.D., 

Emeritus  Professor  of  Midwifery,  Ac,  in  the  University  of  Pennsylvania,  Sec. 

THE  PRINCIPLES  AND  PRACTICE  OF  OBSTETRIC^.     Illns- 

trated  with  large  lithographic  plates  containing  one  hundred  and  fifty-ninef  figujres  from 
original  photographs,  and  with  numerous  wood-cuts.  In  one  large  and  beautifully  printed 
quarto  volume  of  650  double-columned  pages,  strongly  bound  in  cloth,  $14, 


The  work  of  Dr.  Hodge  is  something  more  thaa 
a  simple  presentation  of  his  particalar  riews  in  the 
department  of  Obstetrics;  it  is  sometbing  more  j 
than  an  irdinary  treatise  on  midwifery;  it  is,  in  fact,  i 
a  cyclopaedia  of  midwifery.  He  has  aimed  to  em-; 
body  in  a  iingle  volume  the  whole  science  and  art  of 
Obstetrics.  A.n  elaborate  text  is  combined  with  ac-  j 
curate  and  varied  pictorial  illustrations,  so  that  no  '' 
fact  or  principle  is  left  unstated  or  unexplained,  j 
—Am.  Med.  Times,  Sept.  3,  1864. 

It  18  very  large,  profusely  and  elegantly  illustrat-i 
ed,  and  is  fitted  to  take  its  plaee  near  the  works  of  i 
great  obstetricians.     Of  the  American  works  on  the 

^*;^  Specimens  of  the  plates  and  letter-press 
on  receipt  of  six  cents  in  postage  stamps. 


subject  it  is  decidedly  the  best. — Edinb.  Med.  Jour., 
Dec.  1864. 

We  have  read  Dr.  Hodge's  book  with  great 
pleasure,  and  have  much  satisfaction  in  express- 
ing our  commendation  of  it  as  a  whole.  It  is  cer- 
tainly highly  instructive,  and  in  the  main,  we  be- 
lieve, correct.  The  great  attention  which  the  au- 
thor has  devoted  to  ttie  mechanism  of  parturition, 
taken  along  with  the  conclusions  at  which  he  has 
arrived,  point,  we  think,  conclusively  to  the  fact 
that,  in  Britain  at  least,  the  doctrines  of  Naegele 
have  been  too  blindly  received. — Glasgow  Med. 
Journal,  Oct.  1864. 

will  be  forwarded  to  any  address,  free  by  mail, 


f>AMSBOTHAM  [FRANCIS  H),  M.D. 

^   THE  PRINCIPLES  AND  PRACTICE    OF  OBSTETRIC   MEDJ- 

CINE  AND  SUEQERY,  in  reference  to  the  Process  of  Parturition.  A  new  and  enlarged 
edition,  thoroughly  revised  by  the  author.  With  additions  by  W.  V.  Keating,  M.  D., 
Professor  of  Obstetrics,  Ac,  iYi  the  Jefferson  Medical  College,  Philadelphia.  In  one  hiree 
and  handsome  imperial  octavo  volume  of  650  pages,  strongly  bound  in  leather,  with  rai.«ed 
bands  ;  with  sixty-four  beautiful  plates,  and  numerous  wood-cuts  in  the  text,  containing  in 
all  nearly  200  large  and  beautiful  figures.     $7  00. 


(^TUISON  [LEWIS  A.),  A.M.,  M.D., 

'^  Surgeon  to  the  Presbyterian  Hospital. 

A  MANUAL  OF  OPERATIVE  SURGERY.     In  one  very  handsome 

royal  12mo.  volume  of  about  500  pages,  with  332  illustrations  ;  cloth,  $2  60.  {Now  Ready  ) 


Tbe  work  before  us  is  a  well  printed,  profusely 
illustrated  manual  of  over  four  hundred  and  seventy 
pages.  The  novice,  by  a  perusal  of  the  work,  will 
gain  a  good  idea  of  the  general  domain  of  oparative 
surgery,  while  the  practical  surgeon  has  presented 
to  him  within  a  very  concise  and  intelligible  form 
the  latest  aud  most  approved  selections  of  operative 
procedure.  Thepreci«ion  atd  conciseness  with  which 
the  different  operations  are  described  enable  the 
author  to  compress  an  immense  amount  of  practical 
information  in  a  very  small  compass. — N.  Y.  Medical 
Record,  Aug.  3,  1878. 

This  volume  ie  devoted  entirely  to  operative  sur- 
gery, and  is  iuteuded  to  familiarize  the  student  with 
the  details  of  operations  and  the  differeut  modes  of  i 


performing  them.  The  work  is  handsomely  illnsr 
trated,  and  the  defcriptions  are  clear  and  well  drawn. 
It  is  a  clever  and  useful  volume;  every  student 
should  possess  one.  The  preparation  of  this  work 
does  away  with  the  necessity  of  pondering  over 
larger  works  on  surgery  for  descriptions  of  opera- 
liouH,  as  it  presents  in  a  nut-shell  just  what  is  wanted 
by  the  surgeon  without  an  elaborate  search  to  find 
it.— Md.  Med  Journal,  Aug.  1878. 

The  author's  conciseness  and  the  repleteness  of 
the  work  with  valuable  illustrations  entitle  it  to  be 
classed  with  the  text-books  for  students  of  operative 
surgery,  and  as  one  of  reference  to  the  prKCtitioner, 

Cincinnati  Lancet  and  Clinic,  July  27,  1S7S. 


SKET'S  OPERATIVB  SURGERY.  In  1  vol.  8vo. 
cl.,of660pagaB;  withabout  100 wood-cuts.  $3  25 

COOPER'S  LECTURES  ON  THE  PRINCIPLES  AND 
PlACTICB  OF  SUBGKBT.  In  1  vol.  8vo.  cl'h,  760  p.  $2. 

GIBSON'S  INSTITUTES  AND  PRACTICE  OF  8UR- 
aKRT.  Eighth  edit'n,  improved  and  altered.  With 
thirty-four  plates.  In  two  handsome  oc*,avo  vol- 
umes, about  1000  pp.,  leather,  raised  hand?.  ^P  50. 

THE  PRINCIPLES  AND  PRACTICE  OF  SURGERY. 
By  William  PiRRiK,F.R  S.E.,  Profe^'r  of  Surgery 
ia  the  University  of  Aberdeen.    Edited  by  John 


Neill,  M.D.,  Professor  of  Surgery  in  tbe  Penna. 
Medical  College,  Surg'n  to  the  Pennsylvania  Hos- 
pital, &c.  In  one  very  handsome  octavo  vol.  of 
780  pages,  with  316  illustrations,  cloth,  $3  7,5. 

MILLER'S  PRINCIPLES  OF  SURGERY.  Fourth  Ame- 
rican, from  the  Third  Edinburgh  Edition.  In  one 
large  8vo.  vol.  of  700  pages,  with  340  illustrationp, 
cloth,  $3  75. 

MILLER'S  PRACTICE  OF  SURGERY.  Fourth  Ame- 
rican, from  the  last  Edinburgh  Edition.  lievised  by 
the  American  editor.  In  one  large  8vo.  vol.  of  nearly 
700  pages,  with  364  illustrations:  cloth,  $3  75 


26 


Henry  C.  Lea's  Publications — {Surgery). 


fyROSS  {SAMUEL  D.),  M.D„ 

^-^  Professor  of  Surgery  in  the  Jefferson  Medical  College  of  Philadelphia. 

SYSTEM  OF    SURGERY:   Pathological,  Diagnostic,  Thernpeutic, 

and  Operative.   Illustrated  by  upwards  of  Fourteen  Hundred  Engravings.  Fifth  edition 
carefully  revised,  and  improved.  In  two  large  and  beautifully  printed  imperial  octavo  vol- 
umes of  about  2300  pp.,  strongly  bound  in  leather,  with  raised  bands,  $15.    (Just  Iss^ied.) 
The  continued  favor,  shown  by  the  exhaustion  of  successive  large  editions  of  this  great  work, 
proves  that  it  has  successfully  supplied  a  want  felt  by  American  practitioners  and  students.     In 
th«  present  revision  no  pains  have  been  spared  by  the  author  to  bring  it  in  every  respect  fully 
up  t(  the  day.     To  effect  this  a  large  part  of  the  work  has  been  rewritten,  and  the  whole  en- 
arged  bj  aearly  one-fourth,  notwithstanding  which  the  price  has  been  kept  at  its  former  very 
moderatf  rate.     By  the  use  of  a  close,  though  very  legible  type,  an  unusually  large  amount  of 
matter  is  condensed  in  its  pages,  the  two  volumes  containing  as  much  as  four  or  five  ordinary 
octavos     This,  combined  with  the  most  careful  mechanical  execution,  and  its  very  durable  bind 
ing  renderf,  it  one  of  the  cheapest  works  accessible  to  the  profession.    Every  subject  properly 
belonging  to  the  iomain  of  surgery  is  treated  in  detail,  so  that  the  student  who  possesses  this 
■work  mayAe  said  to  have  in  it  a  surgical  library. 
We  h#ve  m)\v 


brought  ourlask  to  a  conclusion,  and 
have  setdom  read  a  work  with  the  practical  value  of 
which  we  have  been  moreimpressed.  Every  chapter  is 
80  concisely  put  together,  that  the  busy  practitioner, 
when  in  difficulty,  can  at  once  find  the  infoimation  he 
requires.  Ills  work,  on  the  contrary,  i.s  cosmopolitan, 
the  surgery  of  the  world  beinti  fully  represented  in  it. 
The  work,  in  fact,  is  so  historically  unprejudiced,  and 
so  eminentlypractical,that  it  is  almost  a  false  compli- 
ment to  say  tJiatwe  believe  it  to  be  destined  to  occupy 
a  foremost  place  as  a  work  of  reference,  while  a  system 
of  surgery  like  the  present  system  of  surgery  is  the 
practice  of  surgeons.  The  printing  and  binding  of  the 
work  is  unexceptionable;  indeed,  it  contrasts,  in  the 
latter  respect,  remarkably  with  Ensrlish  medical  and 
surgical  cloth-bound  publications,  which  are  generally 
so  wretchedly  stitched  as  to  require  re-binding  before 
they  are  any  time  in  use. — IJub.  Journ.  of  Med.  Sci., 
March,  1874. 

Dr.  Gross's  Surgery,  a  great  work,  has  become  still 
greater,  both  in  size  and  merit,  in  its  most  recent  form. 
The  difference  in  actual  number  of  pages  ia  not  more 
than  1.30,  but.  the  size  of  the  page  having  been  in- 
crea*ed  to  what  we  believe  is  technically  termed  ••ele- 
phant," there  has  been  roomforconsiderableadditions, 
which,  together  with  the  alterations,  are  improve- 
ments.— Land.  Lancei,  Nov.  16, 1872. 

It  combines,  as  perfectly  as  possible,  the  qualities  of 
a  text-book  and  work  of  reference.   We  think  this  last 


elition  of  Gross's  "Surgery,"  will  confirm  his  title  of 
•'  Primus  intn-  Pares."  it  is  learned,  scholar-like,  me- 
thodical, precise,  and  exhaustive.  We  scarcely  think 
any  living  man  could  write  so  complete  and  faultless  a 
treatise,  or  comprehend  more  solid,  instructive  matter 
in  the  given  number  of  pages.  The  labor  must  have 
been  immense,  and  the  work  gives  evidence  of  great 
powers  of  mind,  and  the  highest  order  of  intellectual 
di.-cipline  and  methodical  disposition,  and  arrangement 
of  acquired  knowledge  and  personal  experience. — N.Y. 
Med.  Journ.,  Feb.  1873. 

As  a  whole,  we  regard  the  work  as  the  representative 
"Sy.^tem  of  Surgery"  in  the  Knglish  language. — St. 
Louis  Medical  and  Surg.  Journ.,  Oct.  1872, 

The  two  magnificent  volumes  before  us  afford  a  very 
complete  view  of  the  surgical  knowledge  of  the  day. 
Some  years  ago  we  had  the  pleasure  of  presenting  the 
first  edition  of  Gross's  Surgery  to  the  profession  as  a 
work  of  unrivalled  excellence;  and  now  we  have  the 
result  of  years  of  experience,  labor,and  study,  all  con- 
densed upon  the  great  work  before  us.  And  to  students 
or  practitioners  desirous  of  enriching  theirlibrary  with 
a  treasure  of  reference,  we  can  simply  commend  the 
purchase  of  these  two  volumes  of  immense  research  — 
Qincinnati  Lancet  and  Observer,  Sept.  1872. 

A  complete  system  of  surgery — not  a  mere  text-book 
of  operalion.'?.  but  a. scientific  account  of  surgical  theory 
and  itracticein  all  its  dHpurtments. — Brit,  and  For. 
M'd  C/iiV.i?«w.,  Jan.  1873. 


B 


Y  THE  SAME  AUTHOR. 

A    PRACTICAL  TREATISE    ON  THE  DISEASES,  INJURIES, 

and  Malformations  of  the  Urinary  Bladder,  the  Prostate  Grland,  and  the  Urethra.  Third 
Edition,  thoroughly  Revised  and  Condensed,  by  Samuel  W.  Gross,  M.D.,  Surgeon  to 
the  Philadelphia  Hospital.  In  one  handsome  octavo  volume  of  574  pages,  with  170  illus- 
trations: cloth,  $4  50.  {Just  Issiied.) 
For  reference  andgeneral  information,  the  physician  leases  of  the  urinary  organs. — Atlanta  Med .  Journ.,Oc\. 
or  surgeon  can  find  no  work  that  meets  their  necessities  j  1876. 

more  thoroughly  than  this,  a  revi.-ed  editioii  of  an  ex-  ^  jg  ^j^i^  pleasure  we  now  again  take  up  this  old 
cellent  treatise,  and  no  medical  library  should  be  with- 1  ^^^k  in  a  decidedly  new  dress.  Indeed,  it  must  be  re- 
out  it.  Replete  with  handsome  illustrations  and  good  j  garded  as  a  new  book  in  very  many  of  its  parts.  The 
ideas,  it  has  the  unusual  advantage  ot  being  easily  chapters  on  "Dlsea-^es  of  the  Bladder,"  "Prostate 
compreheuded,by  the  reasonableand  practical  manner  Ijjodyv  and  "  Lithotomy,"  are  splendid  specimens  of 
in  which  the  various  subjects  are  sy«temati5!ed  and  ij^^^criptive  writing;  while  the  chapter  on  "Stricture" 
arraneed  We  heartily  recommend  it  to  the  profession  jg  ^ne  of  the  most  concise  and  clear  that  we  have  ever 
a"  a  valuable  addition  to  the  important  literature  of  dis- 1  re&d.—New  York  Med.  Journ.,  Nov. 1876. 

73  F  THE  SAME  AUTHOR. 

A 


PRACTICAL   TREATISE    ON   FOREIGN  BODIES    IN 

AIR-PASSAGES.     In  1  vol.  8vo.,  with  illustrations,  pp.  468,  cloth,  $2  75. 


THE 


T)RUrrT  {ROBERT),  M.R.C.S.,  Src. 

THE  PRINCIPLES  AND  PRACTICE  OF  MODERN  SURGERY. 

A  new  and  revised  American,  from  the  eighth  enlarged  and  improved  London  edition.  Illus- 
trated with  four  hundred  and  thirty -two  wood  engravings.  In  one  very  handsome  octa-vo 
volume,  of  nearly  700  large  and  closely  printed  pages,  cloth,  $4  00  ;  leather,  $5  00. 

practice  of  surgery  are  treated,  and  so  clearly  and 
perspicaoQsly,  as  to  elucidateeveryimportanttopit. 
Wo  nave  examined  thebook  mostthoroughly,  and 
can  4ay  that  this  success  i8  well  merited.  Hia  book 
moreover,  posaesses  the  inestimable  advantages  of 
having  the  subject*  perfectly  well  arranged  aud 
clatsifled  and  of  being  written  in  a  style  at  once 
clear  ind  succinct. — Am.  Journal  of  Med.  Sciences. 


All  that  the  surgical  student  or  practitioner  could 
desire. — Dublin  Quarterly  Journal. 

It  is  a  most  admirable  book.  We  do  not  know 
irhen  we  have  examined  one  with  more  pleasure. — 
Bonton  Med.  and  Sttrg.  Journal. 

In  Mr.  Druitt'sbook,  though  containlngonly  some 
seven  hundred  pages,  both  the  principles  and  the 


Henry  C.  Lea's  Publications — {Surgery). 


27 


A  SHHURST  {JOHN,  Jr.),  M.D., 

-^^  Prof,  nf  Clinical  Surgery,  Univ.  of  Pa.,  Surgeon  to  the  Episcopal  Hospital,  Philadelphia. 

THE    PRINCIPLES  AND  PRACTICE  OF  SURGERY.     Second 

edition,  enlarged  and  revised.     In  one  very  large  and  handsome  octavo  volume  of  over 
1000  pages,  with  542  illustrations.     Cloth,  $6  ;  leather,  $7.     {Just  Ready.) 

Couscie»tiousne8s  aud  tlioronghnesR  are  two  very  I  Ashbur-it's  Surgery  is  too  well  known  ia  this 
marked  traits  of  character  in  the  author  of  this  country  to  require  special  corameudatiou  from  us. 
book.  Out  of  these  traits  largely  has  grown  the  !  Thig,  its  second  edition,  enlarged  and  thoroughly 
success  of  his  mental  fruit  In  the  paet,  and  the  pre-  J  revised,  brings  it  nearer  our  idea  of  a  model  text- 
sent  olfer  seems  in  no  wise  an  exception  to  what  has  j  book  than  any  recently  published  treatise.  Though 
gone  before.  The  general  arrangement  of  the  vol-  j  numerous  additions  have  been  made,  the  size  of  the 
ume  is  the  same  as  in  the  first  edition,  but  every  part  j  work  is  not  materially  increased  The  main  trouble 
has  been  carefully  revised,  and  much  new  matter  of  text-books  of  modern  times  is  that  they  are  too 
added.— PAi/a.  Med.  Times,  Feb.  1,  1S79.  |  cumbersome.     The  student  needs  a  book  which  will 

,.        ..      furnish  him   the  mo.«t  information  in  the  shortest 

We  have  previously  spoken  of  Dr.  Ashhurst  s  |  time.  In  every  re-spect  this  work  of  Ashhurst  is 
work  in  terms  of  praise.    We  wish  to  reiterate  those  ,  tjjg  model  text-book- full,  comprehensive  and  com- 

terms  here,  and  to  add  that  no  more   satisfactory  -..,._  . 

representation  of  modern  surgery  has  yet  fallen 
from  the  press.  In  point  of  judicial  fairness^,  of 
power  of  condensation,  of  accuracy  and  conciseness 
of  expression  and  thoroughly  good  English,  Prof. 
Ashhurst  has  no  .superior  among  ihe  surgical  writers 
in  America.— ^wj.  Practitioner,  Jan.  1S79. 

The  attempt  to  embrace  iu  a  volnme  of  1000  page.? 
the  whole  field  of  surgery,  general  and  special, 
would  be  a  hopele.ss  ta»k  unless  through  tiie  most 
tireless  industry  in  collating  and  arranging,  and 
the  wisest  judgment  in  condensing  and  excluding. 
These  facilities  have  been  abundantly  employed  by 
the  author,  and  he  has  given  us  a  most  excellent 
treatise,  brought  up  by  the  revision  for  the  second 
editiou  to  the  late.st  date.  Of  course  this  book  is  not 
defcigned  for  specialists,  but  as  a  course  of  general 
surgical  knowledge  and  for  general  practitioners, 
and  as  a  text-book  for  students  it  is  not  surpassed 
by  any  that  has  yet  appeared,  whether  of  home  or 
foreign  authorship.— iV.  Carolina  Med.  Journal, 
Jan.  1S79. 


pact. — Nashville  Jour  of  Med.  and  Surg.,  Jan, 

The  favorable  reception  of  the  first  edition  is  a 
guarantee  of  the  popularity  of  this  edition,  which  is 
fresh  from  the  editor's  hands  with  many  enlarge- 
ments and  improvements.  The  author  of  this  work 
is  deservedly  popular  as  an  editor  and  writer,  and 
his  contributions  to  the  literature  of  surgery  have 
gained  for  him  wide  reputation.  The  volume  now 
offered  the  profession  will  add  new  laurels  to  those 
already  won  by  previous  contributions.  We  can 
only  add  that  the  work  is  well  arranged,  filled  with 
practical  matter,  and  contains  in  brief  and  clear 
language  all  that  is  necessary  to  be  learned  by  the 
student  of  surgery  whilst  in  attendance  upon  lec- 
tures, or  the  general  practitioner  iu  his  daily  routine 
practice. — Md.  Med.  Journal,  Jau.  1S79. 

The  fact  that  this  work  has  reached  a  second  edi- 
tion so  very  soon  after  the  publication  of  the  first 
one,  speaks  more  highly  of  its  merits  than  anything 
we  might  say  in  the  way  of  commendation.  It 
seems  to  have  immediately  gained  the  favor  of  stu- 
dents and  physicians.— C'iyici?!.  Med.  News,  Jan.  '79 


T>RYANT  {THOMAS),  F.R.C.S., 

-»-'  Sxtrgeonto  Guy's  Hotpital, 

THE  PRACTICE  OF  SURGERY.     Second  American,  from  the  Sec- 

ond  and  Revised  English  Edition.     With  Six  Hundred  and  Seventy-two  Enj^ravings  on 

Wood.    In  one  large  and  very  handsome  imperial  octavo  volume  of  over  1000  large  and 

closely  printed  pages.     Cloth,  $6  ;   leather,  $7.     (Just  Ready.) 

This  work  has  enjoyed  the  advantage  of  two  thorough  revisions  at  the  hand  of  the  author  since 

the  appearance  of  the  first  American  edition,  resulting  in  a  very  notable  enlargement  of  size  and 

improvement  of  matter.     In  England  this  has  led  to  the  division  of  the  work  into  two  volumes, 

which  are  here  comprised  in  one,  the  size  being  increased  to  a  large  imperial  octavo,  printed  on 

a  condensed  but  clear  type.     The  series  of  illustrations  has  undergone  a  like  revision,  and  will 

be  found  correspondingly  improved. 

The  marked  success  of  the  work  on  both  sides  of  the  Atlantic  shows  that  the  author  has  suc- 
ceeded iu  the  effort  to  give  to  student  and  practitioner  a  sound  and  trustworthy  guide  in  the 
practice  of  burgery^  while  the  simultaneous  appearance  of  the  present  edition  in  England  and 
in  this  country  affords  to  the  American  reader  the  benefit  of  the  most  recent  advances  made 
abroad  in  surgical  science. 

There  are  so  many  text-books  of  surgery,  go  many  i 
written  by  .skilled  and  distiuguished  hands,  that  to  ob- 


tain the  honor  of  a  third  edition  in  England  is  no  light 
praise.  Mr.  Bryant  merits  this,  by  clearness  of  style, 
and  good  judgment  in  selecting  the  operations  he  re- 
commends, iu  his  new  editions  he  goes  carefully  over 
the  eld  grounds,  in  light  of  later  research.  On  the.'^e 
and  many  allied  points,  Mr.  Bryant  is  a  calm  and  un- 
partisan  observer,  and  bis  book  througboiit  has  the 
great  merit  of  maintaining  the  true  scientific,  judicial 
tone  of  mind.— J/et/.  and  Surg,  lieporttr 
1879. 

The  work  before  us  is  the  American  reprint  of  the 
last  London  edition,  and  has  the  advantage  over  the 
latter  in  being  of  more  convenient  size,  and  in  being 
compressed  into  one  volume.  The  author  has  rewrit- 
ten the  greater  part  of  the  work,  and  has  succeeded, 
in  the  amount  of  new  matter  added,  in  making  it  mark- 
edly distinctive  from  previous  editions.  A  few  extra 
pages  have  been  added,  and  al.so  a  few  new  illustrations 
introduced.  The  publishers  have  presented  the  work 
in  a  creditable  style.  As  a  concise  and  practical  manual 
of  British  surgery  it  is  perhaps  without  an  equal,  and 
will  doubtless  always  be  a  favorite  text-book  with  the 
student  and  practitioner, — N.  1\  Med.  Jiecord,  .March  i 
22,  1S79.  1 


Another  edition  of  this  manual  having  been  calle.l 
for,  the  author  has  availed  himself  of  the  opportunity 
to  make  no  few  alterations  in  the  sabstauce  as  we. I 
as  in  the  airaugernent  of  the  work,  and,  with  a  view 
to  its  improvement,  has  recast  the  materials  and  re- 
vised the  whole.  We  ourselveb  are  of  the  opinion 
that  there  is  no  better  work  on  surgery  extant  — 
Cihcinnati  Med.  News,  March,  1879 
Bryant's  Surgery  has  been  favorably  received  from 
M  h  '->■)  i  the  first,  and  evidently  grows  in  the  esteem  of  the 
March  — ,  !  profession  with  each  succeeding  edition.  In  glanc- 
ing over  the  volume  before  us  we  find  prouf  in  almost 
every  chapter  of  the  thorough  revision  which  the 
worK  has  undergone,  many  parts  having  been  cut 
out  and  replaced  by  matter  entirely  fresh.- i\^.  Y. 
Med.   loam.,  April,  1879. 

Welcome  as  the  new  edition  is,  and  as  much  as  it 
is  entitled  to  commendation,  yet  its  appearance  at 
this  time  is,  in  a  ceriain  sense,  a  matter  of  regret,  as 
it  will  be  in  competition  with  another  work,  lately 
issued  from  the  same  press.  But,  the  difficult  task 
of  forming  a  judgment  as  to  the  relative  merits  of 
Bryant  and  Ashuurst  we  will  not  attempt,  but  pre- 
dict that,  considering  the  high  excellence  of  both, 
many  others  will  likewise  be  forced  to  hesitate  long 
in  making  choice  between  \\iem.. -^Cincinnati  Lan- 
cet and  Clinic,  March  22,  1579. 


28 


Henry  C.  Lea's  Publications— (fifwr^'f?;-?/). 


fJRICHSEN  {JOHN  E.), 

Professor  n/ Surgery  in  University  College,  London,  etc. 

THE  SCIENCE  AND  ART  OF  SURGERY ;  being  a  Treatise  on  Sur- 
gical Injuries,  Diseases,  and  Operations.  Carefully  revised  by  the  author  from  the 
Seventh  and  enlarged  English  Edition.  Illustrated  by  eight  hundred  and  sixty  two  en- 
gravings on  wood.  It  two  large  and  beautiful  octavo  volumes  of  nearly  20<»0  pages  : 
cloth,  $8  50  ;  leather,  $10  50       (Noto  Ready.) 

In  revising  this  standard  work  the  author  has  spared  no  pains  to  render  it  worthy  of  a  continu- 
ance of  the  very  marked  favor  which  it  hns  so  long  enjoyed,  by  bringing  it  thoroughly  on  a 
level  with  the  advance  in  the  science  and  art  of  surgery  made  since  the  iippearance  of  the 
l:i5t  edition.  To  accomplisli  this  has  required  the  addition  of  about  two  hundred  page«  of  text, 
while  the  illustrations  have  undergone  a  m:irked  improvement.  A  hundred  and  fifty  additional 
wood-cuts  have  been  inserted,  while  about  fifty  other  new  ones  have  been  substituted  for  figures 
which  were  not  deemed  satisfactory.  In  its  enlarged  and  improved  form  it  is  therefore  pre- 
sented with  the  confident  anticipation  that  it  will  maintain  its  position  in  the  front  riink  of 
text-bocks  for  the  student,  and  of  works  of  reference  for  the  practitioner,  while  its  exceedingly 
moderate  price  places  it  within  the  reach  of  all. 


The  aeveuth  editioa  is  before  the  world  as  the  last 
Word  ol  surgical  tcieuce.  There  may  be  uiouographs 
which  excel  it  -up  tn  certain  points,  but  as  a  con- 
spectus upun  surgical  principles  and  practice  it  is 
unrivalled.  It  will  well  reward  practitioners  to 
read  it,  for  it  bas  been  a  peculiar  province  of  Mr. 
Erichsen  to  demouhtrate  the  absolute  interdepend- 
ence of  medical  and  surgical  science  We  need 
scarcely  add,  in  conclasiou,  that  we  heartily  com- 
mend the  work  to  students  that  they  may  be 
grounded  in  a  sound  faith,  and  to  practitioners  as 
an  invaluable  guide  at  the  bedside.— .4m  Practi- 
tioner, April,  1878. 

It  is  no  i  lie  compliment  to  say  that  this  is  the  best 
edition  Mr.  Erichsen  has  ever  produced  of  his  well- 
known  book.  Besides  inheriting  the  virtues  of  is 
predecessors,  it  possesses  excellences  quite  its  own. 
Having  stated  that  Mr.  Erichsen  his  incorporated 
into  this  edition  every  recent  improvement  in  the 
science  and  art  of  8urgt'iy,it  would  be  a  supereroga- 
tion to  give  a  detailed  criticism.  In  short,  we  un- 
hesitatiugly  aver  th-it  we  know  of  no  other  single 
work  wliere  the  student  and  practitioner  can  gain  at 
oncesoclear  an  insight  into  the  principles  of  surgery, 
and  so  complete  a  knowledge  of  the  exigencies  of 
surgical  practice.— I/ontZ.^n  Lancet,  Feb.  U,  1878 

For  the  past  twenty  years  Erichsen's  Surgery  has 
maintained  its  place  astheleadingtext-book,  notonly 
in  this  country,  but  in  Great  Britain.  That  it  is  able 
to  hold  its  ground,  is  abundantly  proven  by  the  tho- 
roughneos  with  which  the  present  edition  has  bean 
revit^ed,  and  by  the  large  amount  of  valuable  mate- 
rial that  has  been  added.  Aside  from  this,  c  ne  hun- 
dred and  fifty  new  illustrations  have  been  inserted, 
including  quite  a  number  of  microscopical  appear- 
ances of  path>l  -gical  processes.     So  marked  is  this 


change  for  the  belter,  that  the  work  almost  appears    add  to  the  value  of  this  work, 
as  an  entirely  new  one. —ilferf.  Record,  Feb.  23,1878.  I  Journal,  March,  1878. 


Of  the  many  treatises  on  Sur-i;ery  which  it  has  been 
our  task  to  study,  or  our  pleasure  to  read,  there  is  non« 
which  in  all  points  has  satisfied  us  so  well  as  the  clas.'iio 
treati.'^e  of  Krich.''en.  His  polished,  clear  style,  his  free- 
dom from  prejudice  and  hobbies,  his  unsurpassed  grasp 
of  his  subject,  and  vast  clinical  experience,  qualify  him 
admirably  to  write  a  model  text-book.  "When  we  wish, 
at  the  least  cost  of  time,  to  learn  the  most  of  a  topic  in 
surgery,  we  turn,  by  preference,  to  his  work.  It  is  a 
pleasure,  therefore,  to  see  that  the  appreciation  of  it  is 
general,  and  has  led  to  the  appearance  of  another  tali- 
tion.—Akd.  and  Surg.  lieporter,  Feb.  2, 1878. 

Notwithstanding:  the  increase  in  size,  we  observe  that 
much  old  matter  has  been  omitted.  The  entire  work 
has  been  thoroughly  written  up,  aud  not  merely  amend- 
ed by  a  few  extra  chapters  A  great  improvement  bas 
t3een  made  in  the  illustrations.  One  hundred  and  fifty 
new  ones  have  been  added,  and  many  of  the  old  ones 
have  been  redrawn  The  author  highly  appreciates  the 
favor  wiih  which  his  work  has  been  received  l)y  Ameri- 
can surgeons,  and  has  endeavored  to  render  bis  latest 
edition  more  than  ever  worthy  of  their  approval.  That 
he  has  succeeded  admirably,  must,  we  think,  be  the 
general  opinion.  We  heartily  recommend  the  book  to 
both  student  and  practitioner. — N.  Y.JUed.  Journal, 
Feb. 1878. 

Erichsen  bas  stood  so  prominently  forward  for 
years  as  a  writer  on  Surgery,  that  his  reputation  is 
world  wide,  and  his  name  is  as  familiar  to  the  med- 
ical student  as  to  the  accomplished  and  experienced 
surgeon.  The  work  is  not  a  reprint  of  former  edi- 
tions, but  has  in  many  places  been  entirely  rewrit- 
ten. Recent  improvements  in  surgery  have  not  es- 
caped his  notice,  various  new  operations,  have  been 
thoroughly  analyzed,  aud  their  merits  thoroughly 
discussed.  One  hundred  and  fifty  new  wood-cuts 
■N.  U.  Med.  and  Surg. 


TIOLMES  {TIMOTHY),  M.D., 

J-^  Surgeon  to  St.  George's  Hosjntal,  London. 

SURGERY,  ITS  PRINCIPLES  AND  PRACTICE.  In  one  hand- 
some octavo  volume  of  nearly  1000  pages,  with  411  illustrations.  Cloth,  $6;  leather,  $7. 
{Just  Issued.) 


This  is  a  work  which  has  been  looked  for  on  both 
sides  ofthe  Atlantic  with  much  interest.  Mr.  Holmes 
Is  a  surgeon  of  large  and  varied  experience,  and  one 
of  the  best  known,  and  perhaps  the  most  brilliant 
writer  upon  surgical  subjects  in  England.  It  is  a 
book  for  students— and  an  admirable  one— and  for 
the  busy  general  practitioner.  It  will  give  a  student 
all  the  knowledge  needed  to  pass  a  rigid  examina- 
tion. The  book  fairly  justifiesthe  high  expectations 
that  were  formed  of  it.  Its  style  is  clear  aud  forcible, 
even  brilliant  at  times,  and  the  conciseness  needed 
to  bring  it  within  its  proper  limits  has  no  I  impaired 


its  force  and  distinctness.— iV.  F.  Med.  Record,  April 
U,  1876. 

It  will  be  found  a  most  excellent  epitome  of  sur- 
gery by  the  general  practitioner  who  has  not  the 
time  to  give  attention  to  more  minute  and  extended 
works  and  to  the  medicalstudent.  In  fact,  we  know 
of  no  one  we  can  more  cordially  recommend.  The 
author  has  succeeded  well  in  giving  a  plain  and 
practical  account  of  each  surgical  injury  and  dis- 
ease, and  of  the  treatment  which  is  most  com- 
monly advisable.  It  will  no  doubt  become  a  popu- 
lar work  in  the  profession,  and  especially  as  a  text- 
book.—  Cincinnati  Med.  News,  April,  1876. 


ASHTON  ONTHE  DISEASES,  INJURIES,  and  MAL- 
FORMATIONS OF  THE  RECTUM  AND  ANUS: 
with  remarks  on  Habitual  Constipation.  Second 
American,  from  the  fourth  and  enlarged  London 
Edition.  With  illustrations.  In  one  8vo.  vol.  of 
287  pages,  el<^b,$3  25. 


SARGENT  ON  BANDAGING  AND  OTHER  OPERA- 
TIONS OF  MINOR  SURGERY.  New  edition,  with 
an  additional  chapter  on  Military  Surgery.  One 
12mo.  vol.  of  383  pag9s,  with  18i  wood-cuts.  Cloth, 
!JS175. 


Henry  C.  Lea's  Publications — (Ophthalmology). 


29 


PfAMILTON  {FRANK  H.),  M.D., 

^■*-  Professor  of  Fractures  and  DiHocntions,  Ac,  in  BeUeviie  Hosp.  Med.  College,  New  York. 

A  PRACTICAL  TREATISE  ON   FRACTURES  AND  DISLOCi- 

TIONS.  Fifth  edition,  revised  and  improved.  In  one  large  and  handsome  octavo  voluire 
of  nearly  80a  pages,  with  344  illustrations.  Cloth.  $6  75:  leather,  $6  75.  [Lately  Issned.) 
This  work  is  well  known,  abroad  as  well  as  at  home,  aslhe  highe.«t  authority  on  its  important 
subject — an  authority  recognized  in  the  courts  as  well  as  in  the  schools  and  in  practice — and 
again  manifested,  not  only  by  the  demand  for  a  fifth  edition,  but  by  arrang-ements  now  in  pro- 
gress for  the  speedy  appen  ranee  of  a  translation  in  Germany.  The  repeated  revi.«ions  which  the 
author  has  thus  had  the  opportunity  of  making  have  enabled  him  to  give  the  most  careful  consid- 
eration to  every  portion  of  the  volume,  and  he  has  sedulously  endeavored  in  the  present  issue, 
to  perfect  the  work  by  the  aid  of  his  own  enlarged  experience,  and  to  incorporate  in  it  whatever 
of  value  has  been  added  in  this  department  since  the  issue  of  the  fourth  edition.  It  will  there- 
fore be  found  considerably  improved  in  matter,  while  the  most  careful  attention  has  been  paid 
to  the  typographical  execution,  and  the  volume  is  presented  to  the  profession  in  the  confident 
hope  that  it  will  more  than  maintain  its  very  distinguished  reputation. 

There  is  no  better  work  on  the  subject  in  existence 
tlinn  tliat  of  Dr.  Hamilton.  It  should  be  in  the  posses- 
sion of  every  irenenil  practitioner  and  surgeon.  — T/if 


Am.  Journ.  of  Obstetrics.  Feb  1876. 

The  value  of  a  work  like  this  to  the  practical  physi- 
cian and  surgeon  can  hardly  be  over-estimated,  and  the 
necessity  of  havinir  such  a  book  revised  to  the  latest 
date.'',  not  meri-lv  on  account  ofthe  practical  importance 


of  its  teachings,  but  also  by  reason  of  the  medico-legal 
bearingsof  the  cases  of  which  it  treats,  and  which  have 
recently  been  the  subject  of  usefulpapers  by  Dr  IlaraiN 
ton  and  others,  is  sufficiently  obvious  to  every  one.  The 
present  volume  seems  to  amply  fill  all  the  requisites. 
We  can  safely  recommend  it  as  the  best  of  its  kind  in 
the  English  lantrnage.  and  not  excelled  in  any  other  — 
Journ.  of  Nervous  and  Mental  Disease,  J&n  1876. 


^EOWNE  {EDGAR  A.), 

Surgeon  to  the  Liverpool  Eye  and  Ear  Infirmary,  and  to  the  Dispensary  for  Skin  Disfasfg. 

HOW  TO  USE  THE  OPHTHALMOSCOPE.     Being  Elementary  In- 

structionsin  Ophthalmoscopy,  arranged  for  the  Use  of  Students.    With  thirty-fiveillustia- 
tions.     In  one  small  volume  royal  l2mo.  of  120  pages  :  cloth,  $1.     {Now  Ready.) 


This  capital  little  work  should  be  in  the  hands  of 
ev  ry  medical  student,  and  we  had  alniostsaid  every 
general  practitioner.  Its  explanation  of  the  optical 
principles  on  which  the  ophthalmoscope  is  founded, 
i.r>  80  clear  and  simple  that  the  most  stupid  reader 


could  scarcely  fail  of  understanding  them.  Equally 
satisfactory  are  the  directions  for  the  use  of  tie  in- 
strument and  the  suggestions  to  aid  in  interpreiiiig 
what  is  tiQQa.—Dttroit  Med.  Journ.,  Kov.  1S77. 


o 


ARTER  {R.  BRUDENELL),  F.R.C.S., 

Ophthalmic  Surgeon  to  St.  George's  Hospital,  ttc. 

A  PRACTICAL  TREATISE  ON  DISEASES  OF  THE  EYE.    Edit- 

ed,  with  test-types  and  Additions,  by  John  Green,  M.D.  (of  St.  Louis,  Mo.).  In  one 
handsome  octavo  volume  of  about  500  pages,  and  124  illustrations.  Cloth,  $3  75.  {Just 
Issued.) 

manner,  ea.sy  of  comprehension,  and  hence  the  more 
valuable.  We  would  especially  commend,  however,  as 
worthy  of  high  praise,  the  manner  in  which  the  thera- 
peutics of  disease  of  the  eye  is  elaborated,  for  here  the 
author  is  particularly  clear  and  practical,  where  other 
writers  are  unfortunately  too  often  deficient.  The  liual 
ciiapter  is  devoted  to  a  discussion  of  the  usesand  selec- 
tion of  spectacles,  and  is  admirably  compact,  plain,  and 
useful,  especially  the  paragraphs  on  the  treatment  of 
presbyopia  and  myopia.  In  conclusion,  our  thanks  are 
due  the  author  for  many  useful  hints  in  the  great  sub- 
ject of  ophthalmic  surgery  and  therapeutics,  a  field 
where  of  late  years  we  glean  but  a  few  grains  of  sourd 
w  heat  from  a  mass  of  chaff  — New  York  Medical  Hexord, 
Oct.  23, 1875. 


It  would  be  difficult  for  Mr.  Carier  to  write  an  unin- 
structive  book,  and  impossible  for  him  to  write  an  un- 
interesting one.  Even  on  subjects  with  which  he  is  not 
bound  to  be  familiar,  hecan  discourse  with  a  rare  degree 
of  clearness  and  effect.  Our  readers  will  therefore  not 
be  surprised  to  \earn  that  a  work  by  him  on  the  Diseases 
ot  the  Kve  makes  a  very  valuable  addition  to  ophthal- 
mic literature.  ,  .  .  The  book  will  remain  one  useful 
alike  to  the  general  and  thespecial  practitioner.— ion- 
don  Lancet,  Oct.  30,1875. 

It  is  with  great  pleasure  that  we  can  endorse  ibe  work 
as  a  most  valuable  contribution  to  practical  ophthal- 
mology. Mr.  Carter  never  deviates  from  the  end  he  has 
in  view,  and  presents  the  subjectin  a  clear  and  concise 


VfTELLS  {J.  SOELBERG), 

Professor  of  Ophthalmology  in  King's  College  Hospital,  Ac. 

A  TREATISE  ON    DISEASES  OF  THE  EYE.     Third  American, 

from  the  Fourth  and  Revised  London  Edition,  with  additions  ;  illustrated  with  numerous 
engravings  on  wood,  and  six  colored  plates.  Together  with  selections  from  the  Test-types 
of  Jaeger  and  Snellen.   In  one  large  and  very  handsome  octavo  volume.    {Pre2>aring.) 

TA  URENCE  {JOHN  Z.),  F.  R.  C.S., 

Editor  of  the  Ophthalmic  Review,  &e. 

A  HANDY-BOOK  OF  OPHTHALMIC  SURGERY,  for  the  use  of 

Practitioners,  Second  Edition,  revised  and  enlarged.  With  numerous  illustrations.  In 
one  very  handsome  octavo  volume,  cloth,  $2  75. 

TA  WSON  {GEORGE),  F.R.C.S.  Engl., 

■    Assistant  Surgeon  to  the  Royal  London  Ophthalmic  Hospital,  Moorflelds,Ac. 

INJURIES  OF  THE  EYE,  ORBIT,  AND  EYELIDS:  their  Imme- 
diate and  Remote  Effects.  With  about  one  hundred  illustrations.  In  ^ne  very  hand- 
some octavo  volume,  cloth,  $3  50. 


30 


Henry  C.  Lea's  Publications — {Medical  Jurisprudence). 


nURNETT  {CHARLES  H.),  M.A  ,M.D., 

J-^  Aural  Surg,  to  the  Presb.  Hasp.,  Surgeon-in-tharge.  ofthilafirforDis.  of  the.  Ear,  Phila. 

TPIE    EAR,  ITS    ANATOMY.   PHYSIOLOGY,   AND   DISEASES. 

A  Practical  Treatise  for  the  Use  of  Medical  Students  and  Practitioners.     In  one  hand- 
some octavo  volume  of  615  pages,  with  eighty-seven  illustrations  :  cloth,  $4  60  ;  leather, 
$5  50.      {Just  Ready.) 
Recent  progress  in  the  investigation  of  the  structures  of  the  ear,  and  advances  made  in  the 
modes  of  treating  its  diseases,  wouldseem  to  render  desirable  a  new  work  in  which  all  the  re- 
sources of  the  most  advanced  science  should  be  placed  at  the  disposal  of  the  practitioner.  This 
it  has  been  the  aim  of  Dr.  Burnett  to  accomplish,  and  the  advantage.s  which  he  has  enjoyed  in 
the  special  study  of  the  subject  are  a  guarantee  that  the  result  of  his  labors  1\- ill  prove  of  service 
to  the  profession  at  large,  as  well  as  to  the  specialist  in  this  der>artment. 

Foremost  among  the  numerous  recent  coutribu-  ;  medical  student,  and  its  study  will  well  repay  the 
tions  to  aural  literaturt  will  b^  ranked  this  work  busy  pracfitioner  in  the  pleasuie  he  will  derive  from 
of  Dr.  Burnett.  It  is  impossible  to  do  justice  to  the  agreeable  style  in  which  many  otherwise  dry 
this  volume  of  over  600  pages  in  a  nece>-!=arily  brief    and  mostly  unknown  subjects  are  treated.    To  the 

specialist  the  work  is  of  the  highest  value,  and  his 


notice.  It  must  sufiice  to  add  that  the  booh  is  pro- 
fusely and  accurately  illustrated,  ihe  references  are 
conscientiously  acknowledged,  while  the  result  has 
been  to  produce  a  treatise  which  will  henceforth 
rank  with  the  clas.sic  writings  of  Wilde  acd  V^on 
Trolsch. — The  Lond.  rraitUiontr,  May,  1S79 

On  account  of  the  great  advances  which  have  been 
made  of  late  years  in  otology,  aud  of  the  increased 
lutf  rest  manifested  in  it,  the  medical  profes.-^ion  will 
welcome  this  new  work,  whicli  presents  clearly  aud 
concisely  its  present  aspect,  whilst  clearly  indi- 
cating the  direction  in  which  further  researches  can 
be  most  profitably  carried  on.     Dr.  Burn  tt  from  his 


sense  of  gratitude  to  Dr.  Burnett  will,  we  hope,  be 
proportionate  to  ilie  amount  of  benefit  he  can  obtain 
from  the  careful  study  of  the  book,  and  a  constant 
reference  to  its  trustworthy  pages. — Edinbu  gh 
Med.  Jour.,  Aug.  1S7S. 

The  book  is  designed  especially  for  the  use  of  stu- 
dents and  general  practitioners,  and  places  at  their 
disposal  much  valuable  material.  Such  a  book  as 
the  present  one,  we  think,  ha.>,l()ngbeen  needed, aud 
we  may  congratulate  the  author  on  his  success  iu 
fiUiag  the  gap.  Both  scudent  and  practitioner  can 
study  the  work   witli  a  great  deal  of  benefit.     It  is 


own   matured  experience,  and  availing  himself  of  |  pr^fu-ely  and    beaiitjfully  iUustrated.-JS^  Y.  Bos- 
the  observations  and  discoveries  of  others,  has  pro-    ^""'  ^f"«"«.  ^-'ct   l->.  li>". 


duced  a  work,  which  as  a  text-book,  stands /ftct/c 
'prinecps  in  our  language.  We  had  marked  several 
pa-sages  as  well  worthy  of  quotation  and  the  atten- 
tion of  the  general  practitioner,  l)ut  their  number  aud 
the  space  at  our  command  forbid.  Perhaps  it  is  bet- 
ter, as  the  book  ought  to  be  in  the  hands  of  every 


'piti 

Dr.  Burnett  is  to  be  com  mended  for  having  written 
the  best  book  on  the  subject  in  the  English  language, 
aud  especially  for  the  care  and  attention  he  has 
given  to  the  scientific  side  of  the  subject. — N.  1'. 
Med.  Journ.,  Dec.  1S77. 


BAYLOR  {ALFRED    S.),M.I)., 

Lecturer  on  Med.  Jurisp.  and  Chemistry  in  Guy's  Hospital. 

POISONS  IN  RELATION  TO  MEDICAL  JURISPRUDENCE  AND 

MEDICINE.     Third  American,  from  the  Third  and  Revised  English  Edition.     In  one 


large  octavo  volume  of  850  pages  ;  cloth,  $ 
The  present  is  based  upon  the  two  previous  edi- 
tions; ''but  the  complete  re  vision  rendered  nece.ssary 
by  time  has  converted  it  into  a  new  work."  This 
statement  from  the  preface  contains  all  that  it  is  de- 
sired to  know  in  reference  to  the  upw  edition.  The 
works  of  this  author  are  already  in  th«)  library  of 
every  physician  who  is  liable  to  be  called  upon  for 
medico-legal  testimony  (and  wh  t 'nei.-i  not?),  so  that 
all  that  is  required  to  be  knovvu  about  the  present 
book  is  that  the  author  has  kept  it  abreast  wiih  the 
times  What  makes  it  now,  as  always,  especially 
valuable  to  the  practitioner  is  its  conciseness  and 
practical  character,  only  thosfe  poisonous  substances 

Y  THE  SAME  A U THOU. 


5  60  ;   leather,  $6  50.      {Just  Issued.) 
being  described  which  give  rise  to  legal  luvesliga- 
tions.  — TAc  Clinic,  iXov.  6,  1S7.5. 

Dr.  Taylor  hat  brought  to  bear  on  the  compilation 
of  this  Volume,  stores  of  learning,  experience,  and 
practical  ac([uaiiitance  with  Lis  subjectj  probably  far 
beyoud  what  auy  other  living  authority  on  toxicol- 
ogy could  have  amassed  or  utilized.  He  has  fully 
sustained  his  ret)Utaiion  by  the  consum>nate  skill 
and  legal  acumen  he  has  displayed  in  the  arrange- 
ment of  tlio  subject-matter,  aud  the  result  is  a  work 
ou  Poisons  whicli  will  be  indispensable  to  every  stu- 
dent or  practitioner  in  law  aud  medicine. — 2"he  Dub- 
lin Journ.  i/  Med  Sd.,  Oct.  1S7J, 


B 


MEDICAL  JURISPRUDENCE.   Seventh  American  Edition.   Edited 

by  John  J.  Reese,  M.D.,  Prof,  of  .Med.  Jurisp.  in  the  Univ.  of  Penn.  In  one  large 
octavo  volume  of  nearly  900  pages.  Oloth,  $5  t(0  ;  leather,  $6  00.  {Lately  Issued.) 
To  the  members  of  the  legal  aud  medical  profes-  best  aaihority  ou  this  specialty  inour  language.  Ou 
sioD,  It  is  unnecessary  to  say  anything  commend  a-  i  this  point,  however,  we  will  .-.ay  thai  weconsider  Di . 
tory  of  Taylor's  Medical  Jurisprudence.  We  might  j  Taylor  to  be  the  safet«t  medico-legal  auttiority  tofoi- 
as  well  undertake  to  speak  of  the  nerit  of  Chitty 's  j  low,  ingeneral,  with  which  we  are  acquainted  in  any 
Ple-d,di\\g».—Chieago  Legal  News,  Oct.  10,  IS?."?.         '  language.— Ka   Clin.  Record.  Nov.  1{>73. 

It  is  beyond  question  themost  attractive  as  well  i  Thislastedilion  ofthe  Manualisprobably  thebest 
as  most  reliable  manual  of  medical  J  urisprudence  ^fj^n.^^  it  c^u^j^in„  ,„^re  material  and  i^  s*  orked  up 
published  in  the  English  language.— ^w.  <;^owr«a/ ,  j^j  tiig  latest  vi^^ws  of  the  auihor  asexpressed  in  the 
of  Syphieography,  Oct.  1873.  |  i^^^t  edition  of  ih6  Principles.    Dr.  Uie^e,  the  editor 

It  isaltogethersuperfluousfor  u8toofi"eranything    of  the  Alauual,  has  done  everything  to  make  his 
iu  behalf  of  a  work  on  medical  jurisprudence  by  an    work  accept  able  to  his  medical  countrymea.—.W.  y, 
author  who  i* almost  universally  esteemed  to  be  the    Med.  Record,  Jan.  lo,  1S74. 
or  THE  SAME  AUTHOR.  

THE  PRINCIPLES  AND  PRACTICE  OF  MEDICAL  JURISPRU- 

DENCE,     Second  Edition,  Revised,  with  numerous  Illustrations.    In  two  large  octavo 
volumes,  cloth,  $10  00  ;  leather,  $12  00 
This  great  woric  is  now  recognized  in  England  as  the  fullest  and  most  authoritative  treatise  on 
every  department  of  its  important  subject.  In  laying  it,  in  its  improved  form,  before  the  Amer- 
ican profession,  the  pablisher  trusts  that  it  will  assume  the  same  po.sition  in  this  country. 


Henry  C.  Lea's  Publications — i3fifinellaneous). 


31 


rPHOMPSON  [SIR  HENRY), 

•^  Surgeon  and  Professor  of  Clinicnl  Surgery  to  University  College  Hospital. 

LECTURP]S  ON  DISEASES  OF  THE  URINARY  ORGANS.  Witli 

illustrations  on  wood.  Second  American  from  the  Third  English  Edition.  In  one  neat 
octavo  volume.     Cloth,  $2  26.     (Just  issued.) 

JDY  THE  SAME  AUTHOR.  

ON  THE  PATHOLOGY  AND  TREATMENT  OF  STRICTURE  OF 

THE  URETHRA  AND  URINARY  FISTULyE.  With  plates  and  ^Vood-cuts.  From  the 
third  and  revised  English  edition.  In  one  very  handsome  octavo  volume,  cloth,  $3  50. 
(Lately  Published.) 


R 


OBERTS  [WILLIAM),  M.D., 

Lecturer  on  Medicine  in  the  Manchester  School  of  Medicine,  etc. 

A  PRACTICAL  TREATISE    ON  URINARY  AND  RENAL  DIS* 

EASES,  including  Urinary  Deposits.  Illustrated  by  numerous  cases  and  engravings.  Sec- 
ond American,  from  the  Second  Revised  and  Enlarged  London  Edition.  In  one  large 
and  handsome  octavo  volume  of  616  pages,  with  a  colored  plate  ;  cloth,  $4  50.  (Lately 
Published.) 

mUKE  [DANIEL  HACK),  M.D  , 

^  Joint  author  of  ''The  Manual  of  Psychological  Medicine,^'  Ac. 

ILLUSTRATIONS  OF  THE  INFLUENCE  OF  THE  MIND  UPON 

THE  BODY  IN  HEALTH  AND  DISEASE.  Designed  to  illustrate  the  Action  of  tbe 
Imagination.  In  one  handsome  octavo  volume  of  416  pages,  cloth,  $3  25.  (Lately  Issued.) 

-DLANDFORD  [G.  FIELDING),  M.D.,  F.R.G.P., 

J-^  Lecturer  on  Psychological  Medicine  at  the  School  of  St.  George's  Hospital,  &c. 

INSANITY  AND  ITS  TREATMENT:  Lectures  on  the  Treatment, 

Medical  and  Legal,  of  Insane  Patients.  With  a  Summary  of  the  Laws  in  force  in  the 
United  States  on  the  Confinement  of  the  Insane.  By  Isaac  Ray,  M.  D.  In  one  very 
handsome  octavo  volume  of  471  pages;  cloth,  $3  25. 


It  satisfies  a  want  which  must  have  heeu  sorely 
felt  by  the  busy  general  practitioners  of  this,  country. 
Ic  takes  the  form  of  a  manual  of  clinical  description 
of  the  various  forms  of  insanity,  with  a  description 
of  the  mode  of  examining  persons  suspected  of  in- 
sanity. We  call  particular  attention  to  this  feature 
of  the  book,  as  giviugit  a  unique  value  to  the  gene- 
ral practitioner.  If  we  pass  from  theoretical  eonside- 
ratious  to  descriptions  of  the  varieties  of  insanity  as 


actually  seen  in  practice  and  the  appropriate  treat 
ment  for  them,  we  find  in  Dr.  Blaijdford's  work  a 
considerable  advance  over  previous  writings  on  the 
subject.  His  pictures  of  the  various  forms  of  mental 
disease  are  so  clear  and  good  that  no  reader  can  fail 
to  be  struck  with  their  superiority  to  those  given  in 
Mdinary  manuals  in  the  English  language  or  (so far 
as  our  own  reading  exteudsjinany  other. — London 
Practitioner,  Feb.  1871. 


E A  [HENRY  C). 

'superstition    AND   FORCE:    ESSAYS   ON   THE   WAGER   OF 

LAW,  THE  WAGER  OF  BATTLE,  THE  ORDEAL,  AND  TORTURE.  Third  Revised 
and  Enlarged  Editior .  In  one  handsome  royal  12mo.  volume  of  552  pages.  Cloth, 
$2  50.     (Just  Ready.) 

polemic.  Though  he  obviously  feels  and  thinks 
strongly,  he  succeeds  in  attaining  impartiality. 
Wheti  er  looked  on  as  a  picture  or  a  mirror,  a  work 
such  as  this  has  a  lasting  value. — LippincotVs 
Magazine,  Oct.  1S7S. 

Mr.  Lea's  curious  historical  monographs,  of  which 
oiie  (  f  the  most  important  is  here  reproduced  in  an 
enlarged  form,  have  given  him  an  unique  position 
among  Englisli  and  American  scholars.  He  is  dis- 
tingui.-jhed  for  his  recondite  and  aftluent  lea.rniDg, 
his  power  of  exhaustive  historical  analysis,  the 
breadth  and  accuracy  of  his  researches  among  the 
rarer  sources  of  knowledge,  the  gravity  and  temper- 
ance of  his  staiements,  combined  with  singular 
earnestness  of  conviction,  and  his  warm  attachiueul; 
to  the  cau>e  of  human  freedom  and  intellectual  pro- 
gress.— iV'.  Y.  Tribune,  Aug.  9,  1S7S. 


The  appearance  of  a  new  edition  of  Mr.  Henry  C. 
Lea's  "Superstition  and  Force"  is  a  sign  that  our 
highest  scholar.- hip  is  not  without  honor  in  its  na- 
tive country.  Mr.  Lea  has  met  every  fresh  demand 
for  his  work  with  a  careful  re*?iiiou  of  it,  and  the 
present  edition  is  not  only  fuller  and,  if  possible, 
more  accurate  than  either  of  ihe  preceding,  but, 
from  the  thorough  elaboration  is  more  like  a  har- 
monious concert  and  less  like  a  batch  of  studies. — 
The  JS'ation,  Aug.  1,  1S7S. 

Many  will  be  tempted  to  say  that  this,  like  the 
'Decliueand  Fall,"isoae  of  the  uucruicizable  books 
Its  facts  are  innumerable,  its  deductions  simple  and 
inevitable,  and  its  chtvaux-dt-frise  of  references 
bristling  and  dense  enough  to  make  the  keenest, 
stoutest,  and  best  equipped  assailant  think  twice 
before  advancing.  Nor  is  there  anything  contro- 
versial in  it  to  provoke  assault.     The  author  is  no 


B 


Y  THE  SAME  AUTHOR.    {LateyPrcbli.shed.) 

STUDIES  IN  CHURCH  HISTORY— THE  RISE  OF  THE  TEM- 
PORAL POWER— BENEFIT  OF  CLEROY— EXCOMMUNICATION.  In  one  large 
royal  12mo.  volume  of  516  pp.;  cloth    $2   75.  . 


Tbe  story  was  never  told  more  calmly  or  with 
gr>ater  learning  or  wiser  thought.  Wed'Mibt,  indeed, 
if  my  other  study  of  this  field  can  be  compared  with 
tnis  for  clearness,  accuracy,  and  power.  —  Chicago 
Examiner,  Dec.  1870. 

Mr.  Lea's  latest  work,-'  StudiesinChurch  History," 
fully  sustains  the  promise  of  the  first.  It  deal.-  with 
three  subjects — the  Temporal  Power.  Beaefit  of 
Clergy,  and  Excommunication,  the  record  of  which 


1  as  a  peculiar  importance  for  the  English  student,  and 
Is  a  chapter  on  Ancient  Law  likely  to  be  regarded  as 
inal.  We  can  hardly  pasf^  from  our  mention  of  such 
w^rks  as  these — with  which  that  on  "Sacerdotal 
0  Mhaov"  should  be  included — without  noting  fhft 
literary  phenomenon  that  the  head  of  one  ol  the  first 
American  house.s  is  also  the  writer  of  some  of  its  most 
original  books. — London  Athenceum,  Jan.  7,  1871. 


32 


Henry  C.  Lea's  Publications. 


INDEX   TO    CATALOGUE 


AmerlcaD  Joarnal  of  the  3Iedical  ScieDces 
Abstract,  Mouthly,  of  the  Med.  Scieucei- 
Allen's  Anatoniy    .... 
Anatomical  ^tlas,  by  Smith  and  Horner 
A»hion  on  the  Kectum  and  Anu8 
Attfield'B  Chemistry     .... 
Ashwell  on  Diseases  of  Females 
Ashhur.^t's  Surgery        .... 
Browne  on  Opiuhalmoscope  . 
Browne  on  tlie  Throat    .... 
Burnett  on  the  Ear         .... 
Barnes  on  Diseases  of  Women 
Barnes'  Midwifery,        .... 
Bellamy's  Surgical  Anatomy 
Bryant  8 Practical  Surgfery 
Bloxam's  Chemistry      .... 
Blaudford  on  Insanity  .        .        . 
Basham  on  Renal  Diseases  . 
Brinton  on  the  Stomach 
Barlow's  Practice  ol  Medicine 
Bowman's  (John  E.)  Practical  Chemistry. 
Bowman's  (John  E.)  Medical  Chemistry 
Bristowe's  Practice         .... 
Humstead  on  Venereal 
Biimsiead  and  Cnllerier'sAtlasof  Venereal 
carpenter's  Human  Physiology 
C  irpenter  on  the  Use  and  Abuse  of  Alcohol 
Cornil  and  Ranvier         .... 


PA* 


Carter  on  the  Eye  . 

Cleland's  Dissector 

Classen's  Chemistry 

Clowes'  Chemistry 

Century  of  American  Medicine    . 

Chad  wick  on  Diseases  of  W.imen 

Charcot  on  the  Nervous  System    . 

Chambers  on  Diet  and  Eegiinen  . 

Chambers's  Restorative  Medicine 

Christison  and  Griffith's  iJispeusatory 

Churchill's  System  of  Midwifery 

Churchill  om  Puerperal  Fever      . 

Condie  on  Diseases  of  Children  . 

Cooper's  (B.  B)  Lectures  on  Surgery 

OiUerier's  Atlas  of  Venereal  Diseases 

Cyclopjedia  of  Practical  Medicine'      . 

Dalton's  Human  Physiology 

Davis's  Clinical  Lectures 

Dewees  on  Disease!"  of  Females  . 

Druitt's  ModernSurgery 

Dunglison's  Medical  Dictionary 

Ellis's  Demonstrations  in  Anatomy 

Erichsen's  System  of  Surgery 

Emmet  ou  Diseases  of  Women 

Farquh arson's  Therapeutics 

Fenwick's  Diagnosis 

Finlayson's  Clinical  Diagnosis 

Flint  on  Respiratory  Organs 

Flint  on  tlie  Heart 

Flint's  Practice  of  Medicine. 

Flint's  Essays 

Flint's  Clinical  Medicine 

Flint  on  Phthisis    . 

Flint  on  Percussion 

Fothergill's  Handbook  ofTreatment 

Fothergill's  Antagonism  of  Therapeutic  Agents 

F jwnes's  Elementary  Chemistry 

Fox  on  Diseases  of  the  Skin 

Fuller  on   the  Lungs.  &c. 

Green's  Pathology  and  Morbid  Anatomy 

Gibson's  Surgery 

Gluge's  Pathological  Histology,  by  Leidy 

Gray's  Anatomy 

Galloway's  Analysis       .... 

Griffith's  (B..£.)  Universal  Formulary 

Gross  on  Urinary  Organs      . 

Gross  on  Foreign  Bodies  in  Air-Passages 

Gross's  Principles  and  Practice  of  Surg«ry 

Habershon  on  the  Abdumen  . 

Hamilton  on  Dislocations  and  Fractures 

Bartshorne's  Essentials  ofMedicine 

Hartshorne's  Conspectus  of  the  Medical  Sciences 

Hartshorne's  Anatoniy  and  Physiology 

Hamilton  on  Narvous  Diseases    . 

Heith'e  Practical  Anatomy 

Hoblyn's  Medical  Dictionary      . 


dy 


Hodge  on  Women 

dodge's  Obstetrics 

loUand's  Medical  Notes  and  Reflections   . 
Ho'mes'e  Surgery  .         .        .  .        . 

Holden's  Landmarks  .... 

lorner's  Anatomy  and  Histology 

Hudson  on  Fever 

Hill  on  Venereal  Diseases    .   -     . 
Hillier's  Handbook  of  Skin  Diseases 
Tones  (C.  Handtield)  on  Nervous  Disorders 

Kirkes' Physiology 

Knapp's  Chemical  Technology   . 
'  Lea's  Superstition  and  Force 
Lea's  Studies  in  Church  History 
Lee  on  Syphilis      .... 
Lincoln  on  Electro-Therapeutics 
Leishman's  Midwifery  . 
La  Roche  on  Yellow  Fever. 
La  Roche  on  Pneumonia,  &c. 
Laurence  and  Moon's  Ophthalmic  Surgery 
Lawson  on  the  Eye 

Lehmann'6  Physiological  Chemistry,  2  vols 
Lehmann's  Chemical  Physiology 
Ludlow's  Manual  of  Examinations 
Lyons  on  Fever     .... 
Medical  News  and  Library  . 
Meigs  on  Puerperal  Fever    . 
Miller's  Practice  of  Surgery 
Miller's  Principles  of  Surgery     . 
Montgomery  on  Pregnancy 
Neill  and  Smith's  Compendium  of  Med.  Science 
Obstetrical  Journal 
Parry  on  Extra-Uterine  Prpguancy 
Pavy  on  Digestion 
Pavy  on  Food  .... 

Parrish's  Practical  Pharmacy     . 
Pirrie's  System  of  Surgery  . 
Playfair's  Midwifery     . 
Quain  and  Sharpey's  Anatomy,  by  Le 
Reynolds'  Practice  of  >'edicine  . 
Robertson  Urinary  Diseases 
Ramsbotham  on  Parturition 
Remsen's  Principles  of  Chemistry 
Rigby's  Midwifery 
Rodwell's  Dictionary  of  Science  . 
Stimson's  Operative  Surgery 
Swayne's  Obstetric  Aphorisms    . 
Seller  on  the  Throat 
Sargent's  Minor  Surgery 
Sharpey  and  Quain's  Anatomy,  by  Leidy 
Skey's  Operative  Surgery     . 
Slade  on  Diphtheria 
Schfifer's  Histology 
Smith  (J.  L.)  on  Children      . 
Smith  (H.  H.)  and  Horner's  Anatomical  Atlas 
Smith  (Edward)  on  Consumptio 
Smith  on  Wasting  Diseases  in  Children 
Stilld's  Therapeutics 
Stille  &  Maisch's  Dispensatory 
Starges  on  Clinical  Medicine 
Stokes  on  Fever    . 

Tanner's  Manual  of  Clinical  Medicine 
Tanner  on  Pregnancy    .... 
Taylor's  Medical  Jurisprudence 
Taylor's  Principles  and  Practice  of  Med   J 
Taylor  on  Poisons 
Tuke  on  the  Influence  of  the  Mind 
Thomas  on  Diseases  of  Females 
Thompson  on  Urinary  Organs 
Thompson  on  Stricture  . 
Todd  on  Acute  Diseases 
Woodbury's  Pr^ictice     . 
Walshe  on  the  Heart 
Watson's  Practice  of  Physic 
Wells  on  the  Eye  . 
West  on  Diseases  of  Females 
West  on  Diseases  of  Children 
West  on  Nervous  Disorders  of  Children 
What  te  Observe  in  Medical  Cases 
Williams  on  Consumption   . 
Wilson's  Human  Anatomy  . 
Wilson's  Handbook  of  Cutaneous  Medicine 
Wiihler's  Organic  Chemistry 
Winckel  on  Childbed 


arisp 


HENRY  C.  LEA—Philadelphia. 


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